Inhibitory potential of traditional herbs on α-amylase activity

CONTEXT: There has been enormous interest in the development of alternative medicines for the control of diabetes. Use of carbohydrate-hydrolyzing enzyme inhibitors proved to be an important strategy for the management of postprandial hyperglycemia by delaying the process of carbohydrate hydrolysis and absorption. OBJECTIVE: Three common traditional herbs, namely, stem bark of Terminalia arjuna (Combretaceae), seeds of Eugenia cumini (Myrtaceae), and leaves of Aegle marmelos (Rutaceae), were tested for their α-amylase inhibitory activities to establish antidiabetic potential. MATERIALS AND METHODS: The plant extracts (aqueous, 50%, and 100% methanol) obtained were subjected to an in vitro amylase inhibitory assay using starch as a substrate and pancreatic amylase as the enzyme. Statistical differences and linear regression analysis were performed using GraphPad prism 5 software. RESULTS: The 50% methanol extracts of T. arjuna, E. cumini, and A. marmelos at a concentrations 50-500 μg/mL showed maximum percentage inhibition on amylase activity with IC(50) values of 302 ± 0.55, 632 ± 0.21, and 503 ± 0.28 μg/mL, respectively. However, the 100% methanol extracts of all the three plants showed the least inhibitory activity. DISCUSSION AND CONCLUSION: The results show that T. arjuna > E. cumini > A. marmelos have excellent inhibitory activity and, therefore, might be effective in lowering postprandial hyperglycemia.