Antioxidative stress effect of chromium-chelated pea (Pisum sativum L.) peptides through the Keap1/Nrf2 pathway

Trivalent chromium (Cr(III)) plays an important role in regulating glucose and lipid metabolism. Pea peptides (PP) can chelate Cr(III) but their chelation mechanism and activity remain unclear. The purpose of this study was to prepare chromium-chelated pea peptides (CPP), analyze the structure, and explore the antioxidative stress effect of CPP.

Chromium-chelated pea peptides were first obtained through bio-enrichment methods. Subsequently, the structure of CPP was characterized by ultraviolet (UV) and fluorescence spectroscopy, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and high-performance liquid chromatography-mass spectrometry (HPLC-MS). The study indicated that chromium ions could be bound effectively to PP through carboxyl, carbonyl, and amino ligands, and the CO, NH and OH groups might be the sites during the chelating process. In vitro experiments showed that CPP had superior antioxidant activity to PP in 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, hydroxyl radical scavenging, and ferric reduction ability. Finally, an insulin resistance HepG2 cell model, induced by hyperglycemia, was established.

Chelated pea peptides could regulate the Keap1/Nrf2/HO-1 antioxidative stress signal pathway, promoting nuclear factor erythroid-2-related factor 2 (Nrf2) nuclear translocation and activating the downstream antioxidant gene heme oxygenase-1 (HO-1) to exert antioxidative stress effects, reducing the oxidative stress levels in the insulin-resistant HepG2 cell model. © 2025 Society of Chemical Industry.