MIT-HOL kerdes [3301]: gyogynovenyek

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>Forras: mindegy
>Kerdes: A Cimicifuga racemosa =E9s a Taxus brevifolia n=F6v=E9nyr=F5l minde=
n
inform=E1ci=F3, k=FCl=F6n=F6sk=E9ppen k=FCl=F6nf=E9le tudom=E1nyos=
 kutat=E1sok.
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1: J Agric Food Chem 2001 May 21;49(5):2472-2479

Evaluation of Estrogenic Activity of Plant Extracts for the Potential Treatment
of Menopausal Symptoms.

Liu J, Burdette JE, Xu H, Gu C, van Breemen RB, Bhat KP, Booth N, Constantinou
AI, Pezzuto JM, Fong HH, Farnsworth NR, Bolton JL.

Department of Medicinal Chemistry and Pharmacognosy, Program for Collaborative
Research in the Pharmaceutical Sciences, UIC/NIH Center for Botanical Dietary
Supplements Research, College of Pharmacy, M/C 781, University of Illinois at
Chicago, 833 South Wood Street, Chicago, Illinois 60612, and Department of
Surgical Oncology, University of Illinois at Chicago, 840 South Wood Street,
Chicago, Illinois 60612.

Eight botanical preparations that are commonly used for the treatment of
menopausal symptoms were tested for estrogenic activity. Methanol extracts of
red clover (Trifolium pratense L.), chasteberry (Vitex agnus-castus L.), and
hops (Humulus lupulus L.) showed significant competitive binding to estrogen
receptors alpha (ERalpha) and beta (ERbeta). With cultured Ishikawa
(endometrial) cells, red clover and hops exhibited estrogenic activity as
indicated by induction of alkaline phosphatase (AP) activity and up-regulation
of progesterone receptor (PR) mRNA. Chasteberry also stimulated PR expression,
but no induction of AP activity was observed. In S30 breast cancer cells, pS2
(presenelin-2), another estrogen-inducible gene, was up-regulated in the
presence of red clover, hops, and chasteberry. Interestingly, extracts of Asian
ginseng (Panax ginseng C.A. Meyer) and North American ginseng (Panax
quinquefolius L.) induced pS2 mRNA expression in S30 cells, but no significant
ER binding affinity, AP induction, or PR expression was noted in Ishikawa cells.
Dong quai [Angelica sinensis (Oliv.) Diels] and licorice (Glycyrrhiza glabra L.)
showed only weak ER binding and PR and pS2 mRNA induction. Black cohosh
[Cimicifuga racemosa (L.) Nutt.] showed no activity in any of the above in vitro
assays. Bioassay-guided isolation utilizing ER competitive binding as a monitor
and screening using ultrafiltration LC-MS revealed that genistein was the most
active component of red clover. Consistent with this observation, genistein was
found to be the most effective of four red clover isoflavones tested in the
above in vitro assays. Therefore, estrogenic components of plant extracts can be
identified using assays for estrogenic activity along with screening and
identification of the active components using ultrafiltration LC-MS. These data
suggest a potential use for some dietary supplements, ingested by human beings,
in the treatment of menopausal symptoms.

PMID: 11368622 [PubMed - as supplied by publisher]




2: Altern Ther Health Med 2001 May-Jun;7(3):93-100

Black cohosh: efficacy, safety, and use in clinical and preclinical
applications.

McKenna DJ, Jones K, Humphrey S, Hughes K.

Institute for Natural Products Research in Marine, St. Croix, Minn., USA.

Actaea racemosa L (formerly Cimicifuga racemosa [L] Nutt) (Ranunculaceae),
commonly known as black cohosh, is an herb native to Eastern North America.
Black cohosh has a history of traditional use among Native Americans for the
treatment of a variety of disorders, including various conditions unique to
women such as amenorrhea and menopause. Contemporary uses of black cohosh are
primarily geared toward the treatment of symptoms of menopause, such as hot
flashes, and menopausal anxiety and depression. Extracts also have been shown to
be useful for younger women suffering hormonal deficits following ovariectomy or
hysterectomy, as well as for juvenile menstrual disorders. A number of clinical
studies using Remifemin, a standardized extract, have demonstrated efficacy for
the alleviation of menopausal complaints. The safety profile of black cohosh is
positive, with low toxicity, few and mild side effects, and good tolerability.
In European phytotherapy, Remifemin is commonly prescribed as an effective
alternative to hormone replacement therapy for menopause.

PMID: 11347288 [PubMed - in process]




3: Wei Sheng Yan Jiu 2001 Mar;30(2):77-80

[Estrogenicity of black cohosh (Cimicifuga racemosa) and its effect on estrogen
receptor level in human breast cancer MCF-7 cells].

[Article in Chinese]

Liu Z, Yang Z, Zhu M, Huo J.

Institute of Nutrition and Food Hygiene, Chinese Academy of Preventive Medicine,
Beijing 100050, China.

The estrogenicity of Black Cohosh (Cimicifuga racemosa, CR) was tested in vivo
and in vitro and its effect on estrogen receptor (ER) level of human breast
cancer MCF-7 cells were investigated. Based on the body weight of animals, 75,
150 and 300 mg/kg of CR were administered by tube feeding to immature female
mice for 14 days. Estrus was observed and the uterine and ovary weights of mice
were measured. The optimal dose of CR for the growth of MCF-7 cells was screened
by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay.
Subsequently, Growth curves of MCF-7 cells in blank control, 4.75 micrograms/L
of CR and 0.3 nmol/L of 17 beta-estradiol groups were observed for 5 days. ER
level in MCF-7 cells was analyzed by indirect immunofluorescence assay in flow
cytometry. The results showed that uterine weight increased with the increasing
dosage of CR and the days of estrus was significantly prolonged in the 300 mg/kg
group (P < 0.05). The concentration of CR at 4.75 micrograms/L showed the
strongest enhancement effects (64.7%). The doubling time (TD) of cell growth in
CR group and 17 beta-estradiol group were 32.1 h and 31.7 h respectively, which
were shorter than that of blank control (TD = 35.3 h). Additionally, 4.75
micrograms/L of CR significantly increased ER levels compared with the blank
control (P < 0.01). Taking all the results together, CR has an estrogen-like
action. The enhancing effect of CR on ER level is one of the potential
mechanisms involved with its therapeutic role in climacteric syndrome.

PMID: 11321955 [PubMed - in process]




4: Pharmazie 2001 Mar;56(3):268-9

A new cyclolanostanol arabinoside from the rhizome of Cimicifuga racemosa.

Bedir E, Khan IA.

National Center for Natural Products Research, Research Institute of
Pharmaceutical Sciences, University of Mississippi, USA.

PMID: 11265599 [PubMed - indexed for MEDLINE]




5: Planta Med 2000 Dec;66(8):751-3

Inhibition of neutrophil elastase activity by cinnamic acid derivatives from
Cimicifuga racemosa.

Loser B, Kruse SO, Melzig MF, Nahrstedt A.

Caffeic acid, fukinolic acid as well as cimicifugic acids A, B, E and F isolated
from the rhizomes of Cimicifuga racemosa (Ranunculaceae) inhibited the activity
of neutrophil elastase (EC 3.4.21.37) in a dose-dependent manner. An IC50 of 93
mumol/L was determined for caffeic acid and 0.23 mumol/L for fukinolic acid.
Cimicifugic acid A inhibited the enzyme with an IC50 of 2.2 mumol/L, cimicifugic
acid B with 11.4 mumol/L, and cimicifugic acid F with 18 mumol/L. Cimicifugic
acid E was only a very weak inhibitor.

Publication Types:
Letter

PMID: 11199135 [PubMed - indexed for MEDLINE]




6: J Nat Prod 2000 Jul;63(7):905-10

Triterpene glycosides from Cimicifuga racemosa.

Shao Y, Harris A, Wang M, Zhang H, Cordell GA, Bowman M, Lemmo E.

Solgar Research Center for Excellence, Solgar Vitamin and Herb Company, 1211
Sherwood Avenue, Richmond, Virginia 23220, USA. shaoy at ahp.com

Eight new triterpene glycosides named cimiracemosides A-H, respectively, and
eight known triterpene glycosides were isolated from the rhizome extracts of
black cohosh (Cimicifuga racemosa). The new compounds were determined by
spectral data to be 21-hydroxycimigenol-3-O-alpha-L-arabinopyranoside (1),
21-hydroxycimigenol-3-O-beta-D-xylopyranoside (2),
cimigenol-3-O-alpha-L-arabinopyranoside (3),
12beta-acetoxycimigenol-3-O-alpha-L-arabinopyranoside (4),
24-acetylisodahurinol-3-O-beta-D-xylopyranoside (5), 20(S),22(R),
23(S),24(R)-16beta:23;22:25-diepoxy-12beta-acetoxy-3be ta,23,
24-trihydroxy-9,19-cycloanost-7-ene-3-O-beta-D-xylopyranoside (6),
20(S),22(R),23(S),24(R)-16beta:23;22:25-diepoxy-12beta -acetoxy-3beta,
23,24-trihydroxy-9,19-cycloanost-7-en-3-O-alpha-L-arabinopyrano side (7), and
20(S),22(R),23(S), 24(R)-16beta:23;22:25-diepoxy-12beta-acetoxy-3beta,23,
24-trihydroxy-9,19-cycloanostane-3-O-beta-D-xylopyranoside (8).

PMID: 10924163 [PubMed - indexed for MEDLINE]




7: Chem Pharm Bull (Tokyo) 2000 Mar;48(3):425-7

Cimiracemoside a: A new cyclolanostanol xyloside from the rhizome of Cimicifuga
racemosa.

Bedir E, Khan IA.

National Center for Natural Products Research, Research Institute of
Pharmaceutical Sciences, The University of Mississippi, University 38677, USA.

A new 9,19-cyclolanostane-type triterpene xyloside (1), from the rhizomes of
Cimicifuga racemosa, has been isolated together with four known saponins;
cimiaceroside A, 25-O-methylcimigenol-3-O-beta-D-xylopyranoside, 27-deoxyactein
and 23-O-acetylshengmanol-3-O-beta-D-xylopyranoside. The structure of the new
compound was established as 16beta,23:22beta,25-diepoxy-12-acetoxy-3beta,23,24b
eta-trihydroxy-9,19-cyclolanost-7-ene-3-O-beta-D-xylopyranoside . For the
structure elucidation, 1D- and 2D-NMR experiments and high resolution
electrospray ionization Fourier transformation mass spectrometry (HRESIFTMS)
were used.

PMID: 10726870 [PubMed - indexed for MEDLINE]




8: Planta Med 1999 Dec;65(8):763-4

Fukiic and piscidic acid esters from the rhizome of Cimicifuga racemosa and the
in vitro estrogenic activity of fukinolic acid.

Kruse SO, Lohning A, Pauli GF, Winterhoff H, Nahrstedt A.

Hydroxycinnamic acid esters of fukiic acid and piscidic acid were isolated from
a 50% ethanolic extract obtained from the rhizomes of Cimicifuga racemosa
(Ranunculaceae). Besides 2-E-caffeoylfukiic acid (fukinolic acid),
2-E-feruloylfukiic acid (cimicifugic acid A), 2-E-isoferuloylfukiic acid
(cimicifugic acid B), 2-E-feruloylpiscidic acid (cimicifugic acid E) and
2-E-isoferuloylpiscidic acid (cimicifugic acid F), free caffeic, ferulic and
isoferulic acids were isolated. The estrogenic activity of fukinolic acid was
shown by increased proliferation (126% at 5 x 10(-8) M) of an estrogen dependent
MCF-7 cell system with reference to estradiol (120% at 10(-10) M).

PMID: 10630125 [PubMed - indexed for MEDLINE]




9: Planta Med 2000 Oct;66(7):635-40

Direct analysis and identification of triterpene glycosides by LC/MS in black
cohosh, Cimicifuga racemosa, and in several commercially available black cohosh
products.

He K, Zheng B, Kim CH, Rogers L, Zheng Q.

Department of Research & Development, Pure World Botanicals, Inc., South
Hackensack, New Jersey, USA.

A method to directly identify triterpene glycosides using reversed-phase liquid
chromatography with positive atmospheric pressure chemical ionization mass
spectrometry (LC/(+)APCIMS) was developed. Based on the analysis of the
molecular weight, fragment ions, selected ion chromatograms, a number of
triterpene glycosides, including actein, 27-deoxyactein, cimicfugoside M, and
cimicifugoside, from Cimicifuga racemosa were studied. A chromone, cimifugin,
from C. foetida was also identified. Cimicifugoside M and cimifugin can
specifically serve as indicators for species identification. The method can,
therefore, be used to distinguish black cohosh products from among different
plant species for quality control purposes.

PMID: 11105569 [PubMed - indexed for MEDLINE]




10: J Am Med Womens Assoc 1999 Fall;54(4):181-3

Hormone-modulating herbs: implications for women's health.

Wade C, Kronenberg F, Kelly A, Murphy PA.

Department of Rehabilitation Medicine, Columbia University College of Physicians
and Surgeons, New York, NY 10032, USA.

Women in the United States are increasingly turning to botanical medicines to
treat conditions throughout their life cycles. Many herbs traditionally used for
women's health conditions have been found to contain phytoestrogens.
Phytoestrogens and their metabolites can bind estrogen receptors and can have
both estrogenic and anti-estrogenic effects. Many women are attracted to the
idea of using phytomedicine as an alternative to hormone replacement therapy. It
is unclear, however, whether these herbs are safe for women at risk for breast
cancer or its recurrence. This paper considers the estrogenicity of herbs such
as black cohosh (Cimicifuga racemosa) and the implications for women's health.

Publication Types:
Review
Review, tutorial

PMID: 10531758 [PubMed - indexed for MEDLINE]




11: Am J Health Syst Pharm 1999 Jul 15;56(14):1400-2

Black cohosh: Cimicifuga racemosa.

Pepping J.

Kaiser Permanente, Honolulu, HI, USA.

Publication Types:
Review
Review, tutorial

PMID: 10428447 [PubMed - indexed for MEDLINE]




12: J Womens Health 1998 Jun;7(5):525-9

Comment in:
 J Womens Health Gend Based Med. 1999 May;8(4):431-2

A review of the effectiveness of Cimicifuga racemosa (black cohosh) for the
symptoms of menopause.

Lieberman S.

University of Bridgeport, Connecticut, USA.

In this review of eight human studies on the effectiveness of an extract of
Cimicifuga racemosa on alleviating menopausal symptoms, it is apparent that it
is a safe, effective alternative to estrogen replacement therapy for those
patients in whom estrogen replacement therapy is either refused or
contraindicated.

Publication Types:
Review
Review, tutorial

PMID: 9650153 [PubMed - indexed for MEDLINE]




13: Adv Ther 1998 Jan-Feb;15(1):45-53

Therapeutic efficacy and safety of Cimicifuga racemosa for gynecologic
disorders.

Liske E.

Schaper & Brummer GmbH & Co. KG, International Sales Division,
Salzgitter-Ringelheim, Germany.

The reproducible quality of phytopharmaceuticals--herbal medicines--is an
essential prerequisite for good efficacy and tolerability in the treatment of
functional disorders. In clinical trials and scientific investigations,
standardized assessments (i.e., validated, internationally recognized and
accepted scales) provide the basis for establishing clinical efficacy and
tolerability. Extracts (ethanolic and isopropanolic aqueous, Remifemin) of the
rootstock of the herb Cimicifuga racemosa (black cohosh) are active ingredients
developed for the treatment of gynecologic disorders, particularly climacteric
symptoms. Drug-monitoring and clinical studies documenting experience with C.
racemosa rootstock extracts comprise the database of this herbal treatment for
menopausal symptoms (e.g., hot flashes, profuse sweating, sleep disturbances,
depressive moods). These studies show good therapeutic efficacy and tolerability
profiles for C. racemosa. In addition, clinical and experimental investigations
indicate that the rootstock of C. racemosa does not show hormone-like activity,
as was originally postulated.

Publication Types:
Review
Review, tutorial

PMID: 10178637 [PubMed - indexed for MEDLINE]




14: Maturitas 1996 Oct;25(2):149-53

Cimicifuga and Melbrosia lack oestrogenic effects in mice and rats.

Einer-Jensen N, Zhao J, Andersen KP, Kristoffersen K.

Department of Physiology, Odense University, Denmark.

OBJECTIVES: The natural medicines, Cimicifuga and Melbrosia, are widely sold.
Cimicifuga is an extract of Cimicifuga racemosa (L.), and Melbrosia is a mixture
of Gelee Royale, perga-pollen and pollen. Cimicifuga and Melbrosia are used
through self-medication to relieve symptoms of hot flushes and other menstrual
or menopausal discomfort in many of the Danish women consulting private
gynaecologists. A gynaecologist tends to treat these symptoms with oestrogen, so
the present experiments were therefore made to investigate whether Cimicifuga
and Melbrosia have oestrogenic effects as defined by the classical biological
methods: uterine growth in immature mice and vaginal cornification in
ovariectomized rats. METHODS: Vehicle, 6, 60 or 600 mg/kg Cimicifuga or 30, 300
or 3000 mg/kg Melbrosia was administered orally for 3 days to groups of 10
immature mice and the uterus weight measured on the fourth day. Similarly,
vehicle, 6, 60, 600 mg/kg Cimicifuga or 3, 30, 300 mg/kg Melbrosia was injected
subcutaneously in groups of 12 ovariectomized rats for 3 days and vaginal smears
investigated for signs of cornified cells. All experiments were repeated once.
RESULTS: No signs of an oestrogenic effect connected with the preparations were
found in any of the experiments. CONCLUSIONS: It can be concluded that the
eventual beneficial effects on menstrual or menopausal discomfort connected with
Cimicifuga and Melbrosia self-medication cannot be explained as a traditional
oestrogenic effect as measured in biological experiments.

PMID: 8905606 [PubMed - indexed for MEDLINE]




15: Planta Med 1991 Oct;57(5):420-4

Effects of extracts from Cimicifuga racemosa on gonadotropin release in
menopausal women and ovariectomized rats.

Duker EM, Kopanski L, Jarry H, Wuttke W.

Department of Clinical and Experimental Endocrinology, University of Gottingen,
Federal Republic of Germany.

Remifemin is an ethanolic extract of the rhizome of Cimicifuga racemosa (C.r.)
and is used to relieve climacteric hot flushes. In the present study the effects
of this preparation on LH and FSH secretion of menopausal women were
investigated. After an 8 weeks treatment, LH but not FSH levels were
significantly reduced in patients receiving the Cimicifuga extract. To further
characterize the endocrinologically active principles of this plant extract, a
lipophilic extract of C.r. was prepared and subjected to Sephadex
chromatography. Fractions obtained were tested for their ability to reduce LH
secretion in ovariectomized (ovx) rats and to compete in vitro with 17
beta-estradiol for estrogen receptor binding sites. Three types of
endocrinologically active compounds were obtained: (1) Constituents which were
not ligands for the estrogen receptor but suppress LH release after chronic
treatment, (2) constituents binding to the estrogen receptor and also
suppressing LH release, and (3) compounds which are ligands for the estrogen
receptor but without an effect of LH release. It is concluded that the LH
suppressive effect of C.r. extracts observed in menopausal women and ovx rats is
caused by at least three different synergistically acting compounds.

PMID: 1798794 [PubMed - indexed for MEDLINE]




16: Zentralbl Gynakol 1988;110(10):611-8

[Clinical and endocrinologic studies of the treatment of ovarian insufficiency
manifestations following hysterectomy with intact adnexa].

[Article in German]

Lehmann-Willenbrock E, Riedel HH.

Abteilung Frauenheilkunde im Zentrum, Christian Albrechts-Universitat und
Michaelis-Hebammenschule, Kiel.

60 hysterectomized patients under 40 years old, who all had at least one intact
ovary and still complained of climacteric symptoms, were treated with estriol,
conjugated estrogens, estrogen-gestagen sequential therapy or an extract from
cimicifuga racemosa after randomized distribution into 4 equal groups. Therapy
was controlled after 4, 8, 12 and 24 weeks with a modified Kupperman-Index that
also included trophic disorders of the genitals, and also by serum-FSH and -LH
measurement. In all groups, the modified Kupperman-Index became significantly
lower, the parallel decrease of gonadotropins could not be confirmed
statistically, however. There were no significant differences between groups
concerning therapy success.

Publication Types:
Clinical trial
Randomized controlled trial

PMID: 2841818 [PubMed - indexed for MEDLINE]




17: Planta Med 1985 Aug;(4):316-9

[The endocrine effects of constituents of Cimicifuga racemosa. 2. In vitro
binding of constituents to estrogen receptors].

