A polysaccharide isolated from Ecklonia cava fermented by Lactobacillus brevis inhibits the inflammatory response by suppressing the activation of nuclear factor-κB in lipopolysaccharide-induced RAW 264.7 macrophages.

Abstract

We previously reported that the increment of carbohydrate content in the Viscozyme(®) L (Novozyme Corp., Oklahoma City, OK, USA) extract of Lactobacillus brevis-fermented Ecklonia cava affected the inhibition of nitric oxide (NO) production and that it might be related to the polysaccharide compound. However, there is no report of anti-inflammatory effects of the polysaccharide or its biological mechanism. Here, we investigated the anti-inflammatory effects of the polysaccharide and its biological mechanism in lipopolysaccharide (LPS)-activated RAW 264.7 cells. The polysaccharide isolated from the Viscozyme extract of L. brevis-fermented E. cava (VLFEP) dose-dependently decreased LPS-stimulated NO production without cytotoxicity. Also, VLFEP significantly decreased the production of prostaglandin E(2) (PGE(2)) at the 100 μg/mL concentration. In addition, VLFEP dose-dependently decreased the protein and mRNA expressions of inducible NO synthase, whereas it slightly decreased those of cyclooxygenase 2 and only at the 100 μg/mL concentration. Moreover, VLEFP dose-dependently decreased the productions and/or mRNA expressions of tumor necrosis factor-α and interleukin-6, compared with those of LPS only-stimulated cells. In further experiments, VLFEP considerably reduced the phosphorylation and degradation of inhibitory κB as well as the translocation of nuclear transcription factor-κB (NF-κB) p65 into the nucleus, and its DNA binding was markedly induced by LPS stimulation. This study suggests that VLFEP exerts anti-inflammatory effects by down-regulating the production and expression of pro-inflammatory cytokines and mediators via inhibiting the NF-κB pathway in LPS-stimulated RAW 264.7 cells.