Inhibitory effect of inflexinol on nitric oxide generation and iNOS expression via inhibition of NF-kappaB activation

Mediators Inflamm. 2007;2007:93148. doi: 10.1155/2007/93148. Epub 2007 Apr 3.

Abstract

Inflexinol, an ent-kaurane diterpenoid, was isolated from the leaves of Isodon excisus. Many diterpenoids isolated from the genus Isodon (Labiatae) have antitumor and antiinflammatory activities. We investigated the antiinflammatory effect of inflexinol in RAW 264.7 cells and astrocytes. As a result, we found that inflexinol (1, 5, 10 microM) suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) as well as the production of nitric oxide (NO) in LPS-stimulated RAW 264.7 cells and astrocytes. Consistent with the inhibitory effect on iNOS and COX-2 expression, inflexinol also inhibited transcriptional and DNA binding activity of NF-kappaB via inhibition of IkappaB degradation as well as p50 and p65 translocation into nucleus. These results suggest that inflexinol inhibits iNOS and COX-2 expression through inhibition of NF-kappaB activation, thereby inhibits generation of inflammatory mediators in RAW 264.7 cells and astrocytes, and may be useful for treatment of inflammatory diseases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Astrocytes / cytology
  • Astrocytes / drug effects
  • Astrocytes / metabolism
  • Blotting, Western
  • Cell Line
  • Cell Survival / drug effects
  • Cells, Cultured
  • DNA / metabolism
  • Diterpenes, Kaurane / chemistry
  • Diterpenes, Kaurane / pharmacology*
  • Electrophoretic Mobility Shift Assay
  • Luciferases / genetics
  • Luciferases / metabolism
  • Macrophages / cytology
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Molecular Structure
  • NF-kappa B / genetics
  • NF-kappa B / metabolism*
  • Nitric Oxide / metabolism*
  • Nitric Oxide Synthase Type II / metabolism*
  • Polysaccharides, Bacterial / pharmacology
  • Protein Binding / drug effects
  • Rats
  • Rats, Sprague-Dawley
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • Transfection

Substances

  • Diterpenes, Kaurane
  • NF-kappa B
  • Polysaccharides, Bacterial
  • Recombinant Fusion Proteins
  • ent-1,3,6,11-tetrahydroxykaur-16-ene-15-one 3,11-diacetate
  • Nitric Oxide
  • DNA
  • Luciferases
  • Nitric Oxide Synthase Type II