| Abstrakt: |
Five new taxoids, including a new 23→20abeotaxane with a 6106membered ring system and four 3,8secotaxanes having a 612membered ring system, were isolated from an acetone extract of the leaves and twigs of the Taiwanese yew Taxus sumatrana, Taxaceae. The structures were established as 2α,7β,10αtriacetoxy5αhydroxy23→20abeotaxa420,11dien9,13dione 1, 3E,8E2α,9,10β, 13α,20pentaacetoxy7βhydroxy3,8secotaxa3,8,11trien5one 2, 3E,8E2α,9,10β,13α,20pentaacetoxy5α,7βdihydroxy3,8secotaxa3,8,11triene 3, 3E,8E9,10β,13αtriacetoxy2α,7β,20trihydroxy5α2Ecinnamoyloxy3,8secotaxa3,8,11triene 4, and 3E,8E2α,5α,7β,9,10β,13αhexaacetoxy20hydroxy3,8secotaxa3,8,11triene 5, respectively, on the basis 1D and 2DNMR spectral analyses. The in vitrocytotoxic activity of compounds 1–5against four human tumor cell lines, including HeLa cervical epitheloid, WiDr colon, Daoy medulloblastoma, and Hep2 liver carcinoma tumor cells was evaluated. Whereas compounds 1–3were inactive, the novel taxanes 4and 5showed significant cytotoxicity. [ABSTRACT FROM AUTHOR] |
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