A Comparative Study of the Stability, Transport, and Structure-Activity Relationship of Round Scad Derived Peptides...

Our previous study identified round scad neuroprotective peptides with different characteristics. However, the intrinsic relationship between their structure and bioactivity, as well as their bioavailability, remains unclear. The aim of this study is to elucidate the bioavailability of these peptides and their structure-activity relationship against neuroinflammation. Results showed that the SR and WCP peptides were resistant to gastrointestinal digestion. Additionally, peptides SR, WCP, and WCPF could transport Caco-2 monolayers as intact peptides. The permeability coefficients (P_app) of SR, WCP, and WCPF in Caco-2 monolayer were (1.53 ± 0.01) × 10^-5, (2.12 ± 0.01) × 10^-5, and (8.86 ± 0.03) × 10^-7 cm/s, respectively. Peptides SR, WCP, and WCPF, as promising inhibitors of JAK2 and STAT3, could attenuate the levels of pro-inflammatory cytokines and regulate the NFκB and JAK2/STAT3 signaling pathway in LPS-treated BV-2 cells. WCPF exerted the highest anti-inflammatory activity. Moreover, bioinformatics, molecular docking, and quantum chemistry studies indicated that the bioactivity of SR was attributed to Arg, whereas those of WCP and WCPF were attributed to Trp. This study supports the application of round-scad peptides and deepens the understanding of the structure-activity relationship of neuroprotective peptides.