Identification of a new antioxidant peptide from porcine plasma by in vitro digestion and its cytoprotective effect on H2O2 induced HepG2 model

Antioxidant peptide, referred as Trp-Gly-Pro-Gly-Val-Glu (WGPGVE), was isolated and identified from porcine plasma which hydrolysised 5 h by alkaline protease. The sequence of WGPGVE had hydrophobic amino acids G, V, aromatic W, acidic acid E, well its values hydroxyl, ABTS, DPPH radicals scavenging rates iron chelating rate were improved 30.15%, 10.05%, 38.69%, 51.40% respectively, compared to glutathione (29.32%, 81.06%, 25.43%, 17.82%). Moreover, under in vitro digestion model, it exhibited stable antioxidation (50.15%, 92.49%, 24.29%, 35.35%) after the hydrolysis effect pepsin trypsin. Additionally, could protect HepG2 cells against H2O2 promoting expression superoxide dismutase (SOD), catalase (CAT), peroxidase (GSH-Px) decreasing reactive oxygen species (ROS), malondialdehyde (MDA) contents. Thus, new antioxidant peptide be potentially used pharmaceuticals or functional foods promote application food.