Two enone fatty acids isolated from Gracilaria verrucosa suppress the production of inflammatory mediators by down-regulating NF-κB and STAT1 activity in lipopolysaccharide-stimulated RAW 264.7 cells

Gracilaria verrucosa is a common marine red alga that has anti-oxidant and anti-cancer properties. Recently, we reported that anti-inflammatory constituents of G. verrucosa operate through an unknown mechanism. For this reason, we isolated two enone fatty acids from G. verrucosa and investigated their molecular mechanism in LPS-stimulated RAW264.7 cells. We found that the two compounds inhibited the production of inflammatory markers (nitric oxide, TNF-α, and IL-6) in a dose-dependent manner. We next studied the effects of G. verrucosa compounds on LPS-induced signaling pathways. The two compounds suppressed NF-κB reporter activity by interfering with nuclear translocation of NF-κB and suppressed JAK/STAT (p-STAT1) signaling. These results suggest that G. verrucosa inhibits the production of inflammatory mediators (NO, TNF-α, and IL-6) by suppressing the activation of NF-κB and the phosphorylation of STAT1.