[Article in German]

Jarry H, Harnischfeger G, Duker E.

PMID: 4070446 [PubMed - indexed for MEDLINE]




18: Planta Med 1985 Feb;(1):46-9

[Endocrine effects of constituents of Cimicifuga racemosa. 1. The effect on
serum levels of pituitary hormones in ovariectomized rats].

[Article in German]

Jarry H, Harnischfeger G.

PMID: 3925475 [PubMed - indexed for MEDLINE]




19: Arch Pharm Ber Dtsch Pharm Ges 1968 May;301(5):335-41

[Contents of Cimicifuga racemosa. 5. 27-desoxyacetylacteol].

[Article in German]

Linde H.

PMID: 5249981 [PubMed - indexed for MEDLINE]




20: Arch Pharm Ber Dtsch Pharm Ges 1967 Dec;300(12):982-92

[Contents of Cimicifuga racemosa. 3. On the constitution of the rings A, B and C
of actein].

[Article in German]

Linde H.

PMID: 5249320 [PubMed - indexed for MEDLINE]




21: Arch Pharm Ber Dtsch Pharm Ges 1967 Oct;300(10):885-92

[Contents of Cimicifuga racemosa. 2. On the structure of actein].

[Article in German]

Linde H.

PMID: 5249978 [PubMed - indexed for MEDLINE]




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1: J Biotechnol 2001 Jan 23;85(1):67-73

Stimulation of taxol production and excretion in Taxus spp cell cultures by rare
earth chemical lanthanum.

Wu J, Wang C, Mei X.

Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic
University, Hung Hom, Kowloon, Hong Kong. bcjywu at polyu.edu.hk

The trivalent ion of a rare earth element, lanthanum, was tested for
elicitor-like effects on taxol production in suspension cultures of four
different Taxus spp cells. In T. yunnanensis cell cultures, the lanthanum ion at
concentrations from 1.15 to 23.0 microM stimulated taxol production. The
lanthanum ion also promoted taxol excretion by the T. yunnanensis cells
considerably. The maximum stimulation of taxol production was achieved by the
addition of 5.8 microM La3+ to the culture during mid-log growth phase,
increasing the volumetric taxol yield by nearly threefold, from 2.61+/-0.37 to
9.89+/-1.92 mg l(-1) over a 28 day culture period. At higher concentrations,
i.e. 23.1 and 46.2 microM, however, the lanthanum ion caused significant growth
inhibition. For the other three Taxus cell lines, namely an embryo and a leave
cell of T. chinensis and a stem cell of T. chinensis marv, the addition of
lanthanum ion to the culture only had a significant effect on taxol production
by the T. chinensis marv stem cells, increasing the volumetric yield by about
threefold to 4.69+/-0.76 mg l(-1). These results suggest that lanthanum has
elicitor-like effects on secondary metabolite synthesis of plant cell cultures.

PMID: 11164964 [PubMed - indexed for MEDLINE]




2: Chem Biol 2000 Dec;7(12):969-77

Intramolecular proton transfer in the cyclization of geranylgeranyl diphosphate
to the taxadiene precursor of taxol catalyzed by recombinant taxadiene synthase.

Williams DC, Carroll BJ, Jin Q, Rithner CD, Lenger SR, Floss HG, Coates RM,
Williams RM, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman, WA
99164-6340, USA.

BACKGROUND: The committed step in the biosynthesis of the anticancer drug taxol
in yew (Taxus) species is the cyclization of geranylgeranyl diphosphate to
taxa-4(5),11(12)-diene. The enzyme taxadiene synthase catalyzes this complex
olefin cation cyclization cascade involving the formation of three rings and
three stereogenic centers. RESULTS: Recombinant taxadiene synthase was incubated
with specifically deuterated substrates, and the mechanism of cyclization was
probed using MS and NMR analyses of the products to define the crucial hydrogen
migration and terminating deprotonation steps. The electrophilic cyclization
involves the ionization of the diphosphate with closure of the A-ring, followed
by a unique intramolecular transfer of the C11 proton to the re-face of C7 to
promote closure of the B/C-ring juncture, and cascade termination by proton
elimination from the beta-face of C5. CONCLUSIONS: These findings provide
insight into the molecular architecture of the first dedicated step of taxol
biosynthesis that creates the taxane carbon skeleton, and they have broad
implications for the general mechanistic capability of the large family of
terpenoid cyclization enzymes.

PMID: 11137819 [PubMed - indexed for MEDLINE]




3: Mol Pharmacol 2000 Dec;58(6):1563-9

Reversal of P-glycoprotein and multidrug-resistance protein-mediated drug
resistance in KB cells by 5-O-benzoylated taxinine K.

Okumura H, Chen ZS, Sakou M, Sumizawa T, Furukawa T, Komatsu M, Ikeda R, Suzuki
H, Hirota K, Aikou T, Akiyama SI.

Department of Cancer Chemotherapy, Institute for Cancer Research, Kagoshima
University School of Medicine, Kagoshima, Japan.

A newly synthesized taxoid originally from the Japanese yew Taxus cuspidata,
5-O-benzoylated taxinine K (BTK) was examined for its ability to reverse
P-glycoprotein (P-gp) and multidrug resistance protein (MRP)-mediated multidrug
resistance. BTK reversed the resistance to paclitaxel, doxorubicin (ADM), and
vincristine (VCR) of KB-8-5 and KB-C2 cells that overexpress P-gp by directly
interacting with P-gp. BTK also moderately reversed the resistance to ADM of
KB/MRP cells that overexpress MRP. However, BTK neither inhibited the
transporting activity of MRP nor reduced intracellular glutathione levels in
KB/MRP cells. BTK shifted the distribution of ADM in KB/MRP cells from punctate
cytoplasmic compartments to the nucleoplasm and cytoplasm by inhibiting
acidification of cytoplasmic organelles. These two functions of BTK make it able
to reverse both P-gp- and MRP-mediated MDR. BTK in combination with ADM should
be useful for treating patients with tumors that overexpress both P-gp and MRP.

PMID: 11093797 [PubMed - indexed for MEDLINE]




4: Sheng Wu Gong Cheng Xue Bao 2000 May;16(3):378-82

[Studies of the mechanism of 7-epi-taxol converted to taxol from Taxus extract
catalyzed with Al2O3].

[Article in Chinese]

Zhang ZQ, Su ZG.

State Key Laboratory of Biochemical Engineering, Chinese Academy of Sciences,
Beijing.

Under the catalysis of Al2O3, 7-epi-taxol in Taxus yunnanensis extract could
convert to taxol. The factors including the concentration of CH3OH in the mobile
phase, the type of Al2O3 and the reaction time could influence the isomeric
reaction. The catalysis mechanism fo Al2O3 was investigated. The isomerization
of 7-epi-taxol was under the cooperation of the Lewis souci activity core and
the basic activity core in the surface of Al2O3 at room temperature. The type
and strength of activity core controlled the procedure of reaction, and the
suitable content of CH3OH in the mobile phase would accelerate the reaction.

PMID: 11059285 [PubMed - indexed for MEDLINE]




5: Sheng Wu Gong Cheng Xue Bao 2000 Jul;16(4):500-4

[Study on taxol release in the two-liquid-phase cultures of Taxus cuspidata].

[Article in Chinese]

Wu ZL, Di JS, Yuan YJ, Hu ZD.

Department of Bioengineering, Hebei University of Technology, Tianjin.

Effects of rare earth compound (ammonium sulphate), organic solvents(oleic acid
and dibutylphthalate) and the integrated function of the rare earth compound and
organic solvents were studied on taxol release in the Taxus cuspidata suspension
cultures. And then effects of different organic solvents(paraffin, organic acid,
alcohol and ester), their volumetric fraction and phase toxicity were studied on
taxol release in the two-liquid-phase cultures of Taxus cuspidata. The results
showed that the addition of the rare earth compound or the organic solvents
could strengthen obviously taxol release, especially the organic solvents. But
the addition of the rare earth compound could not strengthen further taxol
release in the twoliquid-phase cultures of Taxus cuspidata. Therefore the
organic solvents were very good permeabilizing reagents, which could enhance
obviously secondary metabolite in the twoliquid-phase cultures of plant cells.
Release percentage of taxol was increased into more than 75% from 40% of the
control.

PMID: 11051828 [PubMed - indexed for MEDLINE]




6: Chem Pharm Bull (Tokyo) 2000 Sep;48(9):1344-6

Taxane diterpenoids from seeds of Taxus mairei.

Shen YC, Chen CY, Hung MC.

Institute of Marine Resources, National Sun Yat-sen University, Kaohsiung,
Taiwan, Republic of China. ycshen at mail.nsysu.edu.tw

A new 2(3-->20) abeotaxane, taxumairone A (1), and a new cis-p-coumaroyl
myo-inositol have been isolated from the seeds of Taxus mairei in addition to
taxin B (2), taxinine A, taxuspine X, decinnamoyltaxinine E,
5alpha-cinnamoyloxy-9alpha,10beta,13alpha- triacetoxy-taxa-4(20)11-diene and
5alpha-cinnamoyloxy-2alpha,9alpha,10beta,+
++13alpha-tetraacetoxy-taxa-4(20)11-diene. The structure of 1 was determined by
2D-NMR spectral analysis and chemical correlation with taxin B (2). Compound 1
exhibited potent cytotoxicity against human colon carcinoma cells with an ED50
of 0.1 microg/ml.

PMID: 10993234 [PubMed - indexed for MEDLINE]




7: Biocell 2000 Aug;24(2):139-44

Cell lines of Taxus species as source of the anticancer drug taxol.

Goleniowski ME.

Laboratorio de Biotecnologia Vegetal, Fac. de Ciencias Agropecuarias,
Universidad Nacional de Cordoba, Argentina. goleniow at ceprocor.uncor.edu

Callus culture of Taxus baccata and Taxus x Media were induced using explants of
young stems and female gametophyte. Culture conditions have been established for
the cell suspension of the different callus cell lines. Callus were induced from
Taxus baccata and Taxus x Media using Murashige and Skoog (MS) medium
supplemented with different concentrations of 2,4 D (2,4-dichlorophenoxyacetic)
and benzylaminopurine (BA). All the cultures grew slowly following the first
subculture and the majority turned brown and ceased growth. The fast growing
callus lines constituted a habituated callus lines (CFGTB; CFGTM; CSTB and
CSTB). These callus lines were used to induce cell suspension in the best
nutritional medium (1 mg/l 2,4-D and 0.1 mg/l BA). The callus exhibited levels
of taxol ranging from 0.1 to 15 mg/Kg on a dry weight basis. Suspension cultures
of Taxus baccata (CSTB and CFGTB) and Taxus x Media (CSTM and CFGTM) were
maintained at 25 degrees C on a MS medium with two weeks transfers. The maximum
taxol production for suspension cell was within the range 5 to 6 mg/l.

PMID: 10979612 [PubMed - indexed for MEDLINE]




8: Sheng Wu Gong Cheng Xue Bao 2000 Mar;16(2):158-60

[Cloning of taxadiene synthase cDNA from the cell line of Taxus cuspidata].

[Article in Chinese]

Hu GW, Ma Z, Wen TY, Yuan YJ.

Nature Products Institute of Biochemistry, Tianjin University.

Taxadiene synthase plays an important role in taxol biosynthesis. RT-PCR was
used for cloning taxadiene synthase cDNA fragment from the cells of T.
cuspidata. The cDNA was cloned into vector pGEM and transformed to E. coli J
M109. The cloned cDNA named pCBMZ was further confirmed by Southern blotting
assay and was sequenced. The result showed that taxadiene synthase cDNA of Taxus
cuspidata was highly homologous with that of Taxus brevifolia.

PMID: 10976317 [PubMed - indexed for MEDLINE]




9: Cancer Lett 2000 Oct 1;158(2):151-4

Cytotoxity of non-alkaloidal taxane diterpenes from Taxus chinensis against a
paclitaxel-resistant cell line.

Fukushima M, Fukamiya N, Okano M, Nehira T, Tagahara K, Zhang SX, Zhang DC,
Tachibana Y, Bastow KF, Lee KH.

Department of Interdisciplinary Studies of Natural Environment, Faculty of
Integrated Arts and Sciences, Hiroshima University, Higashi- 739-8521,
Hiroshima, Japan.

Seven taxane diterpenes were isolated from the EtOH extract of the aerial parts
of Taxus chinensis, and evaluated for cytotoxicity against nine human cell
lines, including a beta-tublin mutant resistant to paclitaxel. Compound 2, a
non-alkaloid-type taxane diterpene, showed significant cytotoxicity in most cell
lines, and notably, equipotent against both parental and beta-tublin mutant
tumor cell lines.

PMID: 10960764 [PubMed - indexed for MEDLINE]




10: PLANT SCIENCE 2000 Aug 22;157(2):173-180

Nitric oxide induces cell death in Taxus cells.

Pedroso MC, Magalhaes JR, Durzan D.

Department Biologia Vegetal, Centro de Biotecnologia Vegetal, Universidade de
Lisboa, Ed. C2, Piso 1, Campo Grande, P-1749-016, Lisbon, Portugal

Sodium nitroprusside (SNP), a nitric oxide donor, or centrifugation at 150 times
unit gravity, caused a nitric oxide burst in oocyte-derived Taxus brevifolia
haploid cultures. This burst, visualized by the specific fluorescent probe
4,5-diaminofluorescein diacetate (DAF-2 DA), preceded a significant increase in
nuclear DNA fragmentation and cell death. DNA fragmentation was detected in situ
by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling
(TUNEL) of DNA 3'-OH groups. Nitric oxide formation and cell death were
significantly decreased by N(G)-monomethyl-L-arginine (L-NMMA), a nitric
oxide-synthase (NOS; EC 1.14.13.39) inhibitor. Our results show that nitric
oxide leads to irreversible DNA fragmentation and cell death under stressful
conditions, and that its effect can be prevented by L-NMMA.

PMID: 10960730 [PubMed - as supplied by publisher]




11: J Exp Bot 2000 Jun;51(347):1027-36

A nitric oxide burst precedes apoptosis in angiosperm and gymnosperm callus
cells and foliar tissues.

Pedroso MC, Magalhaes JR, Durzan D.

Centro de Biotecnologia Vegetal, Departamento Biologia Vegetal, Faculdade de
Ciencias de Lisboa, Bloco C2, Piso 1, Campo Grande, P-1749-016 Lisboa, Portugal.
nop25892 at mail.telepac.pt

Leaves and callus of Kalanchoe daigremontiana and Taxus brevifolia were used to
investigate nitric oxide-induced apoptosis in plant cells. The effect of nitric
oxide (NO) was studied by using a NO donor, sodium nitroprusside (SNP), a nitric
oxide-synthase (NOS) inhibitor, N:(G)-monomethyl-L-arginine (NMMA), and
centrifugation (an apoptosis-inducing treatment in these species). NO production
was visualized in cells and tissues with a specific probe, diaminofluorescein
diacetate (DAF-2 DA). DNA fragmentation was detected in situ by the terminal
deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) method. In
both species, NO was detected diffused in the cytosol of epidermal cells and in
chloroplasts of guard cells and leaf parenchyma cells. Centrifugation increased
NO production, DNA fragmentation and subsequent cell death by apoptosis. SNP
mimicked centrifugation results. NMMA significantly decreased NO production and
apoptosis in both species. The inhibitory effect of NMMA on NO production
suggests that a putative NOS is present in Kalanchoe and Taxus cells. The
present results demonstrated the involvement of NO on DNA damage leading to cell
death, and point to a potential role of NO as a signal molecule in these plants.

PMID: 10948230 [PubMed - indexed for MEDLINE]




12: Oncologist 2000;5(3):185-98

Anti-cancer drug discovery and development in Brazil: targeted plant collection
as a rational strategy to acquire candidate anti-cancer compounds.

Mans DR, da Rocha AB, Schwartsmann G.

Comprehensive Cancer Center (CINCAN), Canoas, RS, Brazil.

Throughout medical history, plant products have been shown to be valuable
sources of novel anti-cancer drugs. Examples are the VINCA: alkaloids, the
taxanes, and the camptothecins, derived from the Madagscan periwinkle plant
Catharantus roseus, the Pacific yew Taxus brevifolia, and the Chinese tree
Camptotheca acuminata, respectively. For this reason, the South-American Office
for Anti-Cancer Drug Development has implemented a large-scale project of
acquisition and testing of compounds isolated from South American medicinal
plants. The species are selected on the basis of a potentially useful
phytochemical composition by consulting ethnopharmacological, chemosystemic, and
ecological information. The collected samples are dried and first extracted with
an organic solvent, then with distilled water. These crude extracts are
evaluated at a concentration of 50 microg/ml for antiproliferative activity
against one cell line. Extracts that significantly inhibit the growth of the
cells (>/=50%) at relatively low concentrations (</=50 microg/ml) are submitted
to the more comprehensive disease-oriented screen of the U.S. National Cancer
Institute. In parallel, these samples are further purified by bioassay-guided
purification, involving repeated fractionation by diverse chromatography
methods. If the active substance is expected to represent a novel structure, it
is identified by appropriate chemical techniques, mechanistic studies are
performed with a wide diversity of tumor models and laboratory techniques, and
efforts are undertaken for the synthesis of potentially more useful analogs.

PMID: 10884497 [PubMed - indexed for MEDLINE]




13: Jpn J Cancer Res 2000 Jun;91(6):638-42

Multidrug resistance reversal activity of taxoids from Taxus cuspidata in KB-C2
and 2780AD cells.

Kobayashi J, Shigemori H, Hosoyama H, Chen Z, Akiyama S, Naito M, Tsuruo T.

Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita-ku,
Sapporo 060-0812, Japan. jkobay at pharm.hokudai.ac.jp.

Some non-taxol-type taxoids having neither an oxetane ring at C-4 and C-5 nor an
N-acylphenyl-isoserine group at C-13, such as taxuspine C,
2'-desacetoxyaustrospicatine, and 2-desacetoxytaxinine J, which were isolated
from the Japanese yew Taxus cuspidata, increased cellular accu-mulation of
vincristine (VCR) in multidrug-resistant 2780AD cells as potently as verapamil,
and efficiently inhibited [(3)H]azidopine photolabeling of P-glycoprotein
(P-gp). Taxuspine C, 2'-desacetoxyaustrospicatine, and 2-desacetoxytaxinine J at
10 microM completely reversed the resistance to colchicine, VCR, and taxol in
KB-C2 cells, which overexpress P-gp, while taxinine and taxinine M showed no
effect. Taxuspine C, 2'-desacetoxyaustrospicatine, and 2-desacetoxytaxinine J
may be candidate pharmaceuticals for reversing multidrug resistance (MDR) and
also may be good modifiers of MDR in cancer chemotherapy.

PMID: 10874217 [PubMed - indexed for MEDLINE]




14: Arch Biochem Biophys 2000 Jul 1;379(1):137-46

Heterologous expression and characterization of a "Pseudomature" form of
taxadiene synthase involved in paclitaxel (Taxol) biosynthesis and evaluation of
a potential intermediate and inhibitors of the multistep diterpene cyclization
reaction.

Williams DC, Wildung MR, Jin AQ, Dalal D, Oliver JS, Coates RM, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman,
Washington, 99164-6340, USA.

The diterpene cyclase taxadiene synthase from yew (Taxus) species transforms
geranylgeranyl diphosphate to taxa-4(5),11(12)-diene as the first committed step
in the biosynthesis of the anti-cancer drug Taxol. Taxadiene synthase is
translated as a preprotein bearing an N-terminal targeting sequence for
localization to and processing in the plastids. Overexpression of the
full-length preprotein in Escherichia coli and purification are compromised by
host codon usage, inclusion body formation, and association with host
chaperones, and the preprotein is catalytically impaired. Since the transit
peptide-mature enzyme cleavage site could not be determined directly, a series
of N-terminally truncated enzymes was created by expression of the corresponding
cDNAs from a suitable vector, and each was purified and kinetically evaluated.
Deletion of up to 79 residues yielded functional protein; however, deletion of
93 or more amino acids resulted in complete elimination of activity, implying a
structural or catalytic role for the amino terminus. The pseudomature form of
taxadiene synthase having 60 amino acids deleted from the preprotein was found
to be superior with respect to level of expression, ease of purification,
solubility, stability, and catalytic activity with kinetics comparable to the
native enzyme. In addition to the major product, taxa-4(5),11(12)-diene (94%),
this enzyme produces a small amount of the isomeric taxa-4(20), 11(12)-diene (
approximately 5%), and a product tentatively identified as verticillene (
approximately 1%). Isotopically sensitive branching experiments utilizing
(4R)-[4-(2)H(1)]geranylgeranyl diphosphate confirmed that the two taxadiene
isomers, and a third (taxa-3(4),11(12)-diene), are derived from the same
intermediate taxenyl C4-carbocation. These results, along with the failure of
the enzyme to utilize 2, 7-cyclogeranylgeranyl diphosphate as an alternate
substrate, indicate that the reaction proceeds by initial ionization of the
diphosphate ester and macrocyclization to the verticillyl intermediate, followed
by a secondary cyclization to the taxenyl cation and deprotonation (i.e.,
formation of the A-ring prior to B/C-ring closure). Two potential
mechanism-based inhibitors were tested with recombinant taxadiene synthase but
neither provided time-dependent inactivation nor afforded more than modest
competitive inhibition. Copyright 2000 Academic Press.

