Hypoglycaemic and anti-diabetic activity of stem bark extracts Erythrina indica in normal and alloxan-induced diabetic rats

The objective of the study is to investigate the alcoholic (AlcE) and aqueous (AqsE) extracts of stem bark of Erythrina indica (Papilionaceae) for hypoglycaemic effects in normal and diabetic rats. Diabetes was induced in rats by a single dose administration of alloxan (120 mg/kg, i.p.) or by injecting dexamethasone (10 mg/kg, i.p.) for 10 days. In normal rats, AlcE and AqsE had significantly decreased the blood glucose level (BGL) in a dose dependent manner after repeated administration for 7 days. In alloxan-induced diabetic rats, both the extracts decreased blood sugar levels with significant improvement in glucose tolerance and body weight at the end of 1st, 2nd and 3rd week after test extract treatment. In case of dexamethasone induced insulin resistant diabetic rats, repeated administration of AlcE and AqsE inhibited the increase in blood glucose level and improved glucose tolerance induced by dexamethasone as compared to dexamethasone induced diabetic rats. These results suggest that both extracts possess hypoglycaemic activity in normal as well as in diabetic rats. Among AlcE and AqsE, AqsE possesses better hypoglycaemic activity than AlcE in all the models. Preliminary phytochemical investigations revealed that alcoholic extracts contain carbohydrates, alkaloids, flavonoids, saponins, phytosterols, phenolics and tannins. Aqueous extract contains carbohydrates, alkaloids, flavonoids, glycosides, phytosterols and triterpenoids. These phytoconstituents may be responsible for the hypoglycaemic activity of the plant.