Intracellular antioxidant activity and intestinal absorption of amaranth peptides released using simulated gastrointestinal digestion with Caco-2 TC7 cells

Abstract

The capacity of amaranth peptides generated using simulated gastrointestinal digestion to exert intracellular antioxidant activity and its potential modification and/or passage through the intestinal cells were studied. The digested protein isolate (APId) and its fractions (gel filtration chromatography) were analysed. The effect of amaranth peptides pre-treatment of Caco-2 TC7 cells treated with 500 μM H2O2 was measured using different biomarkers. All samples led to a partial or complete decrease of reactive oxygen species and different behaviours regarding the enzymatic antioxidant activities (superoxide dismutase and glutathione peroxidase) and reduced glutathione levels. Fractions showed different behaviours after modification by and/or passage across Caco-2 TC7 monolayers suggesting potential activity at local intestinal and/or systemic sites. These results suggested that the APId was a source of bioactive peptides showing antioxidant activity at the intracellular level.