Taxus Canadensis

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Lolita O. Zamir - One of the best experts on this subject based on the ideXlab platform.

  • Two new alkaloidal taxoids from the needles of Taxus Canadensis.
    Bioscience biotechnology and biochemistry, 2006
    Co-Authors: Qing-wen Shi, Lolita O. Zamir, Yong-ming Zhao, Teiko Yamada, Hiromasa Kiyota
    Abstract:

    Two new taxanes with a dimethylamino group on the C-5 side chain were identified for the first time in the needles of the Canadian yew, Taxus Canadensis. Their structures were characterized as 7β,10β,13α-triacetoxy-5α-(3′-dimethylamino-3′-phenylpropanoyl)oxy-2α-hydroxy-2(3→20)abeotaxa-4(20),11-dien-9-one (1) and 2α,10β-diacetoxy-9α-hydroxy-5α-(3′-dimethylamino-3′-phenylpropanoyl)oxy-3,11-cyclotax-4(20)-en-13-one (2).

  • First example of conformational exchange in a natural taxane enolate.
    Magnetic resonance in chemistry : MRC, 2005
    Co-Authors: Qing-wen Shi, Francoise Sauriol, Yong Park, V. H. Smith, Gabriel Lord, Lolita O. Zamir
    Abstract:

    A detailed NMR study and full assignments of the 1H- and 13C-NMR spectral data for a novel enolate taxane isolated from Taxus Canadensis needles is described. The structures of two stable conformers were established using a combination of 1D and 2D NMR techniques including 1H, 1H-COSY, gs-HMQC, gs-HMBC, NOESY and T-ROESY. Ab initio quantum mechanical calculations were performed on the B3LYP/6-31G* level of basis set to assist the NMR findings. Copyright © 2005 John Wiley & Sons, Ltd.

  • Taxanes from rooted cuttings of Taxus Canadensis.
    Journal of natural products, 2004
    Co-Authors: Tracy L Petzke, Qing-wen Shi, Orval Mamer, Francoise Sauriol, Lolita O. Zamir
    Abstract:

    A 3,11-cyclotaxane (1), a new epoxytaxane (2), an abeo-taxane (3), and 26 known taxanes were isolated in rooted cuttings of the Canadian yew (Taxus Canadensis) for the first time. Their chemical structures were characterized as 1β,2α,9α-trihydroxy-10β-acetoxy-5α-cinnamoyloxy-3,11-cyclotaxa-4(20)-en-13-one (1), 2α,9α,10β-triacetoxy-11,12-epoxy-20-hydroxytaxa-4-en-13-one (2), and 7β,9α,10β,13α-tetraacetoxy-11(15→1)abeo-taxa-4(20),11-diene-5α,15-diol (3). Metabolite 2 is a new taxane, metabolite 1 has been reported previously in the needles of Taxus baccata,1,2 and metabolite 3 was previously discovered as a biotransformation product3 but is now reported as a natural product for the first time.

  • Taxanes with C-5-amino-side chains from the needles of Taxus Canadensis.
    Phytochemistry, 2004
    Co-Authors: Qing-wen Shi, Francoise Sauriol, Alain Lesimple, Lolita O. Zamir
    Abstract:

    Five taxanes with an amino-side chain on C-5 were identified for the first time in the needles of the Canadian yew, Taxus Canadensis. Their structures were characterized as 2alpha,7beta,9alpha,10beta,13-pentaacetoxy-11beta-hydroxy-5alpha-(3'-N,N-dimethylamino-3'-phenyl)-propionyloxytaxa-4(20),12-diene (1), 2alpha,9alpha-dihydroxy-10beta,13alpha-diacetoxy-5alpha-(3'-methylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene (2), 2alpha17-dihydroxy-9alpha,10beta,13alpha-triacetoxy-5alpha-(3'-N,N-dimethylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene (3), 2alpha-hydroxy-7beta,9alpha,10beta,13alpha-tetraacetoxy-5alpha-(2'-hydroxy-3'-N,N-dimethylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene (4), and 9alpha-hydroxy-2alpha,10beta,13alpha-triacetoxy-5alpha-(3'-N,N-dimethylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene (5) on the basis of 1D-, 2D-NMR spectroscopic data and high-resolution fast atom bombardment MS analyses. Metabolite (1) was isolated from the needles of the Canadian yew for the first time but had previously been detected in the stems of the Japanese yew, whereas taxanes (2-5) are only now reported. Metabolite (3) is the first reported nitrogen-containing taxane with a 17-hydroxyl substitution.

