Purification, identification, and mechanism of action of novel antioxidant peptides from quinoa (Chenopodium quinoa wild.) protein hydrolysate

The aim of this study was to identify novel antioxidant peptides from quinoa ( Chenopodium quinoa wild.) protein hydrolysates, which were prepared using enzyme combination methods. Eleven novel antioxidant peptides were screened through in silico evaluation, and their structure-activity relationships were further investigated. Molecular docking studies indicated that GPGGGGKGEMF (GF-11) exhibited a higher binding affinity and interaction capacity. GF-11 significantly reduced reactive oxygen species (ROS) levels to 43.20 and malondialdehyde (MDA) levels to 1.92 nmol/mg protein in oxidatively damaged RAW264.7 cells, while also significantly enhancing SOD, GSH-Px, and CAT activities to 25.33, 133.99, and 43.20 U/mg protein, respectively. Furthermore, GF-11 competed with Nrf2 for the binding site on Keap1, promoting the expression of Nrf2, HO-1, and NQO1 proteins, which ultimately activated the Keap1-Nrf2 pathway and mitigated oxidative damage. These findings provide a scientific basis for the application of quinoa antioxidant peptides in the development of functional foods.