Antioxidant peptides derived from chia seeds: optimization, purification, identification, molecular mechanism...

This study aims to optimize the production of antioxidant peptides from chia seeds and to identify peptides that potently inhibit myeloperoxidase (MPO). Using response surface methodology (RSM), flavour protease was selected as the most effective enzyme, with optimal hydrolysis conditions of 5.69 h, 52.34 °C, pH 7.38, and an enzyme-to-substrate ratio (E/S) of 8487.60 U/g. Fractionation showed that peptides <3 kDa exhibited strong antioxidant activity. Four peptides (LSSAML, IKDPDTF, FSPSQRY, and AGSNDESWCQGD) were identified by nano-high-performance liquid chromatograph-tandem mass spectrometry (nano-HPLC-MS/MS) combined with in silico analysis; notably, FSPSQRY and AGSNDESWCQGD are novel peptides that have not been previously reported. Molecular docking and molecular dynamics simulations confirmed their stable binding to MPO. In vitro inhibition assays in a serum system demonstrated that all four peptides significantly suppressed MPO activity, with inhibition rates ranging from 59.9% to 75.8%. Among them, FSPSQRY exhibited the strongest inhibitory effect, with an inhibition rate of 75.8%.