SAPONINS FROM VIETNAMESE GINSENG, PANAX-VIETNAMENSIS HA ET GRUSHV COLLECTED IN CENTRAL VIETNAM .2

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-gin senosides-R3 (12), -R4 (II), -R5 (16), -R6 (17), -R7 (6), -R8 (20), -R 9 (22), together with the identification of sis known saponins includi ng 20-gluco-ginsenoside-Rf (10), ginsenoside-Rc (4), notoginsenoside-R 6 (9), quinquenoside-R(1), (5), gypenoside XVII (2) and majoroside FT (21). The structures of the novel saponins were established on the bas is of chemical and spectral evidence. Vina-ginsenoside-R3 is the first naturally occurring glycoside of dammarenediol II, while vina-ginseno sides-R5 and -R6, two ocotillol-type saponins, are two other examples of saponins having the rare alpha-glucosyl linkage.