Evaluation of the Antihyperglycemic and Antioxidant Effects of Methanol Crude Extract of Unripe Pulp of Carica papaya on Diabetic Male Albino Rats Induced by Alloxan

Abstract

This study investigated the effects of the methanol extract of Carica papaya leaves on anti-diabetic and antioxidant effects in alloxan-induced diabetic rats. Carica papaya leaves were extracted using 80% methanol. 40 healthy rats weighing 110–150 g was grouped into eight (8) groups of five rats each: Group 1 (normal control), Group 2 (negative control), and Group 3 (positive control); Group 4 (200 mg/kg) of extract; Group 5 (400 mg/kg) of extract; Group 6 (600 mg/kg) of extract; Group 7 (800 mg/kg) of extract; and Group 8 (1000 mg/kg) of extract. Diabetes was induced by a single intraperitoneal administration of 120 mg/kg body weight of alloxan. Groups 1-3 served as normal, negative (untreated), and positive (standard drug) controls, respectively; groups 4–8 were treated groups. Administration was done orally for twenty-eight (28) days, and fasting blood glucose levels were obtained at a seven-day interval. After treatments, the rats were anaesthetized, and blood was collected by cardiac puncture for determination of redox status using standard analytical procedures. Diabetic rats treated with Carica papaya leaf extract significantly reduced (p <0.05) their glucose level when compared with the positive control and the negative control. The reduction in fasting blood glucose levels of the extract-treated groups was consistently observable in groups 7 and 8, respectively, which were treated with high doses. The serum glutathione peroxidase, reduced glutathione, catalase, and superoxide dismutase catalase activities of rats treated with extracts showed a significant increase (p<0.05) when compared with the diabetic untreated (negative) control. There was a significant reduction in malondialdehyde levels in all the groups treated with the extract when compared with the diabetic untreated (negative) control. The non-enzymatic antioxidants (Vitamin C and E) increased significantly in some of the treated groups when compared with the negative control. The present study showed that the methanol extract of Carica papaya leaves offered a significant hypoglycemic effect and antioxidant effect in alloxan-induced diabetic rats, which can be a result of the presence of certain phytochemicals responsible for the increase in the antioxidant enzyme activity of the experimental animals.