The Antioxidant Protective Effect of Iris-Squid-Derived Protein Hydrolysates (>10 kDa) in HSF Fibroblast Cells Induced by H2O2

Abstract

One of the supporting factors behind the biomolecules recently used in anti-aging and skin nourishment is their antioxidant properties. Hydrogen peroxide (H2O2) is a well-known small molecule oxidant that induces apoptosis in human skin fibroblast (HSF) cells through the synthesis of inflammatory cytokines. Hence, this study aimed to investigate the antioxidant activities of protein hydrolysates prepared from Iris squid (Symplectoteuthis oualaniensis) (PHCSO) in vitro. Firstly, two peptides with MWs more than 10 kDa (PHCSO-1) and less than 10 kDa (PHCSO-2) were obtained through ultrafiltration and were characterized (molecular pattern amino acid composition, FTIR) before testing the antioxidant activity (DPPH radical scavenging activity and hydroxyl radical scavenging activity). Then, the effects of PHCSOs on HSF cell viability, H2O2-induced oxidative stress model of HSF cells, ROS fluorescence staining, level of cytokines (IL-1, IL-6 and TNF-α) and cellular antioxidant properties (SOD activity, CAT activity, GSH and MDA content) were investigated. The cell morphology was examined through fluorescence staining and inflammatory factors and antioxidant activity analysis showed that superior properties were observed in PHCSO-2 peptide compared to PHCSO-1 and PHCSO. Among the peptides, PHCSO-2 (5 mg/mL) had higher DPPH and hydroxyl radical scavenging activities of 58% and 57%, respectively. On the other hand, the PHCSO-2 treatment reduced the TNF-α activity by 25%, which indicated the effective protection of PHCSO-2 from oxidative stress damage in the skin. These findings proved that peptides with less than 10 kDa were more suitable for therapeutic purposes, with good antioxidant properties. Accordingly, the protein hydrolysate from S. oualaniensis proved to be an excellent marine-based antioxidant peptide, which could be applied in cosmetic, pharmaceutical and food industries.