Inhibitory potential of traditional herbs on α-amylase activity

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.

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.

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.

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.

The results show that T. arjuna > E. cumini > A. marmelos have excellent inhibitory activity and, therefore, might be effective in lowering postprandial hyperglycemia.