Inhibitory effect of polyphenol extracts from peanut shells on the activity of pancreatic α-amylase activity in vitro

Polyphenols possess many beneficial properties, for example, reducing the risk of heart diseases, and acting as natural antioxidants for the food. Polyphenols might possess antinutritional property by inhibiting digestive enzymes and reducing food digestibility. An ultrahigh pressure method was used for preparing polyphenol extracts from peanut shells (PPS). The highest yield of PPS was 71.3 mg of gallic acid equivalents (GAE)/g of shells under the optimized conditions (75% ethanol-water solution, 300 MPa, 4 min, 1: 25 ration of solid to liquid). At the same time, the peaks of five representative fractions have been quantified comparing with standard sample (pyrogallol; catechol; phlorglucinol; quercetin; luteolin). So, polyphenols extracts from peanut shells (PPS) by ultrahigh pressure were assayed for inhibition of pancreatic alpha-amylase activity in vitro. Curve of kinetics of pancreatic alpha-amylase was drawn within 7 min. The time of reaction within 3 min is linear response. The concentration of enzyme was selected as 0.04 mg/mL and the reaction time was selected as 3 min for determination of enzymatic reaction kinetics for the following experiments. The results of the enzyme kinetic studies using Michaelis-Menten and Lineweaver-Burk equations showed the Vmax was 0.62/min and the Km was 5.49 mg/ml, R-2 = 0.9891. The straight line of curve through the origin when the reaction system with reversible inhibitors existed. Thus, it can be inferred from PPS against pancreatic alpha-amylase inhibition type is reversible inhibition.