Structures of new dammarane-type triterpene saponins from the flower buds of Panax notoginseng and hepatoprotective effects of principal ginseng saponins

The saponin fraction from the flower buds of Panax notoginseng exhibited protective effect on liver injury induced by D-galactosamine and lipopolysaccharide. From the saponin fraction with hepatoprotective effect, five new dammarane-type triterpene saponins, notoginsenosides-O (1), -P (2), -Q (3), -S (4), and -T (5), were isolated together with nine known protopanaxadiol oligoglycosides. The structures of the new saponins were elucidated on the basis of chemical and physicochemical evidence. The principal dammarane-type triterpene saponins from the roots and flower buds of Panax notoginseng were found to show potent hepatoprotective effects.