In Vitro Antioxidant Activity and In Vivo Anti-Fatigue Effect of Sea Horse (Hippocampus) Peptides

Abstract

This study investigated changes the in vitro antioxidant activity of <i>Hippocampus</i> polypeptides during enzymatic hydrolysis, including the effects of enzyme species, enzyme concentration, material-liquid ratio, hydrolysis time, pH, and temperature of the reaction system. Its in vivo anti-fatigue activity was also studied. <i>Hippocampus</i> peptide prepared by papain digestion exhibited the highest 1,1-diphenyl-2-picryl-hydrazyl free radical scavenging rate (71.89% ± 1.50%) and strong hydroxyl radical scavenging rate (75.53% ± 0.98%), compared to those prepared by five other commonly used enzymes (i.e., trypsin, neutral protease, compound protease, flavorzyme, and alkaline protease). Additionally, maximum antioxidant activity of <i>Hippocampus</i> polypeptide prepared by papain digestion was reached after hydrolysis for 40 min at pH 6.0 and 60 °C of the reaction system by using 2000 U/g enzyme and a material-liquid ratio of 1:15. Moreover, compared with the control group, <i>Hippocampus</i> peptide prolonged the swimming time by 33%-40%, stabilized the blood glucose concentration, increased liver glycogen levels, and decreased blood lactate levels and blood urea nitrogen levels in mice (<i>p</i> < 0.01). In conclusion, these results indicated that <i>Hippocampus</i> polypeptide prepared by papain digestion under optimal conditions exhibited high degrees of antioxidant and anti-fatigue activity.