Protective Effect of Antioxidant Peptides from Argopecten irradians against Alcoholic Liver Injury

Objective: To investigate the antioxidant effect of peptides from Argopecten irradians and its protective effect and mechanism against ethanol-induced alcoholic liver injury in mice. Methods: A. irradians peptides were prepared by two-step enzymatic hydrolysis followed by membrane separation. The in vitro antioxidant activity of A. irradians peptides, the activating effects on superoxide dismutase (SOD) and alcohol dehydrogenase (ADH) and the potential to promote alcohol metabolism were evaluated. The protective effect and mechanism against alcoholic liver injury in mice were investigated by measuring the activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the serum, and the activities of ADH, acetaldehyde dehydrogenase (ALDH), glutathione peroxidase (GSH-Px), catalase (CAT) and SOD and malondialdehyde (MDA) content in the liver of a mouse model of acute alcoholism. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze the peptide sequences. PeptideRanker and AnOxPePred 1.0 tools were used to predict the potential biological activity of peptides and conduct molecular docking analysis of the peptide with the strongest antioxidant activity to ALDH. Results: Peptides with molecular mass between 200 and 1 000 Da constituted approximately 70.38% of the total peptides. Antioxidant amino acids accounted for 68.75% of the total amino acids. In vitro experiments showed that the half maximal inhibitory concentration (IC50) values of A. irradians peptides were 19.43, 4.53 and 2.19 mg/mL in 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging and Fe2+ chelating assays, respectively. At 5 mg/mL, the hydrolysate of A. irradians activated SOD and ADH by 19.83% and 18.18%, respectively, demonstrating good antioxidant activity and anti-alcoholic potential. In vivo experimental results showed that A. irradians peptides significantly reduced the levels of ALT and AST in mouse serum, enhanced the activity of ADH, ALDH, GSH-Px, SOD and CAT, and reduced the content of MDA. Using PeptideRanker and AnOxPePred 1.0 tools, 44 identified peptides were screened, and 6 of them met the criteria for molecular docking screening. Molecular docking revealed that they had strong binding capacity to ALDH. Among them, DQPHFPF and YSTHPHF formed 7 and 3 hydrogen bonds with ALDH, respectively, which could be activated through molecular interactions with ALDH. Conclusion：This study provides a theoretical reference for the application of peptides products from A. irradians for curing alcohol and protecting liver.