Evaluation of the effect of ethanol extract of Phaseolus vulgaris seeds on haematological parameters of alloxan-induced Wistar diabetic rats

The study was designed to evaluate the effect of ethanol extract of Phaseolus vulgaris seeds on haematological parameters in alloxan -induced diabetic rats. Packed cell volume (PCV), total cholesterol, haemoglobin levels were evaluated. The phytochemical tests were carried out on the extract using standard phytochemical procedures. The condition of hyperglycaemia was attained by a single dose of alloxan (200 mg/kgbw). The rats were divided into six groups containing five rats each. The groups were administered 150 mgkg, 250 mgkg and 350 mgkg 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. 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). The phytoconstituents identified in the extracts are saponin, condensed tannins, flavonoids, alkaloids, cardiac glycosides and phenolic group. The PCV levels showed a significant increase (P<0.05) when compared to the negative control which received no treatment. Similarly, for total cholesterol levels, there was no significant increase compared to the control groups. The haemoglobin levels increased slightly with the administration of the extract when compared to the control group. These results suggest that the seed extract of Phaseolus vulgaris has no negative effect on the haematological parameters evaluated. The seeds could be of benefit in the treatment and management of diabetes mellitus.