Monocyclic and tricyclic analogs of quinolones: mechanism of action

The mode of action of Ro 13-5478 and Ro 14-9578, monocyclic and tricyclic Quinolone analogs, respectively, was examined for Escherichia coli and Staphylococcus aureus. The compounds showed Antibacterial activity and effects on cell morphology, replicative DNA biosynthesis, and gyrase-catalyzed DNA supercoiling that were comparable to those shown by nalidixic acid and by oxolinic acid compounds. The results suggest that their site of action is DNA gyrase and that a bicyclic Quinolone nucleus is not essential for activity.