Identification of novel antioxidant collagen-peptides for preventing and treating H₂O₂-induced oxidative stress in HepG2 cells through in vitro and in silico approaches

Background
Nowadays, the prevalence of oxidative stress-related chronic diseases is increasing. The identification of novel antioxidant collagen-peptides to counteract oxidative stress for individuals’ health have gained significant intention.

Results
In this study, the collagen-peptides with antioxidant activities were separated and identified by ion chromatography (IEC), reversed-phase high-performance liquid chromatography (RP-HPLC), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). The identified antioxidant collagen-peptides were further screened by molecular docking for Keap1-targeted peptide inhibitors and their theoretical interaction mechanisms were investigated. Four novel antioxidant collagen-peptides, GPAGPIGPVG, GPAGPpGPIG, ISGPpGPpGPA and IDGRPGPIGPA with high binding affinity to Keap1 were selected. Molecular docking results demonstrated that the putative antioxidant mechanism of four antioxidant collagen-peptides contributed to their blockage of Keap1-Nrf2 interactions. The results of antioxidant activity of four antioxidant collagen-peptides proved that IDGRPGPIGPA exerted a high scavenging capacity to DPPH and ABTS free radicals, while GPAGPpGPIG improved the resistance of cells to hydrogen peroxide (H2O2) induced oxidative damage by promoting the activation of intracellular antioxidant enzymes and the production of reduced glutathione in human hepatoma (HepG2) cells.

Conclusion
The antioxidant collagen-peptides (GPAGPIGPVG, GPAGPpGPIG, ISGPpGPpGPA and IDGRPGPIGPA) will be developed as the novel functional food for human health in the near future.