Hepatoprotective effect of majonoside R2, the major saponin from Vietnamese ginseng (Panax vietnamensis).

The hepatoprotective effect of majonoside R 2 (MR2), the major saponin constituent from Vietnamese ginseng ( Panax vietnamensis, Araliaceae), was evaluated in vivo on D-galactosamine ( D-GalN)/lipopolysaccharide (LPS)-induced hepatic apoptosis and subsequent liver failure in mice. Pretreatment of mice with MR2 (50 or 10 mg/kg, intraperitoneal) at 12 and 1 h before D-GalN/LPS injection significantly inhibited apoptosis and suppressed following hepatic necrosis. Importantly, the elevation of serum tumor necrosis factor-alpha (TNF-alpha) level, an important mediator for apoptosis in this model, was significantly inhibited by MR2 at a dose of 50 mg/kg. On the other hand, MR2 was found to protect primary cultured mouse hepatocytes from cell death by inhibiting apoptosis induced by D-GalN/TNF-alpha in vitro, as evidenced by DNA fragmentation analysis. These findings suggested that MR2 may have protected the hepatocytes from apoptosis via an inhibition of TNF-alpha production by activated macrophages and a direct inhibition of apoptosis induced by TNF-alpha.