Antidiabetic Activity of Extract and Fractions of Castanopsis costata Leaves on Alloxan-induced Diabetic Mice

Background: In North Sumatra, Castanopsis costata is commonly used by traditional practitioners for the treatment of diabetes mellitus, however, no studies have been carried out to substantiate this practice. Therefore, this study aims to evaluate the anti-diabetic activity of extract and fractions of C. costata leaves in mice with alloxan-induced diabetes. Methods: Swiss albino mice with alloxan-induced diabetes, were acquired and subjected to the experimental evaluations. Subsequently, the fasting blood glucose levels of the diabetic mice groups treated with glibenclamid, extract and fractions, as well as the untreated group, were evaluated after two weeks of therapy. Results: Based on the results, the ethanolic extract of C. costata considerably reduced the mice's blood glucose levels in a dose-dependent manner, at dosages of 25, 50, 100, and 200 mg/kgBW (% DBGL: 21.10%, 46.36%, 58.94%, and 60.93%, respectively). In addition, the water fraction of C. costata leaves produced a greater reduction in blood glucose levels (% DBGL: 78.93%), compared to the ethyl acetate and n-hexane fractions (% DBGL: 67.06% and 58.83%), respectively. Meanwhile, treatment with the antidiabetic drug, glibenclamide (5 mg/kgBW) produced a 50.75% reduction in blood glucose levels. Conclusion: Based on the findings, the extract and fractions of C. costata leaves were concluded to exhibit significant anti-diabetic activity. This supported the claim that traditional practitioners in North Sumatra use the plant extract for diabetes treatment.