Anti-inflammatory activity of ethylacetate fraction of Cliona celata

We evaluated the ability of the ethylacetate fraction of marine sponge, Cliona celata (ECC), harvested from Korean seaside to regulate the expression of inducible nitric oxide synthase (iNOS) in lipopolysaccharide (LPS)-stimulated murine macrophage-like RAW264.7 cells. ECC dose-dependently inhibited both the expression of iNOS protein and mRNA, resulting in decreased production of nitric oxide (NO), with an IC(50) of 80.5 μg/mL. To investigate action mechanism by which ECC inhibits NO production and iNOS expression, we examined the activation of IκB in LPS-stimulated RAW264.7 cells. ECC clearly inhibited translocation of nuclear factor-κB (NF-κB) p65 subunits from cytosol to nucleus, which correlated with its inhibitory effects on IκB-α phosphorylation and degradation. Furthermore, ECC potently suppressed both the reporter gene expression and DNA-binding activity of NF-κB, which was associated with decreased p65 protein levels in the nucleus. Here, we show for the first time that ECC inhibits NF-κB activation through the inhibition of IκB degradation.