MRSA antibiotic 3 (Compound C8) is a small-molecule antibiotic active against Methicillin)-resistant Staphylococcus aureus (MRSA), showing a MIC of 0.5 μg/mL against the standard S. aureus strain (ATCC 29213). MRSA antibiotic 3 potently inhibits the ATPase activity of S. aureus DNA gyrase with an IC50 of 0.32 μM. MRSA antibiotic 3 exhibits strong inhibitory activity against five clinical MRSA isolates, with MIC values ranging from 0.5 to 1 μg/mL. MRSA antibiotic 3 demonstrates negligible cytotoxicity at effective antibacterial concentrations and causes no hemolysis in erythrocytes even at extremely high concentrations. MRSA antibiotic 3 shows significant protective effects in both Galleria mellonella infection and murine sepsis models.
