4.5.4. Intestinal α-Glucosidase Inhibition

An intestinal α-glucosidase enzyme inhibition assay was performed as per the previous method [36]. A total of 20 μL (40 μg) of acetone extract and compounds (**1**–**14**) (40 μg of 2 mg/mL solution dissolved in DMSO) were incubated with 50 μL of rat intestinal α-glucosidase enzyme (89.93 mM, prepared in 0.9% NaCl) in 100 mM phosphate buffer (pH 6.8) for 10 min. After the incubation period, 50 μL of substrate (4-nitroplenyl α-Dglucopyranoside) solution was added. The release of *p*-nitrophenol from substrate was measured by recording the absorbance at 405 nm spectrophotometrically. Acarbose (40 μg of 2 mg/mL solution dissolved in DMSO) was taken as the standard. The activity was expressed and calculated as follows: (Ac − At)/100 × Ac, where Ac was the absorbance of control and At was the absorbance of the test sample.
