SAPONINS FROM FAGONIA-ARABICA

Seven new triterpenoid saponins were isolated and identified from the aerial parts of Fagonia arabica. They were characterized as 3-O-beta-D -xylopyranosy(1 --> 2)-[beta-D-glucopyranosyl(1 --> 3)]-alpha-L-arabin opyranosyl oleanolic acid 28-O-beta-D-glucopyranoside, 3-O-beta-D-gluc opyranosy1(1 --> 2)-[beta-D-glucopyranosyl(1 --> 3)]-alpha-L-arabino p yranosyl oleanolic acid 28-O-beta-D-glucopyranoside, 3-O-beta-D-xylopy ranosyl(1 --> 2)-[beta-D-glucopyranosyl([1 --> 3)]-Phi-L-arabinopyrano syl oleanolic acid, 3-O-beta-D-glucopyranosyl(1 --> 2)-[beta-D-glucopy ranosyl(1 --> 3)]-alpha-L-arabino pyranosyl oleanolic acid, 3-O-beta-D -xylopyranosyl(1 --> 2)-[beta-D-glucopyranosyl (1 --> 3)]-alpha-L-arab inopyranosyl 27-hydroxyoleanolic acid, 28-O-beta-D-glucopyranoside, 3- O-beta-D-xylopyranosyl(1 --> 2)-[beta-D-glucopyranosyl(1 --> 3)]-alpha -L-arabinopyranosyl ursolic acid 28-O-beta-D-glucopyranoside and 3-O-b eta-D-xylopyranosyl (1 --> 2)-[beta-D-glucopyranosyl (1 --> 3)-alpha-L -arabinopyranosyl 27-hydroxyursolic acid 28-O-beta-D-glucopyranoside. The structures of the saponins were established by analyses of their H -1 and C-13 NMR spectra with the aid of 2D experiments. The two genins , 27-hydroxyoleanolic acid and 27-ursolic acid, are new.