ABSTRACT
The skipjack enzymatic peptide 3 (SEP-3) has been previously isolated and purified from a byproduct of skipjack. In this paper, the anti-inflammatory activity and mechanism of SEP-3 in RAW264.7 macrophages activated by lipopolysaccharide (LPS) were investigated. We found that SEP-3 enhanced the proliferation and phagocytic capacity of RAW264.7 macrophages and suppressed the expression of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α. Cells treated with SEP-3 showed decreased phosphorylation of ERK, p38, JNK, NF-κB p65, and IκBα and inhibited NF-κB and mitogen-activated protein kinases (MAPK) inflammatory pathways. Optimal dosage was determined, and modified outcome was identified when SEP-3 treatment was combined with indomethacin. In addition, the metabolites of the dominant microflora of mice gavaged by SEP-3 showed antioxidant activity in vitro. Therefore, we conclude that SEP-3 extracted from skipjack may have a direct or indirect anti-inflammatory effect and can be used as an adjuvant drug to treat inflammatory diseases.
Disclosure statement
No potential conflict of interest was reported by the authors.
Author contributions
Contributions were as follows: C.Y. – data collection, data analysis, writing of manuscript; Y.W. – data collection, writing of manuscript; Z.-g.W. – methodology, data collection, data analysis; K.-m.W.,Z.-k. Z. – data collection, data analysis; B.W. – methodology, supervision; H.-y.L. – resources, writing, review, and editing of manuscript.