Identification and validation of a novel antioxidant peptide from loach (Misgurnus anguillicaudatus): Integrating peptidomics, molecular simulation, and in vitro functional assays

Loach ( Misgurnus anguillicaudatus ) is rich in protein, and its bioactive peptides have antioxidant potential, but specific functional peptides remain to be identified and screened. This study aimed to identify and validate a novel antioxidant peptide from loach. Peptidomic analysis was employed to predict the potential antioxidant function of loach peptides. Combined with evaluations of bioactivity score, sensitization, and toxicity, three candidate peptides were screened and selected, with Tn (GFGGGMGGGFGGGMGMG) as the main candidate. Molecular docking and molecular dynamics simulation showed Tn could bind to Nrf2 protein and maintain certain stability. In vitro , Tn’s DPPH/ABTS radical scavenging and iron reduction abilities were concentration-dependent. Tn significantly increased SOD and GR activities in HUVEC, reduced MDA content, decreased content of ROS, and alleviated apoptosis. This study lays a foundation for high-value utilization of loach and further research on loach antioxidant peptides. • A new antioxidant peptide Tn is identified from loach. • Tn has a good antioxidant ability and cytoprotective effect in vitro : compared with the model group, it increases the level of SOD by 145.5% and decreases the content of ROS by 33.1%. • Water Bridges, hydrogen bonds, or hydrophobic interactions facilitate Tn binding to Nrf2.