Protective effects of silymarin, a milk thistle (Silybium marianum) derivative on ethanol-induced oxidative stress in liver

The production of reactive oxygen species (ROS) is considered to be a major factor in oxidative cell injury. The antioxidant activity or the inhibition of the generation of free radicals is important in providing protection against such hepatic damage. Silymarin, derived from the milk thistle plant, Silybium marianum, has been used in traditional medicine as a remedy for diseases of the liver and biliary tract. In the present study, the effect of hepatoprotective drug silymarin on body weight and biochemical parameters, particularly, antioxidant status of ethanol-exposed rats was studied and its efficacy was compared with the potent antioxidant, ascorbic acid as well as capacity of hepatic regeneration during abstention. Ethanol, at a dose of 1.6 g/kg body wt/day for 4 wks affected body weight in 16-18 week-old male albino rats (Wistar strain weighing 200-220 g). Thiobarbituric acid reactive substance (TBARS) level, superoxide dismutase (SOD), and glutathiones-transferase (GST) activities were significantly increased, whereas GSH content, and catalase, glutathione reductase (GR) and GPx (glutathione peroxidase) activities significantly reduced, on ethanol exposure. These changes were reversed by silybin and ascorbic acid treatment. It was also observed that abstinence from ethanol might help in hepatic regeneration. Silybin showed a significant hepatoprotective activity, but activity was less than that of ascorbic acid. Furthermore, preventive measures were more effective than curative treatment.