Abstract: In recent years, antioxidant peptides with high safety and potent antioxidant capacity have become a hot research field. The aim of this study was to investigate the antioxidant and anti-inflammatory effects of a bioactive peptide derived from egg white proteins, WNWAD (Trp-Asn-Trp-Ala-Asp), and its separations WNW (Trp-Asn-Trp), WAD (Trp-Ala-Asp), WN (Trp-Asn) and AD (Ala-Asp). The protective effect against oxidative stress induced by H2O2 in HEK293 cells was evaluated and the in vitro antioxidant activity was measured by 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical scavenging assay. The impact of WNWAD on the cellular content of oxidized glutathione (GSSG) was tested and its effect on the levels of interleukin-8 (IL-8) and tumor necrosis factor (TNF) was assessed by using commercial enzyme-linked immunosorbent assay kits. The results showed that WNWAD at 40 μmol/L possessed the strongest ABTS radical scavenging capacity with a Trolox equivalent antioxidant capacity (TEAC) value of (98.411 ± 0.020）μmol TE/L, followed by WN, WNW and WAD, whose TEAC values were (96.629 ± 0.008), (94.978 ± 0.003) and (88.807 ± 0.003) μmol TE/L, respectively, while AD had no ABTS radical scavenging potential. The survival rate of the cells was (50.240 ± 0.505)% at a H2O2 concentration of 400 μmol/L, with a statistically significant difference (P < 0.001). All peptides concentration dependently protected HEK293 cells from H2O2-induced oxidative damage. Among these, WNWAD had the strongest cytoprotective activity and the cell survival rate was up to 99.12% at 30 μmol/L. Moreover, WNWAD pronouncedly decrease the cellular GSSG content and lowered the levels of IL-8 and TNF. The results above demonstrated that WNWAD played an important role in reducing oxidative stress in HEK293 cells, enhancing cellular antioxidant activity and resisting inflammations.

Key words: egg white bioactive peptide, 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), HEK293 cell, protection against oxidative damage, glutathione, cytokine