Food phenolics as possible digestive modulators

The interactions between food components and digestive enzymes may impact nutrient absorption. Certain components, particularly polyphenols, are reported to inhibit digestive enzymes and are commonly referred to as anti-nutritional factors. Reports are often contradictory, highlighting the need for consistent methodologies to assess the potential impact of bioactive compounds. This study evaluated the “in vitro” activity of pepsin, trypsin, and chymotrypsin using ovalbumin, gluten, and hemoglobin as substrates in the presence or absence of bioactive natural compounds at physiological concentrations. The results indicate that bioactives may have opposed effects on proteolytic activity depending on the substrate/enzyme combination. A computational approach based on molecular docking and dynamics simulations was used to investigate the interactions between selected bioactives and enzymes or substrates. The “in silico” study included piceid and phloridzin dihydrate, as well as their respective aglycones (resveratrol and phloretin), since the activity of chymotrypsin on ovalbumin was enhanced by resveratrol, piceid, and phloridzin dihydrate, whereas phloretin inhibited it. The results obtained through computational modelling indicate that all four polyphenols are capable of interacting with chymotrypsin. However, only those polyphenols that enhance in vitro proteolytic activity induce a partial unfolding of ovalbumin's structure. This suggests that the effect of polyphenols on protein digestion may be substratedependent, and may vary depending on the specific protein being digested. Acknowledgments: This investigation was supported in part by the National Recovery and Resilience Plan (NRRP), (Mission 4, Component 2, Investment 1.3 - Call for tender No. 341 of 15/03/2022) of the Italian Ministry of University and Research, funded by the European Union– NextGenerationEU, in the frame of the project “Research and innovation network on food and nutrition: Sustainability, Safety and Security (ON Foods), and by the Italian Piano di Sostegno della Ricerca 2022 - Azione A (Linea 2), University of Milan.