Structural characterization, HepG2 cell cytoprotective ability, and antioxidant mechanism of novel antioxidant peptides identified from black soldier fly larvae (Hermetia illucens L.)

This study isolated a novel antioxidant peptide from black soldier fly larvae (BSFL) using enzymatic hydrolysis. Firstly, the BSFL enzymatic hydrolysate was fractionated through ultrafiltration, with the <3 kDa fraction exhibiting the strongest DPPH and ABTS radical scavenging activity. Subsequently, this fraction was further fractionated through gel filtration chromatography and RP-HPLC. Totally, 153 peptides were identified through LC-MS/MS analysis, from which a novel peptide EDEGTYKCVLS (Pep6) was screened according to activity prediction and verification. Pep6 exhibited high radical scavenging capacity and cytoprotective effect on HepG2 cells against H₂O₂ damage, meanwhile significantly increasing the intracellular antioxidant enzymes activity. Molecular docking analysis indicated that Pep6 competitively bound to Keap1, thereby inhibiting the formation of Keap1-Nrf2 complex, ultimately protecting cells from oxidative stress damage. In this study, a novel antioxidant peptide Pep6 was identified from BSFL, and its antioxidant mechanism was elucidated, providing a theoretical basis for its use as a natural antioxidant.