Abstract
From the glycoside mixture with adjuvant activity obtained from the hyacinth bean, the seeds of Dolichos lablab L., six new oleanane-type triterpene bisdesmosides, lablabosides A, B, C, D, E, and F, were isolated together wiht chikusetsusaponin IVa. The structures of lablabosides A, B, and C were determined on the basis of chemical and physicochemical evidence as follows : 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glurcopyranosiduronic acid]-28-O-(β-D-glucopyranosyl) oleanolic acid (lablaboside A), 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-(β-D-glucopyranosyl) 24-epi-hederagenin (lablaboside B), 3-O-[α-L-rhamnopyranosyl (1→2)-β-D-galactopyranosyl (1→2)-β-D-glucopyranosiduronic acid]-28-O-[α-L-rhamnopyranosyl (1→2)-β-D-glucopyranosyl] 24-epi-hederagenin (lablaboside C).
