title: Houttuynia cordata, a novel and selective COX-2 inhibitor with anti-inflammatory activity.
abstract: BACKGROUND
  Houttuynia cordata Thunb. (Saururaceae; HC) has been long used in traditional oriental medicine for the treatment of inflammation diseases. Modern research has implicated inducible cyclooxygenase-2 (COX-2) as a key regulator of the inflammatory process.
  
  
  OBJECTIVE
  In the present study, we aimed to investigate the effect of HC on COX-2. We examined the effects of HC on lipopolysaccharide (LPS)-induced prostaglandin (PG) E(2) production, an indirect indicator of COX-2 activity, and COX-2 gene and protein expression in mouse peritoneal macrophages.
  
  
  METHODS
  LPS-induced mouse peritoneal macrophages were employed as an in vitro model system. LPS-induced PGE(2) production was assessed by enzyme-linked immunosorbant assay and COX-2 protein expression was assessed by Western blot assay.
  
  
  RESULTS
  The results showed that HC was able to inhibit the release of LPS-induced PGE(2) from mouse peritoneal macrophages (IC50 value: 44.8 μg/mL). Moreover, the inhibitory activity of HC essential oil elicited a dose-dependent inhibition of COX-2 enzyme activity (IC50 value: 30.9 μg/mL). HC was also found to cause reduction in LPS-induced COX-2 mRNA and protein expression, but did not affect COX-1 expression. The non-steroidal anti-inflammatory drug (NSAID) and specific COX-2 inhibitor NS398 functioned similarly in LPS-induced mouse peritoneal macrophages.
  
  
  CONCLUSIONS
  Taken together, our data suggest HC mediates inhibition of COX-2 enzyme activity and can affect related gene and protein expression. HC works by a mechanism of action similar to that of NSAIDs. These results add a novel aspect to the biological profile of HC.
authors.affiliation: School of Medicine, Xi'an Jiaotong University, No. 76 Western Yanta Road, Xi'an City, Shaanxi Province 710061, PR China.
authors.forename: Weifeng
authors.initials: W
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Zhou
authors.forename: Yanmin
authors.initials: Y
authors.lastname: Zhang
authors.forename: Langchong
authors.initials: L
authors.lastname: He
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D001483:Base Sequence; D002681:China; D051545:Cyclooxygenase 1 / Q000235:genetics / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000235:genetics / Q000378:metabolism; D052246:Cyclooxygenase 2 Inhibitors / Q000494:pharmacology*; D017931:DNA Primers / Q000235:genetics; D015232:Dinoprostone / Q000096:biosynthesis; D004365:Drugs, Chinese Herbal / Q000494:pharmacology; D020834:Ethnopharmacology; D005260:Female; D052859:Houttuynia / Q000737:chemistry; D066298:In Vitro Techniques; D017737:Macrophages, Peritoneal / Q000187:drug effects / Q000378:metabolism; D008516:Medicine, Chinese Traditional; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D051379:Mice; D009578:Nitrobenzenes / Q000494:pharmacology; D010946:Plants, Medicinal / Q000737:chemistry; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D000893:Anti-Inflammatory Agents; D052246:Cyclooxygenase 2 Inhibitors; D017931:DNA Primers; D004365:Drugs, Chinese Herbal; C442781:Houttuynia cordata extract; D008565:Membrane Proteins; D009578:Nitrobenzenes; D012333:RNA, Messenger; D013449:Sulfonamides; C080955:N-(2-cyclohexyloxy-4-nitrophenyl)methanesulfonamide; C077623:Ptgs2 protein, mouse; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496512:Ptgs1 protein, mouse; D015232:Dinoprostone