  • Canadensenes: Natural and semi-synthetic analogues
    Canadian Journal of Chemistry, 2003
    Co-Authors: Qing-wen Shi, Orval Mamer, Francoise Sauriol, Anastasia Nikolakakis, Lolita O. Zamir
    Abstract:

    The first bicyclic taxanes isolated in the needles of the Canadian yew were named canadensene 1 and 5-epi-canadensene 2. Four additional analogues (3–6), isolated previously in Taxus chinensis and Taxus mairei, and a new natural 5-epi-canadensene analog 7 with a C-20-cinnamoyl group, were characterized for the first time in the needles of Taxus Canadensis. A bicyclic derivative 8 with a docetaxel side chain on C-20 was synthesized using 5-epi-canadensene 2 as starting material. The lack of bioactivities of these bicyclic analogues (tubulin polymerization and cytotoxicities against human cancer cell lines) is discussed.Key words: Taxus Canadensis, Taxaceae, taxanes, natural products, semi-synthesis.

Francoise Sauriol - One of the best experts on this subject based on the ideXlab platform.

Qing-wen Shi - One of the best experts on this subject based on the ideXlab platform.

  • Two New Taxane-Glycosides from the Needles of Taxus Canadensis.
    ChemInform, 2016
    Co-Authors: Hui-min Yan, Qing-wen Shi, Manli Zhang, Francoise Sauriol, Hiromasa Kiyota, Mei Dong
    Abstract:

    Two new taxane-glycosides are isolated from the methanolic extract of the needles of T.Canadensis.Their structures are evaluated by 1D and 2D NMR data analysis and high-resolution fast atom bombardment mass spectroscopy.

  • Two new taxane-glycosides from the needles of Taxus Canadensis
    Zeitschrift für Naturforschung B, 2015
    Co-Authors: Jin Wang, Qing-wen Shi, Manli Zhang, Francoise Sauriol, Hiromasa Kiyota, Hui-min Yan, Mei Dong
    Abstract:

    AbstractTwo minor taxane glycosides were isolated for the first time from the needles of Taxus Canadensis. Their structures were characterized as 2α,5α-diacetoxy-10β-(6′-O-acetyl-β-d-glucopyranosyl)oxy-14β-[(2′R,3′S)-3′-hydroxy-2′-methylbutanoyl]oxytaxa-4(20),11-diene (1) and 2α,14β-diacetoxy-10β-(β-d-glucopyranosyl)oxytaxa-4(20),11-dien-5β-ol (2) on the basis of 1D and 2D NMR data analysis and confirmed by high-resolution fast atom bombardment mass spectrometry.

  • MALDI-MS of Pseudo-Alkaloid Taxanes from Taxus Canadensis
    Chemistry of Natural Compounds, 2014
    Co-Authors: Senlin Hou, Mei Dong, Tiankun Ren, Zhenming Dong, Jie Yang, Qing-wen Shi
    Abstract:

    Six previously reported taxanes with alkaloid side chains were isolated from the methanol extract of the needles of Taxus Canadensis. The structures were established on the basis of 1D and 2D NMR spectroscopic data. The identification of different alkaloid side chains in these taxanes by Matrix Assisted Laser Desorption Mass Spectrometry (MALDI-MS) was discussed.

  • A New Taxane with a 4β,20-Epoxy Ring from the Rooted Cuttings of Taxus Canadensis
    Chemistry of Natural Compounds, 2013
    Co-Authors: Dong Yao, Qing-wen Shi, Francoise Sauriol, Hong Feng Zhang, Yun Huang, Hiromasa Kiyota
    Abstract:

    A new taxane, 2α,5α,10β-triacetoxy-4β,20-epoxytax-11-ene-1β,7β,9α,13α-tetraol (1), was isolated from the rooted cuttings of the Canadian yew, Taxus Canadensis.