PMID: 10864451 [PubMed - indexed for MEDLINE]




15: Phytochemistry 2000 May;54(1):13-7

The configuration of methyl jasmonate affects paclitaxel and baccatin III
production in Taxus cells.

Yukimune Y, Hara Y, Nomura E, Seto H, Yoshida S.

Life Science Laboratory, Mitsui Chemicals Inc., Chiba, Japan.
yukihito.yukimune at mitsui-chem.co.jp

All stereoisomers of methyl jasmonate (MJA) were prepared, and their effects on
cell yield and promotion of paclitaxel (Taxol) and baccatin III production
investigated in cell suspension cultures of Taxus media. (3R,7S)-MJA showed the
strongest cell growth inhibition, followed by (3R,7R)-MJA. In contrast, (3S,7R)-
and (3S,7S)-MJA had very low inhibitory effects, indicating that this inhibition
depends largely on the (3R)-configuration. In terms of the promotion of
paclitaxel and baccatin III production, (3R,7R)-MJA had the highest activity.
Although it showed considerable activity at low concentration, at higher
concentrations the activity was decreased due to strong inhibition of cell
growth. Interestingly, paclitaxel and baccatin III contents increased even at a
high (3S,7R)-MJA concentration, whereas the other isomers had the opposite
effects. These findings are interpreted to suggest that the optimum
configuration is (3R,7R), the (3R)-configuration not being indispensable, and
that the (7R)-configuration is suitable for the promotion of paclitaxel and
baccatin III production.

PMID: 10846740 [PubMed - indexed for MEDLINE]




16: Bull Cancer 1995 Apr;82(4):249-64

[Taxoids: structural and experimental properties].

[Article in French]

Lavelle F, Combeau C, Commercon A.

Centre de recherche de Vitry-Alfortville, Rhone-Poulenc Rorer SA,
Vitry-sur-Seine, France.

Paclitaxel (Taxol) and docetaxel (Taxotere) are the first representatives of a
new class of antitumor compounds. These two taxoids are clinically active
against breast, ovarian and lung cancers. Taxoids are highly complex
diterpenoids form natural origin. Preclinical and clinical developments have
been made possible after a long and sustained chemical effort: paclitaxel is
extracted from the barks of the Pacific yew tree Taxus brevifolia whereas
docetaxel is prepared by hemisynthesis starting from 10-deacetyl-baccatin III,
an inactive precursor found in the needles of the European yew tree Taxus
baccata. These two drugs are active in various in vitro and in vivo preclinical
models (cell lines, cloning of human tumor stem cells, murine grafted tumors,
human xenografts). Taxoids constitute a new class of antimitotic agents
different from vinca-alkaloids: on the one hand, paclitaxel and docetaxel can be
considered as inhibitors of the reaction of depolymerization of microtubules
into tubulin; on the other hand, vinca-alkaloids inhibit reaction of
polymerization of tubulin into microtubules. An active program of medicine
chemistry is done in various pharmaceutical and academic Institutions with two
objectives: knowledge of structure-activity relationships and selection of new
candidates for clinical trials.

Publication Types:
Review
Review literature

PMID: 10846536 [PubMed - indexed for MEDLINE]




17: J Nat Prod 2000 May;63(5):720-2

New taxanes with an opened oxetane ring from the roots of Taxus mairei.

Shen YC, Lo KL, Chen CY, Kuo YH, Hung MC.

Institute of Marine Resources, National Sun Yat-sen University, 70 Lien-Hai
Road, Kaohsiung, Taiwan, Republic of China. ycshen at mail.nsysu.edu.tw

Two novel taxoids, taxumairols N (1) and O (2), have been isolated from extracts
of the roots of Taxus mairei. The structures of 1 and 2 were identified as
7beta,9alpha,10beta,13alpha-tetraacetoxy-2alp ha,
4alpha,5alpha,20-tetrahydroxytax-11-ene and 7beta,9alpha,10beta,
13alpha-tetraacetoxy-1beta,2alpha,4alpha,5alp ha, 20-pentahydroxytax-11-ene on
the basis of 1D and 2D NMR techniques including COSY, HMQC, HMBC, and NOESY
experiments.

PMID: 10843601 [PubMed - indexed for MEDLINE]




18: Vet Hum Toxicol 2000 Jun;42(3):151-4

Detecting Taxus poisoning in horses using liquid chromatography/mass
spectrometry.

Kite GC, Lawrence TJ, Dauncey EA.

Royal Botanic Gardens, Kew, Richmond, Surrey, UK.

A method is described for the analysis of taxine alkaloids by liquid
chromatography/mass spectrometry. It is applicable to the detection of taxine
alkaloids in the stomach contents of horses in which Taxus poisoning is
suspected. Analysis of a leaf extract of Taxus baccata revealed unreported
alkaloids of the same relative molecular mass as taxine B and isotaxine B.

PMID: 10839318 [PubMed - indexed for MEDLINE]




19: Biosci Biotechnol Biochem 2000 Apr;64(4):894-8

Two novel taxane diterpenoids from the needles of Japanese yew, Taxus cuspidata.

Cheng Q, Oritani T, Horiguchi T.

Division of Life Science, Graduate School of Agricultural Science, Tohoku
University, Sendai, Japan. chengq at biochem.tohoku.ac.jp

Two novel taxane diterpenoids were isolated from the needles of Japanese yew,
Taxus cuspidata, and their structures were determined to be
lbeta-hydroxy-7beta-acetoxytaxinine (1) and lbeta,7beta-dihydroxytaxinine (2) on
the basis of spectral analyses including 2D-NMR studies.

PMID: 10830516 [PubMed - indexed for MEDLINE]




20: Biosci Biotechnol Biochem 2000 Apr;64(4):869-72

New taxane diterpenoid from seed of the Chinese yew, Taxus yunnanensis.

Shi Q, Oritani T, Zhao D.

Division of Life Science, Graduate School of Agricultural Sciences, Tohoku
University, Sendai, Japan.

A novel taxane diterpenoid with a rearranged 5/7/6-membered ring system was
isolated from seeds of the Chinese yew, Taxus yunnanensis. Its structure was
established as 9alpha,13alpha-diacetoxy-10beta-benzoxy-5alpha- cinnamoyl-11(1
5-->1)-abeotaxa-4(20),11-dien-15-ol on the basis of a spectroscopic analysis.
Its relative stereochemistry is proposed from the results of NOESY experiments.

PMID: 10830509 [PubMed - indexed for MEDLINE]




21: Mol Phylogenet Evol 2000 Mar;14(3):353-65

Phylogeny of taxaceae and cephalotaxaceae genera inferred from chloroplast matK
gene and nuclear rDNA ITS region.

Cheng Y, Nicolson RG, Tripp K, Chaw SM.

Institute of Botany, Academia Sinica, Taipei, 11529, Taiwan.

Phylogeny of the Taxaceae genera and the monotypic family Cephalotaxaceae has
been extraordinarily controversial. In this paper chloroplast matK genes and
nuclear ITS sequences were determined for all six genera of the two families and
representatives of other conifer families. Analysis using either the
nonsynonymous sites or the deduced amino acid sequences of matK genes strongly
indicates that taxad genera and Cephalotaxaceae are monophyletic, with the
Taxodiaceae/Cupressaceae clade as their sister group. Cephalotaxus is basal to
the taxad genera, among which two clades, Torreya/Amentotaxus and
Taxus/Pseudotaxus/Austrotaxus, are resolved. They correspond to Janchen's two
tribes, Torreyeae and Taxeae. In Taxeae, Austrotaxus is the first to branch off.
Analyses of the nuclear ITS sequence data corroborated the topology of the matK
gene tree. These results refute the views that Cephalotaxaceae has no alliance
with Taxaceae and that Austrotaxus and Amentotaxus should be excluded from the
Taxaceae. We estimated the divergence time between the Taxodiaceae/Cupressaceae
and the Cephalotaxaceae/Taxaceae clades to be 192-230 Myr ago and the divergence
time between taxads and Cephalotaxus to be 149-179 Myr ago. Soon after the
latter divergence event, within 6-8 Myr, the two taxad tribes originated. In
conclusion, our data do not support Florin's claim that taxads could be traced
to Devonian psilophytes (359-395 Myr ago). Copyright 2000 Academic Press.

PMID: 10712841 [PubMed - indexed for MEDLINE]




22: Phytochemistry 2000 Feb;53(3):383-9

Screening of the needles of different yew species and cultivars for paclitaxel
and related taxoids.

van Rozendaal EL, Lelyveld GP, van Beek TA.

Laboratory of Organic Chemistry, Phytochemical Section, Wageningen Agricultural
University, Netherlands.

The needles of several yew species and cultivars were analysed by high-pressure
liquid chromatography for paclitaxel, 10-deacetylpaclitaxel, cephalomannine,
baccatin III, 10-deacetylbaccatin III and brevifoliol. About 750 samples were
collected from five different locations in the Netherlands and the UK. The
results of this screening show a large variation in taxane content between the
different species and cultivars. The content of paclitaxel and
10-deacetylbaccatin III varied from 0 to 500 micrograms/g and 0 to 4800
micrograms/g dried needles, respectively. Brevifoliol was found in a very high
concentration in Taxus brevifolia. 10-Deacetylpaclitaxel, cephalomannine and
baccatin III were found in concentrations ranging from 0 to 500 micrograms/g
dried needles.

PMID: 10703062 [PubMed - indexed for MEDLINE]




23: J Pharm Biomed Anal 1999 Jul;20(3):549-55

High sensitivity ELISA determination of taxol in various human biological
fluids.

Svojanovsky SR, Egodage KL, Wu J, Slavik M, Wilson GS.

Department of Chemistry, University of Kansas, Lawrence 66045, USA.

Taxol (paclitaxel)--the natural product isolated from Pacific yew (Taxus
brevifolia)--is a novel agent with high activity in the treatment of patients
with several malignant tumors including those resistant to other cytotoxic
drugs. The therapeutic index of this promising anticancer drug could be further
increased by the exploration of its pharmacokinetic pharmacodynamic relationship
in cancer patients. Since taxol is highly protein bound, a very specific and
highly sensitive analytical method is required in order to determine free,
protein unbound and biologically active taxol species in human physiological
fluids: plasma; plasma ultrafiltrate; and salivary fluids. In order to
accomplish this, a new indirect competitive enzyme-linked immunosorbent assay
(ELISA), for quantitating such a low bioactive taxol concentration level, has
been developed in our laboratories. This method uses taxol competitive
inhibition of mouse anti-taxol antibodies binding to the solid phase coated
antigen 7-succinyltaxol-bovine serum albumin. This indicates recognition of the
active taxol in the solution phase, where a diluted horseradish peroxidase
labeled goat anti-mouse enzyme conjugate is used. While employing this
technique, after systematic optimization of the experimental conditions, we are
able to detect the anticipated taxol in plasma ultrafiltrate and salivary fluids
at the concentration level of subpicogram per milliliter. The working range of
the assay is approximately five orders in magnitude, i.e. from pg ml(-1) to 100
ng ml(-1). The clinical part of this study verified the working range of the
ELISA method using samples of physiological fluids from a cancer patient treated
with 3 h intravenous (i.v.) infusion of this drug. Our results of taxol
determination in plasma, plasma ultrafiltrate and saliva demonstrate the
applicability of the newly developed ELISA method for further pharmacokinetic
studies of free, biologically active taxol species in cancer patients.

PMID: 10701971 [PubMed - indexed for MEDLINE]




24: Arch Biochem Biophys 2000 Feb 15;374(2):371-80

Molecular cloning of a taxa-4(20),11(12)-dien-5alpha-ol-O-acetyl transferase
cDNA from Taxus and functional expression in Escherichia coli.

Walker K, Schoendorf A, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman,
Washington 99164-6340, USA.

The taxa-4(20),11(12)-dien-5alpha-ol-O-acetyl transferase which catalyzes the
third step of Taxol biosynthesis has been isolated from methyl jasmonate-induced
Taxus cells, and partially purified and characterized (K. Walker, R. E. B.
Ketchum, M. Hezari, D. Gatfield, M. Golenowski, A. Barthol, and R. Croteau,
Arch. Biochem. Biophys. 364, 273-279 1999). A revised purification method
allowed internal amino acid microsequencing of the enzyme, from which primers
were designed and employed to amplify a transacetylase gene-specific fragment.
This radiolabeled, 900-bp amplicon was used as a hybridization probe to screen a
cDNA library constructed from poly(A)(+) RNA isolated from induced Taxus cells,
from which a full-length transacetylase sequence was obtained. Expression of
this clone from pCWori(+) in Escherichia coli JM109 cells yielded the functional
enzyme, as determined by radiochemical assay and combined capillary gas
chromatographic-mass spectrometric verification of the acetylated product. The
full-length DNA has an open-reading frame of 1317 nucleotides corresponding to a
deduced amino acid sequence of 439 residues that exhibits high sequence identity
to the proteolytic fragments of the native enzyme, which the recombinant
transacetylase resembles in properties. Consistent with the size of the
operationally soluble native enzyme, the DNA appears to encode a monomeric
protein of molecular weight 49,079 that bears no N-terminal organellar targeting
information. Sequence comparison of the taxadien-5alpha-ol-O-acetyl transferase
with the few other known acyl transferases of plant origin indicates a
significant degree of similarity between these enzymes (64-67%). The efficient
conversion of taxadien-5alpha-yl acetate to further hydroxylated intermediates
of the Taxol pathway confirms the significance of this acylation step and
suggests this taxadienol transacetylase to be an important target for genetic
manipulation to improve Taxol production. Copyright 2000 Academic Press.

PMID: 10666320 [PubMed - indexed for MEDLINE]




25: Phytochemistry 1999 Dec;52(8):1565-9

Taxane diterpenoids from the seeds of Chinese yew Taxus chinensis.

Shen YC, Chen YJ, Chen CY.

Institute of Marine Resources, National Sun Yat-sen University, Kaohsiung,
Taiwan, Republic of China.

The taxoid chinentaxunine has been isolated from the seeds of Chinese yew Taxus
chinensis, and its structure determined on the basis of spectral and chemical
methods. In addition, the known taxol C, paclitaxel, 10-deacetyl taxol A,
10-deacetyl-7-epitaxol, 10-deacetyl-10-oxo-7-epi-taxol, taxinine M, taxchinin A,
10-deacetyl taxinine B and taxuspine X were also isolated and identified from
this source.

PMID: 10647221 [PubMed - indexed for MEDLINE]




26: J Control Release 2000 Jan 3;63(1-2):141-53

Preparation, characterization, cytotoxicity and pharmacokinetics of liposomes
containing water-soluble prodrugs of paclitaxel.

Ceruti M, Crosasso P, Brusa P, Arpicco S, Dosio F, Cattel L.

Dipartimento di Scienza e Tecnologia del Farmaco, Universita di Torino, Via
Pietro Giuria 9, 10125, Torino, Italy.

Paclitaxel (Taxol) is a diterpenoid isolated from Taxus brevifolia, used
clinically for the treatment of ovarian and breast cancer. Due to its aqueous
insolubility it is administered dissolved in ethanol and Cremophor EL
(polyethoxylated castor oil), which has serious side effects. In order to
eliminate this vehicle, in previous work we entrapped paclitaxel in conventional
and in polyethylene glycol coated liposomes. However, in neither formulation did
we obtain satisfactory entrapment efficiency. In this study we increased the
paclitaxel concentration entrapped in liposomes by incorporating different
water-soluble prodrugs, such as the 2'-succinyl, 2'-methylpyridinium acetate and
2'-mPEG ester paclitaxel derivatives, in the lipid vesicles. Liposomes
containing 2'-mPEG (5000)-paclitaxel showed the best performance in terms of
stability, entrapment efficiency and drug concentration (6.5 mgml(-1)). The in
vitro cytotoxic activity of this liposomal prodrug was similar to that of the
parent drug. The pharmacokinetic parameters for the free and for the liposomal
prodrugs fitted a bi-exponential plasma disposition. The most important change
in pharmacokinetic values of the prodrug vs. the free drug liposomal
formulations was t(1/2)beta, plasma lifetime, which was longer in liposomes
containing 2'-mPEG (5000)-paclitaxel.

PMID: 10640588 [PubMed - indexed for MEDLINE]




27: J Control Release 2000 Jan 3;63(1-2):19-30

Preparation, characterization and properties of sterically stabilized
paclitaxel-containing liposomes.

Crosasso P, Ceruti M, Brusa P, Arpicco S, Dosio F, Cattel L.

Dipartimento di Scienza e Tecnologia del Farmaco, Universita di Torino, Via
Pietro Giuria 9, 10125, Torino, Italy.

Paclitaxel (Taxol) is a diterpenoid isolated from Taxus brevifolia, approved by
the FDA for the treatment of ovarian and breast cancers. Due to its low
solubility in water, it is clinically administered dissolved in Cremophor EL,
(polyethoxylated castor oil) and ethanol, which cause serious side effects.
Inclusion of paclitaxel in liposomal formulations has proved to be a good
approach to eliminating this vehicle and improving the drug's antitumor
efficacy. We prepared different conventional and PEGylated liposomes containing
paclitaxel and determined encapsulation efficiency, physical stability and drug
leakage in human plasma. The best conventional liposome formulation was composed
of ePC/PG 9:1, while for PEGylated liposomes the best composition was
ePC/PG/CHOL/PEG(5000)-DPPE 9:1:2:0.7. PEGylated liposomes were found to be less
stable during storage than the corresponding conventional liposomes and to have
lower drug release in human plasma at 37 degrees C. In vitro cytotoxic
activities were evaluated on HT-29 human colon adenocarcinoma and MeWo melanoma
cell lines. After 2 and 48 h, conventional liposomes had the same cytotoxicity
as free paclitaxel, while PEGylated liposomes were as active as free drug, only
after 48 h. Pharmacokinetics and biodistribution were evaluated in Balb/c mice
after i.v. injection of paclitaxel, formulated in Cremophor EL or in
conventional or in PEGylated liposomes. Encapsulation of paclitaxel in
conventional liposomes produced marked differences over the free drug
pharmacokinetics. PEGylated liposomes were long-circulating liposomes, with an
increased t(1/2) beta 48.6 h, against t(1/2) beta 9.27 h of conventional
liposomes. Biodistribution studies showed a considerable decrease in drug uptake
in MPS-containing organs (liver and spleen) at 0.5 and 3 h after injection with
PEGylated compared to conventional liposomes.

PMID: 10640577 [PubMed - indexed for MEDLINE]




28: FEMS Microbiol Lett 2000 Dec 15;193(2):249-53

Taxol from Tubercularia sp. strain TF5, an endophytic fungus of Taxus mairei.

Wang J, Li G, Lu H, Zheng Z, Huang Y, Su W.

The Key Laboratory of Ministry of Education for Cell Biology and Tumor Cell,
Engineering and School of Life Sciences, Xiamen University, 361005, Xiamen, PR
China.

The diterpenoid taxol is an important anticancer agent used widely in the
clinic. The purpose of this work was to identify a taxol-producing endophytic
fungus (strain TF5) isolated from Taxus mairei and study its anticancer
activities. Strain TF5 was identified as a Tubercularia sp. according to the
morphology of the fungal culture, the mechanism of spore production and the
characteristics of the spores. Strain TF5 produced taxol, when grown in potato
dextrose liquid medium and analyzed by thin layer chromatography, high
performance liquid chromatography, ultraviolet and mass spectrometry. The fungal
taxol, which was isolated from the organic extract of the TF5 culture, had
strong cytotoxic activity towards KB and P388 cancer cells in vitro, tested by
the MTT assay. Observed with immunofluorescence and electron microscopy, the
fungal taxol enhanced microtubule stability and bundling in culture cells and
induced tubulin polymerization in vitro similar to the authentic taxol.

PMID: 11111032 [PubMed - indexed for MEDLINE]




29: Biotechnol Prog 1999 Nov-Dec;15(6):1072-7

Kinetic studies of paclitaxel production by Taxus canadensis cultures in batch
and semicontinuous with total cell recycle.

