Evaluation of antidiabetic effect of ethanol extract of Phaseolus vulgaris SEEDS ON alloxan-induced Wistar diabetic rats

This work was designed to evaluate the anti-diabetic efficacy of ethanol extract of Phaseolus vulgaris seeds in normal and in alloxan -induced diabetic rats. The blood glucose level of the rats was checked before the administration of alloxan using One Touch Glucometer and test strips. The rats were then fasted for 16 hours, but with free access to water after which they received an intraperitoneal injection of alloxan 200 mg/kg body weight. The rats were orally given 20 ml each of 75% glucose solution after 3 hours to prevent hypoglycemia. The animals were allowed free access to food and water after alloxan administration. After 48 hours of the alloxan administration, blood was collected orbito rectally and their glucose level was checked using One Touch glucometer and test strips. The rats were divided into six groups containing five rats each. The groups were administered 150 mg, 250 mg and 350 mg doses of ethanolic extract of Phaseolus vulgaris seed per kg body weight respectively. Administration in all instances was by gavage using intubation cannular. These treatments were repeated for five consecutive days. To a positive control group of five rats was administered 5 mg of glibenclamide (a standard anti-diabetic drug) per kg body weight for five consecutive days. Another group of five rats used as negative control did not receive any treatment. The non-diabetic group received neither alloxan nor the extract. The 24-hour acute toxicity test of the orally administered ethanolic extract of Phaseolus vulgaris seeds showed that the extract is non-toxic because no death was recorded. Antidiabetogenic potential of the extract was investigated by pretreatment of two groups of rats with 350 mg/kg of the extract for one and two weeks respectively. The result showed that all the doses were significantly (P<0.05) effective in reducing blood sugar level of alloxan induced hyperglycaemic rats when compared to the control diabetic rats that were treated with glibenclamide (a standard antidiabetic drug). However, the best reduction in blood glucose level was observed with ethanolic extract at a dose of 150 mg/kgbw. The antidiabetogenic groups showed a significant reduction( P<0.05) in the glucose levels post induction of Alloxan. These results suggest that the seed extract of Phaseolus vulgaris may possess hypoglycemic effect and could be of benefit in the treatment and management of diabetes mellitus, controlling the blood sugar as well as in preventing or delaying the onset of diabetes mellitus.