title: Synthetic 3-arylideneflavanones as inhibitors of the initial stages of biofilm formation by Staphylococcus aureus and Enterococcus faecalis.
abstract: The antimicrobial activity of twenty two synthetic flavonoids is reported. Among them three 3-arylideneflavanones, 2b, 2c, and 2i, were shown to be highly active against Staphylococcus aureus, S. epidermidis, and Enterococcus faecalis reference strains, with MIC (minimal inhibitory concentration) values ranging from 4.68 microg/ml (14.3 microM) to 37.5 microg/ml (119.7 microM). The synergy of oxacillin and vancomycin with 2c, evaluated as fractional inhibitory concentration index (FICI) was shown (against planktonic culture of S. aureus A3 and E. faecium 138/09 clinical strains). The presence of 2c in the culture medium diminished the initial adhesion of bacteria to an abiotic surface. Such an effect resulted in a decrease in biofilm formation during prolonged culture. Unfortunately, 2e failed to eradicate the S. aureus mature biofilm which was already preformed, however, decreased the number of live biofilm cells. The biofilm of E. faecalis was more susceptible to the action of 3-arylideneflavanone 2c than the S. aureus biofilm. The finding that 3-arylideneflavanones are lipophilic, cause bacterial aggregation, and influence the integrity of membranes making them permeable to SYTO 9/propidium iodide dyes may implicate the cytoplasmic membrane as a target site for these compounds activity.
authors.affiliation: Department of Immunology and Infectious Biology, University of Łódź, Banacha 12/16, 90-237 Łódź, Poland.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Budzyńska
authors.forename: Marek
authors.initials: M
authors.lastname: Rózalski
authors.forename: Wiesława
authors.initials: W
authors.lastname: Karolczak
authors.forename: Marzena
authors.initials: M
authors.lastname: Wieckowska-Szakiel
authors.forename: Beata
authors.initials: B
authors.lastname: Sadowska
authors.forename: Barbara
authors.initials: B
authors.lastname: Rózalska
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D013293:Enterococcus faecalis / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology; D044950:Flavanones / Q000138:chemical synthesis / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000502:physiology
chemical_list: D000900:Anti-Bacterial Agents; D044950:Flavanones