title: Flavonoids from Inula britannica reduces oxidative stress through inhibiting expression and phosphorylation of p47(phox) in VSMCs.
abstract: BACKGROUND
  Inula britanica Linn. (Compositae) is a traditional Chinese medicinal herb that has been used to treat bronchitis and inflammation. The total flavonoid extracts (TFEs) isolated from its flowers can inhibit neointimal formation induced by balloon injury in vivo.
  
  
  OBJECTIVE
  To investigate the mechanism by which TFE suppresses oxidative stress generation and the subsequent inflammation response in vitro.
  
  
  METHODS
  The cultured vascular smooth muscle cells (VSMCs) form rats were exposed to oxidative stress following pretreatment with or without TFE at different concentration. Then, fluorescence staining was used to detect superoxide anion (O₂(˙-)) production, and the lever of maleic dialdehyde (MDA) and superoxide dismutase (SOD) was measured at the same time. Furthermore, tumor necrosis factor-α (TNF-α) was measured by enzyme linked immunosorbent assay (ELISA), reverse transcription-PCR and western blot were performed to detect the expression activity of p47(phox) gene, and immunoprecipitation was used to test the level of p47(phox) phosphorylation.
  
  
  RESULTS
  TFE inhibited the production of O₂(˙-) induced by H₂O₂ in VSMCs, with decrease in secretion of TNF-α; elevated the activity of SOD in the medium, similar to the effect of quercetin; reduced the level of MDA in culture medium of VSMCs. The pretreatment with TFE resulted in decrease the level of p47(phox) mRNA and protein, and even p47(phox) phosphorylation in VSMCs, compared with H₂O₂ control.
  
  
  CONCLUSIONS
  These findings demonstrate that TFE is capable of attenuating the oxidative stress generation and the subsequent inflammation response via preventing the overexpression and activation of p47(phox) and the increased TNF-α secretion in VSMCs in vitro.
authors.affiliation: Department of Biochemistry and Molecular Biology, Institute of Basic Medicine, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, Shijiazhuang, PR China.
authors.forename: Hong-Bing
authors.initials: HB
authors.lastname: Zhang
authors.forename: Jin-Kun
authors.initials: JK
authors.lastname: Wen
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Sui-Bing
authors.initials: SB
authors.lastname: Miao
authors.forename: Guo-Yan
authors.initials: GY
authors.lastname: Ma
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Wang
authors.forename: Bin
authors.initials: B
authors.lastname: Zheng
authors.forename: Mei
authors.initials: M
authors.lastname: Han
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D005419:Flavonoids / Q000378:metabolism / Q000494:pharmacology*; D035264:Flowers; D005786:Gene Expression Regulation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism; D066298:In Vitro Techniques; D007249:Inflammation / Q000188:drug therapy; D038143:Inula; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000201:enzymology / Q000378:metabolism*; D019255:NADPH Oxidases / Q000037:antagonists & inhibitors / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D008517:Phytotherapy; D028321:Plant Preparations / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D005419:Flavonoids; D028321:Plant Preparations; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D013481:Superoxides; D006861:Hydrogen Peroxide; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1