Ginsenoside Rg8, a New Dammarane-Type Triterpenoid Saponin from Roots of Panax quinquefolium

A new dammarane-type triterpenoid saponin, ginsenoside Rg(8) (1), was isolated from the roots of Panax quinquefolium, along with five known saponins, (20E)-ginsenoside F(4) (2), ginsenosides Rh(1) (3), Rg(2) (4), F(1) (5), and (20R)-ginsenoside Rh(1) (6). The structure of ginsenoside Rg(8) (1) was determined to be (3beta,6alpha,12beta,20E)-24,25-epoxy-3,12,23-trihydroxydammar-20(22)-en-6-O-alpha-L-rhamnopyranosyl(1-->2)-beta-D-glucopyranoside by various spectroscopic analyses. Among the known saponins, (20E)-ginsenoside F(4) (2) and ginsenoside F(1) (5) were first reported from the title plant.