Preventive effects of saponins from the Pueraria lobata root on in vitro immunological liver injury of rat primary hepatocyte cultures

Preventive effects of nine saponins obtained from Puerariae Radix (the roots of Pueraria lobata) 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 individual saponins differed. Structure-activity relationships for the sapogenol moiety suggested that the hydroxy group at C-29 would reduce the hepatoprotective activity while the hydroxy group at C-21 could enhance the hepatoprotective activity. Furthermore, structure-activity relationships for the sugar moiety suggested that the oxygen-bearing group at C-5" would enhance the hepatoprotective activity, though the configuration of the hydroxy group at C-3" could be less important for hepatoprotective activity.