Xanthine Oxidase Inhibitory Peptides From Sea Cucumber (Stichopus japonicus): Virtual Screening, Molecular Dynamics, and in Vitro Assessment

This study employed a computer aided virtual screening strategy integrating water solubility, toxicity, and xanthine oxidase (XOD) binding affinity to identify novel XOD inhibitory peptides from sea cucumber (Stichopus japonicus) proteins. Two peptides, WGNEEF and GGPGDR, were successfully screened, synthesized, and experimentally validated. Molecular docking revealed that GGPGDR exhibited stronger binding affinity to XOD than WGNEEF. In vitro assays demonstrated that GGPGDR and WGNEEF exhibited significant XOD inhibitory activity, with IC 50 values of 1.09 ± 0.04 mg/mL and 2.52 ± 0.06 mg/mL, respectively. Both peptides also showed notable antioxidant capacity in a concentration dependent manner, and WGNEEF displayed particularly strong radical scavenging activity, achieving scavenging rates of 37.59%, 73.69%, and 99.01% against DPPH, ABTS + , and •OH radicals at 1.2 mg/mL. Cytotoxicity evaluation confirmed acceptable biocompatibility, with LO2 cell viability exceeding 80% for both peptides. Molecular dynamics simulations revealed that the GGPGDR/XOD complex possessed higher structural stability, as reflected by lower RMSD, a more compact conformation, and a more persistent hydrogen bond network. Collectively, these findings provide structural insight into peptide-XOD interactions and support the potential of sea cucumber-derived peptides as functional ingredients for hyperuricemia management. Practical Applications The peptides WGNEEF and GGPGDR, derived from Stichopus japonicus , exhibit xanthine oxidase inhibitory and antioxidant activities, showing potential as natural ingredients in functional foods or dietary supplements for the management of hyperuricemia and gout.