2.4.2. Alpha-Glucosidase Inhibitory Assay

The method described by Elsnoussi et al. [18] was adopted in this assay. Varying concentrations (0.1–1.0 mg/ml) of both A. ringens extract and standard drug (acarbose) were made separately. Then, 50 μL from the resulting stock solution was incubated (25°C for 10 min) after mixing with 100 μL of 1.0 M α-glucosidase solution prepared in 0.1 M phosphate buffer (pH 6.9). This was immediately followed by addition of 50 μL of 5 mM pNPG solution in 0.1 M phosphate buffer (pH 6.9) and further incubated at 25°C for 5 minutes. Absorbance was measured at 405 nm, and inhibition of α-glucosidase by A. ringens was calculated, and the IC₅₀ was determined using nonlinear regression curve.