Saponin and sapogenol. XXXII. Chemical constituents of the seeds of Vigna angularis (Willd.) Ohwi et Ohashi. (2). Azukisaponins I,II,III, and IV.

Six oleanene-oligoglycosides named azukisaponins I (1), II (2), III (3), IV (4), V, and VI were isolated from azuki beans, the seeds of Vigna angularis (WILLD.) OHWI et OHASHI (Leguminosae). Among them, the structures of azukisaponins I, II, III, and IV were elucidated as 3-O-β-D-glucopyranosyl (1→2)-β-D-glucuronopyranosyl sophoradiol (1), 3-O-β-D-glucopyranosyl (1→2)-β-D-glucuronopyranosyl soyasapogenol B (2), 3-Oβ-D-glucopyranosyl (1→2)-β-D-glucuronopyranosyl azukisapogenol (3), and 3-O-(β-D-glucopyranosyl)-28-O-β-D-glucopyranosyl (1→6)-β-D-glucuronopyranosyl gypsogenic acid (4), respectively on the basis of chemical and physicochemical evidence.