Effects of black tea extract on carbon tetrachloride-induced lipid peroxidation in liver, kidneys, and testes of rats.

Previous studies have shown that green tea and black tea have antioxidant effects and chemopreventive activity against chronic disease including some forms of cancer. We have, therefore, examined the effects of an aqueous extract of black tea against carbon tetrachloride-induced lipid peroxidation as determined by the formation of thiobarbituric acid reactive substances in liver, kidneys and testes of rats. A 0.7% black tea extract was used which contained 2 mg of black tea extract solids per mL. Black tea was administered as drinking water for 3, 6, 9 and 12 months before and during carbon tetrachloride (CCl(4)) treatment in female and male rats. Rats were treated with a single oral dose of CCl(4) 1.0 mL/kg. All rats were killed 24 h after CCl(4) treatment. All animals were dosed with CCl(4) at the end of the 3, 6, 9, and 12 month of treatment. Black tea treatment for 75 days produced a decrease in CCl(4)-induced hepatic lipid peroxidation but significant decreases in thiobarbituric acid reactive substances occurred 3 months after treatment in both female and male rats. In liver and kidneys, black tea alone increased lipid peroxidation by 30%-50% in female and male rats. However, black tea decreased CCl(4)-induced lipid peroxidation in liver of female and male rats by approximately 49% and 37%, respectively. Black tea decreased CCl(4)-induced lipid peroxidation in testes by approximately 37% at a dose of 1.0 mL CCl(4)/kg. These results suggest that the protective effects of black tea against CCl(4)-induced lipid peroxidation in liver, kidneys and testes is due at least partly to its antioxidant properties, scavenging CCl(4)-associated free radicals. Copyright 2002 John Wiley & Sons, Ltd.