Posttreatment Effects of Olea Europaea L. Leaf Extract on Carbon Tetrachloride-Induced Liver Injury and Oxidative Stress in Rats

The aim of this study is to examine the therapeutic effects of Olea europaea L. leaf extract on carbon tetrachloride (CCl4)-induced liver damage in rats. In the experiments, 3- to 4-month-old 28 male Sprague-Dawley rats were divided into four groups: control, O. europaea leaf extract, CCl4, and curative. The CCl4 and curative groups received CCl4 (0.2mL/kg) intraperitoneally for 10 days to form hepatic injury. O. europaea (80mg/kg) leaf extract was given orally to the curative group dissolved in distilled water the following 14 days. Hepatic and antioxidant enzyme levels, p53, caspase 3, lipid peroxidation marker malondialdehyde (MDA), and also DNA fragmentation levels were determined to establish oxidative stress in hepatic cell damage and its consequences. After formation of liver damage, oral administration of the O. europaea significantly reduced CCl4-induced elevations of serum alkaline phosphatase, aspartate aminotransferase and alanine aminotransferase levels (P<.001), MDA levels of both blood (P<.001) and liver tissues (P<.001), DNA fragmentation (P<.001), p53 (P<.001), and caspase 3 (P<.001) levels of liver tissues. Also this administration in curative group significantly increased CCl4-induced reductions of superoxide dismutase (SOD) (P<.001) and catalase (CAT) (P<.001) activity of blood samples and decreased SOD (P<.001) and CAT (P<.05) activity observed in liver tissue curative groups compared with CCl4 curative group. In CCl4 group, liver tissue samples exhibited remarkable damage because of CCl4 and reduction of these damages were observed in the curative group. Our results showed that O. europaea leaf extract was effective in reducing hepatic damage caused by CCl4 by reducing lipid peroxidation, regulating antioxidant enzymes, and minimizing DNA damage.