Studies on the constituents of Aster tataricus L.f. IV. Structures of aster saponins isolated from the herb.

Abstract

Five echinocystic acid glucuronide saponins, aster saponins Ha, Hb, Hc, Hd and foetidissimoside A (=kirengesho-masaponin I), were isolated from the ground part of Aster tataricus L. f. (Compositae) as their methyl esters, and their structures were determined based on spectral evidence and chemical degradation. These saponins have a common prosapogenin structure, echinocystic acid-3-O-glucopyranosiduronic acid, and differ in the structures of the 28-O-linked sugar moieties.Aster saponin Ha is a 28-[α-L-arabinopyranosyl]ester, Hb, a 28-[O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] ester Hc, a 28-[O-β-D-xylopyranosyl-(1→3)-O-β-D-xylopyranosyl-(1→4)-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] ester and Hd, a 28-[O-β-D-xylopyranosyl-(1→3)-O-β-D-sylopyranosyl-(1→4)-[O-β-D-apiofuranosyl-(1→3)]-O-α-L-rhamnopyranosyl-(1→2)-α-L-arabinopyranosyl] ester of the prosapogenin.