Saussureamines A, B, C, D, and E, new anti-ulcer principles from Chinese Saussureae Radix

Five new amino acid-sesquiterpene adducts, saussureamines A, B, C, D, and E, were isolated from Chinese Saussureae Radix, the dried root of Saussurea lappa CLARKE, together with a new lignan glycoside, (-)-massoniresinol 4"-O-beta-D-glucopyranoside. Their structures were determined on the basis of chemical and physicochemical evidence. Among of these compounds, saussureamines A, B, C showed anti-ulcer effect on HCl/ethanol-induced lesions in rats, and saussureamine A also exhibited a inhibitory activity on stress-induced ulcer formation in mice. During the course of these studies, facile conversion from sesquiterpene having an alpha-methylene gamma-lactone function to amino acid-sesquiterpene adduct has been accomplished by means of Michael type addition reaction.