BIOCHEMICAL STUDIES ON α-AMYLASE INHIBITOR EXTRACTED FROM WHITE KIDNEY BEAN (Phaseolus vulgaris)

Crude extract of white kidney beans (Phaseolus vulgaris) showed inhibitory activity against porcine pancreatic α-amylase and human salivary α-amylase. Alpha amylase inhibitors are substances which alter the catalytic action of alpha amylase on starch and consequently slow down or stop the breakdown of starch. The obtained extract was examined qualitatively for phytochemical constituents and total protein content was determined by Lowry method. The crude extract was also studied for α-amylase inhibition activity which showed a linear relationship between the percentage of inhibition and inhibitor concentrations. Optimum temperature was 37ºC, optimum periods for preincubation and incubation were 15 and 60 min. Nearly 90 % of inhibition was occurred after 60 min from the beginning of incubation. Kidney bean crude extract inhibits porcine pancreatic α-amylase and human saliva α-amylase in a non-competitive manner.