Preclinical evaluation of the antidiabetic effect of Eugenia jambolana seed powder in streptozotocin-diabetic rats

The world is facing an explosive increase in the incidence of diabetes mellitus and cost-effective complementary therapies are needed. The effects of Eugenia jambolana, a household remedy for diabetes, were studied. Streptozotocin diabetic female albino Wistar rats weighing 150-200 g (N = 6) were fed E. jambolana seed powder (250, 500 or 1000 mg/kg) for 15 days. Diabetic rats fed 500 and 1000 mg/kg seed powder showed an increase in body weight on day 20 in relation to day 5 (6 +/- 4.7, 9 +/- 7.8 vs diabetic control -16 +/- 7.1 g, P < 0.001), a decrease in fasting blood glucose (75 +/- 11.9, 123 +/- 14.4 vs diabetic control -34 +/- 12.1 mg/dl, P < 0.001), a difference in post-treatment fasting and peak blood glucose (38 +/- 11.9, 36 +/- 14.2 vs diabetic control 78 +/- 11.9 mg/dl, P < 0.001), and a difference in liver glycogen (50 +/- 6.8, 52 +/- 7.5 vs normal control 90 +/- 6.6 microg/g of liver tissue, P < 0.001). Tri-terpenoids, tannins, gallic acid, and oxalic acid were the chemical constituents detected in E. jambolana seed. The best results were obtained with an oral dose of 500 mg/kg. Subacute toxicity studies with a single administration of 2.5 and 5.0 g/kg seed powder showed no mortality or abnormality. These data on the antidiabetic effect of E. jambolana seed are adequate for approval of phase 2 clinical trials to evaluate this seed powder as complementary therapy in type 2 and type 1 diabetes.