The Mechanisms of Alpha ‐Amylase Inhibition by Flavan‐3‐Ols and the Possible Impacts of Drinking Green Tea on Starch Digestion

AbstractMany studies have shown that flavan ‐3‐ols inhibit mammalian alpha‐amylases but the published IC50 andKi values vary up to a thousand times. We therefore tested the effects of 6 pure flavan ‐3‐ols—abundant in green tea—on the activity of pure porcine pancreatic alpha‐amylase (PPA) under steady‐state kinetic conditions. We used both amylose and maltopentaose as substrates, along with spectrophotometry and chromatography as analytical tools, respectively. A Docking approach w as also used to probe the interaction between PPA and each flavan‐3‐ol. The results showed that the 6 flavan‐3‐ols inhibit amylose hydrolysis withKi comprised between 7 and 34  μM, according to a mixed inhibition profile for gallocatechin gallate, and a competitive inhibition profile for the 5 other flavanols. Only the galloyl‐containing flavan‐3‐ols inhibited the maltopentaose hydrolysis with aKi of about 30  μM according to a noncompetitive profile. We conclude that dietary flavan‐3‐ols could inhibit starch digestion nonnegligibly. The results of the docking trials were concordant with the kinetic data and have noticeably revealed that thecis‐flavan‐3‐ols epigallocatechin gallate and epicatechin gallate bind similarly to PPA, involving π‐stacking with Trp59.

Source: Journal of Food Science - October 5, 2018 Category: Food Science Authors: V éronique Desseaux, Pierre Stocker, Pierre Brouant, El Hassan Ajandouz Tags: Health, Nutrition, & Food Source Type: research