Yew

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Hideyuki Shigemori - One of the best experts on this subject based on the ideXlab platform.

  • Bioactive taxoids from the Japanese Yew Taxus cuspidata
    Medicinal research reviews, 2002
    Co-Authors: Jun'ichi Kobayashi, Hideyuki Shigemori
    Abstract:

    A series of new taxoids, named taxuspines A-H and J-Z (1-25) and taxezopidines A-H and J-L (26-36), have been isolated together with 37 known taxoids (37-73) including paclitaxel (53) from the Japanese Yew, Taxus cuspidata Sieb. et Zucc. (Taxaceae). These new taxoids possess various skeletons containing 5/7/6, 6/10/6, 6/5/5/6, 6/8/6, or 6/12-membered ring systems. Among the new taxoids, some non-taxol-type compounds remarkably reduced CaCl(2)-induced depolymerization of microtubules, or increased cellular accumulation of vincristine in multidrug-resistant tumor cells as potent as verapamil. On the other hand, chemical derivatization of taxinine (37), one of major taxoids obtained from this Yew, led to the discovery of unusual reactions of taxinine derivatives. Here we describe our recent results on the isolation, structure elucidation, and bioactivity of these new and known taxoids and the formation of unexpected products of the unusual reactions of taxinine.

  • taxuspines a c new taxoids from japanese Yew taxus cuspidata inhibiting drug transport activity of p glycoprotein in multidrug resistant cells
    ChemInform, 1994
    Co-Authors: Jun'ichi Kobayashi, Hideyuki Shigemori, Aya Ogiwara, Hirokazu Hosoyama, Naotoshi Yoshida, Takuma Sasaki, Shigeo Iwasaki, Mikihiko Naito, Takashi Tsuruo
    Abstract:

    Abstract Three new taxoids, taxuspines A ∼ C (1 ∼ 3), possessing different skeletons from usual taxane diterpenoids consisting of a 6/8/6-membered ring system have been isolated together with known taxoids (4 ∼ 12) from stems of the Japanese Yew Taxus cuspidata Sieb. et Zucc. and the structures elucidated on the basis of spectroscopic data. Most of the taxoids increased cellular accumulation of vincristine in multidrug-resistant tumor cells, while taxol (12) did not show such an activity. The taxoids (1 ∼ 11) showed no or weak cytotoxicity and among them, 2 and 6 reduced appreciably CaCI2-induced depolymerization of microtubules. These results suggest that some taxoids may be useful for overcoming multidrug resistance in tumor cells.

Jun'ichi Kobayashi - One of the best experts on this subject based on the ideXlab platform.

  • Bioactive taxoids from the Japanese Yew Taxus cuspidata
    Medicinal research reviews, 2002
    Co-Authors: Jun'ichi Kobayashi, Hideyuki Shigemori
    Abstract:

    A series of new taxoids, named taxuspines A-H and J-Z (1-25) and taxezopidines A-H and J-L (26-36), have been isolated together with 37 known taxoids (37-73) including paclitaxel (53) from the Japanese Yew, Taxus cuspidata Sieb. et Zucc. (Taxaceae). These new taxoids possess various skeletons containing 5/7/6, 6/10/6, 6/5/5/6, 6/8/6, or 6/12-membered ring systems. Among the new taxoids, some non-taxol-type compounds remarkably reduced CaCl(2)-induced depolymerization of microtubules, or increased cellular accumulation of vincristine in multidrug-resistant tumor cells as potent as verapamil. On the other hand, chemical derivatization of taxinine (37), one of major taxoids obtained from this Yew, led to the discovery of unusual reactions of taxinine derivatives. Here we describe our recent results on the isolation, structure elucidation, and bioactivity of these new and known taxoids and the formation of unexpected products of the unusual reactions of taxinine.

