Silymarin: An effective hepatoprotective agent against diethylnitrosamine-induced hepatotoxicity in rats

This study investigates the putative hepatoprotective and antioxidant activity of silymarin (SIL) on diethylnitrosamine (DEN)-induced liver damage in male Wistar rats. A single intraperitoneal administration of DEN (200mg/kg) to rats resulted in significantly elevated serum levels of AST, ALT, ALP, LDH, gamma-GT, and BIL compared with controls after 30 days in serum. In contrast, the liver tissue showed a significant decrease in the levels of AST, ALT, and ALP, and an increase in LDH and gamma-GT. Elevated levels of lipid peroxidation (LPO) were observed in the liver tissue after DEN administration. Quantitative analysis of catalase (CAT) and superoxide dismutase (SOD) revealed lower activities of these key antioxidant enzymes in the liver upon DEN administration. The status of antioxidant vitamins, vitamin C and vitamin E, were also found to be decreased in DEN-exposed rats. When rats with DEN- induced hepatotoxicity were treated with SIL (50mg/kg, orally) for 30 days, the levels of AST, ALT, ALP, LDH, gamma-GT, and BIL reverted to near normalcy, whereas the hepatic concentration of CAT, SOD, vitamin C, and vitamin E were significantly increased, and that of LPO significantly lowered, when compared with DEN-exposed, untreated rats. These results suggest that SIL is able to significantly alleviate the hepatotoxicity and oxidative stress induced by DEN in rats.