Suppressive effects of methoxyflavonoids isolated from Kaempferia parviflora on inducible nitric oxide synthase (iNOS) expression in RAW 264.7 cells

J Ethnopharmacol. 2011 Jul 14;136(3):488-95. doi: 10.1016/j.jep.2011.01.013. Epub 2011 Jan 18.


Ethnopharmacological relevance: The rhizomes of Kaempferia parviflora Wall. ex Baker have been traditionally used in Thailand to treat abscesses, gout, and peptic ulcers.

Aim: Previously, we reported that the chloroform fraction of a Kaempferia parviflora extract had an inhibitory effect on rat paw-edema. In the present study, we isolated the constituents of this fraction and investigated the anti-inflammatory mechanism against nitric oxide (NO) production, tumor necrosis factor-α (TNF-α) and the expression of inducible nitric oxide synthase (iNOS) as well as phosphorylated extracellular signal-regulated kinase (p-ERK), and phosphorylated c-Jun N-terminal kinase (p-JNK). In addition, effects of trimethylapigenin (4) on the enzyme activities of protein kinases possibly leading to iNOS expression were examined to clarify the targets.

Materials and methods: The chloroform fraction was isolated using silica gel column chromatography and HPLC. Isolated compounds were tested against NO and TNF-α using RAW264.7 cells. Cytotoxicity and iNOS, p-ERK and p-JNK expression were also examined.

Results: Three active components, 5,7-dimethoxyflavone (2), trimethylapigenin (4), and tetramethylluteolin (5), markedly inhibited the production of NO in lipopolysaccharide (LPS)-activated RAW264.7 cells. Compounds 2, 4, and 5 moderately inhibited production of TNF-α. Compounds 2, 4, and 5 strongly inhibited expression of iNOS mRNA and iNOS protein in a dose-dependent manner, but did not inhibit p-ERK or p-JNK protein expression. The most active compound, 4, did not inhibit the enzyme activity of inhibitor of κB kinases or mitogen-activated protein kinases, but inhibited that of spleen tyrosine kinase (SYK).

Conclusion: The mechanism responsible for the anti-inflammatory activity of methoxyflavonoids from the chloroform fraction of the rhizomes of Kaempferia parviflora is mainly the inhibition of iNOS expression, and the inhibition of SYK by 4 may be involved in the suppression of LPS-induced signaling in macrophages.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / isolation & purification
  • Anti-Inflammatory Agents / pharmacology*
  • Anti-Inflammatory Agents / therapeutic use
  • Apigenin / isolation & purification
  • Apigenin / pharmacology
  • Apigenin / therapeutic use
  • Cell Line
  • Dose-Response Relationship, Drug
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Flavones / isolation & purification
  • Flavones / pharmacology*
  • Flavones / therapeutic use
  • Flavonoids / isolation & purification
  • Flavonoids / pharmacology
  • Flavonoids / therapeutic use
  • Inflammation / drug therapy
  • Inflammation / metabolism
  • Intracellular Signaling Peptides and Proteins / antagonists & inhibitors
  • JNK Mitogen-Activated Protein Kinases / metabolism
  • Lipopolysaccharides
  • Luteolin / isolation & purification
  • Luteolin / pharmacology
  • Luteolin / therapeutic use
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Mice
  • Nitric Oxide / biosynthesis*
  • Nitric Oxide Synthase Type II / genetics
  • Nitric Oxide Synthase Type II / metabolism*
  • Phytotherapy*
  • Plant Extracts / chemistry
  • Plant Extracts / pharmacology*
  • Plant Extracts / therapeutic use
  • Protein-Tyrosine Kinases / antagonists & inhibitors
  • RNA, Messenger / metabolism
  • Rhizome
  • Syk Kinase
  • Tumor Necrosis Factor-alpha / metabolism
  • Zingiberaceae / chemistry*


  • Anti-Inflammatory Agents
  • Flavones
  • Flavonoids
  • Intracellular Signaling Peptides and Proteins
  • Lipopolysaccharides
  • Plant Extracts
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • 5,7-dimethoxyflavone
  • Nitric Oxide
  • Apigenin
  • Nitric Oxide Synthase Type II
  • Protein-Tyrosine Kinases
  • Syk Kinase
  • Syk protein, mouse
  • Syk protein, rat
  • Extracellular Signal-Regulated MAP Kinases
  • JNK Mitogen-Activated Protein Kinases
  • Luteolin