Saponins from Vietnamese Ginseng, Panax vietnamensis HA et Grushv. Collected in central Vietnam. II

Further investigation on the saponin composition of rhizomes and roots of Panax vietnamensis HA et GRUSHV. has resulted in the isolation and structural elucidation of seven new dammarane saponins named vina-ginsenosides-R3 (12), -R4 (11), -R5 (16), -R6 (17), -R7 (6), -R8 (20), -R9 (22), together with the identification of six known saponins including 20-gluco-ginsenoside-Rf (10), ginsenoside-Rc (4), notoginsenoside-R6 (9), quinquenoside-R1 (5), gypenoside XVII (2) and majoroside F1 (21). The structures of the novel saponins were established on the basis of chemical and spectral evidence. Vina-ginsenoside-R3 is the first naturally occurring glycoside of dammarenediol II, while vina-ginsenosides-R5 and -R6, two ocotillol-type saponins, are two other examples of saponins having the rare alpha-glucosyl linkage.