The chemical constituents of Taxus have been extensively investigated worldwide as a result of the discovery of paclitaxel with its remarkable anti-cancer activity.1,2) Although more than 450 taxane diterpenes have been discovered to date, the biogenesis of paclitaxel and taxoids is still unclear. Verticillene is considered to be the most likely intermediate between geranylgeranyl pyrophosphate and the taxane diterpenes. [3][4][5] In continuation of our research on the taxane diterpenoids of endemic Taxus species, [6][7][8][9][10][11][12][13][14] a phytochemical study of T. sumatrana was carried out. A chromatographic fractionation of an acetone extract of the leaves and twigs of the plant has resulted in the isolation of three new taxane diterpenes, named tasumatrols M (1), N (2) and O (3). In addition, two known taxane, 7-deacetylcanadensene (4) and 2a,7b,13a-triacetoxy-5a,9a-dihydroxy-2(3→20) abeotaxa-4(20),11-dien-10-one were also isolated. The structures of 1-3 were established on the basis of spectroscopic analyses, especially 1-and 2D NMR.The HR-ESI-MS of 1 revealed a quasi-molecular ion peak at m/z 575.2466 [MϩNa] ϩ consistent with the molecular formula C 28 H 40 O 11 and nine degrees of unsaturation. The IR spectrum displayed absorption bands diagnostic of hydroxyl, double bonds and ester groups. Both showed HMBC correlation with C-7, C-8 and C-9 at d C 62.6, 128.2 and 141.1. The relative configuration of 1 was determined through comparing 1 H-NMR data and the coupling constants with those of 7-deacetylcanadensene (4) 17) and from its NOESY spectrum that showed correlations between H-10/H-7; H-1/Me-16; Me-17/H-2 and H-13/Me-16 (Fig. 1). Finally, acetylation of 1 provided compound 5 identical with a product derived from acetylation of 4. Hence, the structure of 1 was established and named tasumatrol M.The HR-ESI-MS of 2 revealed the molecular formula C 28 H 38 O 11 (two protons less than 1), as derived from a quasimolecular ion at m/z 573.2310 ([MϩNa] ϩ ). The 13 C-NMR of 2 (Table 2) Investigation of an acetone extract of the leaves and twigs of Taxus sumatrana has resulted in the isolation of two new bicyclic taxoids, tasumatrols M (1), and N (2) and a new baccatin III derivative, tasumatrol O (3) together with the previous known 7-deacetylcanadensene (4) and 2a a,7b b,13a a-triacetoxy-5a a,9a a-dihydroxy-2(3→20) abeotaxa-4(20),11-dien-10-one. The structures of these taxanes were established on the basis of spectroscopic analyses, especially 1-and 2D NMR, and chemical derivatization.

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 α‐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 O‐acetyl 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.

Investigation of an acetone extract of the leaves and twigs of Taxus sumatrana has resulted in the isolation of two new bicyclic taxoids, tasumatrols M (1), and N (2) and a new baccatin III derivative, tasumatrol O (3) together with the previous known 7-deacetylcanadensene (4) and 2a a,7b b,13a a-triacetoxy-5a a,9a a-dihydroxy-2(3→20) abeotaxa-4(20),11-dien-10-one. The structures of these taxanes were established on the basis of spectroscopic analyses, especially 1-and 2D NMR, and chemical derivatization.

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)