title: Induction of nitric oxide & tumour necrosis factor-alpha by Psoralea corylifolia.
abstract: OBJECTIVE
  Psoralea corylifolia (PC) is an herb widely used in medicine for the treatment of a variety of ailment. PC is also known to have immunomodulatory activity. However, its mechanism of action is not known. In the present study we investigated effect of PC on nitric oxide (NO) and tumour necrosis factor-alpha (TNF-alpha) production in mouse peritoneal macrophages and also examined the mechanism by which PC regulates NO production.
  
  
  METHODS
  MTT assay performed for cell viability test and nitrite concentration was measured by using Griess reagent. The amount of TNF-alpha secreted by the cells was measured by a modified enzyme-linked immunosorbent assay (ELISA). Expression of iNOS was investigated by western blot analysis.
  
  
  RESULTS
  PC in combination with recombinant interferon-gamma (rIFN-gamma) showed a marked co-operative induction of NO production, with no effect on NO production by itself. The increased production of NO from rIFN-gamma plus PC-stimulated cells was almost completely inhibited by pre-treatment with pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor kappa B (NF-kappaB). Furthermore, treatment of peritoneal macrophages with rIFN-gamma plus PC caused a significant increase in tumour necrosis factor-alpha (TNF-alpha) production. PDTC also decreased the effect of PC on TNF-alpha production significantly.
  
  
  CONCLUSIONS
  As NO and TNF-alpha play an important role in immune function and host defense, PC treatment could modulate several aspects of host defense mechanisms due to stimulation of the inducible nitric oxide synthase.
authors.affiliation: College of Oriental Medicine, Institute of Oriental Medicine, Oriental Medical Science Center, Kyung Hee University, Seoul, Republic of Korea.
authors.forename: Hyo-Jin
authors.initials: HJ
authors.lastname: An
authors.forename: Min-Jun
authors.initials: MJ
authors.lastname: Seo
authors.forename: In-Young
authors.initials: IY
authors.lastname: Choi
authors.forename: Rae-Kil
authors.initials: RK
authors.lastname: Park
authors.forename: Sejin
authors.initials: S
authors.lastname: Jeong
authors.forename: Ju-Young
authors.initials: JY
authors.lastname: Lee
authors.forename: Hyung-Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Jae-Young
authors.initials: JY
authors.lastname: Um
authors.forename: Seung-Heon
authors.initials: SH
authors.lastname: Hong
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D007371:Interferon-gamma / Q000494:pharmacology; D017737:Macrophages, Peritoneal / Q000187:drug effects* / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009569:Nitric Oxide / Q000096:biosynthesis*; D010936:Plant Extracts / Q000494:pharmacology*; D029907:Psoralea; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
chemical_list: D010936:Plant Extracts; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma