Saponins from Fagonia arabica

Abstract

Seven new triterpenoid saponins were isolated and identified from the aerial parts of Fagonia arabica. They were characterized as 3-O-β- d-xylopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)]-α- l-arabinopyranosyl oleanolic acid 28-O-β- d-glucopyranoside , 3-O-β- d-glucopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)]-α- l- arabino pyranosyl oleanolic acid 28-O-β- d-glucopyranoside , 3-O-β- d-xylopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)]-α- l-arabinopyranosyl oleanolic acid, 3-O-β- d-glucopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)]-α- l-arabino pyranosyl oleanolic acid, 3-O-β- d-xylopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)]-α- l-arabinopyranosyl 27- hydroxyoleanolic acid, 28-O-β- d-glucopyranoside , 3-O-β- d-xylopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)]-α- l- arabinopyranosyl ursolic acid 28-O-β- d-glucopyranoside and 3-O-β- d-xylopyranosyl (1 → 2)-[β- d-glucopyranosyl (1 → 3)-α- l-arabinopyranosyl 27-hydroxyursolic acid 28-O-β- d-glucopyranoside . The structures of the sapomins were established by analyses of their 1H and 13C NMR spectra with the aid of 2D experiments. The two genins, 27-hydroxyoleanolic acid and 27-ursolic acid, are new.