Triterpenoid Saponins from Aster auriculatus

Abstract

Three new triterpenoid saponins (1–3), together with one known saponin scaberoside B₆ methyl ester (4) were isolated from an ethanol extract of roots of Aster auriculatus. The structures of 1–3 have been determined on the basis of spectral and chemical evidence as 3-O-β-D-glucuronyl-16α-hydroxy-olean-12-en-28-oic acid 28-O-[α-L-arabinopyranosyl(1 → 4)-α-L-rhamnopyranosyl(1 → 2)]-[β-D-xylopyranosyl(1 → 3)-β-D-xylopyranosyl(1 → 3)]-α-L-arabinopyranoside (1), the methyl ester of 3-O-β-D-glucuronyl-16α-hydroxy-olean-12-en-28-oic acid 28-O-[β-D-xylopyranosyl(1 → 3)-α-L-arabinopyranosyl(1 → 4)]-[β-D-apiofuranosyl(1 → 3)]-α-L-rhamnopyranosyl(1 → 2)-β-D-xylopyranoside (2), and 3-O-β-D-glucuronyl-olean-12-en-28-oic acid 28-O-β-D-xylopyranosyl(1 → 3)-β-D-xylopyranosyl(1 → 4)-α-L-rhamnopyranosyl(1 → 2)-α-L-arabinopyranoside (3).

Key Words:

• Aster auriculatus
• Compositae
• triterpenoid saponins auriculatusaponin D(1), E(2), and F(3)