Phisalaphong M, Linden JC.

Department of Chemical Engineering, Colorado State University, Fort Collins,
Colorado 80523, USA.

Suspension cultures of Taxus canadensis were elicited with methyl jasmonate (MJ)
under defined headspace ethylene concentrations. Kinetic studies of growth,
nutrient consumption, pH variation, and paclitaxel accumulation were conducted
in batch cultures and semicontinuous culture with total cell recycle. A dramatic
increase of paclitaxel was obtained when the cultures were elicited with 100
microM MJ, but cell growth was thereby arrested. Supplementation of acetyl-CoA
and MJ to the culture proved to be another way to improve paclitaxel yields.
Using semicontinuous culture with total cell recycle, paclitaxel accumulation
was increased by a factor of 4.0 relative to that in the batch culture during 35
days of cultivation.

PMID: 10585192 [PubMed - indexed for MEDLINE]




30: Lancet 1999 Sep 25;354(9184):1090

Coma in a park.

Pilz B, Mesner C, Baetgen S, Luft FC.

Elisabeth Diakonissen-und-Krankenhaus and Franz Volhard Clinic, Medical Faculty
of the Charite, Humboldt University of Berlin, Germany.

PMID: 10509501 [PubMed - indexed for MEDLINE]




31: J Nat Prod 1999 Aug;62(8):1147-50

Isolation of two highly methylated polyketide derivatives from a yew-associated
penicillium species

Stierle DB, Stierle AA, Ganser BK.

Department of Chemistry, Montana Tech of the University of Montana, Butte,
Montana 59701, USA.

Two selective antifungal agents were produced by a Penicillium sp. isolated from
the inner bark of the Pacific yew tree, Taxus brevifolia. The structures of
these highly methylated polyketide derivatives were deduced by detailed analysis
of both 1D and 2D NMR and difference NOE spectra. Both compounds were active
against the plant pathogen, Sclerotinia sclerotiorum in the standard disk assay.

PMID: 10479323 [PubMed - as supplied by publisher]




32: Oncologist 1996;1(4):221-222

A Tribute to Bruce Chabner.

Kaufman D.

The Jackson Clinic, Jackson, Tennessee, 38301, USA.

After more than 25 years at the National Cancer Institute and 13 years as the
Director of the NCI's Division of Cancer Treatment, Dr. Bruce Chabner left the
NIH in April 1995 to accept a new position at the Massachusetts General
Hospital. This decision followed several months of agonizing contemplation. I
think Bruce recognized earlier and more perspicaciously than most that the
climate at the NCI was about to change dramatically, leaving diminishing
opportunities under governmental auspices for the anti-cancer drug discovery and
development as well as the clinical research he so loves. Among the many
accomplishments of this phase in the career of Bruce Chabner-the preliminary
phase of what we assume will be even greater accomplishments as he moves to the
private sector-undoubtedly the most meaningful and enduring are the
contributions of those whose formative experiences in basic and clinical
research came while under his tutelage. One of the key missions of the NIH's
Intramural Research Program has been the training of the next generation of
scientists; as will be demonstrated in this volume, Bruce Chabner has succeeded
remarkably in this endeavor. I could think of no better way to honor Bruce
Chabner than to gather his students to discuss their own research. Thus, on
April 7, 1995, a symposium of Chabner alumni was held in the Masur Auditorium of
Building 10. Opening the program was Bruce's own laboratory mentor, Dr. Joe
Bertino, whence Bruce's lifelong passion for folate metabolism and methotrexate
research. Following Dr. Bertino were his scientific grandchildren, in
approximate chronological order of their time studying with Dr. Chabner. As
directors of cancer centers, heads of oncology departments, heads of
laboratories, and as working scientists and clinicians, each has achieved
prominence in clinical oncology and each has maintained a high level of
productivity in both laboratory and clinical research. Just as I am certain that
Dr. Bertino takes pride in the accomplishments of his pupil, the accomplishments
and prominence of these authors, Dr. Chabner's students, reflect their early
mentoring and their recent research serve as testament and tribute. Allow me to
briefly recapitulate the highlights to date of the career of Dr. Bruce Chabner.
He graduated summa cum laude from Yale College in 1961, and from Harvard Medical
School in 1965, followed by house staff training at the Peter Bent Brigham
Hospital. He first came to the NCI as a Clinical Associate in 1967. In 1969
Bruce left the NCI to return to Yale University, where he entered the laboratory
of Dr. Joe Bertino. Dr. Chabner and Dr. Bertino did pioneering clinical research
in the use of leucovorin rescue following methotrexate. In 1971 Bruce returned
to the NCI as a Senior Investigator in the Laboratory of Clinical Pharmacology,
where he continued research in methotrexate pharmacology and began studying
mechanisms of resistance to methotrexate. In 1976 he was named the first Chief
of the newly created Clinical Pharmacology Branch in the Clinical Oncology
Program (COP). In 1980 he was named Associate Director of COP and in 1982 Dr.
Vince DeVita asked Bruce to succeed him as Director of the Division of Cancer
Treatment. Dr. Chabner has received numerous awards and honors in recognition of
his scientific achievements, including the David A. Karnofsky Memorial
Lectureship of the American Society of Clinical Oncology in 1985, and the
Melville Jacobs Award of the American Radium Society in 1986. Dr. Chabner was
promoted to the flag rank of Rear Admiral in the Public Health Service (PHS) in
1991. He received numerous PHS awards and medals, including its highest award,
the Distinguished Service Medal, which was awarded for his contributions to the
development of the important anti-cancer drug paclitaxel (Taxol&reg;). Although
methotrexate has been used for more than 40 years, Dr. Chabner's early
pharmacological research was essential for the full development of this agent as
a clinically useful drug. Early in his career, he developed and refined assay
methods for determining plasma levels of methotrexate. This work made possible
the accurate prediction, based on plasma methotrexate levels, of bone marrow
toxicity in patients treated with this drug, and allowed safe clinical use of
methotrexate in conjunction with leucovorin. Methotrexate levels are now
routinely used to determine the dose and duration of leucovorin treatment
necessary to prevent methotrexate toxicity. Dr. Chabner's research group made
the important discovery of the intracellular conversion of antifolates to an
altered form that inhibits other intracellular enzymes in addition to DHFR. This
work led to an understanding of certain mechanisms of methotrexate resistance
whereby cells lose the ability to modify the drug, and also directly led to the
synthesis and clinical testing of drugs specifically targeting the unique
enzymes that are inhibited by the modified antifolate drugs. Additionally, the
first evidence of gene amplification in a drug-resistant human malignancy came
from this group, when DHFR was found to be amplified in a patient with
small-cell lung carcinoma. Bruce's recent work involves the general phenomenon
of multi-drug resistance, as exemplified by Dr. Susan Bates's article in this
issue. As Director of the Division of Cancer Treatment (DCT) from 1982 through
1995, and as we now know, the last Director of this now-defunct entity, Dr.
Chabner became a true leader of a national and international research program
whose mission was, simply, to improve the therapy for cancer. Both the DCT's
intramural preclinical and clinical programs and the diverse country-wide
extramural programs supported by the DCT made many important advances during
these years. Perhaps most exemplary of the importance of his leadership was the
story of Taxol&reg; development, important clinical aspects of which are
discussed herein by Dr. Ross Donehower. In 1990, the first reports were received
by the NCI that Taxol&reg;, an anti-cancer drug isolated from the bark of the
Pacific yew tree, Taxus brevifolia, was remarkably active in women with
refractory ovarian cancer who had been previously treated with platinum
compounds. Paclitaxel had been discovered many years earlier, but because of
very limited supply of the drug and because of its toxicity in early clinical
testing, its development had been very slow prior to these reports. The NCI
immediately embarked upon a major effort to rapidly increase the supply of the
drug to ensure expeditious clinical confirmation of the initial result, to test
the drug in a variety of other cancers, to optimize its dosing and scheduling,
and to assure wide availability of the drug. Within two years the supply problem
was solved, the activity of the drug in ovarian cancer was confirmed, and
significant activities in breast cancer and non-small cell lung cancer were
found. Taxol&reg; was approved for use, first in ovarian cancer, then in breast
cancer, and is now-just five years later-one of the most important drugs in the
oncologist's armamentarium. This rapid development project was unprecedented in
cancer drug development. Bruce's leadership in organizing and supporting this
very complex collaborative effort involving the NCI, Bristol-Myers Squibb, the
U.S. Forestry Service and the Bureau of Land Management was essential to its
success. All of this was accomplished in spite of powerful, albeit wrong-headed,
political opposition from Capitol Hill. Bruce finessed this brilliantly. In the
military, the words "honor" and "duty" are frequently used to describe the
career or the individual acts of an officer. Admiral Chabner, in all his
endeavors-physician, scientist, teacher, the leader of a national cancer
research program-is known among his many friends and colleagues as a man who has
conducted his office with highest honor, with scrupulous intellectual and
ethical integrity, and in a manner going far beyond the call of duty. His
leadership of the Division of Cancer Treatment was born from more than a sense
of duty to the office; it grew from his love of and respect for both science and
medicine, from the knowledge and experience that came from years in the
laboratory contemplating and doing research, and, ultimately, from the desire to
improve the lives of patients with cancer. These qualities will assure his
continued success at Massachusetts General Hospital. From Advances in Cancer
Treatment: The Chabner Symposium. Stem Cells 1996;14:3-4.

PMID: 10387991 [PubMed - as supplied by publisher]




33: Pol Merkuriusz Lek 1999 Jan;6(31):27-9

[Pharmacological action of paclitaxel].

[Article in Polish]

Potemski P, Pluzanska A.

Zakladu Farmakologii Akademii Medycznej w Lodzi.

Paclitaxel (taxol, Tax) is a novel plant product isolated from the Pacific yew
(Taxus brevifolia). It has a unique mechanism of action, because it induces very
stable and dysfunctional microtubules. Paclitaxel has a broad spectrum of
antineoplastic activity. It has been successfully used in the treatment of
ovarian cancer, metastatic breast cancer, lung cancer, carcinoma of the head and
neck, malignant melanoma and other human neoplasms. Tax has response rates of
20-36% in patients with refractory ovarian cancer. Toxic effects include
myelosuppresion, hypersensitivity reactions, peripheral neuropathy, cardiac
disturbances, alopecia. However, studies evaluating the drug still are ongoing
paclitaxel seems to be one of the most promising antineoplastic agents.

Publication Types:
Review
Review, tutorial

PMID: 10344150 [PubMed - indexed for MEDLINE]




34: Proc Natl Acad Sci U S A 1999 Apr 13;96(8):4256-61

A common pharmacophore for cytotoxic natural products that stabilize
microtubules.

Ojima I, Chakravarty S, Inoue T, Lin S, He L, Horwitz SB, Kuduk SD, Danishefsky
SJ.

Department of Chemistry, State University of New York at Stony Brook, Stony
Brook, NY 11794-3400, USA.

Taxol (paclitaxel), a complex diterpene obtained from the Pacific yew, Taxus
brevifolia, is arguably the most important new drug in cancer chemotherapy. The
mechanism of cytotoxic action for paclitaxel-i.e., the stabilization of
microtubules leading to mitotic arrest-is now shared by four recently identified
natural products, eleutherobin, epothilones A and B, and discodermolide. Their
ability to competitively inhibit [3H]paclitaxel binding to microtubules strongly
suggests the existence of a common binding site. Recently, we have developed
nonaromatic analogues of paclitaxel that maintain high cytotoxicity and tubulin
binding (e.g., nonataxel). We now propose a common pharmacophore that unites
paclitaxel, nonataxel, the epothilones, eleutherobin, and discodermolide, and
rationalizes the extensive structure-activity relationship data pertinent to
these compounds. Insights from the common pharmacophore have enabled the
development of a hybrid construct with demonstrated cytotoxic and
tubulin-binding activity.

PMID: 10200249 [PubMed - indexed for MEDLINE]




35: J Cancer Res Clin Oncol 1999;125(1):20-7

Effects of paclitaxel in combination with radiation on human head and neck
cancer cells (ZMK-1), cervical squamous cell carcinoma (CaSki), and breast
adenocarcinoma cells (MCF-7).

Pradier O, Rave-Frank M, Schmidberger H, Bomecke M, Lehmann J, Meden H, Hess CF.

Department of Radiotherapy and Radiation Oncology, University of Gottingen,
Germany. opradier at med.uni-goettingen.de

BACKGROUND AND PURPOSE: The anticancer drug paclitaxel, a natural product from
Taxus brevifolia, is a microtubule-stabilising agent, which has been shown to
block different cells in the G2/M phase of the cell cycle and so modulate their
radioresponsiveness. We investigated the radiosensitizing potential of
paclitaxel in human head and neck cancer cells (ZMK-1), in cervical squamous
cell carcinoma cells (CaSki) and in breast adenocarcinoma cells (MCF-7).
METHODS: ZMK-1 cells were incubated with paclitaxel for 3, 9, or 24 h before
irradiation. ZMK-1-, CaSki- and MCF-7 cells were incubated with paclitaxel for
24 h after irradiation. The paclitaxel concentration (70 nM, 7 nM, 0.7 nM) was
chosen to obtain equivalent toxicity at the different incubation times (3 h, 9
h, 24 h respectively). Radiation doses were from 0 to 8 Gy. Cell survival was
measured by a standard clonogenic assay after a 9-day incubation. Flow cytometry
was used to measure the capacity of paclitaxel to cause accumulation of cells in
the G2/M phase of the cell cycle. RESULTS: Paclitaxel alone was cytotoxic in a
time- and concentration-dependent manner. Up to 36% of the ZMK-1 cells
accumulated in G2/M after treatment for 24-36 h. If the cells were incubated
with paclitaxel before irradiation the isoeffect enhancement ratios for ZMK-1
cells, determined at the 37% survival level, were 0.81, 1.48 and 1.15 for 3-h,
9-h, and 24-h pre-incubations respectively. For a paclitaxel incubation of 24 h
after irradiation, the isoeffect enhancement ratios, determined at the 37%
survival level, were 0.72, 0.76 and 1.2 for the ZMK-1. CaSki, and MCF-7 cells
respectively. CONCLUSION: In the three cell lines no radiosensitizing effect of
paclitaxel could be demonstrated unambiguously. The use of asynchronized cells
or the support of cellular repair mechanisms while the cells are blocked in G2/M
could partly explain the results.

PMID: 10037273 [PubMed - indexed for MEDLINE]




36: J Nat Prod 1998 Oct;61(10):1277-8

Dihydroramulosin from Botrytis sp.

Stierle DB, Stierle AA, Kunz A.

Department of Chemistry, Montana Tech of the University of Montana, Butte,
Montana 59701, USA. DSTIERLE at MTECH.EDU

Botrytis sp., isolated from the inner bark of the Pacific yew, Taxus brevifolia,
was shown to produce ramulosin (1), 6-hydroxyramulosin (2), and the new compound
8-dihydroramulosin (3). The structure of dihydroramulosin was deduced from the
NMR spectra and confirmed by chemical conversion from ramulosin.

PMID: 9784167 [PubMed - indexed for MEDLINE]




37: Med Res Rev 1998 Sep;18(5):299-314

Camptothecin and taxol: discovery to clinic.

Wall ME.

Research Triangle Institute, Research Triangle Park, NC 27709-2194, USA.

Camptothecin (CPT) is a pentacyclic alkaloid isolated from wood and bark of
Camptotheca acuminata. Initially it was found to be highly active in a number of
mouse in vivo cancer assays. Subsequently, CPT was found to uniquely inhibit an
enzyme, topoisomerase I, which is involved in DNA replication. A number of CPT
analogs are in advanced clinical trial, and two, Topotecan and CPT-11, have been
approved for marketing by the FDA. taxol, a taxane alkaloid, was isolated from
Taxus brevifolia. Taxol is a highly cytotoxic compound active in several mouse
antitumor assays. It was subsequently found to uniquely inhibit tubulin, a
protein involved in mitosis. After clinical evaluation, it has become the drug
of choice for treatment of ovarian cancer.

Publication Types:
Review
Review, tutorial

PMID: 9735871 [PubMed - indexed for MEDLINE]




38: Oncology (Huntingt) 1998 Jan;12(1 Suppl 1):23-7

Taxanes in adjuvant and neoadjuvant therapies for breast cancer.

O'Leary J, Volm M, Wasserheit C, Muggia F.

Kaplan Comprehensive Cancer Center, New York University Medical Center, New
York, New York, USA.

Paclitaxel (Taxol) is a diterpene originally obtained from the bark of the
Pacific Yew Tree, Taxus Brevifolia. Its mechanism of action is unique. It
stabilizes microtubule polymerization, thus blocking cells in the G2/M phase of
the cell cycle. In breast cancer, initial studies using paclitaxel demonstrated
high activity. The first study was reported in 1991 by Holmes et al who gave
paclitaxel as a 24-hour infusion at 250 mg/m2 to 25 patients with metastatic
breast cancer following only one prior chemotherapy regimen--they achieved a 56%
response rate. Since then, numerous studies have confirmed the effectiveness of
paclitaxel in patients with metastatic disease. A second taxane, docetaxel
(Taxotere), has also demonstrated excellent activity. Clinical research is now
focused on integrating the taxanes into combination drug regimens and into
neoadjuvant and adjuvant schedules for patients with early stage breast cancer,
as well as looking at the biologic determinants of response and resistance to
taxanes. This article will review developments in the use of taxanes in the
adjuvant and neoadjuvant settings and it will review the information on possible
molecular markers that may be useful in predicting tumor responsiveness to
taxanes.

Publication Types:
Review
Review, tutorial

PMID: 9516599 [PubMed - indexed for MEDLINE]




39: Chem Biol 1995 Nov;2(11):721-7

The relationship between an endangered North American tree and an endophytic
fungus.

Lee JC, Yang X, Schwartz M, Strobel G, Clardy J.

Department of Chemistry, Cornell University, Ithaca, NY 14853-1301, USA.

BACKGROUND: The Florida torreya (Torreya taxifolia) began a catastrophic decline
in the late 1950s and is now the rarest tree in North America for which a full
species designation has been established. The trees have common plant disease
symptoms, but the reason for the decline has never been identified. T.
taxifolia's imminent extinction gains special poignancy through its close
relationship to the Pacific yew (Taxus brevifolia), which produces the potent
anticancer agent, taxol. RESULTS: An examination of the endophytic fungal
communities of wild torreyas consistently found a filamentous fungus,
Pestalotiopsis microspora, associated with diseased trees and also with most
symptomless trees. P. microspora can be cultured in the laboratory, and when it
is introduced into greenhouse-grown torreyas, it causes disease symptoms similar
to those seen in the field. The fungus can then be reisolated from these
deliberately infected trees. The phytotoxins pestalopyrone, hydroxypestalopyrone
and pestaloside have been isolated and characterized from axenic fungal
cultures, and both pestalopyrone and hydroxypestalopyrone can be isolated from
artificially infected torreyas. In addition, pestaloside has antifungal activity
against other fungal endophytes of T. taxifolia. CONCLUSIONS: The filamentous
fungus, P. microspora, has an endophytic-pathologic relationship with T.
taxifolia. The fungus resides in the inner bark of symptomless trees, and
physiological or environmental factors could trigger its pathological activity.
P. microspora produces the phytotoxins pestalopyrone, hydroxypestalopyrone, and
pestaloside which give rise to the disease. Pestaloside, which also has
antifungal activity, could reduce competition from other fungal endophytes
within the host.

PMID: 9383479 [PubMed - indexed for MEDLINE]




40: Chem Biol 1994 Oct;1(2):107-12

Conformation of a water-soluble derivative of taxol in water by 2D-NMR
spectroscopy.

Gomez Paloma L, Guy RK, Wrasidlo W, Nicolaou KC.

Department of Chemistry, Scripps Research Institute, La Jolla, CA 92037, USA.

BACKGROUND: Taxol is a natural product produced by the Pacific yew, Taxus
brevifolia, that has emerged as a prominent chemotherapeutic agent for the
treatment of solid tumors. It binds to microtubules, stabilizing them and
arresting cells in mitosis. Taxol has been produced synthetically and a wealth
of structure-activity data has recently emerged. To data, however, no single
conformational model exists for the interpretation of these data. Studies of
taxol and its analogs in organic solvents showed two distinct conformations, one
in which the 3'-benzamido group and the 2-benzoyl group are in close proximity,
and another in which the 2-benzoyl group is instead close to the 3'-phenyl
group. We decided to use a derivative of taxol that has improved
water-solubility to determine the structure of taxol in water. RESULTS: We have
synthesized and characterized a stable water-soluble derivative of taxol that
binds to microtubules and has a cytotoxicity profile very similar to that of
taxol. 1D and 2D 1H NMR experiments with this bioactive compound in D2O indicate
the presence of one conformer with a well-defined structure. In this structure,
the 2-benzoyl group is clustered with the 3'-phenyl group. CONCLUSION: The
determination of the conformation of taxol in water may allow quantitative
three-dimensional interpretation of the structure-activity data obtained for
taxol, and hence enable the design of novel taxol mimics.

