title: Bacteriostatic action of synthetic polyhydroxylated chalcones against Escherichia coli.
abstract: In previous work the bacteriostatic action of trihydroxylated chalcones against Staphylococcus aureus ATCC 25 923 was investigated. In this work the action of 2',4',2-(OH)3-chalcone, 2',4',3-(OH)3-chalcone and 2',4',4-(OH)3-chalcone against Escherichia coli ATCC 25 922 was evaluated. Growth kinetic curves of E. coli were made in nutritive broth added with increasing drug concentrations. The specific growth rates of the microorganisms were calculated by a kinetic turbidimetric method, which was previously probed and the minimal inhibitory concentrations (MIC's) were evaluated by a mechanism of action proposed. The MICs of 2',4',3-(OH)3-chalcone and 2',4',2-(OH)3-chalcone were 46 microg/ml and 122 microg/ml, respectively. The 2',4',4-(OH)3-chalcone was inactive. The MIC value of 2',4',3-(OH)3-chalcone (46 microg/ml), more active than 2',3-(OH)2-chalcone (72.2 microg/ml) may be due to the introduction of an electron donating group (-OH) at position 4' in the aromatic A-ring, which activates the region that includes the 2'-hydroxyl neighbor group and the alpha,beta-unsaturated carbonyl group.
authors.affiliation: Laboratory of Physical-Chemistry, Department of Chemistry, National University of San Luis, Chacabuco 917, 5700 San Luis, Argentina.
authors.forename: María de los Angeles
authors.initials: Mde L
authors.lastname: Alvarez
authors.forename: Valeria E P
authors.initials: VE
authors.lastname: Zarelli
authors.forename: Nora B
authors.initials: NB
authors.lastname: Pappano
authors.forename: Nora B
authors.initials: NB
authors.lastname: Debattista
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D002599:Chalcone / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000187:drug effects* / Q000254:growth & development; D017665:Hydroxyl Radical / Q000737:chemistry*; D008826:Microbial Sensitivity Tests; D013329:Structure-Activity Relationship
chemical_list: D000900:Anti-Bacterial Agents; D017665:Hydroxyl Radical; D002599:Chalcone