Evaluation of the Phytochemical Composition and Hypoglycaemic Activity of Methanolic Leaves Extract of Costus afer in Albino Rats

Medicinal plants are reservoirs of natural products with anti-diabetic potentials. In the present study we screened Costus afer for the presence of plant products and to study the effects of the methanolic leaf extract of the plant on fasting blood glucose of normal rats. Adult male wistar strain albino rats were given graded doses (200-800mg/kg) of the methanolic leaf extract of Costus afer, standard hypoglycaemic drug glibenclamide or a combination of the two in the presence or absence of oral glucose feeding. Fasting blood glucose was monitored for 6 hours post administration of drugs. Phytochemical studies revealed relative amounts of alkaloids, flavanoids, tannins, phenols, glycosides and terpenoids. Costus afer showed significant hypoglycaemic effect (p<0.05) comparable with the standard drug. However, the plant extract did not reduce blood glucose in glucose fed rats. Also, a combination of plant extract and glibenclamide caused a significant reduction in fasting blood sugar of both glucose loaded and unloaded rats. The results validate the use of Costus afer as a hypoglycaemic plant in native medicine. These effects could be attributed to its phytochemical constituents. Costus afer could be a promising plant for the development of anti-diabetic drugs.