  • taxuspines a c new taxoids from japanese Yew taxus cuspidata inhibiting drug transport activity of p glycoprotein in multidrug resistant cells
    ChemInform, 1994
    Co-Authors: Jun'ichi Kobayashi, Hideyuki Shigemori, Aya Ogiwara, Hirokazu Hosoyama, Naotoshi Yoshida, Takuma Sasaki, Shigeo Iwasaki, Mikihiko Naito, Takashi Tsuruo
    Abstract:

    Abstract Three new taxoids, taxuspines A ∼ C (1 ∼ 3), possessing different skeletons from usual taxane diterpenoids consisting of a 6/8/6-membered ring system have been isolated together with known taxoids (4 ∼ 12) from stems of the Japanese Yew Taxus cuspidata Sieb. et Zucc. and the structures elucidated on the basis of spectroscopic data. Most of the taxoids increased cellular accumulation of vincristine in multidrug-resistant tumor cells, while taxol (12) did not show such an activity. The taxoids (1 ∼ 11) showed no or weak cytotoxicity and among them, 2 and 6 reduced appreciably CaCI2-induced depolymerization of microtubules. These results suggest that some taxoids may be useful for overcoming multidrug resistance in tumor cells.

K Patrick C Low - One of the best experts on this subject based on the ideXlab platform.

  • lee kuan Yew and his key leadership ways
    Social Science Research Network, 2011
    Co-Authors: K Patrick C Low
    Abstract:

    In this article, a university don discusses the key leadership ways of Singapore’s first Prime Minister Lee Kuan Yew, the Father of Modern Singapore, a cosmopolitan Citystate. His communication style and ways are also examined. The various skills, qualities and traits that Lee Kuan Yew has, over the years shown from his not-in-power days (colonial days) to his present Minister Mentor position, can, in fact, be emulated by businesses and business leaders who want to succeed and/or even excel.

Gennadi Gudi - One of the best experts on this subject based on the ideXlab platform.

  • infrared and raman spectroscopic methods for characterization of taxus baccata l improved taxane isolation by accelerated quality control and process surveillance
    Talanta, 2015
    Co-Authors: Gennadi Gudi, Andrea Krahmer, I Koudous, Jochen Strube, Hartwig Schulz
    Abstract:

    Different Yew species contain poisonous taxane alkaloids which serve as resources for semi-synthesis of anticancer drugs. The highly variable amounts of taxanes demand new methods for fast characterization of the raw plant material and the isolation of the target structures during phyto extraction. For that purpose, applicability of different vibrational spectroscopy methods in goods receipt of raw plant material and in process control was investigated and demonstrated in online tracking isolation and purification of the target taxane 10-deacetylbaccatin III (10-DAB) during solvent extraction. Applying near (NIRS) and mid infrared spectroscopy (IRS) the amount of botanical impurities in mixed samples of two different Yew species (R2=0.993), the leave-to-wood ratio for Taxus baccata material (R2=0.94) and moisture in dried Yew needles (R2=0.997) can be quantified. By partial least square analysis (PCA) needles of different Coniferales species were successfully discriminated by Attenuated Total Reflectance-Fourier-Transform Infrared Spectroscopy (ATR-FT-IR). The analytical potential of ATR-FT-IR and Fourier Transform-Raman Spectroscopy (FT-RS) in process control of extraction and purification of taxanes is demonstrated for determination of the water content in methanolic Yew extracts (R2=0.999) and for quantification of 10-DAB (R2=0.98) on a highly sophisticated level. The decrease of 10-DAB in the plant tissue during extraction was successfully visualized by FT-IR imaging of thin cross sections providing new perspectives for process control and design.

Carl Erik Olsen - One of the best experts on this subject based on the ideXlab platform.

  • constituents of the Yew trees
    Phytochemistry, 1999
    Co-Authors: V S Parmar, Amitabh Jha, Kirpal S Bisht, Poonam Taneja, S K Singh, Ashok Kumar, Rajni Jain, Carl Erik Olsen
    Abstract:

    Yew trees, taxonomically classified under the genus Taxus, are sources of a number of physiologically active compounds of different classes. Taxane derivatives with various carbon skeletons, lignans, flavonoids, steroids and sugar derivatives have been isolated from different Taxus species. Compounds isolated from the genus Taxus between 1908 and December 1997 have been comprehensively reviewed.