Study of structure--hepatoprotective relationships of oleanene-type triterpenoidal glucuronides obtained from several fabaceous plants on rat primary hepatocyte cultures.

The protective effects of nine oleanene-type triterpenoidal glucuronides obtained from several fabaceous plants (Lupinus polyphyllus x arboreus Hybrid, Astragalus complanatus, Wistaria brachybotrys) on in vitro immunological liver injury in primary cultured rat hepatocytes were studied. Although all tested saponins showed hepatoprotective action, the levels of activity of the individual saponins differed. Structure-activity relationships for the sapogenol moiety suggested that the presence of the carbonyl group at C-22 would show a similar hepatoprotective effect to that of the hydroxyl group at C-22 while the presence of the hydroxyl group at C-30 would reduce the hepatoprotective action. This structure-activity relationship substantiated other recently obtained data. Furthermore, the beta-orientation of the hydroxyl group at C-21 is more effective than the alpha-configuration in regard to the hepatoprotection. Furthermore, structure-activity relationships for the sugar moiety substantiated previously obtained data that the hydroxyl group at C-5" enhances the hepatoprotective action.