Fleroxacin is a fluoroquinolone antibiotic that displays antibacterial activity against gram positive and gram negative bacteria. Fleroxacin inhibits bacterial DNA gyrase and helicase. In vitro, fleroxacin inhibits DNA unwinding and ATPase activities of Bloom helicase, stabilizing the enzyme in a low activity conformation, disrupting ATP hydrolysis and blocking helicase translocation on DNA strands. Additionally, fleroxacin
increases reactive oxygen species (ROS) and peroxidation of squalene when exposed to UVA light, indicating phototoxicity in vitro.