title: [Inhibitory effects of biochanin A on the efflux pump of methicillin-resistant Staphylococcus aureus (MRSA)].
abstract: OBJECTIVE
  To study the inhibitory effect of biochanin A on efflux system of Methicillin-resistant Staphylococcus aureus (MRSA).
  
  
  METHODS
  Inhibitory effects of biochanin A on efflux system of Strain MRSA41577 were evaluated using double dilution method, two plate method and fluorescence spectrophotometry. Real time PCR and SDS-PAGE were applied to detect the expression of MRSA41577 norA and to analyze the changes of MRSA41577 efflux protein before and after dosing biochanin A in association with liquid chromatography mass spectrometry to determinate protein variation.
  
  
  RESULTS
  Biochanin A alone had no inhibitory effect on MRSA41577, but it showed synergy effect with ciprofloxacin in inhibition MRSA41577 in which 40pg/mL biochanin A decreased the minimum inhibitory concentration (MIC) value of ciprofloxacin from 64 microg/mL to 8 microgg/mL. Biochanin A significantly increased the accumulation of ciprofloxacin in MRSA41577 in a time-dependent manner. At 15 min, biochanin A increased ciprofloxacin in MRSA41577 by 83%, which is similar to that of reserpine (positive control). Further mechanism studies indicated that biochanin A could reduce the expression of nor A in ciprofloxacin-treated MRSA41577. After incubated with biochanin A and ciprofloxacin for 16 h, the relative expression of nor A of MRSA41577 was reduced by 65%. SDS-PAGE analysis showed that the total protein profiles of MRSA41577 were significantly changed after treatment with biochanin A for 16h, in which both norA protein and efflux system ABC transporter ATP-binding protein were significantly decreased.
  
  
  CONCLUSIONS
  Biochanin A could inhibit Methicillin-resistant Staphylococcus aureus efflux system through reducing pathogen' s expression of nor A and norA protein.
authors: Dan
authors: D
authors: Zou
authors: Kunpeng
authors: K
authors: Xie
authors: Haiting
authors: H
authors: Wang
authors: Yuxian
authors: Y
authors: Chen
authors: Mingjie
authors: M
authors: Xie
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D001692:Biological Transport / Q000187:drug effects; D019833:Genistein / Q000494:pharmacology*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D008826:Microbial Sensitivity Tests
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D019833:Genistein; C004541:biochanin A