New antioxidant and antiglycation active triterpenoid saponins from the root bark of Aralia taibaiensis

Abstract

Four new oleanane type triterpenoid saponins ( 1– 4) and a known saponin ( 5) were isolated from the root bark of Aralia taibaiensis Z.Z. Wang et H.C. Zheng. The structures of the four new compounds were elucidated as 3- O-{ β- d-glucopyranosyl-(1 → 2)-[ β- d-glucopyranosyl-(1 → 3)]- β- d-glucurono-pyranosyl}-olean-11,13(18)-diene-28-oic acid 28- O- β- d-glucopyranosyl ester ( 1), 3- O-{ β- d-gluco-pyranosyl-(1 → 3)-[ α- l-arabinofuranosyl-(1 → 4)]- β- d-glucuronopyranosyl}-olean-11,13(18)-diene-28-oic acid 28- O- β-D-glucopyranosyl ester ( 2), 3- O-{ β- d-glucopyranosyl-(1 → 2)-[ α- l-arabinofuranosyl-(1 → 4)]- β- d-glucuronopyranosyl}-oleanolic acid 28- O- β-D-glucopyranosyl ester ( 3) and 3- O-{ β- d-glucopyranosyl-(1 → 2)-[ β- d-glucopyranosyl-(1 → 3)]- β- d-glucuronopyranosyl}-oleanolic acid 28- O- β- d-glucopyranosyl ester ( 4), on the basis of extensive spectral analysis and chemical evidence. Compounds 1– 5 exhibited moderate effects on antioxidant and antiglycation activities, which correlated with treatment of diabetes mellitus.