COMPARISON OF ALPHA-AMYLASE ENZYME INHIBITION AND DPPH FREE RADICAL SCAVENGING ACTIVITIES OF SOME MEDICINAL PLANTS

Abstract

Numerous medicinal plants in Vietnam have been used as a remedy for the prevention and treatment of diabetes. In this study, the inhibitory activity of the α-amylase enzyme and the free radical scavenging capacity of some medicinal herbs such as Psidium guajava leaves, Mangifera indica leaves, Physalis angulata, Pandanus amaryllifolia leaves, Ficus glomerata leaves, Artocarpus altilis leaves, and Gomphrena celosioides were compared to identify suitable medicinal sources for application in the treatment of type 2 diabetes. The results showed that the ethanol extracts of the above medicinal herbs exhibited α-amylase inhibitory activity with IC₅₀ values of 136.8; 184.7; 228.3; 159.1; 264.5; 152.4; and 204.4µg/ml, respectively. Furthermore, it was determined that the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity of these medicinal herbs at a concentration of 100 µg/ml was 58.5%; 47.8%; 38.6%; 38.2%; 39.4%; 51.1%; and 33.7%, respectively. Thus, the Psidium guajava leaf extract showed the highest α-amylase inhibitory activity and DPPH free radical scavenging activity, providing a basis for the application of guava leaves in the prevention and treatment of type 2 diabetes.