3.6.2. α-Amylase Inhibition Assay

The α-amylase inhibitory potential was performed by reacting different concentrations of extracts with α-amylase and starch solution, as described by reference [60] with some modifications. Sample’s solution (250 μL) was mixed with 250 μL of 0.02 M PBS (pH 6.9) containing the α-amylase enzyme (240 U/mL) and incubated for 20 min at 37 °C. Soluble starch (1%, PBS 0.02, pH 6.9) was added to the mixture and further incubated at 37 °C for 20 min. The reaction was stopped by adding 250 μL of dinitrosalicylic acid and the incubation of the solution at 90 °C in a water bath for 10 min. The cooled reaction mixture was diluted with 1 mL deionized water and the absorbance was measured at 540 nm. The α-amylase inhibitory activity was expressed as a percentage of inhibition.