| 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 mg/ml and 122 mg/ml, respectively. The 2´,4´,4-(OH)3-chalcone was inactive.... |
