A novel 3,8-seco-taxane metabolite from the seeds of the Chinese yew, Taxus mairei

Isolation and cytotoxicity evaluation of taxanes from the barks of Taxus wallichiana var. mairei

“…Compared to 4-6 and 16, the introduction of an O-b-xylose in R 2 (7)(8)(9)(10)(11) or loss of the C-13 ester side chain (14-15) greatly decrease their activities, which is consistent with the reported SAR of taxol analogues. 27 Interestingly, despite of the general low activity, the O-b-xylose bearing compounds 7-11 reserved their anti-proliferative activity and showed selective cytotoxicity towards certain cancer cell lines.…”

“…8 Previous phytochemical studies on this plant have led to the isolation a number of taxanes, some of which showed significant cytotoxicity. [9][10][11][12][13][14] In our screening program aimed at the discovery of structurally unique and biologically significant taxanes from Taxus plants, a new taxane glucoside, 7b,9a,10b-triacetoxy-13a-hydroxy-5a-O-(b-D-glucopyranosyl) taxa-4(20),11-diene (1), and 14 known analogues ( Fig. 1), 2-deacetoxytaxinine J 15 (2), 2-deacetoxyaustrospicatine 16 (3), cephalomannine 17 (4), 10-deacetyl-7-epi-taxol 18 (5), taxol 19 (6), 7-xylosyl-10-deacetyl taxol 20 (7), 7-b-xylosyl-cephalomannine 20 (8), 7-b-xylosyl-taxol 20 (9), 7-b-xylosyl-10-deacetyl-cephalomannine 20 (10), 7-xylosyl-10-deacetyl taxol C 20 (11), taxinine M 21 (12), taxacin 22 (13), 10-deacetylbaccatin III 23 (14), and baccatin III 17,20 (15) were isolated from the barks of T. wallichiana var.…”

Tri‐ and Bicyclic Taxoids from the Taiwanese Yew Taxus sumatrana

“…The IR spectrum showed the presence of ester (1732 cm C-NMR, and DEPT spectra. The UV spectrum of 4 showed an absorption maximum at 277 nm (log e ¼ 3.87) due to a [10]. Although this skeleton was proposed by Pattenden and co-workers [11] as a precursor in taxane biosynthesis as early as 1985, the biosynthesis of taxane diterpenes remains unclear [12].…”

“…2). The singlet signal at d(H) 5.69, which showed correlations with C(9), C(11), C(12), and C(15), as well as with an AcO CO group at d(C) 169.7 in the HMBC spectrum, was assigned to be HÀC (10) J correlation with C(9) in the HMBC experiment, was attributed to HÀC (7). The chemical shift of HÀC (7) suggested that the remaining AcO group is attached to C(7) [6], although the expected long-range correlation between HÀC(7) and CO (9) was not observed in the HMBC spectrum.…”

New Natural Taxane Diterpenoids fromTaxus Species since 1999

“…Besides them, 42 had a unique structure (Table 25): (11aH)-12-exo-methylidene, no substitution at C(5), C(10), C(13) and C (20), and 6-OH group [88]. As shown in Tables 23 and 24, all of the known bicyclic taxanes are fully functionalized at 2-, 5-, 7-, 9-, 10-, 13-and 20-positions, thus, this compound would be an intermediate of bicyclic taxane biosynthesis.…”