Structures of acetylated oleanane-type triterpene saponins, rarasaponins IV, V, and VI, and anti-Hyperlipidemic constituents from the pericarps of sapindus rarak

Abstract

The methanolic extract and its saponin fraction (methanol-eluted fraction) of the pericarps of Sapindus rarak DC. were found to suppress plasma triglyceride elevation in olive oil-treated mice. From the active fraction, three new acylated oleanane-type triterpene saponins, rarasaponins IV (1), V (2), and VI (3), were isolated. The structures of 1-3 were elucidated on the basis of chemical and spectroscopic evidence. The principle saponin constituents, hederagenin 3-0-α-l-arabinopyranosyl-(1→3)-α-l- rhamnopyranosyl-(1→2)-α-l-arabinopyranoside (4) and hederagenin 3-0-(3,4-di-0-acetyl-α-l-arabinopyranosyl)-(1→3)-α-l- rhamnopyranosyl-(1→2)-α-l- arabinopyranoside (5), showed inhibitory effects on plasma triglyceride elevation at a dose of 200 mg/kg, per os. © 2009 Pharmaceutical society of Japan.