E-senegasaponins A and B, Z-senegasaponins A and B, Z-senegins II and III, new type inhibitors of ethanol absorption in rats from senegae radix, the roots of Polygala senega L. var latifolia Torrey et Gray

New inhibitors of ethanol absorption, E-senegasaponins a and b, Z-senegasaponins a and b, Z-senegins II and III, were isolated from Senegae Radix, the roots of Polygala senega L. var latifolia Torrey et Gray, together with senegins II and III. Their chemical structures have been elucidated on the basis of chemical and physicochemical evidence, and the geometrical isomeric structures of methoxycinnamoyl moiety in each saponin were found to show tautomer-like behavior. The inhibitory effects of senegasaponins, senegins, and their related compounds have been examined, and some structure-activity relationship have been found.