Enzymes Inhibition and Antidiabetic Effect of Isolated Constituents from Dillenia indica

Aims. This study was designed to investigate the enzyme inhibitory and antidiabetic activity for the constituents isolated from Dillenia indica. Methods. The leaves of D. indica were extracted with methanol and subjected to fractionation and chromatographic separation, which led to the isolation of seven compounds: betulinic acid (1), n-heptacosan-7-one (2), n-nonatriacontan-18-one (3), quercetin (4), β sitosterol (5), stigmasterol (6), and stigmasteryl palmitate (7). Among these isolates, compounds 1, 4, 5, and 6 were evaluated for in vitro enzyme inhibition and compounds 4, 5 and 6 were evaluated for antidiabetic activity in streptozotocin-nicotinamide induced diabetic mice. Results. Compounds 1, 4, 5, and 6 showed 47.4, 55.2, 48.8, and 44.3% α-amylase inhibition, respectively, and 52.2, 78.2, 52.5, and 34.2% α-glucosidase inhibition, respectively, at the dose of 50 µg/kg. Compounds 4, 5 and 6 also showed significant (∗P < 0.05) antidiabetic activity in streptozotocin-nicotinamide induced diabetic mice at the dose of 10 mg/kg. Conclusion. These results provide evidence that Dillenia indica might be a potential source of antidiabetic agents.