Scytonemin, an ultraviolet sunscreen pigment isolated from the extracellular sheath of cyanobacteria, has been reported to exert anti-inflammatory effect. In this study, we examined the effect of scytonemin on lipopolysaccharide (LPS)-induced production of inflammatory mediators, including nitric oxide (NO), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β), in macrophages and investigated the molecular mechanisms responsible for its effects. Scytonemin significantly inhibited NO production and inducible nitric oxide (iNOS) mRNA expression in LPS-stimulated macrophages. The secretion and mRNA expression of TNF-α and IL-1β were also suppressed by scytonemin treatment in RAW 264.7 cells. Further study demonstrated that scytonemin attenuated LPS-induced NF-κB/Rel activation in RAW 264.7 cells. In addition, scytonemin suppressed phorbol ester-induced skin inflammation in BALB/c mice. These results suggest that scytonemin inhibits the expression of inflammatory mediators, at least in part, by blocking NF-κB/Rel activity and might be a potential therapeutic agent for the treatment of inflammatory diseases.
- Copyright © 2011 by The American Association of Immunologists, Inc.