Selenium-containing soybean antioxidant peptides: Preparation and comprehensive comparison of different selenium supplements

Present study aimed to prepare and identify antioxidative peptides from selenium-containing soybeans, and to investigate their bioavailability and protective effects against oxidative stress-related diseases. Seleniumcontaining soybean antioxidative peptides (Mw < 1 kDa, SePPs) hydrolyzed by Neutrase and Alcalase reached the highest cellular antioxidant activity (EC50 value 320.5 +/- 39.71 mu g/L). SePPs could be efficiently absorbed through Caco-2 monolayer, and then significantly reverse the tumor necrosis factor-alpha (TNF-alpha)-induced inflammatory cytokine, phosphorylated c-Jun N-terminal kinases (p-JNK) and nuclear factor-kappa B (NF-kappa B) levels in EA. hy926 cells (p < 0.05). D-galactose-induced aging mice model showed that liver superoxidase dismutase (SOD) and glutathione peroxidase-1 (GPx-1) were enhanced, while aspartate aminotransferase (AST), alanine aminotransferase (ALT) and NF-kappa B were decreased by SePPs significantly (p < 0.05). SePPs could inhibit brain oxidative stress via regulating MAPK/NF-kappa B pathway. Comparing with Na2SeO3, selenomethionine (SeMet) and selenium-free peptides, SePPs was found to present synergistic effects of selenium and peptides in antioxidant activity.