Pueraria lobata-derived peptides hold promise as a novel antioxidant source by mitigating ethanol-induced oxidative stress in HepG2 cells through regulating the Keap1/Nrf2 pathway.

The protective effects and mechanisms of antioxidant peptides from Pueraria lobata protein (PLP) against ethanol-induced oxidative injury in HepG2 cells were investigated, including peptide structure analysis. PLP was hydrolyzed and purified using ultrafiltration, Sephadex G-15 gel, DEAE-52 cellulose column and RP-HPLC. LC-MS/MS analysis and molecular docking identified four candidate peptides-YLWVGA, LLVYY, VLSALP, and DVLPLA. Among these, YLWVGA demonstrated the strongest antioxidant activity, likely attributed to its lowest CDOCKER energy, additional key binding sites and hydrogen bonds with Keap1 compared to other peptides, along with a T-type π-π stacking interaction. This resulted in reduced Reactive Oxygen Species (ROS) and Malondialdehyde (MDA) levels, as well as decreased liver injury markers, indicating improved cellular integrity. This protective effect could be responsible for activating the Keap1/Nrf2 signaling pathway, which upregulated antioxidant enzymes including Catalase (CAT), Glutathione Peroxidase (GSH-Px), Superoxide Dismutase (SOD) to strengthen defenses. The outcomes demonstrated the potential of YLWVGA as a functional food additive for managing oxidative stress-related diseases.