RESUMO
Background & objectives: This study was undertaken to evaluate the glycaemic potential of aqueous extract of Psidium guajava unripe fruit peel on blood glucose level (BGL) of normal and streptozotocin induced mild and severely diabetic rats as an extension of our previous work carried out on Psidium guajava ripe fruit peel. Methods: The aqueous extract of P. guajava unripe fruits was prepared. Male 6-8 wk old albino Wistar rats were selected for the experiments. Diabetes was induced by streptozotocin infection. Blood glucose levels were measured by glucose oxidase method. Antihyperglycaemic activity of the extract was assessed in mild and severely diabetic rats. Results: The maximum fall of 21.2 per cent (P<0.01) and 26.9 per cent (P<0.01) after 3 h of glucose administration during glucose tolerance test (GTT) was observed in BGL from a dose of 400 mg/kg, identifi ed as the most effective dose, in normal and mild diabetic rats respectively. In severely diabetic rats the maximum fall of 20.8 and 17.5 per cent in fasting blood glucose (FBG) and post prandial glucose (PPG) levels, and 50 per cent (P<0.01) in urine sugar levels was observed with the same dose. Haemoglobin level increased by 5.2 per cent (P<0.05) and body weight by 2.5 per cent (P<0.05) after 21 days treatment. Interpretation & conclusions: Normal, mild and severely diabetic rat models had shown hypoglycaemic as well as antidiabetic effect of the unripe guava fruit peel aqueous extract. Further studies need to be done to characterize the active components of the peel.