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

• Autores: Véronique Desseaux, Pierre Stocker, Pierre Brouant, El Hassan Ajandouz
• Localización: Journal of food science, ISSN 0022-1147, Vol. 83, Nº 11, 2018, págs. 2858-2865
• Idioma: inglés
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• Resumen

  • Many studies have shown that flavan-3-ols inhibit mammalian alpha-amylases but the published IC50 and Ki 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 was 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 with Ki 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 a Ki 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 the cis-flavan-3-ols epigallocatechin gallate and epicatechin gallate bind similarly to PPA, involving π-stacking with Trp59.; © 2018 Institute of Food Technologists®.