Abstract: The purpose of this experiment was to investigate the protective effect of Phaseolus vulgaris peptides (PVPs) on H2O2-induced oxidative damage in HepG2 cells and to elucidate the underlying mechanism. HepG2 cells were cultured in vitro, which were divided into blank group, model group (subjected to 2 mmol/L H2O2 stimulation for 1 h after 24 h culture under normal conditions), and low-, medium- and high-dose PVPs (subjected to 2 mmol/L H2O2 stimulation for 1 h after 24 h culture in the presence of PVPs at 50, 100 and 200 μg/mL) groups. The cell proliferation rate was measured by WST-1 assay, the reactive oxygen species (ROS) level by flow cytometry, and the intracellular antioxidant enzyme activity by enzyme linked immunosorbent assay, and the expression of apoptotic proteins by Western blot. The results showed that PVPs could alleviate growth inhibition induced by H2O2 in HepG2, reduce the levels of ROS and intracellular malondialdehyde, increase superoxide dismutase, catalase and glutathione peroxidase activity, and down-regulate p53 and caspase-3 protein expression. In conclusion, PVPs has a protective effect on H2O2-induced oxidative damage in HepG2 cells through inhibiting the expression of apoptotic proteins, regulating the cellular redox system, scavenging intracellular reactive oxygen species, and increasing intracellular activity of antioxidant enzymes.

Key words: Phaseolus vulgaris peptides, oxidative stress, antioxidant enzyme system, apoptosis protein