title: Antibacterial activity and proposed action mechanism of a new class of synthetic tricyclic flavonoids.
abstract: OBJECTIVE
  This study reports on the inhibitory and bactericidal properties of a new synthetized flavonoid.
  
  
  RESULTS
  Tricyclic flavonoid 1 has been synthesized through a two-step reaction sequence. The antimicrobial effects were tested using the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Also DNA fragmentation assay, fluorescence microscopy and SEM were used to study the mechanism of action. Our tested flavonoid displayed a strong antimicrobial activity with MIC and MBC values as low as 0·24 μg ml(-1) against Staphylococcus aureus and 3·9 μg ml(-1) against Escherichia coli. Flavonoid 1 displayed antimicrobial properties, causing not only the inhibition of bacterial growth, but also killing bacterial cells. The mechanism of action is related to the impairment of the cell membrane integrity and to cell agglutination.
  
  
  CONCLUSIONS
  Tricyclic flavonoid 1 was found to have a stronger antibacterial effect at lower concentrations than those described in the earlier reports.
  
  
  CONCLUSIONS
  Based on the strong antimicrobial activity observed, this new tricyclic flavonoid has a good potential for the design of new antimicrobial agents.
authors.affiliation: Faculty of Biology, Biology Department, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: C
authors.initials: C
authors.lastname: Babii
authors.affiliation: Faculty of Chemistry, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: L G
authors.initials: LG
authors.lastname: Bahrin
authors.affiliation: Faculty of Biology, Biology Department, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: A-N
authors.initials: AN
authors.lastname: Neagu
authors.affiliation: Faculty of Biology, Biology Department, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: I
authors.initials: I
authors.lastname: Gostin
authors.affiliation: Faculty of Biology, Biology Department, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: M
authors.initials: M
authors.lastname: Mihasan
authors.affiliation: Faculty of Chemistry, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: L M
authors.initials: LM
authors.lastname: Birsa
authors.affiliation: Faculty of Biology, Biology Department, The Alexandru Ioan Cuza University of Iasi, Iasi, Romania.
authors.forename: M
authors.initials: M
authors.lastname: Stefan
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects; D005419:Flavonoids / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D015394:Molecular Structure; D013211:Staphylococcus aureus / Q000187:drug effects
chemical_list: D000900:Anti-Bacterial Agents; D000890:Anti-Infective Agents; D005419:Flavonoids
keywords: bactericidal effect; cell agglutination; growth inhibition; membrane integrity impairment; synthetic flavonoid