Elucidating the antioxidant mechanism of novel peptides from Lablab purpureus: Integrated in silico screening, quantum chemical analysis, and cytoprotection.

Lablab purpureus is an underutilized legume and a promising source of bioactive peptides. This study combined peptidomics, virtual screening, and in vitro verification to screen novel antioxidant peptides from L. purpureus and elucidated their mechanisms via molecular docking and quantum chemistry analysis. A total of 99 peptide sequences were identified, among which six peptides with potential antioxidant activity were selected, each demonstrating stable binding to Keap1. In addition, the benzene ring of phenylalanine, the imidazole group of histidine, and the indole group of tryptophan in peptides act as electron donors to scavenge free radicals. DWYKGPTL exhibited the highest antioxidant activity and maintained stability under various processing conditions. Furthermore, DWYKGPTL significantly alleviated oxidative stress in HepG2 cells by reducing MDA accumulation and LDH release, while upregulating endogenous antioxidant enzymes. These findings provide a theoretical basis for the molecular mechanism of L.purpureus peptides and support their application as functional food ingredients.