MRSAantibiotic3 (Compound C8) is an antibiotic targeting methicillin-resistant Staphylococcus aureus (MRSA). It exhibits a minimum inhibitory concentration (MIC) of 0.5 μg/mL against the standard strain of Staphylococcus aureus (ATCC 292130). MRSAantibiotic3 effectively inhibits the ATPase activity of S. aureus DNA Gyrase, with an IC50 of 0.32 μM. It demonstrates potent inhibitory activity against five clinical MRSA isolates, with MIC values ranging from 0.5 to 1 μg/mL. At effective antibacterial concentrations, MRSAantibiotic3 shows minimal cytotoxicity and does not cause hemolysis even at high concentrations. Additionally, it provides significant protection in both greater wax moth larva infections and mouse septicemia models.