BIOACTIVE SAPONINS AND GLYCOSIDES - XI - STRUCTURES OF NEW DAMMARANE-TYPE TRITERPENE OLIGOGLYCOSIDES, QUINQUENOSIDE-I, QUINQUENOSIDE-II, QUINQUENOSIDE-III, QUINQUENOSIDE-IV, AND QUINQUENOSIDE-V, FROM AMERICAN GINSENG, THE ROOTS OF PANAX-QUINQUEFOLIUM L

The methanolic extract and I-butanol-soluble fraction of American gins eng, the roots of Panax quinquefolium L., were found to exhibit a prot ective effect on liver injury induced by D-galactosamine and lipopolys accharide. Five new dammarane-type triterpene oligoglycosides called q uinquenosides I, II, III, IV, and V were isolated together with fourte en known dammarane-type triterpene oligoglycosides such as chikusetsus aponin IVa, pseudo-ginsenoside-RC1, malonyl-ginsenoside-Rb-1, and noto ginsenosides-A, -C, and -K from the 1-butanol-soluble fraction. From t he ethyl acetate-soluble fraction, four known acetylenic compounds and 6'-O-acetyl ginsenoside-Rg(1) were isolated. The structures of quinqu enosides I, II, III, IV, and V were determined on the basis of chemica l and physicochemical evidence as 3-O-[6-O-(E)-2-butenoyl-beta-D-gluco pyranosyl(1 --> eta-D-glucopyranosyl]-20-O-(beta-D-glucopyranosyl) 20( S)-protopanaxadiol (quinquenoside I), 3-O-[6-O-(E)-2-octenoyl-beta-D-g lucopyranosyl(1 --> 2)-beta-D-glucopyranosyl]-20-O- [beta-D-glucopyran osyl(1 --> 6)-beta-D-glucopyranosyl] 20(S)-protopanaxadiol (quinquenos ide II), 3-O-[beta-D-glucopyranosyl (1 --> eta-D-glucopyranosyl]-20-O- (beta-D-glucopyranosyl) 20(S)-protopanaxadiol (quinquenoside III), 3-O -[beta-D-glucopyranosyl(1 --> ta-D-glucopyranosyl]-20-O-[beta-D-glucop yranosyl(1 --> 6)-beta-D-glucopyranosyl]-3 beta,7 beta,20(S)-trihydrox ydammar-5,24-diene (quinquenoside IV), and 3-O-[beta-D-glucopyranosyl( 1 --> 2)-beta-D-glucopyranosyl]-20-O- [alpha-D-glucopyranosyl(1 --> 4) -beta-D-glucopyranosyl(1 --> 6)-beta-D-glucopyranosyl] 20(S)-protopana xadiol (quinquenoside V).