  • Chemical Studies on Taxus Canadensis
    Chemistry & biodiversity, 2013
    Co-Authors: Fang Qin, Si-ming Wang, Rui-xia Guo, Yue-feng Zhang, Qing-wen Shi
    Abstract:

    A series of new taxanes, 1–93, have been isolated, together with 37 known taxoids including Taxol® (paclitaxel) and cephalomannine, from the Canadian yew, Taxus Canadensis (Taxaceae) in the past 30 years. These new taxoids possess various skeletons containing 5/7/6, 6/10/6, 6/5/5/6, 6/8/6, and 6/12 ring systems and six new taxanes with four novel skeletons, i.e., a taxane with a 6/6/8/6 ring system, a taxane with a [3.3.3] propellane skeleton, three taxanes with [3.3.3] [3.4.5] dipropellane sytems, as well as a novel taxane with a unique 5/5/4/6/6/6 hexacyclic skeleton, containing a unique [3.3.2] propellane, were isolated for the first time from natural sources. It should be emphasized that 13-acetyl-9-dihydrobaccatin III, a very useful starting material for the semisynthesis of Taxol® and Taxotere®, represents the most abundant taxane in the needles of this yew tree. These findings establish the above mentioned yew tree as significantly different from the remaining species. On the other hand, some chemical modifications on the taxanes isolated from this plant were carried out.

Orval Mamer - One of the best experts on this subject based on the ideXlab platform.

  • Taxanes from rooted cuttings of Taxus Canadensis.
    Journal of natural products, 2004
    Co-Authors: Tracy L Petzke, Qing-wen Shi, Orval Mamer, Francoise Sauriol, Lolita O. Zamir
    Abstract:

    A 3,11-cyclotaxane (1), a new epoxytaxane (2), an abeo-taxane (3), and 26 known taxanes were isolated in rooted cuttings of the Canadian yew (Taxus Canadensis) for the first time. Their chemical structures were characterized as 1β,2α,9α-trihydroxy-10β-acetoxy-5α-cinnamoyloxy-3,11-cyclotaxa-4(20)-en-13-one (1), 2α,9α,10β-triacetoxy-11,12-epoxy-20-hydroxytaxa-4-en-13-one (2), and 7β,9α,10β,13α-tetraacetoxy-11(15→1)abeo-taxa-4(20),11-diene-5α,15-diol (3). Metabolite 2 is a new taxane, metabolite 1 has been reported previously in the needles of Taxus baccata,1,2 and metabolite 3 was previously discovered as a biotransformation product3 but is now reported as a natural product for the first time.

  • Canadensenes: Natural and semi-synthetic analogues
    Canadian Journal of Chemistry, 2003
    Co-Authors: Qing-wen Shi, Orval Mamer, Francoise Sauriol, Anastasia Nikolakakis, Lolita O. Zamir
    Abstract:

    The first bicyclic taxanes isolated in the needles of the Canadian yew were named canadensene 1 and 5-epi-canadensene 2. Four additional analogues (3–6), isolated previously in Taxus chinensis and Taxus mairei, and a new natural 5-epi-canadensene analog 7 with a C-20-cinnamoyl group, were characterized for the first time in the needles of Taxus Canadensis. A bicyclic derivative 8 with a docetaxel side chain on C-20 was synthesized using 5-epi-canadensene 2 as starting material. The lack of bioactivities of these bicyclic analogues (tubulin polymerization and cytotoxicities against human cancer cell lines) is discussed.Key words: Taxus Canadensis, Taxaceae, taxanes, natural products, semi-synthesis.

  • Semi-Synthesis of an O-Glycosylated docetaxel analogue
    Bioorganic & medicinal chemistry, 2003
    Co-Authors: Anastasia Nikolakakis, Francoise Sauriol, Orval Mamer, Khadidja Haidara, Lolita O. Zamir
    Abstract:

    A 7β-O-glycosylated docetaxel analogue was semi-synthesized from 9-dihydro-13-acetylbaccatin III, the most abundant taxane isolated from the needles of Taxus Canadensis. It was shown to be more bioactive than paclitaxel according to the tubulin assay. It had a reduced potency in the MCF7 cell line cytotoxicity assay compared to paclitaxel, but it demonstrated better activity against the drug resistant cell line MCF7-ADR. In addition, the presence of one sugar moiety on C-7 doubled the water solubility versus that of paclitaxel.

