title: Anti-quorum sensing potential of Adenanthera pavonina.
abstract: BACKGROUND
  Quorum sensing (QS) in Pseudomonas aeruginosa plays a key role in virulence factor production, biofilm formation and antimicrobial resistance. Because of emerging antimicrobial resistance in P. aeruginosa, there is a need to find an alternate nonantibiotic agent for the control of infections caused by this organism.
  
  
  OBJECTIVE
  To evaluate anti-QS activity of Adenanthera pavonina L., a medicinal plant used in traditional medicine.
  
  
  METHODS
  Preliminary screening for anti-QS activity of ethanol extract of A. pavonina was carried out using Chromobacterium violaceum CV026 biosensor strain and inhibition of QS-regulated violacein production was quantified using C. violaceum ATCC12472. Bioassay guided fractionation of ethanol extract resulted in ethyl acetate fraction (AEF) with strong anti-QS activity and AEF was evaluated for inhibition of QS-regulated pyocyanin production, proteolytic, elastolytic activity, swarming motility and biofilm formation in P. aeruginosa PAO1.
  
  
  RESULTS
  AEF, at 0.5 mg/ml, inhibited pyocyanin production completely and at 1 mg/ml of AEF, complete inhibition of proteolytic and elastolytic activities were observed. However, viability of P. aeruginosa PAO1 was not affected at the tested concentrations of AEF as observed by cell count. Swarming motility was inhibited at the concentration of 0.1 mg/ml of AEF. Thin layer chromatography and biosensor overlay of AEF showed violacein inhibition zone at Rf value 0.63.
  
  
  CONCLUSIONS
  From the results of this study, it can be concluded that A. pavonina extracts can be used as effective anti-QS agents.
authors.affiliation: Yenepoya Research Center, Yenepoya University, University Road, Deralakatte, Mangalore, Karnataka, India.
authors.forename: Halkare Suryanarayana
authors.initials: HS
authors.lastname: Vasavi
authors.affiliation: Yenepoya Research Center, Yenepoya University, University Road, Deralakatte, Mangalore, Karnataka, India.
authors.forename: Ananthapadmanabha Bhagwath
authors.initials: AB
authors.lastname: Arun
authors.affiliation: Yenepoya Research Center, Yenepoya University, University Road, Deralakatte, Mangalore, Karnataka, India.
authors.forename: Punchappady-Devasya
authors.initials: PD
authors.lastname: Rekha
keywords: Adenanthera pavonina; Pseudomonas aeruginosa; Quorum sensing; Virulence