Identification and molecular docking of antioxidant peptides from hemp seed protein hydrolysates

The aim of this study was to assess the antioxidant activities of hemp seed protein hydrolysates (HPH) and identify antioxidant peptides. In vitro chemical-based assays indicated that HPH (0.4 mg/mL) possessed high ABTS radical cation scavenging activity (52.3 ± 0.1%), Fe2+-chelating activity (52.9 ± 0.9%) and hydroxyl radical scavenging activity (50.9 ± 1.3%). HPH (0.4 mg/mL) significantly elevated the cell viability (from 55.7 ± 1.2% to 80.0 ± 2.0%), and prevented the production of reactive oxygen species accompanied by increasing the antioxidant enzyme activities in HepG2 cells with H2O2-induced oxidative stress. After separation with gel filtration chromatography and reversed-phase high-performance liquid chromatography, two potential antioxidant peptides were firstly identified as Tyr-Gly-Arg-Asp-Glu-Ile-Ser-Val (YGRDEISV) and Leu-Asp-Leu-Val-Lys-Pro-Gln (LDLVKPQ) by liquid chromatography-tandem mass spectrometry. Molecular docking showed that the putative antioxidant mechanism of both peptides was attributed to their blockage of the entrance to myeloperoxidase active cavity. The (−) CDOCKER energy was 114.6 kcal/mol for peptide YGRDEISV, and 82.8 kcal/mol for peptide LDLVKPQ. Additionally, both of the peptides had good water-solubility and stability, no allergenicity or toxicity according to in silico prediction. Our findings suggest the potential for the development of HPH as an antioxidant.