Evaluation of the antioxidant effect of opioid peptides on intestinal cells

Resumen del póster presentado al 11th European Nutrition Conference celebrado en Madrid del 26 al 29 de octubre de 2011.[Introduction]: In recent years, nutrition and food sciences have been focused on biologically active peptides that are liberated from food proteins by enzymatic hydrolysis or fermentative process. Some of these peptides have been reported to exert a variety of functions in vivo. During last decade much effort has been done on peptides with activities on cardiovascular system, but there is much less data available about the role of food peptides in intestine-modulatory functions. Intestinal epithelial cells are exposed to oxidative stress that has been shown to participate in the aetiology of several human degenerative diseases including inflammation, cardiovascular and neurodegenerative disorders and cancer. Although opioid peptides have been demonstrated to exert an important role in the gastrointestinal tract, no data about their antioxidant protective effects have been reported to date. [Objectives]: The aim of this work was to evaluate the antioxidant potential of opioid peptides derived from food proteins elucidating their mechanism of action on intestinal cells. [Method/Design]: Antioxidant activity of opioid peptides was initially assayed using three in vitro methods, two of them focused on measuring peroxyl and superoxide radicals scavenging activity, and one assay based on peptides’ capacity to reduce Fe3+ to Fe2+. Peptides showing the highest in vitro antioxidant activity were assayed in Caco-2 cell lines stressed with hydrogen peroxide. The protective effects of peptides were estimated by the determination of total glutathione (GSH) and intracellular formation of peroxyl radicals. [Results]: Opioid peptides showed in vitro antioxidant activity through their capacity to scavenge oxygen radicals and reduce iron. Those peptides showing higher activity were assayed in Caco2 cells, demonstrating that they did not affect Caco2 cell viability. Moreover, first results conducted show a promising antioxidant role of opioid peptides on intestinal cells. [Conclusions]: Our study has demonstrated that opioid peptides derived from food proteins exert potent antioxidant activity through different mechanisms of action. Moreover, protective effects of these peptides against oxidant compounds produced in intestinal cells make them a promising strategy to prevent oxidative stress-related disorders.Peer Reviewe