Abstract
In this study,10 novel anti-inflammatory peptides were identified from duck liver,and their molecular mechanism was demonstrated based on machine learning and molecular docking.Using Sephadex G-15 gel chromatography separation,reversed-phase high-performance liquid chromatography purification,liquid chromatography-tandem mass spectrometry identification,and BIOPEP database comparison,10 novel anti-inflammatory peptides were initially found.Their splendid angiotensin-converting enzyme(ACE)inhibition and anti-inflammatory properties were confirmed by machine learning.With binding energies less than-20.93 kJ/mol,molecular docking revealed that they could efficiently bind to the active pockets of tumor necrosis factor α(TNF-α),interleukin 6(IL-6),cyclooxygenase 2(COX-2),and nuclear factor κB(NF-κB)proteins with efficiency,indicating that the compounds can spontaneously form complexes through hydrogen bonding and hydrophobic interactions with the protein binding pockets.In the lipopolysaccharide-induced RAW264.7 cell model,the release of NO,TNF-α,and IL-6 and the mRNA expression of inflammatory factors(TNF-α,IL-6,COX-2,and NF-κB)were significantly inhibited by these peptides.We concluded it might be due to their anti-inflammatory effects by inhibiting the protein phosphorylation of inhibitor of NF-κB(IKBα)in the cytoplasm and preventing the translocation of NF-κB p65 in the cytoplasm to the nucleus,thereby regulating the NF-κB signaling pathway.This study is essential for the screening of anti-inflammatory peptides and the investigation of the mechanism of action.