RESUMO
In the streptozotocin induced diabetic rats treated separately with aqueous, ethanol, acetone and chloroform extracts of the seeds of B. nigra, the increase in serum glucose value between 0 and 1 hr of glucose tolerance test (GTT) was the least (29 mg/dl) in aqueous extract treated animals while it was 54, 44 and 44 mg/dl with chloroform, acetone and ethanol extracts respectively. In further studies carried out with aqueous extract, the effective dose was found to be 200 mg/kg body weight in GTT. Administration of 200 mg/kg body weight of aqueous extract to diabetic animals daily once for one month brought down fasting serum glucose (FSG) levels while in the untreated group FSG remained at a higher value. In the treated animals the increase in glycosylated hemoglobin (HbA1c) and serum lipids was much less when compared with the levels in untreated diabetic controls. These findings suggest that further studies with the aqueous extract of B. nigra seeds on its antidiabetic activity would be useful.