MEDICINAL FOODSTUFFS .6. HISTAMINE-RELEASE INHIBITORS FROM KIDNEY BEAN, THE SEEDS OF PHASEOLUS-VULGARIS L - CHEMICAL STRUCTURES OF SANDOSAPONIN-A AND SANDOSAPONIN-B

Two new olean-12-ene-type triterpene oligoglycosides, named sandosapon ins A and B, were isolated from kidney bean, the seed of Phaseolus vul garis L., together with three known saponins, soyasaponins I and V and dehydrosoyasaponin I. The structures of sandosaponins A and B were de termined on the basis of chemical and physicochemical evidence, which included the chemical derivation of sandosapogenol from a known sapoge nol, soyasapogenol B. Five saponins obtained from kidney bean were fou nd to inhibit histamine release from rat exudate cells induced by an a ntigen-antibody reaction and, among them, sandosaponins A and B showed the most potent inhibitory activity.