abeo‐Taxane Diterpenoids from the Taiwanese Yew Taxus sumatrana

Abstract

Chemical investigation of the acetonic extract of the leaves and twigs of Taxus sumatrana (Taxaceae) led to the isolation of four new taxane diterpene esters, taiwantaxins A-D (1-4, resp.). Their structures were determined primarily on the basis of 1D- and 2D-NMR techniques as well as MS. Compound 1 is a rearranged taxane diterpenoid possessing an opened oxetane ring moiety containing C(4), C(5), and C(20). The metabolites 2 and 3 belong to a 5/6/6 taxene system having a rare five-membered gamma-lactone ring comprising C(8), C(9), C(10), and C(19). Compound 4 is an example of a taxane diterpene containing a 6/8/6 ring system with a tetrahydrofuran ring comprising C(2), C(3), C(4), and C(20). The 11(15-->1)abeo-taxane diterpenoids, taiwantaxins A-C (1-3, resp.) are lacking an O-bearing functionality at either C(13) or C(14). Compound 2 showed significant cytotoxic activity against human PC-3 tumor cells.

α-Glucosidase Inhibitory and Cytotoxic Taxane Diterpenoids from the Stem Bark of Taxus wallichiana

“…Its 13 C NMR spectrum showed resonances for four carbonyls (δ C 206.1, 193.5, 170.8, 166.7), four methyls (δ C 23.2, 22.8, 17.9, 8.9), a pair of olefinic carbons (δ C 166.9, 137.3), a methine (δ C 45.2), an anomeric carbon (δ C 104.4), six oxymethines (δ C 85.2, 77.8, 76.0, 74.3, 70.5, 69.4), three methylenes (δ C 40.0, 37.0, 27.5), two oxymethylenes (δ C 76.0, 66.0), two quaternary carbons (δ C 69.8, 56.2), two oxygenated quaternary carbons (δ C 90.7, 80.0), and an aromatic ring (δ C 129.2–133.5) (Table ). The NMR data of the aglycone moiety of 5 resembled closely those of 15-benzoyl-10-deacetyl-2-debenzoyl-10-dehydro-11(15→1) abeo -baccatin III, except for the presence of a methylene in 5 instead of an oxymethine proton assigned for C-13 . Therefore, 5 was suggested to be a 9,10-diketo- abeo -taxoid glycoside.…”

Cytotoxic Activity of Taxus Sumatrana (Miq.) De Laub. Bark, Leaves, and Shoots on Hela, T47d, and McF-7/Her2 Cell Lines

“…The tasumatrols A-Z were reported isolated from leaves and twigs [10][11][12][13][14][15]. The leaves and twigs also isolated Taiwantaxins A-D isolated [16] and other chemical compounds [17,18]. Some of the isolated compounds reported have cytotoxic activities.…”

“…Some of the isolated compounds reported have cytotoxic activities. Among them are wallifoliol (KB and Hepa 59 T/VGH), taxuspine F, and 3, 6, 7, 10-deacetylbaccatin III (Hepa cells), tasumatrol F (A-498, NCI-H226, A549, and PC-3 tumor cells), Tasumatrols I and K (Hepa59T/VGH, NCI, HELA, DLD-1, and Med cell lines), tasumatrol P (HELA and Daoy tumor cells), tasumatrol Z (Hep2 cell line), and Taiwantaxin B (PC-3 tumor cells) [9][10][11][12][13][14][15][16][17]. The results of clinical studies also indicated that paclitaxelcontaining regimens on breast cancer patients provided additional benefits [19].…”