An In Vitro Study on the inhibitory Activities of Eugenia jambolana Seeds Against Carbohydrate Hydrolyzing Enzymes

Herbal medicines have been used since prehistoric times by different cultures worldwide for treatment of diabetes. In the present investigation, the effect of untreated and heat-treated aqueous extracts from Eugenia jambolana Lam (Myrtaceae) seeds on carbohydrate hydrolyzing enzymes, namely, porcine pancreatic alpha-amylase, rat intestinal alpha-glucosidase, and sucrase, have been studied using in vitro model systems. Untreated E. jambolana extract (EJU) significantly inhibited (p <= 0.01) alpha-amylase, alpha-glucosidase, and sucrase activities in a dosedependent manner, with the exception of sucrase, where the increased sample concentration did not increase the sucrase inhibitory activity. Heat treatment of the sample resulted in a significant increase (p = 0.01) in the alpha-amylase inhibitory activity of the sample, while a marginal increase in the alpha-glucosidase and sucrase inhibitory activities were observed, however, they did not reach statistical significance. EJU showed IC50 values of 3.4%, and 68 and 56 mu g mL-1 for alpha-amylase, alpha-glucosidase, and sucrase, respectively, while the IC50 values for heat-treated E. jambolana extract (EJH) were 2.4%, and 66 and 54 mu g mL-1, respectively. Further, a significant correlation (p = 0.01; r = 0.833) was observed between alpha- amylase, alpha-glucosidase, and sucrase inhibitory activities of both EJU and EJH. These findings emphasize that inhibition of carbohydrate hydrolyzing enzymes is one of the mechanisms through which E. jambolana exerts its hypoglycemic effect in vivo.