ABSTRACT

The use of medicinal plants is of global importance because of their low side effects, accessibility and affordability when compared with conventional medicine. Citrullus lanatus (water melon) is popular in indigenous system of folk medicine and it is known to contain bioactive compounds such as cucurbitacin, triterpenes, sterols and alkaloids, vitamins, minerals. The present study was aimed at evaluating the ameliorative effect of methanolic extract of the rind of Citrullus lanatus (water melon) on biochemical indices of wistar rats administered used motor engine oil orally. Twenty five male Wistar rats were divided at random into five groups containing five (5) rats per groups. Group A were administered normal feed and water, Group B were administered 4m1/kg of Used motor engine oil only, Group C were administered Used motor engine oil (4m1/kg) + Vitamin C (100mg/kg), Group D were administered Used motor engine oil (4m1/kg) + extract of Citrullus lanatus (250 mg/kg) and Group E were administered Used motor engine oil (4mllkg) + extract of Citrullus lanatus (500 mg/kg). The extract was administered orally by gavage once daily for a period of 21 days. At the end of the treatment, the animals were sacrificed for biochemical assays. In this study the result obtained showed that administration of Used motor engine oil lead to a significant increase in Malondialdehyde concentration in group B animals (3.59 ± 0.47), while there was a reduction in Superoxide dismutase (11.43±0.61) and Catalase (10.96 ± 0.17) activities in the kidney of the rats. The administration of methanolic extract of rind of Citrullus lanatus at 250mg/kg restored SOD, CAT and MDA levels to near normal values. Result for liver function assay showed a significant increase in AST (32.57±1.68), ALT (31.45±1.33), ALP (6 1.22±2.05) and BIL (0.85 ±0.04) in the serum of rats administered Used motor engine oil only (Group B), when compared to the groups treated with vitamin C (100mg/kg) and extract (250mg/kg and 500mg/kg) respectively. Total protein concentration was significantly higher in the vitamin C and extract treated groups when compared to the group administered used motor engine oil only. The results of kidney function assay, revealed that creatinine concentration was significantly high (1.10± 0.05) and urea concentration (27.03±0.8 9) were significantly low in the group administered Used motor engine oil only when compared to the groups that received vitamin C and extract of Citrullus lanatus (250mg/kg and 500mg/kg) respectively. The result of this study, indicate that methanolic extract of rind of watermelon have anti-oxidative and, hepatoprotective properties in Used motor engine oil induced toxicity in wistar rats.