Antioxidant Activity of a Phascolosoma esculenta Protein Hydrolysate and Its Effects on Scratch Closure in MRC-5 Cell Monolayers

Phascolosoma esculenta (P. esculenta) is rich in protein, and its peptides exhibit diverse biological activities. This study aimed to evaluate the antioxidant activity and scratch closure in MRC-5 cell monolayers of P. esculenta protein hydrolysate (PEP). PEP was obtained by enzymatic hydrolysis and ultrafiltration and was primarily composed of low-molecular-weight peptides (60.5%, <1 kDa). PEP exhibited in vitro antioxidant activities, including scavenging of 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH), with half-maximal inhibitory concentration (IC50) values of 0.93 and 4.68, respectively. PEP also exhibited reducing power. PEP increased superoxide dismutase (SOD) and catalase (CAT) activities, decreased the content of reactive oxygen species (ROS), and increased the survival time under heat and oxidative stress of Caenorhabditis elegans, thereby conferring protection against oxidative stress. Additionally, PEP possessed the ability to accelerate scratch closure in MRC-5 cell monolayers. This study provides a basis for high-value utilization of P. esculenta and for further investigation of its antioxidant peptides.