Abalone visceral peptides containing Cys and Tyr exhibit strong in vitro antioxidant activity and cytoprotective effects against oxidative damage

The in vitro antioxidation and cytoprotection of abalone visceral peptides against oxidative damage were investigated. Results show that the DPPH· scavenging activities of the 16 chemically synthesized peptides were significantly and positively correlated with their reducing power. Their scavenging activities against ABTS·⁺ were positively correlated with their ability to inhibit linoleic acid oxidation. Only Cys containing peptides exhibited good DPPH· scavenging activity, while only Tyr containing peptides showed significant ABTS·⁺ scavenging activity. In the cytoprotection assay, all four representative peptides significantly increased the viability of H₂O₂-damaged LO2 cells and the activities of GSH-Px, CAT, and SOD, and all decreased MDA levels and LDH leakage, in which the Cys-containing peptides were more effective at increasing the activities of antioxidant enzymes, while the Tyr-containing peptides were more effective at decreasing MDA levels and LDH leakage. Abalone visceral peptides containing both Cys and Tyr exhibit strong in vitro and cellular antioxidation.