STUDIES ON THE CHEMICAL CONSTITUENTS OF TAXUS YUNNANENSIS
WM Chen, PL Zhang, B Wu and QT Zheng (Institute of Materia Medica, Chinese Academy of Medical Sciences, Beijing 100050)
The ethanolic extract of the bark of Taxus yunnanensis Cheng et L.K. Fu. showed significant antineoplastic effect on the transplantable tumors in mice. The life survival ofP388 leukemic bearing mice was increased (84%)and the growth of B_(16) melanoma in mice was inhibited (53%).From this extract eight taxane diterpenoids and taxane alkaloids have been isolated.Seven of them have been identified as taxinine E(1), taxinine J(2), 1-acetoxy-5-deacetyl baccatin Ⅰ(4 ), baccatin Ⅲ(5), taxol (6), cephalomannine (7), 7 -xylosyl - 10 -deacetyl taxol (8)from their physical and spectroscopic properties. A new taxane diterpenoid, named yunnanxanc (3) was elucidated as taxa-4 (20), 11 - diene- 2α, 5α, 10β,14β- tetraoln2α,5α,10β- triacetaten - 14β-α - methyl-β- hydroxylbutyratebyhighfield ~1H NMR, ~(13)C NMR, ~1H-~1HCOSY, ~(13)C-~1HCOSY, ~(13)C-~1HCOLOC and X-ray analysis. It showed the inhibitory effect on A_(2780) DDP, KB and HCT-8 cell line in vitro. All of the eight compounds were isolated from this species for the first time.