Modulation of proteolytic activity by dietary polyphenols is dependent on both substrate and enzymes

Phenols/polyphenols (PPs) have a role in the regulation of metabolism and a beneficial impact on some chronic diseases. However, PPs are often referred to as anti-nutritional factors, being reportedly able to inhibit proteases. Reports on this topic are often conflicting - mostly because of different experimental conditions - stressing the need to evaluate the effect of PPs through standardized approaches. Here, we evaluated the effect of several PPs (at physiological concentrations) on pepsin and trypsin activity using albumin, lysozyme, gluten, and hemoglobin as substrates. Results show that PPs may affect proteolytic activity in even opposite ways, depending on both the protein substrate and the enzyme. Although further analysis is required to define the intervening interactions in the case of specific substrate/enzyme/PPs combinations, these results underscore the possibility of considering PPs as “digestion promoting agents” in the formulation of functional foods.