Free Radical Scavenging Activity of Fermented Soybean Milk

This study was conducted to investigate the free radicals scavenging activity and cytoprotective effects of Lactobacillus plantarum YS-1 Fermented Soy Milk (FSM-LPYS1) in Caco-2 human colon adenocarcinoma cells damaged by hydrogen peroxide (H2O2)-induced oxidation. Lactic Acid Bacteria (LAB) fermentation improves the food quality, safety and also increases the biological activity and adds nutritional value to these fermented products. FSM-LPYS1 showed a remarkable in vitro activity against 2, 2-Diphenyl-1-Picrylhydrazyl (DPPH) and hydroxyl radical (•OH). FSM-LPYS1 significantly decreased the levels of intracellular Reactive Oxygen Species (ROS), lipid peroxidation, and enhanced the activities and expression levels of Catalase (CAT), Superoxide Dismutase (SOD) and glutathione peroxidase (GSH-Px) in H2O2-treated Caco-2 cells (p<0.05). FSM-LPYS1 also reduced the protein levels of IL-8 and NF-kB in Caco-2 cells. These results clearly indicated that FSM- LPYS1 had impressively scavenged free radicals and were able to reduce the H2O2-induced oxidative damage in Caco-2 cells by reducing the intracellular ROS generation, restraining lipid peroxidation, and by raising the endogenous antioxidant enzyme activity. In addition, the FSM-LPYS1 could also reduce the H2O2-induced inflammation reaction. FSM-LPYS1 is a functional food which has antioxidant properties and it can be used as high quality soybean processing food for exploitation of health benefits. In addition, FSM-LPYS1 also significantly reduced the IL-8 and NF-kB protein expression.