Mechanisms of suppression of nitric oxide production by 3-O-methylquercetin in RAW 264.7 cells

Jiunn Song Jiang, Chwen Ming Shih, Sheng Hao Wang, Tzu Ting Chen, Chun Nan Lin, Wun-Chang Ko

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


Rhamnus nakaharai Hayata (Rhamnaceae) is used as a folk medicine in Taiwan for treating constipation, inflammation, tumors, and asthma. 3-O-Methylquercetin (3-MQ), a main constituent of the plant, has been reported to have potential for use in the treatment of asthma. The mechanisms of anti-inflammation of 3-MQ are still unclear. Nitric oxide (NO) production induced by lipopolysaccharide (LPS) through iNOS expression in RAW 264.7 cells, a mouse macrophage cell line, may reflect the degree of inflammation and may provide a measure for assessing the effect of drugs on the inflammatory process. Therefore, we were interested in investigating the mechanisms of suppression of NO production by 3-MQ in RAW 264.7 cells. 3-MQ (1-10 μM) concentration-dependently inhibited LPS (100 ng/mL)-induced NO production in RAW 264.7 cells. The IC50 value was calculated to be 4.23 μM. 3-MQ (1-10 μM) significantly and concentration-dependently inhibited LPS (100 ng/mL)-induced iNOS protein and mRNA expressions in cells. The IC50 values were calculated to be 4.36 and 6.53 μM, respectively. There was no significant difference among these three IC50 values of 3-MQ. In conclusion, 3-MQ may exert its anti-inflammatory effect through the inhibition of iNOS DNA transcription.

Original languageEnglish
Pages (from-to)281-287
Number of pages7
JournalJournal of Ethnopharmacology
Issue number2
Publication statusPublished - Jan 16 2006


  • 3-O-Methylquercetin
  • Anti-inflammation
  • iNOS mRNA expression
  • iNOS protein expression
  • Rhamnaceae
  • Rhamnus nakaharai

ASJC Scopus subject areas

  • Pharmacology


Dive into the research topics of 'Mechanisms of suppression of nitric oxide production by 3-O-methylquercetin in RAW 264.7 cells'. Together they form a unique fingerprint.

Cite this