PMID: 9383378 [PubMed - indexed for MEDLINE]




41: J Nat Prod 1997 Nov;60(11):1207-9

New phomopsolides from a Penicillium sp.

Stierle DB, Stierle AA, Ganser B.

Department of Chemistry, Montana Tech, University of Montana, Butte 59701, USA.
DSTERLE at PO1.MTECH.EDU

Investigation of the bioactive compounds from a Penicillium sp. isolated from
the inner bark of the Pacific yew, Taxus brevifolia, led to the isolation of the
known furanone 1, and a series of phomopsolides. The phomopsolide fractions
contained phomopsolides A and B, which have previously been described, and three
new phomopsolides. The structures of the new phomopsolides were deduced by
comparison of their NMR spectra to those of the known compounds.

PMID: 9392888 [PubMed - indexed for MEDLINE]




42: Diagn Cytopathol 1997 Sep;17(3):209-12

Taxol effect: bizarre mitotic figures (abnormal spindle asters) in a malignant
peritoneal effusion: report of a case.

Jordan CD, Wells WA.

Department of Pathology, Dartmouth-Hitchcock Medical Center, Lebanon, New
Hampshire 03756, USA.

Taxol (Paclitaxol) is a diterpenoid taxane derivative found in the bark and
needles of the Western yew, Taxus brevifolia, indigenous to the old growth
forests of the Pacific Northwest. As compared with other antineoplastic agents
(vinca alkaloids and colchicine) that enhance microtubule disassembly, taxol
promotes microtubule polymerization. In interphase cells, abnormal microtubular
bundles or arrays are seen. In mitotic cells, abnormal spindle asters form. Such
morphologic changes have been described frequently in cell culture systems and
in in vitro systems using fresh tumor tissue. To our knowledge, these changes
have not been described in a peritoneal effusion specimen from a patient with
stage III ovarian cancer treated with taxol. In addition, the mitotic
stabilization produced interpretative difficulties in evaluating the peritoneal
fluid because a vast majority of the presumed malignant cells were in mitosis
and, hence, not evaluable by ordinary cytologic criteria.

PMID: 9285194 [PubMed - indexed for MEDLINE]




43: Strahlenther Onkol 1997 May;173(5):281-6

The effect of paclitaxel on the radiosensitivity of gynecological tumor cells.

Rave-Frank M, Meden H, Jaschke A, Tanzer A, Boghun O, Fietkau R.

Klinik fur Strahlentherapie und Radioonkologie, Gottingen.

BACKGROUND: Paclitaxel, a natural product from Taxus brevifolia, is a
microtubule stabilizing agent, which has been shown to block different cells in
the G2/M phase of the cell cycle and consequently, to modulate their
radioresponsiveness. Our aim was to test the cytotoxic and radiosensitizing
potential of paclitaxel, with respect to different gynecological tumors with
varying radiosensitivities. MATERIAL AND METHOD: We performed clonogenic assays
and flow cytometry on 2 cell lines, MCF-7 (breast) and CaSki (cervix) cells, and
on 2 primary ovarian tumor samples (OC-I and OC-II). The cells were irradiated
with 200 kV X-rays, radiation doses of up to 8 Gy were applied either as single
doses or in 2 Gy fractions. Paclitaxel concentrations varied from 0.07 to 700
nM, incubation times varied from 3 to 120 h. RESULTS: Paclitaxel alone changed
the cell cycle distribution of the cells tested and was cytotoxic in a time and
concentration dependent manner. When combined with radiation, most schedules
resulted in additive effects of the combined treatments. However, for MCF-7
cells, when 7 nM paclitaxel, applied 24 h before irradiation, were combined with
fractionated irradiation a supra-additive effect with a SER of 1.2 was found.
For CaSki cells, under comparable conditions the SER was 1.13 but the effects
were not statistically significant. CONCLUSION: Under specific conditions,
paclitaxel exerted a weak radiosensitizing effect on breast and cervical
carcinoma cells. A therapeutic gain may be possible on the basis of an optimal
paclitaxel/radiation scheduling.

PMID: 9176559 [PubMed - indexed for MEDLINE]




44: Arch Biochem Biophys 1997 Jan 15;337(2):185-90

Taxol production and taxadiene synthase activity in Taxus canadensis cell
suspension cultures.

Hezari M, Ketchum RE, Gibson DM, Croteau R.

Institute of Biological Chemistry, and Department of Biochemistry and
Biophysics, Washington State University, Pullman 99164-6340, USA.

The cyclization of geranylgeranyl diphosphate to taxa-4(5),11(12)-diene
represents the first committed, and a slow, step in the complex biosynthetic
pathway leading to the anticancer drug Taxol. The cyclization enzyme, taxadiene
synthase, has been previously purified from Pacific yew (Taxus brevifolia) stem
and characterized, and the corresponding cDNA has been isolated. To better
assess the role of taxadiene synthase in the control of pathway flux in Canadian
yew (T. canadensis) cells, a reliable system for production of Taxol in
suspension culture, the enzyme from this source was isolated and shown to be
chromatographically, electrophoretically, and kinetically identical to that of
T. brevifolia stem. Results from the analysis of enzyme activity levels during
the time course of Taxol accumulation in developing cell cultures of T.
canadensis indicate that rate-limiting transformations lay farther down the
pathway than the cyclization step in this system.

PMID: 9016812 [PubMed - indexed for MEDLINE]




45: Chem Biol 1996 Dec;3(12):1021-31

Fluorescent taxoids.

Guy R, Scott Z, Sloboda R, Nicolaou K.

Department of Chemistry, The Skaggs Institute of Chemical Biology, The Scripps
Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037,
USA.

BACKGROUND: Taxol is a natural product produced by the Pacific Yew, Taxus
brevifolia, that has emerged as a prominent chemotherapeutic agent for the
treatment of solid tumors. Taxol's biochemical mode of action has been well
studied: it binds to microtubules, stabilizing them and preventing their
depolymerization to tubulin subunits. At lower dosage levels, taxol also
interferes with the normal dynamics of the tubulin-microtubule equilibrium. This
biochemical effect causes taxol's ultimate physiological effect, cell cycle
arrest; taxol is thought to block anaphase A of mitosis. Taxol also causes a
number of intriguing secondary effects on interphase cells that are poorly
understood. We believed that a bio-active fluorescent taxol derivative could be
a useful tool in the study of these cellular mechanisms, especially in
interphase cells. RESULTS: We have synthesized and characterized a series of
stable, fluorescently labeled derivatives of taxol that bind to microtubules and
have cytotoxicities similar to that of taxol. Fluorescence microscopy
experiments in interphase human foreskin fibroblast (HFF) cells indicate that
one of these, a sulforhodamine taxoid, is particularly well suited for optical
microscopy. The use of this taxoid in HFF cells revealed a previously undetected
localization of taxoids to the nucleolus during interphase. CONCLUSIONS: The
production of a new fluorescent derivative of taxol provides a useful tool,
enabling cellular biologists to study taxol's mechanism of action. It is hoped
that this material will prove particularly useful for the study of taxol's
effects upon interphase cells. Although in common usage for the last 20 years,
Taxol is now a registered trademark of Bristol-Myers Squibb. The copyright of
Bristol-Myers Squibb is recognized when Taxol or taxol is used in this article.

PMID: 9000007 [PubMed - indexed for MEDLINE]




46: Am J Physiol 1996 Dec;271(6 Pt 1):C1957-62

Effects of taxol on isolated rat hepatocyte metabolism.

Manzano A, Roig T, Bermudez J, Bartrons R.

Unitat de Bioquimica, Unitat de Biofisica, Universitat de Barcelona, Spain.

Taxol is a natural product, isolated from Taxus brevifolia, with increasing
clinical applications because of its potent antitumor activity. Although it is
mainly metabolized in the liver, its effect on hepatocyte metabolism has been
scarcely investigated. In this study, the response of isolated rat hepatocytes
to taxol was evaluated by correlating the changes observed in global indexes
such as viability and heat dissipation with those produced in oxygen consumption
and intracellular metabolites (ATP, fructose 2,6-bisphosphate, and lactate). The
results indicate that taxol reduces aerobic metabolism, which induces an
insufficient increase of the ATP via anaerobic glycolysis. Moreover, incubations
of isolated mitochondria with taxol indicate that the respiratory chain is
directly affected by this drug.

PMID: 8997198 [PubMed - indexed for MEDLINE]




47: J Biol Chem 1996 Apr 19;271(16):9201-4

A cDNA clone for taxadiene synthase, the diterpene cyclase that catalyzes the
committed step of taxol biosynthesis.

Wildung MR, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman,
Washington 99164-6340, USA.

The committed step of taxol (paclitaxel) biosynthesis is catalyzed by
taxa-4(5),11(12)-diene synthase, a diterpene cyclase responsible for
transforming the ubiquitous isoprenoid intermediate geranylgeranyl diphosphate
to the parent olefin with a taxane skeleton. To obtain the corresponding cDNA
clone, a set of degenerate primers was constructed based on consensus sequences
of related monoterpene, sesquiterpene, and diterpene cyclases. Two of these
primers amplified a 83-base pair fragment that was cyclase-like in sequence and
that was employed as a hybridization probe to screen a cDNA library constructed
from poly(A)+ RNA extracted from Pacific yew (Taxus brevifolia) stems. Twelve
independent clones with insert size in excess of 2 kilobase pairs were isolated
and partially sequenced. One of these cDNA isolates was functionally expressed
in Escherichia coli, yielding a protein that was catalytically active in
converting geranylgeranyl diphosphate to a diterpene olefin that was confirmed
to be taxa-4(5),11(12)-diene by combined capillary gas chromatography-mass
spectrometry. The sequence specifies an open reading frame of 2586 nucleotides,
and the complete deduced polypeptide, including a long presumptive plastidial
targeting peptide, contains 862 amino acid residues and has a molecular weight
of 98,303, compared with about 79,000 previously determined for the mature
native enzyme. Sequence comparisons with monoterpene, sesquiterpene, and
diterpene cyclases of plant origin indicate a significant degree of similarity
between these enzymes; the taxadiene synthase most closely resembles (46%
identity, 67% similarity) abietadiene synthase, a diterpene cyclase from grand
fir.

PMID: 8621577 [PubMed - indexed for MEDLINE]




48: J Ethnopharmacol 1996 Apr;51(1-3):239-53; discussion 253-4

Camptothecin and taxol: from discovery to clinic.

Wall ME, Wani MC.

Research Triangle Institute, Research Triangle Park, NC 27709-2194, USA.

Camptothecin (CPT) and taxol are secondary metabolites found in the stembark of
Camptotheca acuminata, a native of China, and Taxus brevifolia, found in the
northwest Pacific coastal region of the USA, respectively. The compounds were
isolated through bioassay-guided fractionation of various extracts and through
chromatographic fractions. Their unique and hitherto unknown structures were
elucidated by nuclear magnetic resonance, mass spectrometry and X-ray analysis.
Both compounds have unique mechanisms of antitumor activity; CPT uniquely
inhibits an enzyme, topoisomerase I, involved in DNA replication, while taxol
binds to a protein, tubulin, thus inhibiting cell division. Taxol has been
called the best new anticancer agent developed from natural products, showing
particular efficacy against ovarian cancer. CPT and analogs singly or combined
with cisplatinum show efficacy against solid tumors, breast, lung, and
colorectal, which hitherto have been unaffected by most cancer chemotherapeutic
agents.

Publication Types:
Historical article

PMID: 9213622 [PubMed - indexed for MEDLINE]




49: Biochemistry 1996 Mar 5;35(9):2968-77

Mechanism of taxadiene synthase, a diterpene cyclase that catalyzes the first
step of taxol biosynthesis in Pacific yew.

Lin X, Hezari M, Koepp AE, Floss HG, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman,
99164-6340, USA.

The first committed step in the formation of taxol has been shown to involve the
cyclization of geranylgeranyl diphosphate to taxa-4(5),11(12)-diene. The
formation of this endocyclic diterpene olefin isomer as the precursor of taxol
was unexpected, since the exocyclic isomer, taxa-4(20),11(12)-diene, had been
predicted as the initial product of the taxol pathway on the basis of metabolite
co-occurrence. [1-2H2,20-2H3] and [20-2H3]geranylgeranyl diphosphates were
employed as substrates with the partially purified taxadiene synthase from
Pacific yew (Taxus brevifolia) stems to examine the possibility of a preliminary
cyclization to taxa-4(20),11(12)-diene followed by isomerization to the more
stable endocyclic double bond isomer. GLC-MS analysis of the derived
taxa-4(5),11(12)-diene, via selected ion monitoring of the parent ion and the
P-15 and C-ring fragment ions, compared to those of unlabeled standard, showed
the olefin product to possess a deuterium enrichment essentially identical to
that of the acyclic precursor, thus ruling out the putative isomerization step.
With [4-2H2]geranylgeranyl diphosphate as substrate, similar product analysis
established the enzymatically derived taxa-4(5),11(12)-diene to contain only one
deuterium atom, consistent with direct formation from a taxenyl cation by
deprotonation at C5. (+/-)-Casbene, (+/-)-verticillene, and
(+/-)-taxa-4(20),11(12)-diene were tested as possible olefinic intermediates in
taxa-4(5),11(12)-diene formation by a series of inhibition, trapping, and direct
conversion experiments; no evidence was obtained that these exogenous olefins
could serve as intermediates of the cyclization reaction. However, GLC-MS
analysis of the taxadiene product derived by enzymatic cyclization of
[1-3H]geranylgeranyl diphosphate in 2H2O indicated little incorporation of
deuterium from the medium and suggested a rapid internal proton transfer in a
tightly bound olefinic intermediate. Analysis of the enzymatic product generated
from [10-2H1]geranylgeranyl diphosphate confirmed the intramolecular hydrogen
transfer from C11 of a verticillyl intermediate to the C-ring of
taxa-4(5),11(12)-diene. From these results, a stereochemical mechanism is
proposed for the taxadiene synthase reaction involving the initial cyclization
of geranylgeranyl diphosphate to a transient verticillyl cation intermediate,
with transfer of the C11 alpha-proton to C7 to initiate transannular B/C-ring
closure to the taxenyl cation, followed by deprotonation at C5 to yield the
taxa-4(5),11(12)-diene product directly.

PMID: 8608134 [PubMed - indexed for MEDLINE]




50: J Nat Prod 1996 Mar;59(3):246-50

Taxol production in nodule cultures of Taxus.

Ellis DD, Zeldin EL, Brodhagen M, Russin WA, McCown BH.

Department of Horticulture, University of Wisconsin, Madison 53706, USA.
ELVIS at bcr.bc.ca

The in vitro synthesis of secondary compounds from plants is one source of
scarce and valuable phytopharmaceuticals. Often, some level of cellular or
tissue differentiation is needed for the biosynthesis of many of these important
compounds. Nodule cultures, consisting of cohesive multicellular units
displaying a high degree of differentiation, were initiated from cultured
needles of seven Taxus cultivars (Taxus cuspidata, Taxus x media 'Hicksii',
Taxus x hunnewelliana 'Richard Horsey', Taxus x media 'Dark Green Spreader',
Taxus x media 'L. C. Bobbick', and Taxus brevifolia). Under normal
semicontinuous perfusion culture conditions (bimonthly refreshments to yield
0.2% sucrose), only trace amounts of taxol were detected from Taxus nodule
cultures. However, with an elevated sucrose level (0.5% or 1.0%), taxol
production was enhanced in T. cuspidata nodules to approximately 12 micrograms
taxol/g nodule dry weight (dw). Stimulation of taxol production by elevated
sucrose levels occurred even in the absence of other nutrients. The effect of
increased sucrose on taxol induction does not appear to be due to an osmotic
effect in the medium, suggesting that the increase in taxol production may be
correlated with a metabolic process within the nodules. Although sucrose had a
significant effect on taxol production, taxane precursors or elicitors of
terpenes, as well as other plant secondary metabolites, had no effect on the
production of taxol from these cultures. In addition to taxol, the higher
sucrose levels also induced the production of 7-epi-10-deacetyltaxol,
cephalomannine, and 7-epi-10-deacetylcephalomannine, so that total content of
these taxanes equaled approximately 39 micrograms taxane/g dw nodules.

PMID: 8882426 [PubMed - indexed for MEDLINE]




51: Invest New Drugs 1996;14(1):49-54

New microtubular agents in pediatric oncology.

Seibel NL, Reaman GH.

Department of Hematology/Oncology, Children's National Medical Center,
Washington, D.C, USA.

The taxanes are a new group of anticancer agents with a novel mechanism of
action. They promote microtubule assembly and stabilize the microtubules.
Paclitaxel (Taxol), the first agent in this group in clinical trials was
isolated from the Pacific yew, Taxus brevifolia in 1971. Both in preclinical and
clinical studies, paclitaxel and its semisynthetic analog docetaxel exhibit
significant antitumor activity. This review will provide an overview of the
clinical experience with the group of anti-microtubular agents, the taxanes in
pediatric oncology.

Publication Types:
Review
Review, tutorial

PMID: 8880393 [PubMed - indexed for MEDLINE]




52: Arch Biochem Biophys 1995 Oct 1;322(2):437-44

Purification and characterization of taxa-4(5),11(12)-diene synthase from
Pacific yew (Taxus brevifolia) that catalyzes the first committed step of taxol
biosynthesis.

Hezari M, Lewis NG, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman
99164-6340, USA.

The first step in the biosynthesis of taxol in Pacific yew (Taxus brevifolia) is
the cyclization of the universal diterpene precursor geranylgeranyl
pyrophosphate to taxa-4(5),11(12)-diene. This parent olefin of the taxane
diterpenoids is then elaborated to taxol and related compounds by a complex
series of reactions involving oxidations and side-chain acylations. Cyclization
activity is located principally in yew stem bark and adhering cambium. The
operationally soluble cyclization enzyme was partially purified (approximately
600-fold) by combination of anion exchange, hydrophobic interaction, and
dye-ligand chromatography. Nondenaturing, followed by denaturing, polyacrylamide
gel electrophoresis, in combination with gel permeation chromatography, allowed
the identification of taxadiene synthase as a monomeric protein of molecular
weight 79,000. In general properties (divalent metal ion requirement, kinetic
constants, molecular weight), the taxadiene synthase of Pacific yew is similar
to the diterpene cyclase abietadiene synthase involved in resin acid
biosynthesis in other gymnosperms. However, in pH optimum and response to
inhibitors, these two diterpene cyclases are distinctly different. The activity
(and enzyme protein) levels of Pacific yew taxadiene synthase are much lower
than those for abietadiene synthase of lodgepole pine stem (constitutive) or of
grand fir stem (wound-inducible) and the enzyme is not inducible to higher
levels by stem wounding or elicitor treatment.

PMID: 7574719 [PubMed - indexed for MEDLINE]




53: J Nat Prod 1995 Sep;58(9):1315-24

The search for a taxol-producing microorganism among the endophytic fungi of the
Pacific yew, Taxus brevifolia.

Stierle A, Strobel G, Stierle D, Grothaus P, Bignami G.

Department of Plant Pathology, Montana State University, Bozeman 59717, USA.

Endophytic microbes associated with the Pacific yew tree, Taxus brevifolia, were
examined as potential sources of the anticancer drug taxol [1], a secondary
metabolite of the host organism. The first promising organism found was the
novel fungus, Taxomyces andreanae, which was isolated from the inner bark of a
yew tree growing in northwestern Montana. It appears to produce taxol and other
taxanes in de novo fashion when grown in semi-synthetic liquid media. The
presence of 1 in the fungal extract was confirmed by mass spectrometry,
comparative chromatographic behavior with "yew" taxol, reactivity with
taxol-specific monoclonal antibodies, and 9KB cytotoxicity studies. Both
acetate-1-14C and phenylalanine UL-14C served as precursors of taxol-14C in
fungal culture labeling studies, confirming the de novo synthesis of 1 by the
fungus. Immunoassay techniques are currently being used to screen extracts of
Taxomyces andreanae for new taxanes, and to determine if other endophytic fungi
are taxol producers.

PMID: 7494141 [PubMed - indexed for MEDLINE]




54: J Med Chem 1995 Aug 18;38(17):3411-4

Synthesis and evaluation of some 10-mono- and 2',10-diesters of
10-deacetylpaclitaxel.

