Four new triterpenoidal saponins acylated with one monoterpenic acid from Gleditsia sinensis

Abstract

Four new oleanane-type triterpenoidal glycosides, named gleditsiosides A-D (1-4), were isolated from the anomalous fruits of Gleditsia sinensis. Using modern NMR techniques, including DQF-COSY, HETCOR, HOHAHA, HMBC, and ROESY experiments and MS analysis as well as chemical methods, their structures were determined as 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)- bet a-D-glucopyranosyl oleanolic acid 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha- L-rhamnopyranosyl-(1-->2)-[(6S,2E)-6-hydroxy-2,6-dimethyl-2, 7-octadienoyl-(1-->6)]-beta-D-glucopyranosyl ester (1); 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)- bet a-D-glucopyranosyl oleanolic acid 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-alpha- L-rhamnopyranosyl-(1-->2)-[(2E)-2-hydroxylmethyl-6-hydroxy-6-methy l-2 ,7-octadienoyl-(1-->6)]-beta-D-glucopyranosyl ester (2); 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)- bet a-D-glucopyranosyl echinocystic acid 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[beta- D-galactopyranosyl-(1-->2)]-alpha-L-rhamnopyranosyl-(1-->2)-[(2E)-2-h ydroxylmethyl-6-hydroxy-6-methyl-2, 7-octadienoyl-(1-->6)]-beta-D-glucopyranosyl ester (3); and 3-O-beta-D-xylopyranosyl-(1-->2)-alpha-L-arabinopyranosyl-(1-->6)- bet a-D-glucopyranosyl echinocystic acid 28-O-beta-D-xylopyranosyl-(1-->3)-beta-D-xylopyranosyl-(1-->4)-[beta- D-galactopyranosyl-(1-->2)]-alpha-L-rhamnopyranosyl-(1-->2)-[(6S, 2E)-6-hydroxy-2,6-dimethyl-2, 7-octadienoyl-(1-->6)]-beta-D-glucopyranosyl ester (4).