Assessment of organ weight changes in normal and streptozotocin-induced diabetic rats treated with Olea europaea L. leaf extract

Purpose: To evaluate the antidiabetic activity of crude extract of Olea europaea L. (CEOE) leaves in streptozotocin induced-diabetic rats and also to determine its tannin content. Methods: Thirty (30) male, normoglycemic Wistar rats (170- 250 g) were randomly divided into five groups of six rats each. Group 1, which served as the normal control group, received distilled water while groups 2 and 3, were administered 200 and 600 mg/kg of CEOE extract daily for 18 days, respectively. Group 4 was given glibenclamide (Glibil; 3 mg/kg) while group 5 served as the untreated diabetic control group. Diabetes was induced with a single intraperitoneal injection of streptozotocin (50 mg/kg) and rats with blood glucose levels >= 250 mg/dL were confirmed to be diabetic. The blood glucose concentration, water and feed intake, tannin content of CEOE as well as the weight of organs were determined. Results: The results showed that O. europea contained a large amount of tannins (806.22 +/- 0.036 mu g Tannic Acid Equivalent/g Extract). Administration of the extract (200 and 600 mg/kg) significantly decreased polydipsia and polyphagia, and reversed weight loss in rats with diabetes (p < 0.05 and p < 0.01, respectively) in comparison with glibenclamide. Conclusion: The antidiabetic activity of the crude extract of O. europea was higher than that observed with glibenclamide, thus validating the folkloric use of this plant in diabetes care. Further investigation of Olea europea, including thorough chemical and pharmacological studies, are required.