Utilization of Chum Salmon (Oncorhynchus keta) Skin Gelatin Hydrolysates to Attenuate Hydrogen Peroxide-Induced Oxidative Injury in Rat Hepatocyte BRL Cell Model

Six chum salmon skin gelatin hydrolysates with degree of hydrolysis of 4.7–13.5% were generated by Alcalase and papain and showed scavenging activities to 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, and superoxide anion radicals. Potential protection of these hydrolysates against H2O2-induced oxidative injury in rat hepatocyte line (BRL cells) was assessed in vitro, based on cell viability, leakage of lactate dehydrogenase, thiobarbituric acid reactive substances (TBARS), glutathione content, glutathione reductase, and catalase of the cells. The hydrolysates exhibited protection on the hepatocytes, reflected by an enhanced cell viability (about 6.2–87.9%), glutathione reductase (about 28.2–85.9%) or catalase (about 43.3–116.9%) activity, and decreased lactate dehydrogenase leakage (about 2.7–34.7%) or TBARS content (about 4.1–39.3%). On the contrary, cellular glutathione content gave an unnoticeable difference among the investigated groups. These hydrolysates also showed protection against DNA damage in the cells. Cytoprotection of these hydrolysates possessed a dosage-dependence manner. More importantly, there was a high correlation (0.7 < r < 0.9) between DPPH or superoxide anion radical scavenging activity of these hydrolysates and three cellular antioxidant indices (glutathione content, glutathione reductase, and catalase activity).