In vitro study on α-amylase inhibitory activity of an Indian medicinal plant, Phyllanthus amarus

Objective : The objective of this study was to evaluate the a-amylase inhibitory activity of different extracts of Phyllanthus amarus against porcine pancreatic amylase in vitro.
Materials and Methods : The plant extracts were prepared sequentially with ethanol, chloroform, and hexane. Each extract was evaporated using rotary evaporator, under reduced pressure. Different concentrations (10, 20, 40, 60, 80, and 100 μg/mL) of each extract were made by using dimethyl sulfoxide (DMSO) and subjected to α-amylase inhibitory assay using starch azure as a substrate. The absorbance was read at 595 nm using spectrophotometer. Using this method, the percentage of α-amylase inhibitory activity and IC₅₀ values of each extract was calculated.
Results : The chloroform extract failed to inhibit a-amylase activity. However, the ethanol and hexane extracts of P. amarus exhibited appreciable α-amylase inhibitory activity with an IC50 values 36.05 ± 4.01 μg/mL and 48.92 ± 3.43 μg/mL, respectively, when compared with acarbose (IC ₅₀ value 83.33 ± 0.34 μg/mL).
Conclusion : This study supports the ayurvedic concept that ethanol and hexane extracts of P. amarus exhibit considerable a-amylase inhibitory activities. Further, this study supports its usage in ethnomedicines for management of diabetes.