Rao KV, Bhakuni RS, Johnson J, Oruganti RS.

Department of Medicinal Chemistry, College of Pharmacy, University of Florida,
Gainesville 32610, USA.

10-Deacetylpaclitaxel, isolated from the bark of Taxus brevifolia, was converted
into paclitaxel in one composite step (trimethylsilylation, acetylation, and
desilylation) and in an overall yield of 80-85%. A series of 10-monoesters of
10-deacetylpaclitaxel are prepared by protection of the 2'- and 7-hydroxyls with
a chloroacetyl group, acylation, and deprotection. Depending on the reaction
conditions, the 10-monoesters, either exclusively or accompanied by the
2',10-diesters, are formed. The mono- and diesters were evaluated using the
L-1210 cell culture assay. The 10-monoesters were comparable to paclitaxel and
more active than the corresponding 2',10-diesters. The
10-[(4-methoxyphenyl)acetyl], 10-(2-nitrobenzoyl), and 10-(phenylacetyl) esters
were found to be somewhat more active than paclitaxel.

PMID: 7650695 [PubMed - indexed for MEDLINE]




55: J Nat Prod 1995 Jul;58(7):1003-14

Taxane-specific monoclonal antibodies: measurement of taxol, baccatin III, and
"total taxanes" in Taxus brevifolia extracts by enzyme immunoassay.

Grothaus PG, Bignami GS, O'Malley S, Harada KE, Byrnes JB, Waller DF, Raybould
TJ, McGuire MT, Alvarado B.

Hawaii Biotechnology Group, Inc., Aiea 96701, USA.

Three monoclonal antibodies with either specificity to taxol or baccatin III, or
cross-reactivity with several common taxanes have been prepared and used to
develop sensitive competitive-inhibition enzyme immunoassays. The hybridomas
producing these monoclonal antibodies were obtained by fusing P3X63Ag8.653
plasmacytoma cells and splenocytes from mice hyperimmunized with keyhole limpet
hemocyanin-7-succinyltaxol or -7-succinylbaccatin III conjugates. Direct and
indirect competitive inhibition enzyme immunoassays were developed with these
monoclonal antibodies and microtiter plates coated with bovine serum albumin
conjugates of the complementary hapten. Detection limits for the direct
competitive inhibition enzyme immunoassays, conducted in buffer containing 10%
MeOH, were 0.6 nM taxol for 3C6 (anti-taxol); 1.1 nM baccatin III for 3H5
(anti-baccatin III); and 0.6 nM taxol or baccatin III for 8A10 (anti-taxane).
The immunoassays accurately detected taxol, baccatin III, and "total taxanes" in
crude MeOH extracts of Taxus brevifolia bark and in hplc fractions of these
extracts.

PMID: 7561893 [PubMed - indexed for MEDLINE]




56: Pharm Res 1995 Jul;12(7):1003-10

A new large-scale process for taxol and related taxanes from Taxus brevifolia.

Rao KV, Hanuman JB, Alvarez C, Stoy M, Juchum J, Davies RM, Baxley R.

Department of Medicinal Chemistry University of Florida, Gainesville 32610-0485,
USA.

PURPOSE. In view of the demonstrated antitumor activity of taxol, ready
availability of the drug is important. The current isolation methods starting
from the bark of Taxus brevifolia involve multiple manipulations, leading to
only taxol and in a yield of 0.01%. A new process consisting of a single reverse
phase column is introduced here, and the present purpose is to determine its
large scale applicability. METHODS. The chloroform extractable fraction of the
bark of T. brevifolia is applied directly on to a C-18 bonded silica column in
25% acetonitrile/water, with elution using a step gradient: 30-50%
acetonitrile/water. On standing, eight different taxanes, including taxol,
crystallize out directly from different fractions. The crystals are filtered and
purified further by recrystallization. Taxol and four other taxanes are purified
this way. The other three require a short silica column. Taxol is freed from
cephalomannine by selective ozonolysis. RESULTS. The large scale process gave
taxol (0.04%), 10-deacetylbaccatin III (0.02%), 10-deacetyl taxol-7-xyloside
(0.1%), 10-deacetyl taxol-C-7-xyloside (0.04%), 10-deacetyl
cephalomannine-7-xyloside (0.006%), taxol-7-xyloside (0.008%), 10-deacetyl taxol
(0.008%) and cephalomannine (0.004%). Processing of the needles of T. brevifolia
gave brevifoliol (0.17%), and that of the wood, 10-deacetyl taxol-C-7-xyloside
(0.01%) and 10-deacetyl taxol-C. CONCLUSIONS. The reverse phase column process
is simpler (one column, direct crystallization), more efficient (eight taxanes
obtained simultaneously) and also gives higher yields.

PMID: 7494794 [PubMed - indexed for MEDLINE]




57: Semin Oncol 1995 Jun;22(3 Suppl 7):28-31

Phase I study of escalating doses of paclitaxel (Taxol) with fixed doses of
ifosfamide, carboplatin, and etoposide.

Boros L, Garrow GC, Asbury RF, Chang AY.

Division of Oncology/Hematology, Genesee Hospital, Rochester, NY 14607-4050,
USA.

The combination of ifosfamide (with mesna uroprotection), carboplatin, and
etoposide (ICE) has demonstrated activity in a variety of cancers. Paclitaxel
(Taxol; Bristol-Myers Squibb Company, Princeton, NJ), a dipertene compound
extracted from the Pacific yew Taxus brevifolia, appeared a good candidate for
study as an addition to the ICE regimen (ICE-T) because of its broad antitumor
activity, its unique mechanism of action, and its toxicity profile, which was
not expected to impact the ICE regimen adversely. In a phase I study, we
evaluated the impact of adding escalating doses of paclitaxel (120 mg/m2, 135
mg/m2, 150 mg/m2, and 175 mg/m2) to the ICE regimen in 13 previously untreated
(with two exceptions) patients with breast cancer, sarcoma, lung cancer, and
adenoid cystic carcinoma. In general, ICE-T was well tolerated with some
myelosuppression observed. Responses were seen at all dose levels. To date, the
maximal tolerated dose of paclitaxel has not been reached; we are currently
administering 175 mg/m2.

Publication Types:
Clinical trial
Clinical trial, phase i

PMID: 7610396 [PubMed - indexed for MEDLINE]




58: Semin Oncol 1995 Jun;22(3 Suppl 6):41-6

A phase II trial of paclitaxel in squamous cell carcinoma of the head and neck
with correlative laboratory studies.

Smith RE, Thornton DE, Allen J.

Division of Hematology and Oncology, Ohio State University College of Medicine,
Columbus, USA.

Head and neck cancer is a major cause of cancer-related deaths. In general,
early stage head and neck cancers are effectively treated with either radiation
or surgery. More advanced tumors often require combined-modality therapy with
both radiation therapy and surgery. Recent investigations indicate that the
addition of chemotherapy may be helpful. One of the newer chemotherapy agents
that appears to have significant activity against head and neck cancer is
paclitaxel (Taxol; Bristol-Myers Squibb Company, Princeton, NJ). Paclitaxel,
originally derived from the western yew Taxus brevifolia, acts by increasing the
stability of microtubules and preventing mitosis. Recent evidence indicates that
the microtubule system is vital to the release of various cytokines and that
modulation of cytokine release may play a major role in the drug's antitumor
activity. We report a phase II trial of paclitaxel in patients with head and
neck cancer, not only to evaluate its clinical effects, but also to study its
effect on cytokine release. We assessed interleukin-1 beta (IL-1 beta) and tumor
necrosis factor-alpha production by using a sensitive enzyme-linked
immunosorbent assay to assess the serum of patients receiving paclitaxel and to
detect cytokine release in vitro. The objective response rate was 36%, with 12%
complete responses and 24% partial responses. No IL-1 beta or tumor necrosis
factor-alpha was detected in patient serum at any time during the infusion of
paclitaxel or after overnight incubation with patient monocytes. No proIL-1 beta
was detected in in vitro cultures of paclitaxel-treated patient monocytes. When
monocytes were stimulated with endotoxin, IL-1 beta production was greatest at
48 hours, suggesting that paclitaxel can prime cells to produce greater
quantities of cytokines after a second stimulus.

Publication Types:
Clinical trial
Clinical trial, phase ii

PMID: 7597432 [PubMed - indexed for MEDLINE]




59: Lung Cancer 1995 Jun;12 Suppl 2:S101-6

Phase II study with paclitaxel for the treatment of advanced inoperable
non-small cell lung cancer.

Gatzemeier U, Heckmayr M, Neuhauss R, Schluter I, Pawel JV, Wagner H, Dreps A.

Department of Thoracic Oncology, Hospital Grosshansdorf, Hamburg, Germany.

Paclitaxel is a plant product isolated from the bark of the Western yew (Taxus
brevifolia) that promotes the formation and stabilization of microtubules. This
leads to growth arrest in the G2/M phase of the cell cycle. Paclitaxel has
demonstrated significant antineoplastic activity in different tumor types, most
notably in ovarian and breast carcinoma. In two Phase II trials (Eastern
Cooperative Oncology Group [ECOG]/M.D. Anderson) in patients with previously
untreated Stage IIIB-IV non-small cell lung cancer (NSCLC), response rates of
21% and 24% were reported. We are performing a Phase II trial investigating the
efficacy of paclitaxel in patients with inoperable Stage IIIB-IV NSCLC.
Forty-three patients were treated, 31 males and 12 females, with a median age of
59 years (range, 29-75), ECOG performance status 0-2, Stage IIIB 30%, Stage IV
70%. Patients were treated every 3 weeks with 225 mg/m2 as a 3-h infusion with
standard premedication. Preliminary efficacy results from 37 patients include
partial remissions in eight (21.6%) patients, no change in 22 (59.5%) and
disease progression in seven (19%) patients. Eight patients are still receiving
therapy. The hematologic toxicities (n = 43) were mild, and no World Health
Organization (WHO) Grade 4 neutropenia was observed. Nonhematologic toxicities
were Grade 1/2 polyneuropathy in 97.6%, Grade 1-3 myalgia/arthralgia in 76%, and
Grade 1-3 nausea/vomiting in 18.6% of the patients. In conclusion, paclitaxel is
an active single agent in this patient population. Mild hematologic toxicities
were observed in the 3-h infusion setting (compared with 24-h infusion) and
therapy was well tolerated.(ABSTRACT TRUNCATED AT 250 WORDS)

Publication Types:
Clinical trial
Clinical trial, phase ii
Multicenter study

PMID: 7551941 [PubMed - indexed for MEDLINE]




60: Ann Oncol 1995 May;6(5):489-94

Paclitaxel-induced neuropathy.

Postma TJ, Vermorken JB, Liefting AJ, Pinedo HM, Heimans JJ.

Department of Neurology, Free University Hospital, Amsterdam, The Netherlands.

BACKGROUND: Paclitaxel (Taxol) is a new antineoplastic agent derived from the
bark of the western yew, Taxus brevifolia, with important activity against
several tumors such as ovarian cancer, breast cancer, lung cancer and head and
neck cancer. Because it promotes microtubule assembly, neuropathy occurs as one
of its toxic side effects. Our purpose was to evaluate the incidence, severity,
dose-dependency and reversibility of paclitaxel-induced neuropathy. PATIENTS AND
METHODS: We prospectively studied 27 patients treated with single-agent
paclitaxel at three dose levels. Paclitaxel was administered by 3-hour
intravenous infusion every three weeks in all patients, and if possible, all
were evaluated neurologically before paclitaxel, after every other cycle and
after discontinuation of therapy. We used a standardized questionnaire and
neurologic examination with emphasis on neuropathic symptoms and signs. The
severity of symptoms and signs was scored. Quantitatively, vibratory perception
threshold (vibrameter) and grip strength (dynamometer) were measured. RESULTS:
Six, 14 and seven patients were treated with 135 mg/m2, 175 mg/m2 and 250-300
mg/m2, respectively. Neuropathic symptoms occurred in 50%, 79% and 100%,
neuropathic signs in 83%, 86% and 100%, and dose-limiting neurotoxicity in 0%,
21% and 71% of patients, respectively. Neurotoxicity progressed with higher
cumulative dose and was more pronounced with higher dose per course.
Paclitaxel-induced neuropathy was predominantly sensory in character, though
minor motor signs were present. Follow-up data of 12 patients after
discontinuation of paclitaxel therapy showed that paclitaxel-induced neuropathy
is at least partially reversible. CONCLUSIONS: Paclitaxel-induced neuropathy is
a dose-dependent phenomenon, occurring with higher cumulative dose and higher
dose per cycle. Using 3-weekly 3-hour infusions of paclitaxel, dose-limiting
neurotoxicity can be expected in patients treated with 250 mg/m2 or more each
cycle.

Publication Types:
Clinical trial

PMID: 7669713 [PubMed - indexed for MEDLINE]




61: J Biol Chem 1995 Apr 14;270(15):8686-90

Cyclization of geranylgeranyl diphosphate to taxa-4(5),11(12)-diene is the
committed step of taxol biosynthesis in Pacific yew.

Koepp AE, Hezari M, Zajicek J, Vogel BS, LaFever RE, Lewis NG, Croteau R.

Institute of Biological Chemistry, Washington State University, Pullman
99164-6340, USA.

The biosynthesis of taxol (paclitaxel) and related taxoids in Pacific yew (Taxus
brevifolia) is thought to involve the cyclization of geranylgeranyl diphosphate
to a taxadiene followed by extensive oxygenation of this diterpene olefin
intermediate. A cell-free preparation from sapling yew stems catalyzed the
conversion of [1-3H]geranylgeranyl diphosphate to a cyclic diterpene olefin
that, when incubated with stem sections, was converted in good radiochemical
yield to several highly functionalized taxanes, including 10-deacetyl baccatin
III and taxol itself. Addition of the labeled olefin to a yew bark extract,
followed by radiochemically guided fractionation, provided sufficient product to
establish the structure as taxa-4(5),11(12)-diene by two-dimensional NMR
spectroscopic methods. Therefore, the first dedicated step in taxol biosynthesis
is the conversion of the universal diterpenoid precursor geranylgeranyl
diphosphate to taxa-4(5),11(12)-diene, rather than to the 4(20),11(12)-diene
isomer previously suggested on the basis of the abundance of taxoids with double
bonds in these positions. The very common occurrence of taxane derivatives
bearing the 4(20)-ene-5-oxy functional grouping, and the lack of oxygenated
derivatives bearing a 4(5)-double bond, suggest that hydroxylation at C-5 of
taxadiene with allylic rearrangement of the double bond is an early step in the
conversion of this olefin intermediate to taxol.

PMID: 7721772 [PubMed - indexed for MEDLINE]




62: J Nat Prod 1995 Apr;58(4):583-5

Brevitaxin, a new diterpenolignan from the bark of Taxus brevifolia.

Arslanian RL, Bailey DT, Kent MC, Richheimer SL, Thornburg KR, Timmons DW, Zheng
QY.

Hauser Chemical Research, Inc., Boulder, Colorado 80301, USA.

The first terpenolignan, brevitaxin [1], has been isolated from the bark of
Taxus brevifolia. Identification was carried out using spectral methods, and the
regiochemistry and cytotoxicity of 1 are discussed.

PMID: 7623034 [PubMed - indexed for MEDLINE]




63: Cancer Res 1995 Feb 15;55(4):753-60

Camptothecin and taxol: discovery to clinic--thirteenth Bruce F. Cain Memorial
Award Lecture.

Wall ME, Wani MC.

Research Triangle Institute, Research Triangle Park, North Carolina 27709-2194.

Camptothecin and taxol are secondary metabolites found, respectively, in the
wood bark of Camptotheca acuminata, a native of China, and Taxus brevifolia,
found in the northwest Pacific coastal region of the United States. The
compounds were isolated guided by bioassay on various extracts and
chromatographic fractions. Their unique and hitherto unknown structures were
elucidated by nuclear magnetic resonance, mass spectrometry, and X-ray analysis.
Both compounds have unique mechanisms of antitumor activity; camptothecin
uniquely inhibits an enzyme, topoisomerase I, involved in DNA replication. Taxol
binds to a protein, tubulin, thus inhibiting cell division. Taxol has been
called the best new anticancer agent developed from natural products, showing
particular efficacy against ovarian cancer. Camptothecin and analogues singly or
combined with cisplatin show efficacy against solid tumors, breast, lung, and
colorectal, which hitherto have been unaffected by most cancer chemotherapeutic
agents.

Publication Types:
Historical article
Review
Review, tutorial

PMID: 7850785 [PubMed - indexed for MEDLINE]




64: Cancer Invest 1995;13(4):381-404

Taxanes: a new class of antitumor agents.

Huizing MT, Misser VH, Pieters RC, ten Bokkel Huinink WW, Veenhof CH, Vermorken
JB, Pinedo HM, Beijnen JH.

Department of Pharmacy, Slotervaart Hospital, Amsterdam, The Netherlands.

Taxanes belong to a new group of antineoplastic agents with a novel mechanism of
action for a cytotoxic drug. They promote microtubule assembly and stabilize the
microtubules. Paclitaxel, the first agent in this group to become available, was
isolated from the Pacific yew, Taxus brevifolia, in 1971. In preclinical and
clinical studies, paclitaxel and its semisynthetic analog docetaxel exhibit
significant antitumor activity. This review deals with the physicochemical
properties, pharmacology, and results of preclinical and clinical trials of the
taxanes.

Publication Types:
Review
Review, tutorial

PMID: 7627725 [PubMed - indexed for MEDLINE]




65: Recenti Prog Med 1994 Dec;85(12):587-90

[Current approaches in the medical treatment of advanced ovarian carcinoma].

[Article in Italian]

Aitini E, Cavazzini G, Cantore M, Rabbi C, Pari F, Mambrini A, Malavasi V,
Smerieri F.

Ovarian cancer is most frequently diagnosed at an advanced stage. In recent
years there has been intense interest in the chemotherapy of this disease. About
cisplatin, the most active agent in the treatment of advanced ovarian cancer,
some questions are only partially answered, as the optimal dose, the duration of
treatment, the role of ciplatin-based two-, three-, or four-drug regimens, the
role of intraperitoneal therapy, the use of old and new drugs in
cisplatin-resistant patients. Carboplatin is currently the most important
cisplatin analogue with a toxicity pattern very different from that of the
parent compound, but, up to date, the combination of these two drugs does not
seem to be any better than standard chemotherapy. Among new drugs, three deserve
particular attention: taxol, a natural produce from the bark of the Pacific yew
Taxus brevifolia, taxotere, a taxoid obtained by semisynthesis from the needles
of the European yew Taxus baccata and gemcitabine, a cytostatic agent with a
close resemblance to cytosine-arabinoside. Anyway, new approaches must continue
to be sought too: among these, probably gene therapy may offer the best
mechanism to overcome both intrinsic and acquired drug resistance.

Publication Types:
Editorial
Review
Review, tutorial

PMID: 7899684 [PubMed - indexed for MEDLINE]




66: Proc Natl Acad Sci U S A 1994 Oct 25;91(22):10690-4

Erratum in:
 Proc Natl Acad Sci U S A 1995 Jan 17;92(2):646

Idiotypic mimicry and the assembly of a supramolecular structure: an
anti-idiotypic antibody that mimics taxol in its tubulin-microtubule
interactions.

Leu JG, Chen BX, Diamanduros AW, Erlanger BF.

Department of Pharmacology, Columbia University, New York, NY 10032.

Taxol, originally extracted from the bark of the western yew, Taxus brevifolia,
is reportedly the first of a new class of anti-cancer agents. It acts by
promoting and irreversibly stabilizing microtubule assembly, thus interfering
with the dynamic processes required for cell viability and multiplication. With
the aim of using immunological techniques to study the mechanism of action of
taxol, a monoclonal anti-idiotypic antibody that mimics taxol was prepared,
using an auto-anti-idiotypic strategy. It and its Fab fragment inhibited the
binding of [3H]taxol to microtubules. Moreover, like taxol, both promoted the
assembly of tubulin into microtubules. These findings provide an example of an
anti-idiotypic antibody capable of assembling an organized supramolecular
structure from soluble cellular components. In addition, it further establishes
the ability of anti-idiotypic antibodies to be functional mimics of ligand
molecules bearing no structural similarity to immunoglobulins. The variable
regions of the antibody have been sequenced. With the exception of the
complementarity-determining region 3, the sequence of the heavy chain variable
region is strikingly similar to that of an anti-idiotypic antibody raised to
anti-insulin. The finding that a polypeptide can mimic taxol raises the
possibility that taxol acts as a peptidomimetic compound that interferes with
the function of an endogenous polypeptide.