  • New minor taxanes analogues from the needles of Taxus Canadensis
    Bioorganic & medicinal chemistry, 2003
    Co-Authors: Qing-wen Shi, Orval Mamer, Francoise Sauriol, Lolita O. Zamir
    Abstract:

    Seven new taxanes were isolated from the needles of the Canadian yew: unusual functional groups, positions and/or stereochemical features are described. Their chemical structures were rigorously characterized by detailed high resolution NMR analyses and confirmed by high resolution Fast Atom Bombardment Mass Spectrometry. Unlike paclitaxel and Taxuspine D, these taxanes had no effect on tubulin assembly.

  • New taxanes from the needles of Taxus Canadensis.
    Journal of natural products, 2003
    Co-Authors: Qing-wen Shi, Orval Mamer, Francoise Sauriol, Lolita O. Zamir
    Abstract:

    Ten new taxanes were isolated from the methanol extract of the needles of the Canadian yew, Taxus Canadensis. On the basis of their spectral analysis, their structures were established as 9alpha-hydroxy-2alpha,7alpha,10beta-triacetoxy-5alpha-cinnamoyloxy-3,11-cyclotaxa-4(20)-en-13-one (1), 9alpha,10beta-diacetoxy-5alpha-cinnamoyloxy-3,11-cyclotaxa-4(20)-en-13-one (2), 9alpha,20-dihydroxy-2alpha,10beta,13alpha-triacetoxytaxa-4(5),11(12)-diene (3), 2alpha,9alpha,10beta-triacetoxy-20-cinnamoyloxy-11,12-epoxytaxa-4-en-13-one (4), 9alpha-hydroxy-2alpha,10beta,13alpha-triacetoxy-5alpha-(3'-methylamino-3'-phenyl)-propionyloxytaxa-4(20),11-diene (5), 2alpha,10beta-diacetoxy-5alpha,9alpha-dihydroxytaxa-4(20),11-dien-13-one (6), 2alpha,9alpha-diacetoxy-5alpha,10beta-dihydroxytaxa-4(20),11-dien-13-one (7), 5alpha,9alpha-dihydroxy-2alpha,10beta,13alpha-triacetoxytaxa-4(20),11-diene (8), 5alpha,10beta-dihydroxy-2alpha,9alpha,13alpha-triacetoxytaxa-4(20),11-diene (9), and 7beta,11beta-dihydroxy-2alpha,9alpha,10beta,13-tetraacetoxy-5alpha-cinnamoyloxytaxa-4(20),12-diene (10). Taxane 1 is the first example of a 3,11-cyclotaxane with a 7-epi-alpha-oxygenated group. Taxane 4 is the first taxane with a C-11,12-epoxide ring as well as a C-4(5)-endo-double bond. Taxanes with a 12(13) double bond as in 10 instead of the usual 11(12) double bond have been found so far only in the needles, stem, and seeds of the Japanese yew.

Taber D. Allison - One of the best experts on this subject based on the ideXlab platform.

  • Further studies on sex expression in Taxus Canadensis Marshall1
    Journal of The Torrey Botanical Society, 2008
    Co-Authors: Taber D. Allison
    Abstract:

    Abstract Sex expression was examined in two island populations of the monoecious Taxus Canadensis at the Apostle Island National Lakeshore, USA. Long-term observations of tagged plants supported earlier published conclusions based on comparisons among populations of the effect of size and age on sex expression, measured as standardized phenotypic gender. As populations of plants increased in size and age, strobilus ratios became more male-biased and gender concordance increased. Male-biased plants remained male-biased and female-biased plants remained female-biased; gender switching was not a feature of either of these populations. The two Taxus Canadensis populations were mapped to examine spatial dispersion of plants and plant attributes, such as size, strobilus production, and gender. Frequency distribution of gender in both populations was significantly bimodal supporting earlier studies; this conclusion held even when small (typically male) plants with unstable gender were excluded from the analysis....

