Antioxidant peptides have elicited interest for the versatility of their use in the food and pharmaceutical industry. In the current study, antioxidant peptides were prepared by microwave-assisted alkaline protease hydrolysis of collagen from sea cucumber (Acaudina molpadioides). The results showed that microwave irradiation significantly improved the degree of hydrolysis of collagen and the hydroxyl radical (OH⋅) scavenging activity of hydrolysate. The content and OH⋅ scavenging activity of collagen peptides with molecular weight ≤ 1 kDa (CPS) in the hydrolysate obtained at 250 W increased significantly compared with the non-microwave-assisted control. CPS could scavenge OH⋅ and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical in a dose-dependent manner. The scavenging activity of OH⋅ and DPPH radical was 93.1% and 41.2%, respectively, at CPS concentration of 1 mg/mL. CPS could significantly promote RAW264.7 cell proliferation and reduce the Reactive Oxygen Species (ROS) level of H2O2-induced damage in RAW264.7 cells in a dose-dependent manner. Furthermore, all CPS-treated groups exhibited an increase in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and a decrease in malondialdehyde (MDA) level compared with the control. These results showed that CPS could effectively protect RAW264.7 cells from H2O2-induced damage, implying the potential utilization of CPS as a natural antioxidant for food and pharmaceutical applications.
Keywords: Acaudina molpadioides; antioxidant peptides; microwave-assisted hydrolysis; oxidative stress protection.