Antioxidant Effect of Ethanol Extract of C. sativus on Streptozotocin-Induced Diabetic Rat Liver

Abstract

The present study investigated the antioxidant effect of ethanol extract of Cucumis sativus on streptozotocin (STZ)-induced diabetic rat liver. Adult male Wistar albino rats (n = 25, mean weight = 215 ± 15 g) were randomly assigned to five groups of 5 rats each: normal control, diabetic control, metformin, 200 mg/kg body weight (bwt) extract and 300 mg/kg bwt extract groups. Diabetes mellitus was induced in the rats via intraperitoneal injection of 50 mg/kg bwt STZ. The diabetic rats were then treated for 21 days with either metformin (50 mg/kg bwt) or the extract at doses of 200 and 300 mg/kg bwt, respectively. Activities of antioxidant enzymes such as catalase, superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GR) as well as antioxidant molecules like retinoic acid, ascorbic acid and α-tocopherol were evaluated in liver homogenate. The results showed that induction of diabetes mellitus with STZ significantly increased the fasting blood glucose (FBG) concentrations of the rats (p < 0.05). However, treatment of the diabetic rats with the extract markedly reduced the FBG concentration and body weights of rats (p < 0.05). Treatment of diabetic Wistar rats with ethanol extract of C. sativus significantly increased activities of the antioxidant enzymes and molecules as well as concentrations of nitric oxide (NO), but it markedly reduced the concentrations of hepatic total protein (TP) and malondialdehyde (MDA) (p < 0.05). These results suggest that ethanol extract of the medicinal plant can enhance antioxidant defense in the liver of STZ-induced diabetic rats.