7,8-Dihydroxyflavone exhibits anti-inflammatory properties by downregulating the NF-κB and MAPK signaling pathways in lipopolysaccharide-treated RAW264.7 cells

Int J Mol Med. 2012 Jun;29(6):1146-52. doi: 10.3892/ijmm.2012.935. Epub 2012 Mar 13.

Abstract

7,8-Dihydroxyflavone (7,8-DHF), a member of the flavonoid family, has received considerable attention as a selective tyrosine kinase receptor B agonist. Several studies have indicated that 7,8-DHF has neurotrophic and antioxidant activities. However, little is known about the cellular and molecular mechanisms underlying the anti-inflammatory activity of 7,8-DHF. Therefore, we investigated whether 7,8-DHF affects the expression of inflammatory mediators in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. Our results indicated that 7,8-DHF significantly attenuated secretion of LPS-induced inflammatory mediators nitric oxide (NO), prostaglandin E₂ (PGE₂) and interleukin-1β (IL-1β) in RAW264.7 cells. Additionally, LPS-induced expression of inducible NO synthase (iNOS), cyclooxygenase (COX)-2 and IL-1β was decreased by pre-treatment with 7,8-DHF. Our results also showed that 7,8-DHF reduces LPS-induced nuclear factor-κB (NF-κB) activity via the suppression of the nuclear translocation of NF-κB p65 and the degradation of inhibitor κB (lκB). In addition, 7,8-DHF inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs) such as extracellular-signal-related kinase (ERK), p38, and c-Jun N-terminal kinase (JNK). These results suggest that the anti-inflammatory property of 7,8-DHF is related to the downregulation of iNOS, COX-2 and IL-1β, due to NF-κB inhibition as well as to the negative regulation of MAPK activation in RAW264.7 cells. Thus, 7,8-DHF may be a novel therapeutic agent for the prevention of various inflammatory diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology*
  • Cell Line
  • Cell Survival / drug effects
  • Cyclooxygenase 2 / metabolism
  • Dinoprostone / biosynthesis
  • Down-Regulation / drug effects*
  • Enzyme Activation / drug effects
  • Flavones / pharmacology*
  • Gene Expression Regulation / drug effects
  • I-kappa B Proteins / metabolism
  • Interleukin-1beta / genetics
  • Interleukin-1beta / metabolism
  • Lipopolysaccharides / pharmacology*
  • MAP Kinase Signaling System / drug effects*
  • Mice
  • Mitogen-Activated Protein Kinases / metabolism*
  • NF-kappa B / metabolism*
  • Nitric Oxide / biosynthesis
  • Nitric Oxide Synthase Type II / metabolism
  • Phosphorylation / drug effects
  • Protein Transport / drug effects
  • Proteolysis / drug effects

Substances

  • 6,7-dihydroxyflavone
  • Anti-Inflammatory Agents
  • Flavones
  • I-kappa B Proteins
  • Interleukin-1beta
  • Lipopolysaccharides
  • NF-kappa B
  • Nitric Oxide
  • Nitric Oxide Synthase Type II
  • Ptgs2 protein, mouse
  • Cyclooxygenase 2
  • Mitogen-Activated Protein Kinases
  • Dinoprostone