Two new triterpene saponins from the anti-inflammatory saponin fraction of Ilex pubescens root

The saponin fraction from the ethanolic extracts of the root of Ilex pubescens Hook. et ARN. (Ilexaceae) was found to exhibit potent anti-inflammatory effects on carrageenan-induced paw edema in rats. Two novel triterpene saponins, pubescenosides C and D (1 and 2, resp.), together with five known saponins were isolated from this saponin fraction. The structures of 1 and 2 were elucidated as (20β)-3-O-[β-D-glucopyranosyl- (1→2)-β-D-xylopyranosyl]ursa- 12,18-dien-28-oic acid 28-O-β-d-glucopyranosyl ester, and (20β)-3-O-[α-L-rhamnopyranosyl- (1→2)-β-D-glucopyranosyl-(1→2)-β- D-xylopyranosyl]ursa-12, 18-dien-28-oic acid 28-O-β-D-glucopyranosyl ester, respectively, on the basis of chemical and spectroscopic data. Five known saponins isolated from the saponin fraction were identified as ilexsaponin B₁, B₂, B₃, A₁, and chikusetsusaponin IV_a (3-7, resp.).