Alpha-amylase inhibitory assay of Ocimum extracts

A total of 250 μl of Ocimum extract samples was placed in tubes, and to each tube, 125 μl of 0.02 M sodium phosphate buffer (pH 6.9) with α-amylase (5 mg/ml) was added. Sodium phosphate buffer (pH 6.9) (500 μl, 0.02 M) was then added to each tube, and the mixtures were incubated at 25°C for 20 min. Next, 600 μl of starch solution (2%) in 0.03 M phosphate buffer (pH 6.9) was added and incubated further at 25°C for 10 min. Dinitrosalicyclic acid (500 μl) was added to stop the reaction. The reaction tubes were incubated in a water bath at 100°C for 10 min. Subsequently, 6 ml of water was added, and optical density (OD) was measured at 540 nm. The α-amylase inhibitory activity was calculated as follows:

For control, the sample was replaced with water.

Microsoft Excel software (version 2010) was used to determine P values by Tukey’s test. P values of < 0.05 were considered to be significant.