Antioxidant effect of whey digested peptides in Caco-2 cells

Several whey peptides have been evaluated with bioactive properties, however, few studies have evaluated these effects in biological models. The cultivation of Caco-2 cells represents a good study model that mimics gastrointestinal conditions and allows the evaluation of the interaction of peptides with intracellular pathways. The aim of this study was to evaluate the antioxidant potential of whey hydrolysate (WPH) in Caco-2 cells against an oxidative stimulus. Using the INFOGEST method of simulated static digestion, we obtained a high degree of hydrolysis (35.2%) and peptides resistant to digestion. These peptides were characterized in relation to molecular size by the FPLC technique and hydrophobicity by the HPLC technique. The analyzes identified peptides of molecular size in the range of 200 to 400 Da (50.7%), with medium hydrophobicity. Treatment with Caco-2 cells showed that different concentrations of WPH did not cause cytotoxicity, assessed by MTT. Stimulation with 1mM hydrogen peroxide induced an increase in the production of reactive oxygen species (ROS) and a decrease in the content of GSH (the main cellular antioxidant). WPH was able to partially decrease ROS levels and had a tendency to increase intracellular GSH content in a dose-dependent manner. Nitric oxide secretion levels were not affected in stimulated Caco-2 cells. This work shows that peptides resistant to digestion, of low molecular size and with medium hydrophobicity, present antioxidant activity in the face of the complexity of mechanisms and reactions of cellular machinery. The results contribute to the potential use of these peptides as a food supplement.