RESUMEN
Searching for new alternatives to antibiotic treatments is crucial to surmount the multidrug-resistant bacteria. In this work, the antimicrobial activity of synthetic imidazolidines was evaluated as well as their modulating effect on the resistance to fluoroquinolones in a S. aureus strain (SA-1199B), which overexpresses the norA gene that encodes the NorA efflux pump. Results showed weak antimicrobial activity (512 µg mL-1) for two fluorobenzylidene derivatives against this bacterial strain, while the other benzylidene derivatives were inactive. Despite this fact, both fluorinated compounds were able to enhance the activity of norfloxacin and ciprofloxacin against SA-1199B up to 6.4- and 3.2-fold, respectively. In addition, both derivatives potentiated the action of ethidium bromide against this strain, suggesting that the modulating effect probably involves the inhibition of the NorA efflux pump, which is in concordance with the fluorimetic assays and molecular docking analyses performed in this work.
Asunto(s)
Antibacterianos/farmacología , Proteínas Bacterianas/antagonistas & inhibidores , Imidazolidinas/farmacología , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/antagonistas & inhibidores , Staphylococcus aureus/efectos de los fármacos , Antibacterianos/síntesis química , Antibacterianos/química , Proteínas Bacterianas/metabolismo , Relación Dosis-Respuesta a Droga , Imidazolidinas/síntesis química , Imidazolidinas/química , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Estructura Molecular , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/metabolismo , Staphylococcus aureus/metabolismo , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Imidazoline derivatives with different exocyclic substituents were simply prepared from common starting materials. The procedures were carried out in an eco-friendly manner. The antioxidant activity of these derivatives was explored by different experimental assays, such as ABTS.+ and DPPH. scavenging assay, as well as reducing power assay. The structural differences are discussed in terms of the results. Sulfur analogs showed higher antioxidant activity than their oxygenated counterparts. The same tendency was observed in microbiological studies, in which the same imidazoline compounds were assayed for light-mediated activity against of Staphylococcus aureus and Escherichia coli strains. A light-enhanced activity was observed for almost all the sulfated imidazolines after exposure to UV-A (400-320â nm) light.