Effect of amaranth bioactive peptides on the gastrointestinal system

Abstract

The digestive system constitutes a complex barrier and a defense system against toxic agents and pathogens transmitted through food. The intestinal mucosa is constantly exposed to oxidants, mutagens, and carcinogens in the diet that cause oxidative stress, inflammatory processes, apoptosis, or transformation into tumor cells. In this chapter, we present studies related to relevant biological activities at the intestinal level exerted by amaranth seed proteins. The generation of potentially bioactive peptides through the simulated gastrointestinal digestion process, SGID, and its absorption are analyzed. These peptides showed activity against different oxygen reactive species, ROS, in in vitro acellular tests, and effects on ROS, GSH, and antioxidant enzymes in Caco-2 TC7 cells. In addition, some in vivo effects have been reported in rats’ intestinal lining after ingesting amaranth proteins. Moreover, it has been demonstrated, in vitro and in vivo, that amaranth proteins and fiber affect the ability to displace cholesterol from model micelles and increase cholesterol excretion via feces. Regarding the antiproliferative effect of amaranth proteins, peptides released after SGID exert a potential antiproliferative activity over HT-29 tumor cells, with the induction of cell necrosis and apoptosis. Amaranth lectin’s antiproliferative effect is also discussed throughout the chapter.