Acylated Flavonol Bisdesmosides, Sinocrassosides A(3)-A(7) and B-3, with Aminopeptidase N Inhibitory Activity from Sinocrassula indica

Six new acylated flavonol bisdesmosides, sinocrassosides A(3), A(4), A(5), A(6), A(7) and B-3 (1-6, resp.), were isolated from the MeOH extract of the whole plant of Sinocrassida indica. The Structures Of 1-6 were elucidated on the basis of chemical and physicochemical evidence. Among them, 2 and 6 which have an acyl group in the 3'''-position were found to show strong inhibitory effects on aminopeptidase N activity, which were stronger than that of curcumin.