Saponin and Sapogenol. XLI.1)Reinvestigation of the Structures of Soyasapogenols A, B, and E, Oleanene-Sapogenols from Soybean. Structures of Soyasaponins I, II, and III

Abstract

A full account of the structure revision of soyasapogenols is presented. The structures of soyasapogenols A, B, and E have been confirmed to be expressed as 3β,21β,22β,24-tetrahydroxyolean-12-ene (1), 3β,22β,24-trihydroxyolean-12-ene (2), and 3β,24-dihydroxyolean-12-en-22-one (5), respectively, rather than the previously reported 3β,21α,22α,24-tetrahydroxyolean-12-ene (1’), 3β,21α,24-trihydroxyolean-12-ene (2’), and 3β,24-dihydroxyolean-12-en-21-one (5’). In consequence, the structures of soyasaponins I, II, and III are formulated as 3-O-[α-L-rhamnopyranosyl(1→2)-β-D-galactopyranosyl(l→2)-β-D-glucuronopyranosyl]soyasapogenol B (8), 3-O-[α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl(1→2)-β-D-glucuronopyranosyl]soyasapogenol B (9), and 3-O-[β-D-galactopyranosyl(1→2)-β-D-glucuronopyranosyl]soyasapogenol B (10), respectively. © 1988, The Pharmaceutical Society of Japan. All rights reserved.