Biologically active triterpenoid saponins from Acanthopanax senticosus

Three new triterpenoid saponins, acanthopanaxosides A (1), B (7), and C (13), were isolated from the leaves of Acanthopanax senticosus, together with 12 known saponins. The structures of these new saponins were established as 3-O-beta-D-glucopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyl-30-nor-olean-12,20(29)-dien-28-oic acid 28-O-alpha-L-rhamnopyranosyl (1 -> 4)-6-O-acetyl-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl ester (1), 3-O-beta-D-glucopyranosyl-(1 -> 2)-R-Larabinopyranosyl oleanolic acid 28-O-alpha-L-rhamnopyranosyl-(1 -> 4)-6-O-acetyl-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl ester ( 7), and 3-O-alpha-L-rhamnopyranosyl-(1 -> 2)-alpha-L-arabinopyranosyl-3 beta-hydroxyolean-12-ene-28,29-dioic acid ( 13), on the basis of spectroscopic analysis and chemical degradation. Among the known compounds, sessiloside and tauroside H-1 are reported for the first time from A. senticosus. The biological activity of compounds 1-15 was examined against pancreatic lipase. Ciwujianoside C-1 (6), tauroside H-1 (11), 3-O-alpha-rhamnopyranosyl-(1 -> 2)-alpha-arabinopyranosyl mesembryanthemoidigenic acid (12), acanthopanaxoside C (13), sessiloside (14), and chiisanoside (15) inhibited pancreatic lipase activity in vitro. In turn, ciwujianosides C-2 (3), D-2 (5), C-4 (8), and C-3 (10) and hederasaponin B (9) enhanced this enzyme.