Chromene suppresses the activation of inflammatory mediators in lipopolysaccharide-stimulated RAW 264.7 cells

Inflammation is complex process involving a variety of immune cells that defend the body from harmful stimuli. However, pro-inflammatory cytokines and inflammatory mediators can also exacerbate diseases such as cancer. The aim of this study was to identify a natural effective remedy for inflammation. We isolated a functional algal chromene compound from Sargassum siliquastrum, named sargachromanol D (SD). We evaluated the anti-inflammatory effect of SD on lipopolysaccharide (LPS)-exposed RAW 264.7 cells by measuring cell viability, cytotoxicity, and production of inflammatory mediators such as nitric oxide (NO), prostaglandin E-2 (PGE(2)), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), and the pro-inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1 beta, and IL-6. SD inhibited production of NO and PGE(2) from LPS-induced cells by preventing the expression of inflammatory mediators such as iNOS and COX-2 in a dose-dependent manner. Concurrently, levels of the pro-inflammatory cytokines TNF-alpha, IL-1 beta, and IL-6 were reduced with increasing concentrations of SD. In addition, SD inhibited the activation of NF-kappa B and mitogen-activated protein kinases (MAPKs) pathways in a concentration-dependent manner. These restilts indicate that SD inhibits LPS-stimulated inflammation by inhibition of the NF-kappa B and MAPKs pathways in macrophages. (C) 2014 Elsevier Ltd. All rights reserved.