PMID: 7840821 [PubMed - indexed for MEDLINE]




67: J Nat Prod 1994 Oct;57(10):1404-10

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of
paclitaxel and related taxanes.

Gimon ME, Kinsel GR, Edmondson RD, Russell DH, Prout TR, Ewald HA.

Texas A&M University, Department of Chemistry, College Station 77843.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has
been demonstrated for the analysis of Taxus brevifolia extracts. The detection
limit for the taxanes contained therein is estimated at 1 pmol using the matrix
4-nitroaniline at a matrix-to-analyte molar ratio of 100:1. Acquisition and
calibration of the mass spectral data requires less than 5 min. The [M+H]+,
[M+Na]+, and [M+K]+ ions provide mol wt confirmation and structurally
significant fragment ions indicative of the various substituent groups located
on the diterpene skeleton are formed.

PMID: 7807125 [PubMed - indexed for MEDLINE]




68: J Nat Prod 1994 Oct;57(10):1391-403

Profiling taxanes in Taxus extracts using lc/ms and lc/ms/ms techniques.

Kerns EH, Volk KJ, Hill SE, Lee MS.

Bristol-Myers Squibb Pharmaceutical Research Institute, Analytical Research and
Development Department, Wallingford, Connecticut 06492-7660.

Analytical methodology developed for the trace analysis of natural products in
crude extracts was utilized for the rapid and systematic structure elucidation
of taxanes in Taxus extracts and process intermediates. This method integrates
analytical hplc, uv detection, uv spectroscopy, full-scan ionspray mass
spectrometry and tandem mass spectrometry on-line. The identification of
structure of a taxane is based on comparing the mass spectrometric
characteristics of the taxane with the paclitaxel substructural "template."
Analytical data for taxanes in preparations from Taxus brevifolia and Taxus
baccata were observed, including chromatographic characteristics using a
standard hplc system, molecular weight, and collision induced dissociation (cid)
tandem mass spectrometry (ms/ms) product ion spectra. The data obtained for 18
taxanes from natural sources using this method provided a taxane profile
database useful for the rapid identification of taxanes in mixtures and samples
of limited quantity.

PMID: 7807124 [PubMed - indexed for MEDLINE]




69: Radiother Oncol 1994 Aug;32(2):124-8

Comment in:
 Radiother Oncol. 1994 Aug;32(2):95-7

Taxol in combination with acute and low dose rate irradiation.

Minarik L, Hall EJ.

Center for Radiological Research, College of Physicians and Surgeons of Columbia
University, New York, NY 10032.

Taxol is an investigational antineoplastic agent which acts by stabilizing
microtubules, thereby preventing normal mitosis. It is believed to block cells
in the G2/M phase of the cell cycle. The drug is a natural product isolated from
the yew, Taxus brevifolia. We have used a cell line derived from human cervical
carcinoma to investigate the combination of Taxol with high and low dose rate
137Cs irradiation. An additive effect for Taxol plus radiation was observed;
supra-additivity or synergism is not suggested by our data. In the cell line
studied, drug concentrations that accumulate cells to some degree in the G2/M
phase of the cycle lead to cell lethality, so that no radiosensitizing effect is
possible. We have also shown that the cytotoxic effect of Taxol is not limited
to the G2/M phase of the cell cycle. In the clinic, Taxol shows promise both as
a chemotherapeutic agent and as a possible adjunct to radiation. The present
work demonstrates the need for further studies of Taxol plus radiation with a
variety of human cell lines of normal and malignant origin.

PMID: 7972905 [PubMed - indexed for MEDLINE]




70: J Nat Prod 1994 Jul;57(7):1017-21

Isolation and structure elucidation of new taxoids from Taxus brevifolia.

Chen R, Kingston DG.

Department of Chemistry, Virginia Polytechnic Institute and State University,
Blacksburg 24061-0212.

An investigation of Taxus brevifolia extracts afforded two taxoids characterized
by the A-nortaxol ring system. These were identified as 7,13-dideacetyl-9,10-
debenzoyltaxchinin C [1] and 9-deacetyl-9-benzoyl-10-debenzoylbrevifoliol [4].
Structures were elucidated by spectroscopic methods, and in particular by
comparison of nmr data with those of taxchinin C and brevifoliol.

PMID: 7964783 [PubMed - indexed for MEDLINE]




71: Phytochemistry 1994 Jul;36(5):1241-4

Seasonal and tissue variation in taxane concentrations of Taxus brevifolia.

Vance NC, Kelsey RG, Sabin TE.

USDA Forest Service, Pacific Northwest Research Station, Corvallis, OR 97331.

Analysis of seven taxanes: taxol, baccatin III, 10-deacetyltaxol,
10-deacetylbaccatin III, 7-xylosyl-10-deacetyltaxol, cephalomannine and
brevifoliol in extracts from bark and foliage of pacific yew (Taxus brevifolia)
showed a gradient of decreasing concentration from stem base to branch tip. This
decrease is attributed to the generally higher concentration of taxanes in the
phloem tissue and the decrease in inner bark thickness from base to branch tip.
Analysis of taxanes extracted from stem bark and needles sampled over a growing
season showed that most taxane concentrations were significantly lower in the
needles than in the bark. Typically, taxane concentrations in bark increased
from May through August; whereas, in needles, concentrations changed little
during that period. Two exceptions were baccatin III, which in the summer
reached levels equivalent to bark, and brevifoliol which increased from March to
August, reaching levels in needles nine times greater than bark.

PMID: 7765363 [PubMed - indexed for MEDLINE]




72: Nature 1994 Feb 17;367(6464):630-4

Comment in:
 Nature. 1994 Feb 17;367(6464):593-4

Total synthesis of taxol.

Nicolaou KC, Yang Z, Liu JJ, Ueno H, Nantermet PG, Guy RK, Claiborne CF, Renaud
J, Couladouros EA, Paulvannan K, et al.

Department of Chemistry, Scripps Research Institute, La Jolla, California 92037.

Taxol, a substance originally isolated from the Pacific yew tree (Taxus
brevifolia) more than two decades ago, has recently been approved for the
clinical treatment of cancer patients. Hailed as having provided one of the most
significant advances in cancer therapy, this molecule exerts its anticancer
activity by inhibiting mitosis through enhancement of the polymerization of
tubulin and consequent stabilization of microtubules. The scarcity of taxol and
the ecological impact of harvesting it have prompted extension searches for
alternative sources including semisynthesis, cellular culture production and
chemical synthesis. The latter has been attempted for almost two decades, but
these attempts have been thwarted by the magnitude of the synthetic challenge.
Here we report the total synthesis of taxol by a convergent strategy, which
opens a chemical pathway for the production of both the natural product itself
and a variety of designed taxoids.

PMID: 7906395 [PubMed - indexed for MEDLINE]




73: J Nat Prod 1994 Feb;57(2):277-86

Determination of taxanes in Taxus brevifolia extracts by tandem mass
spectrometry and high-performance liquid chromatography.

Hoke SH 2nd, Cooks RG, Chang CJ, Kelly RC, Qualls SJ, Alvarado B, McGuire MT,
Snader KM.

Department of Chemistry, Purdue University, West Lafayette, IN 47907.

A tandem mass spectrometric (ms/ms) method using desorption chemical ionization
is described for the quantitation of taxol [1], cephalomannine [2], and baccatin
III [3] found in Taxus brevifolia bark and needle extracts. A parent ion scan
was used to simultaneously determine the weight percentages of 1-3 in bark and
needle samples by the method of standard addition. In an alternative experiment,
the concentration of 1 in the same samples was determined by ms/ms using
trideuterated 10-acetyltaxol [7a] as an internal standard. High-performance
liquid chromatography (hplc) was also used to determine the weight percentages
of 1-3 in the same T. brevifolia bark and needle extracts with an external
standard. The ms/ms method of quantitation by internal standard is the best
overall method of analysis examined. With this method, 1 was quantitated in the
T. brevifolia extracts at the low picomole level with a relative standard
deviation of 17% or better for all samples analyzed with an analysis time of
less than five min per sample. The precision, level of quantitation, and speed
of analysis of the three methods of taxane quantitation are compared.

PMID: 7909835 [PubMed - indexed for MEDLINE]




74: Hematol Oncol Clin North Am 1994 Feb;8(1):121-40

Paclitaxel (Taxol) in breast cancer.

Arbuck SG, Dorr A, Friedman MA.

Cancer Therapy Evaluation Program, National Cancer Institute, Bethesda,
Maryland.

Paclitaxel (Taxol) is a diterpine plant compound that was isolated initially
from the bark of the western yew tree, Taxus brevifolia, but can now be produced
by semisynthesis from a renewable source. Paclitaxel is the first new agent in
the past decade to have confirmed single agent activity in breast cancer in
excess of 50%. A 28% response rate has been reported in doxorubicin-refractory
patients. Ongoing studies include attempts to combine paclitaxel with other
drugs used for breast cancer treatment and with radiation.

Publication Types:
Review
Review, tutorial

PMID: 7908664 [PubMed - indexed for MEDLINE]




75: Cancer Pract 1994 Jan-Feb;2(1):27-33

Paclitaxel: a new antimitotic chemotherapeutic agent.

Gotaskie GE, Andreassi BF.

Paclitaxel, a compound derived from the bark of the Pacific yew, Taxus
brevifolia, is an antimitotic cytotoxic agent with a mechanism of action
different from other antimitotics such as vincristine and vinblastine. Instead
of causing disassembly of microtubules, paclitaxel forms extremely stable and
nonfunctional microtubules, which causes inhibition of many cell functions and
the interruption of the cell cycle. Procurement of paclitaxel has raised
environmental concerns, leading researchers to explore a variety of approaches
to obtain the drug: extraction from yew needles of a paclitaxel precursor that
can be converted to paclitaxel, genetic manipulation of plants to increase
yield, propagation of yew trees, semisynthesis, total chemical synthesis, and
paclitaxel-producing fungus. Clinical trials involving paclitaxel have
demonstrated antineoplastic effects in several classically refractory tumors:
ovarian cancer, breast cancer, non-small-cell lung cancer, and head and neck
tumors. Several toxic effects have been attributed to paclitaxel, including
hypersensitivity reactions, cardiotoxicities, neutropenia, peripheral
neuropathy, mucositis, gastrointestinal toxicities, alopecia, arthralgias, and
myalgias. Clinical implications for these toxicities are addressed.

Publication Types:
Review
Review, tutorial

PMID: 7914453 [PubMed - indexed for MEDLINE]




76: Int J Clin Lab Res 1994;24(1):6-14

Taxol (paclitaxel): a novel anti-microtubule agent with remarkable
anti-neoplastic activity.

Foa R, Norton L, Seidman AD.

Dipartimento di Scienze Biomediche e Oncologia Umana, Sezione Clinica, Turin,
Italy.

Taxol (paclitaxel), an anti-microtubule agent extracted from the needles and
bark of the Pacific yew tree Taxus brevifolia, has shown a remarkable
anti-neoplastic effect in human cancer in phase I studies and early phase II and
III trials thus far conducted. This has been reported primarily in advanced
ovarian and breast cancer, although significant activity has also been
documented in small-cell and non-small-cell lung cancer, head and neck cancers,
and with lower activity in metastatic melanoma. The clinical utilization of
Taxol had been previously somewhat restricted by its limited availability, a
limitation that has recently been overcome by combined efforts of
pharmaceutical, agricultural, and governmental agencies. In this review we shall
address the pre-clinical data which have led to the use of Taxol in man, the
main clinical results thus far obtained, the toxicities associated with its use,
current ongoing trials and future clinical directions of this promising agent.

Publication Types:
Review
Review, academic

PMID: 7910054 [PubMed - indexed for MEDLINE]




77: Clin Oncol (R Coll Radiol) 1994;6(1):40-8

Clinical, toxicological and pharmaceutical aspects of the antineoplastic drug
taxol: a review.

Guchelaar HJ, ten Napel CH, de Vries EG, Mulder NH.

Department of Clinical Pharmacy, Medisch Spectrum Twente, Enschede, The
Netherlands.

Taxol, a diterpene alkaloid isolated from the bark of Taxus brevifolia, has a
unique mechanism of action. The drug promotes the formation of microtubule
polymers in a cell, by reversibly and specifically binding the beta-subunit of
tubulin. Taxol is administered intravenously by a 3-24-hour infusion at 3-week
intervals. Myelosuppression, especially neutropenia, appears to be the dose
limiting toxicity in solid tumours at 200-250 mg/m2. Furthermore, side effects
such as sensory neurotoxicity (with typical numbness, tingling and painful
paraesthesiae in the extremities), diarrhoea and alopecia appear frequently.
Mucositis appears to be the non-haematological dose limiting side effect at 390
mg/m2 that has been determined in patients with leukaemia. Hypersensitivity
reactions, which have been fatal in individual cases, might be schedule
dependent. Furthermore, antiallergic prophylaxis must be given, although this
precaution might not be considered to be fully protective. Phase I studies
performed with combinations of taxol and cisplatin, doxorubicin or
cyclophosphamide have indicated the feasibility of these regimens and show
promise for future investigations. Addition of granulocyte-colony stimulating
factor (G-CSF), aimed at modulating myelosuppressive toxicity, showed in Phase I
studies that the taxol dose could be increased to 250 mg/m2, with peripheral
neuropathy as the dose limiting toxicity. In Phase II studies, taxol has been
shown to be effective, including producing complete tumour remission, in
advanced drug refractory ovarian carcinoma (19%-36% response rate), previously
treated patients with metastatic breast carcinoma (27%-62% response rate),
advanced non-small lung cancer (21%-24% response rate), advanced small cell lung
cancer (37% response rate) and advanced head and neck cancer (34% response
rate).(ABSTRACT TRUNCATED AT 250 WORDS)

Publication Types:
Review
Review, tutorial

PMID: 7909688 [PubMed - indexed for MEDLINE]




78: Isr J Med Sci 1994 Jan;30(1):70-8

Taxol: initial Israeli experience with a novel anticancer agent.

Sulkes A, Beller U, Peretz T, Shacter J, Hornreich G, McDaniel C, Winograd B.

Department of Oncology, Beilinson Medical Center, Petah Tikva, Israel.

Taxol is a novel taxane derivative obtained from the bark of the Pacific yew,
Taxus brevifolia, which has demonstrated substantial antitumor activity in early
clinical trials. Intensive research efforts were necessary to overcome both
supply problems and hypersensitivity reactions to the drug and thus assure its
widespread use. Taxol is active in a variety of neoplasias, including advanced
breast and ovarian tumors resistant to drugs such as doxorubicin and cisplatin,
respectively. We report here the initial experience with taxol in these two
disease entities in Israel, at three institutions within the framework of large
multinational trials. These studies compared a) the use of two dose levels of
taxol, and b) short, 3-h administration vs. a longer 24-h infusion of the drug.
A total of 107 Israeli patients, 38 with ovarian cancer and 69 with breast
cancer, were given 706 courses of taxol. Our results show that the
administration of taxol at doses ranging between 135 and 175 mg/m2 is indeed
feasible and that 3-h infusions are as well tolerated as longer administration.
The main hematological toxicity was leukopenia, which was promptly reversible
and was more pronounced both at the higher dose level and with the more
prolonged infusion. Of the nonhematological side effects, the most prominent
were alopecia, mild nausea and vomiting, limb paresthesias, fatigue and myalgia.
Allergic reactions following routine premedication were mild and infrequent,events did not occur. Taxol is an important addition to the anticancer
chemotherapy armamentarium.

Publication Types:
Clinical trial
Multicenter study
Randomized controlled trial
Review
Review literature

PMID: 7908013 [PubMed - indexed for MEDLINE]




79: Semin Oncol 1993 Aug;20(4 Suppl 3):56-60

Use of paclitaxel (Taxol) in squamous cell carcinoma of the head and neck.

Forastiere AA.

Johns Hopkins Oncology Center, Baltimore, MD 21287-8936.

The identification of new active agents is essential if we are to alter the
current survival rates for patients with squamous cell carcinoma of the head and
neck. Paclitaxel (TAXOL) is a taxane derivative isolated from the bark of the
western yew Taxus brevifolia. The drug has a novel mechanism of action promoting
microtubule assembly and stabilizing the tubulin polymers. One phase II trial of
paclitaxel (250 mg/m2) in head and neck cancer patients is in progress. The
preliminary results of this Eastern Cooperative Oncology Group trial indicate
that paclitaxel has activity against this tumor: two complete and seven partial
responses in 19 patients assessable for response. Grades 3 and 4 neutropenia and
grades 1 and 2 neuropathy were frequently observed toxicities. Future directions
include a National Cancer Institute-sponsored confirmatory trial using the same
dose and schedule of paclitaxel. The European Organization for Research and
Treatment of Cancer plans a randomized comparison of paclitaxel versus weekly
methotrexate. The Eastern Cooperative Oncology Group will pursue testing of
paclitaxel at two different doses (200 and 135 mg/m2) in combination with
cisplatin in patients with advanced head and neck cancer.

Publication Types:
Review
Review, tutorial

PMID: 8102018 [PubMed - indexed for MEDLINE]




80: Semin Oncol 1993 Aug;20(4 Suppl 3):46-9

Overview of paclitaxel (Taxol) in advanced lung cancer.

Ettinger DS.

Johns Hopkins Oncology Center, Baltimore, MD 21287-8936.

Paclitaxel (TAXOL), a novel diterpene plant product isolated from the western
yew Taxus brevifolia, is an active agent in the treatment of lung cancer. In two
studies, the drug produced 21% and 24% objective response rates among patients
with non-small cell lung cancer. A response rate of 34% was reported in a single
trial involving patients with extensive-stage small cell lung cancer. Additional
trials are needed to evaluate single-agent paclitaxel in the treatment of small
cell lung cancer. Studies also are planned to measure the effect of paclitaxel
as a radiosensitizer and in combination regimens with other active agents for
the treatment of lung cancer.

Publication Types:
Review
Review, tutorial

PMID: 8102017 [PubMed - indexed for MEDLINE]




81: Nature 1993 Jul 29;364(6436):464-6

Design, synthesis and biological activity of protaxols.

Nicolaou KC, Riemer C, Kerr MA, Rideout D, Wrasidlo W.

Department of Chemistry, Scripps Research Institute, La Jolla, California 92037.

Taxol is a product isolated from the Pacific yew tree (Taxus brevifolia) and is
a potent microtubule-stabilizing agent which has recently been approved for
treatment of otherwise intractable ovarian cancer. Despite taxol's therapeutic
promise, its aqueous insolubility (< 0.004 mg ml-1) hampers its clinical
application. Here we report the design, synthesis and biological activity of a
series of taxol-releasing compounds (protaxols) with improved pharmacological
properties. These prodrugs were designed to increase their aqueous solubility
and allow for taxol release under basic or physiological conditions. We
demonstrate the stability of these prodrugs at pH < or = 7 and their ability to
release taxol in a basic medium. Taxol-like microtubule-stabilizing activity
appears after the release of taxol. In vitro these prodrugs have cytotoxic
properties against tumour cell lines comparable to those of taxol; moreover,
human plasma catalyses the release of active taxol. These protaxols have greater
potential as anticancer agents than the parent compounds taxol and taxotere
(Fig. 1a).

PMID: 8101355 [PubMed - indexed for MEDLINE]




82: Clin Pharm 1993 Jun;12(6):401-15

Paclitaxel: a new antineoplastic agent for refractory ovarian cancer.

Gregory RE, DeLisa AF.

Oncology Center Pharmacy, Johns Hopkins Hospital, Baltimore, MD 21287-6180.

The chemistry, pharmacology, pharmacokinetics, clinical efficacy, adverse
effects, and dosage of paclitaxel are reviewed. Paclitaxel is a diterpenoid
taxane derivative found in the bark and needles of the western yew, Taxus
brevifolia. Although it shares some structural similarities with other natural
alkaloids, it contains a unique taxane ring. It is also unique in that its
mechanism of action involves interruption of mitosis by promoting and
stabilizing microtubule formation. Paclitaxel doses greater than 60 mg/sq m i.v.
consistently produce mean peak plasma concentrations of 2-13 microM. Liver
metabolism and biliary excretion are probably responsible for most of the drug's
elimination. In clinical trials, paclitaxel has shown substantial activity
against advanced, refractory ovarian cancer, metastatic breast cancer, and lung
cancer. Paclitaxel may slow the course of melanoma and is being investigated in
patients with advanced head and neck cancer and gastrointestinal cancer.
Neutropenia is the major dose-limiting toxic effect of paclitaxel. Other adverse
effects include hypersensitivity reactions, cardiac toxicity, and neurotoxicity.
The recommended dosage for the treatment of recurrent metastatic ovarian cancer
is 135 mg/sq m i.v. given over 24 hours every three weeks. It is recommended
that neutrophil-count and platelet-count recovery be allowed to occur before the
next treatment cycle is begun. Paclitaxel's activity against refractory ovarian
cancer has not been matched since the inclusion of cisplatin in treatment
regimens.