  • Reproductive biology of the monoecious clonal shrub Taxus Canadensis
    Bulletin of the Torrey Botanical Club, 1996
    Co-Authors: Paul Wilson, Michelle Buonopane, Taber D. Allison
    Abstract:

    WILSON, P. (Department of Biology, California State University, 18111 Nordhoff Street, Northridge, CA 91330-8303), M. BUONOPANE (Department of Biology, Bates College, Lewiston, ME 04240) AND T D. ALLISON (Department of Forestry and Wildlife, University of Massachusetts, Amherst, MA 01002). Reproductive biology of the monoecious clonal shrub Taxus Canadensis. Bull. Torrey Bot. Club 123: 7-15 1996.-Strobilus production, pollination, and maturation were studied in Taxus Canadensis, a procumbent clonally-spreading shrub. Plants that produced many cones had greater shoot growth; no obvious tradeoff between sexual effort and vegetative growth was observed. T Canadensis is monoecious, but plants showed considerable variation in phenotypic gender. Because related species are dioecious, we hypothesize that T. Canadensis evolved from a dioecious ancestor. Monoecy may have been favored as a means of assuring pollination via selfing; the proportion of ovules pollinated was positively correlated with the number of male cones on a plant. Selfing may be at the cost of inbreeding depression; 26% of the female cones aborted, about twice the percentage of the dioecious Taxus cuspidata. Application of nutrient fertilizer did not reduce the abortion percentage. Seed and aril maturation in T. Canadensis occurred over a three month period, much more gradually than in T cuspidata. Removal of the seeds, probably by antagonistic rodents, was very rapid and thorough in T Canadensis. Asynchronous ripening and monoecy may help reduce seed predation by rodents by reducing the conspicuousness of "fruiting" displays relative to the dioecious species.

  • Self-fertility in Canada yew (Taxus Canadensis Marsh.)'
    Bulletin of the Torrey Botanical Club, 1993
    Co-Authors: Taber D. Allison
    Abstract:

    in Canada yew (Taxus Canadensis Marsh.). Bull. Torrey Bot. Club 120: 115120. 1993.-Self-fertility was examined in a Canada yew (Taxus Canadensis) population in southeastern Minnesota. Bagged yew branches and unbagged control branches showed no significant differences in seed production, proportion of pollinated seeds that matured, or seed masses. Greater than 99% of male strobili were located on current growth, but a significant proportion of female strobili (> 33%) were located on growth two years or older. There was no consistent trend in location of these strobilus types on higher or lower branches. Results from other studies examining consequences of monoecy in Canada yew support the conclusions of this study that Canada yew is self-fertile and that self-pollination enhances seed production when pollen is limiting.

  • The influence of deer browsing on the reproductive biology of Canada yew (Taxus Canadensis marsh.). III: Sex expression
    Oecologia, 1992
    Co-Authors: Taber D. Allison
    Abstract:

    Browsed Canada yew (Taxus Canadensis) populations have a higher proportion of males and a lower proportion of monoecious plants than unbrowsed yew populations. The proportion of monoecious plants increases with time following protection from browsing suggesting that deer browsing causes male-biased sex expression in Canada yew. In contrast, results from comparing browsed and unbrowsed populations, exclosure studies, and browse simulation experiments indicate that strobilus ratios and phenotypic gender of browsed yews may be female-biased. In part, these results correspond to the influence of size on sex expression in Canada yew; small yews tend to be male, but if monoecious, have female-biased strobilus ratios. Large yews are monoecious, but have male-biased strobilus ratios. There is, however, no consistent relationship between size and gender in Canada yew, suggesting that in some circumstances, yews shift allocation to female function in response to browsing.

  • The influence of deer browsing on the reproductive biology of Canada yew (Taxus Canadensis marsh.)
    Oecologia, 1992
    Co-Authors: Taber D. Allison
    Abstract:

    Browsed Canada yew ( Taxus Canadensis ) populations have a higher proportion of males and a lower proportion of monoecious plants than unbrowsed yew populations. The proportion of monoecious plants increases with time following protection from browsing suggesting that deer browsing causes male-biased sex expression in Canada yew. In contrast, results from comparing browsed and unbrowsed populations, exclosure studies, and browse simulation experiments indicate that strobilus ratios and phenotypic gender of browsed yews may be female-biased. In part, these results correspond to the influence of size on sex expression in Canada yew; small yews tend to be male, but if monoecious, have female-biased strobilus ratios. Large yews are monoecious, but have male-biased strobilus ratios. There is, however, no consistent relationship between size and gender in Canada yew, suggesting that in some circumstances, yews shift allocation to female function in response to browsing.

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