Saponins from Fagonia glutinosa

Abstract

Twelve triterpenoid saponins, including six new, were isolated and identified from the aerial parts of Fagonia glutinosa. The new saponins were characterised as 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl(1-->3)]-alpha-L - arabinopyranosyl-27-hydroxy oleanolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-[beta-D-glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl ursolic acid, 3-O-alpha-L-arabinopyranosyl ursolic acid 28-O-beta-D-glucopyranosyl ester, 3-O-[beta-D-xylopyranosyl(1-->2)][beta- D-glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl ursolic acid, 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D- glucopyranosyl(1-->3)]-alpha-L-arabinopyranosyl ursolic acid 28-O-beta-D-glucopyranosyl ester and 3-O-[beta-D-glucopyranosyl(1-->2)][beta-D-glucopyranosyl(1-->3)]-alpha-L - arabinopyranosyl-27-hydroxy ursolic acid 28-O-beta-D-glucopyranosyl ester. The structures of the saponins were established by spectral and chemical evidences. The assignments of the NMR signals were performed by means of HOHAHA, 1H-1H COSY, ROE, HMQC and HMBC experiments.