Tasumatrols P‐T, Five New Taxoids from Taxus sumatrana.

Abstract

The phytochemical investigation of the more polar fractions from the leaves and twigs of Taxus sumatrana (Taxaceae) afforded five new taxane diterpene esters, tasumatrols P -T (1 -5) possessing an 11(15 ! 1),11(10 ! 9)-diabeotaxane skeleton. Compounds 1, 4, and 5 contain an a-hydroxy group at C(14), while 3 has no OH group at either C(13) or C(14). Compound 2 is a natural 4,5-acetonide derivative, while 4 has an unusual spiro-connected 2-hydroxy-2-phenyl-1,3-dioxolane ring. Ten known taxoids, were also isolated in the course of the chromatographic fractionation. Five additional new Oacetyl derivatives 3a, 4a, 4b, 5a, and 5b were prepared from the taxanes 3 -5. The structures of all new compounds were established on the basis of their spectroscopic analyses. Compound 1 showed mild cytotoxic activity against human Hela and Daoy tumor cells.Introduction. -Taxoids are chemically diverse diterpenes isolated from different species of yew trees (family Taxaceae) [1 -3]. The clinical effectiveness of paclitaxel (Taxol ) as a microtubule-stabilizing therapeutic agent for treatment of several malignancies has motivated many natural-product chemists and biologists to isolate new taxoids and investigate their antitumor activity [4 -6]. A C 21 taxane ester was recently reported from Taxus sumatrana (Miq. ) de Laub. (Taxaceae) growing in Taiwan [7]. In our continuing search for new and bioactive natural taxoids from the more polar fractions of T. sumatrana [8 -10], a re-investigation of a taxoid-rich extract of this species was carried out. Herein, we report the isolation of five new taxane diterpene esters, tasumatrols P -T (1 -5), all possessing the 11(15 ! 1),11(10 ! 9)-diabeotaxane skeleton. Compound 2 is a natural 4,5-acetonide derivative, whereas 4 displays a spiro-connected 2-hydroxy-2-phenyl-1,3-dioxolane moiety at C(4). Ten known taxoids were also isolated and identified as 5-decinnamoyltaxinin J [11], (2a,5a,7b,10b,13a)-2,7,13-tris(acetyloxy)-5,10-dihydroxy-2(3 ! 20)-abeotaxa-4(20),11-dien-9-one [12], (2a,5a,7b,9a,13a)

Recent Progress in the Chemistry and Biology of Paclitaxel (TaxolTM) and Related Taxanes

“…Tasumatrols P-T (2.1.14-2.1.18) (Figure 8.4) were isolated from the leaves and twigs of Taxus sumatrana in 2007 [27]. These compounds possess an 11(15 !…”