Anti-inflammatory effect of enzymatic hydrolysates from Styela clava flesh tissue in lipopolysaccharide-stimulated RAW 264.7 macrophages and in vivo zebrafish model

BACKGROUND/OBJECTIVES: In this study, potential anti-inflammatory effect of enzymatic hydrolysates from Styela clava flesh tissue was assessed via nitric oxide (NO) production in lipopolysaccahride (LPS) induced RAW 264.7 macrophages and in vivo zebrafish model. MATERIALS/METHODS: We investigated the ability of enzymatic hydrolysates from Styela clava flesh tissue to inhibit LPS-induced expression of pro-inflammatory mediators in RAW 264.7 macrophages, and the molecular mechanism through which this inhibition occurred. In addition, we evaluated anti-inflammatory effect of enzymatic hydrolysates against a LPS-exposed in in vivo zebrafish model. RESULTS: Among the enzymatic hydrolysates, Protamex-proteolytic hydrolysate exhibited the highest NO inhibitory effect and was fractionated into three ranges of molecular weight by using ultrafiltration (UF) membranes (MWCO 5 kDa and 10 kDa). The above 10 kDa fraction down-regulated LPS-induced expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), thereby reducing production of NO and prostaglandin E(2) (PGE(2)) in LPS-activated RAW 264.7 macrophages. The above 10 kDa fraction suppressed LPS-induced production of pro-inflammatory cytokines, including interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. In addition, the above 10 kDa fraction inhibited LPS-induced phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), and p38. Furthermore, NO production in live zebrafish induced by LPS was reduced by addition of the above 10 kDa fraction from S. clava enzymatic hydrolysate. CONCLUSION: The results of this study suggested that hydrolysates derived from S. clava flesh tissue would be new anti-inflammation materials in functional resources.