Publication Types:
Review
Review, tutorial

PMID: 7691462 [PubMed - indexed for MEDLINE]




83: Science 1993 Apr 9;260(5105):214-6

Comment in:
 Science. 1993 Apr 9;260(5105):154

Taxol and taxane production by Taxomyces andreanae, an endophytic fungus of
Pacific yew.

Stierle A, Strobel G, Stierle D.

Department of Plant Pathology, Montana State University, Bozeman 59717.

Taxomyces andreanae, a fungal endophyte, was isolated from the phloem (inner
bark) of the Pacific yew, Taxus brevifolia. The fungus is hyphomyceteous and,
when grown in a semi-synthetic liquid medium, produced taxol and related
compounds. Taxol was identified by mass spectrometry, chromatography, and
reactivity with monoclonal antibodies specific for taxol. Both [1-14C]acetic
acid and L-[U-14C]phenylalanine served as precursors of [14C]taxol in fungal
cultures. No taxol was detected in zero-time cultures or in the small agar plugs
used to inoculate the culture flasks.

PMID: 8097061 [PubMed - indexed for MEDLINE]




84: Pharm Res 1993 Apr;10(4):521-4

Taxol and related taxanes. I. Taxanes of Taxus brevifolia bark.

Rao KV.

University of Florida, College of Pharmacy, Department of Medicinal Chemistry,
Gainesville 32610-0485.

The published procedures for the isolation of taxol from the Pacific yew (Taxus
brevifolia) and other species of Taxus are cumbersome, and the yields of taxol
are in the range of 0.0075-0.01%. This paper describes a simple and efficient
procedure for the isolation of taxol and its major natural analogues from the
bark of T. brevifolia consisting of a single chromatographic column (using
silica gel, Florisil, or a reverse-phase C18-silica), followed by
crystallization. Isolated yields of taxol from five "pooled" bark samples
(blended from many different batches by the supplier) were in the range of
0.02-0.04%, and from bark collected from a more restricted locale, yields
reached 0.06%. The procedure also yielded taxol analogues, such as
10-deacetylbaccatin III (0.02-0.04%), 10-deacetyltaxol-7-xyloside (0.06-0.1%),
taxol-7-xyloside (0.005-0.01%), 10-deacetyltaxol (0.01-0.02%),
10-deacetylcephalomannine-7-xyloside (0.006-0.01%), and cephalomannine
(0.005-0.007%). Of these, 10-deacetyltaxol-7-xyloside is the most abundant
taxane in the Pacific yew bark.

PMID: 8097872 [PubMed - indexed for MEDLINE]




85: J Natl Cancer Inst 1993 Mar 3;85(5):384-8

Comment in:
 J Natl Cancer Inst. 1993 Mar 3;85(5):346-7

Phase II study of taxol in patients with untreated advanced non-small-cell lung
cancer.

Murphy WK, Fossella FV, Winn RJ, Shin DM, Hynes HE, Gross HM, Davilla E, Leimert
J, Dhingra H, Raber MN, et al.

Department of Medical Oncology, University of Texas M.D. Anderson Cancer Center,
Houston 77030.

BACKGROUND: Taxol, a complex plant product (a diterpene) extracted from the bark
of Taxus brevifolia, has demonstrated substantial anticancer activity in ovarian
and breast cancers, malignant melanoma, and acute myelogenous leukemia. Due to
allergic reactions in phase I and early phase II studies, use of a 24-hour
infusion of taxol with prophylactic dexamethasone, diphenhydramine, and
cimetidine has been recommended. PURPOSE: In this phase II study, we attempted
to determine the efficacy and toxicity of taxol in patients with advanced (stage
IIIB or IV) non-small-cell lung cancer who had never received chemotherapy.
METHODS: Patients were not excluded because of prior surgery or because of
radiotherapy administered more than 4 weeks before study entry. Taxol was
administered in the hospital at a dose of 200 mg/m2 as an intravenous infusion
over 24 hours and repeated every 3 weeks, provided that patients had recovered
from any toxic effects. Dexamethasone, cimetidine, and diphenhydramine were
given before chemotherapy to prevent hypersensitivity reactions. Therapy was
continued for at least two courses unless there was rapid disease progression
and for at least three courses if no change was observed and no grade 3 or 4
toxic effects occurred. Treatment was continued for six more courses after
maximum response or for two more courses after complete remission but was
discontinued if disease progressed. RESULTS: Of the 27 patients entered in the
study, 25 were assessable for toxic effects and response. One patient had an
allergic reaction that was not life threatening. The overall response rate was
24% (one complete response and five partial responses). An additional seven
patients (28%) had minor response. Granulocytopenia was the dose-limiting toxic
effect, and neutropenic fever occurred in eight of 118 courses. One additional
patient developed neutropenic sepsis with hypotension but recovered with
intensive treatment. CONCLUSIONS: Taxol appears to have activity against
non-small-cell carcinoma of the lung. IMPLICATIONS: A phase II study combining
taxol, etoposide, and cisplatin and using hematopoietic stimulating factors is
now proposed. The optimal dose for combination chemotherapy has yet to be
determined. An important consideration is potential cardiac effects of taxol
with other drugs.

Publication Types:
Clinical trial
Clinical trial, phase ii
Multicenter study

PMID: 8094466 [PubMed - indexed for MEDLINE]




86: Cancer 1993 Jan 15;71(2 Suppl):594-600

Age does not influence taxol dose intensity in recurrent carcinoma of the ovary.

Bicher A, Sarosy G, Kohn E, Adamo DO, Davis P, Jacob J, Chabner BA, Reed E.

Medicine Branch, National Cancer Institute, Bethesda, Maryland 20892.

BACKGROUND. In the treatment of advanced-stage ovarian cancer, it is common
practice to treat elderly patients in a less aggressive fashion than young
patients. This approach is based on the notion that age is associated with poor
patient tolerance to aggressive chemotherapy. Relatively little data exist to
support this contention. The most exciting new chemotherapy agent to be
developed in the last 10 years is taxol, a diterpeniod derivative of the
Northwestern yew Taxus brevifolia. METHODS. The ability to administer
dose-intensive taxol to adult patients with recurrent ovarian cancer was
assessed retrospectively, and the question was asked whether the administered
dose intensity of taxol was unfavorably influenced by age. Forty-eight patients
with recurrent ovarian carcinoma received taxol at an initial dose of 250 mg/m2
every 3 weeks. Age in this cohort ranged from 26 to 74 years, with a median of
55. Twenty-nine percent (14 of 48) of the patients treated were 61 years of age
or greater. Criteria for administration of taxol included a creatinine clearance
of > 45 ml/minute, minimal abnormalities in liver function tests, good
performance status, and the absence of substantial comorbid disease. RESULTS.
Elderly patients in this cohort (age > 60 years) did not differ from younger
patients with respect to administered dose intensity, number of cycles of
therapy administered, or the occurrence of serious or mild toxicities.

Publication Types:
Clinical trial
Clinical trial, phase i
Clinical trial, phase ii

PMID: 7678382 [PubMed - indexed for MEDLINE]




87: J Immunol Methods 1993 Jan 14;158(1):5-15

An enzyme immunoassay for the determination of taxol and taxanes in Taxus sp.
tissues and human plasma.

Grothaus PG, Raybould TJ, Bignami GS, Lazo CB, Byrnes JB.

Hawaii Biotechnology Group, Inc., Aiea 96701.

A rapid and sensitive indirect competitive inhibition enzyme immunoassay (CIEIA)
method has been developed for quantitating taxanes in extracts of Taxus
brevifolia Nutt. tissue and in human plasma. High titer rabbit polyclonal
antibodies (pAb) were raised against a conjugate of 7-succinyltaxol and keyhole
limpet hemocyanin. The presence of taxane analyte competitively inhibited the
binding of the rabbit anti-taxane pAbs to a 7-succinyltaxol-bovine serum albumin
solid phase coating antigen. The CIEIA detected taxol and cephalomannine in
concentrations as low as 0.3 ng/ml (3.5 x 10(-4) microM), but did not detect
baccatin III or 10-deacetylbaccatin III at concentrations below 1000 ng/ml (1.7
microM and 1.8 microM, respectively). This method is useful for estimating the
taxane content of T. brevifolia extracts and may be useful for monitoring the
taxol plasma level of taxol-treated patients.

PMID: 8094087 [PubMed - indexed for MEDLINE]




88: J Natl Cancer Inst Monogr 1993;(15):141-7

Taxol: a history of pharmaceutical development and current pharmaceutical
concerns.

Adams JD, Flora KP, Goldspiel BR, Wilson JW, Arbuck SG, Finley R.

Drug Management and Authorization Section, National Cancer Institute, Bethesda,
MD 20892.

Taxol, a unique diterpene anticancer compound derived from the bark of the Taxus
brevifolia (Pacific yew) tree, induces cytotoxicity by a novel mechanism of
action. An antimicrotubule agent, Taxol promotes the formation and stabilization
of the tubulin polymer unlike other anticancer agents that induce microtubule
disassembly. Because of its poor aqueous solubility, Taxol is formulated as a
solution in 50% Cremophor EL and 50% dehydrated alcohol, USP. The Cremophor EL
and dehydrated alcohol vehicle used in the formulation of Taxol creates some
interesting challenges for its preparation and administration. The
pharmaceutical concerns associated with the preparation and administration of
Taxol are discussed.

Publication Types:
Review
Review, tutorial

PMID: 7912520 [PubMed - indexed for MEDLINE]




89: Cancer Chemother Pharmacol 1993;33(1):48-52

Steady-state plasma concentrations and effects of taxol for a 250 mg/m2 dose in
combination with granulocyte-colony stimulating factor in patients with ovarian
cancer.

Jamis-Dow CA, Klecker RW, Sarosy G, Reed E, Collins JM.

Division of Clinical Pharmacology, Food and Drug Administration, Rockville, MD
20850.

Taxol, a natural product initially isolated from the stem bark of the western
yew Taxus brevifolia, is undergoing phase II and III evaluation due to its
reported activity against a variety of tumors. Previous studies have described
correlations between plasma concentrations and toxicity when taxol is given (a)
at lower doses, (b) for shorter infusion times, and (c) without
granulocyte-colony-stimulating factor. Because the 24-h infusion schedule is
most commonly used in current clinical trials, we attempted to correlate
steady-state plasma concentrations of taxol achieved with a 24-h continuous i.v.
infusion with toxicities and responses. Plasma samples from 48 refractory
ovarian cancer patients were obtained 1-2 h prior to the end of the first taxol
infusion. Taxol concentrations were measured by high-performance liquid
chromatography (HPLC). Interpatient variation of taxol plasma concentrations was
small (mean +/- SD, 0.85 +/- 0.21 microM. Total taxol body clearance was 256 +/-
72 ml min-1 m-2 (mean +/- SD). Taxol plasma protein binding was 88.4% +/- 1.3%
(mean +/- SD, n = 9). Grade 3-4 hematologic toxicity, mainly leukopenia,
occurred in 92% of the patients. The leukopenia was transient and did not
warrant a reduction in the dose of taxol. Grade 3-4 nonhematologic toxicity
occurred in 8% of the patients. No severe hypersensitivity reaction or grade 3-4
neurotoxicity was observed. Correlations of plasma concentrations and toxicities
were not feasible due to the high frequency of hematologic effects and the low
frequency of nonhematologic toxicity. The low degree of interpatient variation
in plasma concentrations hindered the development of correlations with response.

PMID: 7505722 [PubMed - indexed for MEDLINE]




90: J Ethnopharmacol 1992 Aug;37(1):1-11

The pharmacology of extinction.

Huxtable RJ.

Department of Pharmacology, College of Medicine, University of Arizona, Tucson
85724.

It is impossible to predict what compounds of pharmacological interest may be
present in an unexamined species. The extinction of such species may result,
therefore, in the loss of therapeutically significant compounds. The fact that
science will never know what has been lost does not lessen the significance of
the loss. A number of species are discussed to exemplify the potential loss.
Ginkgo biloba is an ancient plant, apparently saved from a natural extinction by
human intervention. From this tree, the ginkgolides have been isolated. These
are potent inhibitors of platelet activating factor and hold promise in the
treatment of cerebral ischemia and brain edema. Two species, the tree Taxus
brevifolia and the leech Hirudo medicinalis, are threatened as a result of human
activity. Both have recently yielded complex compounds of therapeutic
importance. The antitumor agent, taxol, is obtained from T. brevifolia and the
thrombin inhibitor, hirudin, is found in H. medicinalis. Catharanthus roseus,
source of the anticancer agents vincristine and vinblastine, although not
threatened, derives from a largely unexamined but severely stressed ecosystem of
some 5000 plant species. In other examples, ethnobotanical knowledge of certain
plants may be lost while the species survive, as exemplified by the suppression
of the Aztec ethnobotany of Mesoamerica by the invading Spanish. Finally, the
fallacy of the 'snail darter syndrome', where species may be viewed as too
insignificant to worry about, is exposed by consideration of the pharmacological
activities of a sea hare (a shell-less marine mollusc) and various leeches.

Publication Types:
Review
Review, academic

PMID: 1453701 [PubMed - indexed for MEDLINE]




91: J Nat Prod 1992 Apr;55(4):432-40

Effects of genetic, epigenetic, and environmental factors on taxol content in
Taxus brevifolia and related species.

Wheeler NC, Jech K, Masters S, Brobst SW, Alvarado AB, Hoover AJ, Snader KM.

Weyerhaeuser Research Center, Centralia, Washington 98531.

The demand for taxol, a promising cancer chemotherapeutic agent, far exceeds
supply. Presently, taxol is derived from the bark of the Pacific yew, Taxus
brevifolia, a small, slow-growing evergreen tree native to the northwestern
United States. Knowledge of the distribution and magnitude of genetic and
non-genetic sources of variation in taxol content in the genus Taxus is
necessary if supply issues are to be met through plant harvesting. Analytical
determinations of taxol, cephalomannine, and baccatin III in more than 200 trees
representing several populations of T. brevifolia and other yew taxa indicate
that (1) significant variation in taxane content exists among and within
populations and species, (2) taxol levels exceeding those reported for T.
brevifolia bark were found in shoots of individual trees from most taxa studied,
and (3) the season in which samples are collected and handling procedures can
influence taxane content.

PMID: 1355111 [PubMed - indexed for MEDLINE]




92: J Nat Prod 1991 May-Jun;54(3):893-7

Taxinine M, a new tetracyclic taxane from Taxus brevifolia.

Beutler JA, Chmurny GM, Look SA, Witherup KM.

Chemical Synthesis and Analysis Laboratory, PRI/DynCorp. NCI-Frederick Cancer
Research and Development Center, Maryland 21702-1201.

PMID: 1955887 [PubMed - indexed for MEDLINE]




93: J Nat Prod 1990 Sep-Oct;53(5):1249-55

Taxus spp. needles contain amounts of taxol comparable to the bark of Taxus
brevifolia: analysis and isolation.

Witherup KM, Look SA, Stasko MW, Ghiorzi TJ, Muschik GM, Cragg GM.

Program Resources, NCI-Frederick Cancer Research Facility, Maryland 21701.

New sources for the antitumor natural product taxol [1] are needed as demands
for this promising cancer chemotherapeutic agent increase. Presently, supplies
of taxol for clinical studies are obtained from the bark of Taxus brevifolia, a
potentially limited source. Using analytical methods, the needles and stems of
six Taxus species have been examined for taxol [1] and 10-deacetylbaccatin III
[5], a related compound that can be converted to taxol through a semi-synthetic
route. Amounts of taxol comparable to quantities reported from the bark of T.
brevifolia were found in the needles of four of the Taxus species investigated.
In addition, taxol was isolated from the needles of one Taxus species. Thus,
Taxus needles may provide a renewable source of this valuable compound.

PMID: 1981374 [PubMed - indexed for MEDLINE]




94: Cancer 1990 Jun 1;65(11):2478-81

A phase II trial of taxol in metastatic melanoma.

Legha SS, Ring S, Papadopoulos N, Raber M, Benjamin RS.

University of Texas M.D. Anderson Cancer Center, Houston 77025.

Taxol is an investigational new drug which is currently undergoing Phase II
evaluation in various tumors. It is a plant alkaloid extracted from the western
Yew, Taxus brevifolia. In this study, patients with metastatic melanoma who were
previously untreated, received Taxol at a starting dose of 250 mg/m2 delivered
as a continuous intravenous (IV) infusion over 24 hours, at 3-week intervals.
All patients were premedicated with oral dexamethasone and IV diphenhydramine
hydrochloride as prophylaxis against allergic reactions. Three of 25 patients
had a partial response (PR) for a response rate of 12% (CI, 3%-31%). In addition
four patients had objective regression of tumor that failed to qualify for a PR
but these responses were as durable, lasting 6 to 17 months. No patient
experienced acute allergic reactions. The major toxicity of Taxol was
neutropenia requiring dose reduction to 200 mg/m2 in a majority of the patients.
Our data confirm that Taxol has definite although limited activity against
metastatic melanoma.

PMID: 1970948 [PubMed - indexed for MEDLINE]




95: J Nat Prod 1986 Jul-Aug;49(4):665-9

New taxanes from Taxus brevifolia, 2.

Huang CH, Kingston DG, Magri NF, Samaranayake G, Boettner FE.

PMID: 2878063 [PubMed - indexed for MEDLINE]




96: J Clin Oncol 1986 May;4(5):762-6

Phase I study of taxol using a 5-day intermittent schedule.

Legha SS, Tenney DM, Krakoff IR.

Taxol is a plant product derived from the western yew, Taxus brevifolia. We have
conducted a phase I clinical study of Taxol used intravenously daily for 5 days
at 3-week intervals. The starting dose was 5 mg/m2 daily, and the highest dose
used was 40 mg/m2 daily for 5 days. The daily dosage of Taxol was mixed in 250
mL of intravenous fluid and infused over a period of 1 hour. A total of 20
patients with metastatic solid tumors refractory to standard therapy received 45
courses of therapy. Taxol was generally well tolerated and caused no significant
nausea or vomiting. A mild degree of diarrhea was reported by six patients, and
a moderate degree of stomatitis at the higher dose levels developed in four
patients. All patients treated in the dosage range of 20 mg/m2 to 40 mg/m2
experienced nearly complete alopecia. Myelosuppression, predominantly in the
form of leukopenia, was the dose-limiting toxicity. The nadir of leukopenia was
reached between days 8 and 12 followed by complete recovery between days 15 and
21. Leukopenia was first observed following the Taxol dosage level of 20
mg/m2/d, was moderately severe at the dosage level of 30 mg/m2/d, and was severe
at the dosage level of 40 mg/m2/d. No objective tumor regression was observed. A
starting dosage level of 30 mg/m2/d for 5 days is recommended for phase II
trials using this schedule.

PMID: 2871137 [PubMed - indexed for MEDLINE]




97: J Nat Prod 1982 Jul-Aug;45(4):466-70

New taxanes from Taxus brevifolia.

Kingston DG, Hawkins DR, Ovington L.

The isolation of two taxanes from Taxus brevifolia Nutt. is described, together
with the isolation of two acetylated taxol derivatives from an acetylated
fraction from the same plant. The compounds were identified on the basis of
their spectroscopic properties as taxa-4(20),11-diene-2 alpha, 5 alpha, 7 beta,
9 alpha, 10 beta, 13 alpha-hexaol 2,7,9,10,13-pentaacetate (1)
(decinnamoyltaxinine J), 10-deacetylbaccatin III (2), taxol 2',7-diacetate (3),
and 10-deacetyltaxol 2',7-diacetate (4).

PMID: 7130988 [PubMed - indexed for MEDLINE]




98: Cancer Treat Rep 1978 Aug;62(8):1219-22

Cytologic evidence that taxol, an antineoplastic agent from Taxus brevifolia,
acts as a mitotic spindle poison.

Fuchs DA, Johnson RK.

PMID: 688258 [PubMed - indexed for MEDLINE]




99: J Am Chem Soc 1971 May 5;93(9):2325-7

Plant antitumor agents. VI. The isolation and structure of taxol, a novel
antileukemic and antitumor agent from Taxus brevifolia.

Wani MC, Taylor HL, Wall ME, Coggon P, McPhail AT.

PMID: 5553076 [PubMed - indexed for MEDLINE]