In Vitro And In Silico Approaches To Assess Modulation Of Digestive Proteases By Food-Derived Bioactives

The interactions between various food components and digestive-tract enzymes can alter how food nutrients are absorbed and have an impact on an individual's health. Some food components - especially polyphenols - reportedly inhibit some digestive enzymes and are commonly referred to be anti-nutritional factors. Reports on this subject frequently contradict one another, emphasizing the necessity of using consistent methodologies to assess the potential impact of bioactive compounds. In this study, the activity of pepsin, trypsin, and chymotrypsin was evaluated “in vitro” using ovalbumin, gluten, and hemoglobin as substrates in the presence/absence of twenty-five bioactive compounds at physiological concentrations. Results show that bioactives may affect proteolytic activity in opposite ways, depending on the substrate and the enzyme. A computational approach based on molecular docking and dynamics simulations was then applied to investigate the interactions that selected bioactives may have with the enzymes and substrates. Piceid and phloridzin dihydrate were studied, along with their respective aglycones (resveratrol and phloretin). Resveratrol, piceid and phloridzin dihydrate enhanced the activity of chymotrypsin on ovalbumin, whereas the phloridzin dihydrate aglycone (phloretin) inhibited it. “In silico” results show that all the four polyphenols can interact with chymotrypsin but only those polyphenols enhancing the in vitro proteolytic activity (resveratrol/piceid; phloridzin dihydrate) could alter the structure of ovalbumin determining a partial unfolding. Thus, a substrate-dependent relationship can be brought forward to explain why polyphenols may affect protein digestion in opposite ways. The evidence gathered here suggests caution in generalizing polyphenols as a single category of 'anti-nutritional factors' and highlights the potential of individual molecules within this class as 'digestive modulating agents'.