Protective effect of black and green tea against carbon tetrachloride-induced oxidative stress in rats

To assess the effects of green and black tea on carbon tetrachloride (CCl4)-induced oxidative stress in rats.

This study was completed in the period of January to April 2005. Male wistar albino rats (6 weeks old) were randomly assigned to one of 3 diets (12 rats/group), control diet, black tea diet, or green tea diet. At the end of dietary treatment, a single dose of CCl4 (2.5 ml/kg intraperitoneally) in paraffin (1:1 v/v) was given to 6 rats in each group after overnight fasting. The remaining 6 rats of each group received the same amount of paraffin only intraperitoneally. Thiobarbituric acid reactive substance were used as indicators of oxidative stress. The results were further confirmed by tissue histopathology.

The present study demonstrates that there was a significant (p<0.001) increase in alanine aminotransferase (ALT) activity, TBARS, and in vitro hemolysis; and a significant (p<0.05) decrease in total plasma antioxidant status by CCl4 injection. However, green and black tea supplemented groups treated with CCl4 showed protective effects, as the in vitro hemolysis, ALT, TBARS levels were significantly lowered and total plasma antioxidant activity was significantly raised compared to the control group injected with CCl4. The endogenous antioxidant component glutathione (GSH) was significantly (p<0.001) raised in groups fed with green/black tea prior to CCl4 injection as compared to controls treated with CCl4.

The results of this study suggest that both black and green tea possess preventive effects against CCl4 induced damage in rats.