Medicinal flowers. III. Marigold. (1): Hypoglycemic, gastric emptying inhibitory, and gastroprotective principles and new oleanane-type triterpene oligoglycosides, calendasaponins A, B, C, and D, from Egyptian Calendula officinalis

The methanolic extract and its 1-butanol-soluble fraction from the flowers of Calendula officinalis were found to show a hypoglycemic effect, inhibito ry activity of gastric emptying, and gastroprotective effect. From the 1-bu tanol-soluble fraction, four new triterpene oligoglycosides, calendasaponin s A, B, C, and D, were isolated, together with eight known saponins, seven known flavonol glycosides, and a known sesquiterpene glucoside, Their struc tures were elucidated on the basis of chemical and physicochemical evidence . The principal saponin constituents, glycosides A, B, C, D, and F, exhibit ed potent inhibitory effects on an increase in serum glucose Levels in gluc ose-loaded rats, gastric emptying in mice, and ethanol- and indomethacin-in duced gastric lesions in rats. Some structure-activity relationships are di scussed.