Type II topoisomerase inhibitor 1 is a potent and selective E. coli DNA gyrase inhibitor ( IC 50 : 1.7 nM), and forms hydrogen bonds with Asp73 residue. Type II topoisomerase inhibitor 1 inhibits topoisomerase IV activity ( IC 50 : 0.98 μM). Type II topoisomerase inhibitor 1 can be used in the research of antibacterial area.