Effect of pyridone carboxylic acid anti-microbials on the generation of reactive oxygen species in vitro

The effects of ofloxacin, ciprofloxacin and balofloxacin on the reactive oxygen species (ROS) levels generated by human neutrophils was examined in vitro; ROS generated in a cell-free, xanthine-xanthine oxidase system was also assessed. The species investigated were superoxide radical anion (O₂^-), hydrogen peroxide (H,O,) and hydroxyl radical (OH·). Both ofloxacin and ciprofloxacin markedly decreased the levels of O₂^-, H₂O₂ and OH· generated by human neutrophils. On the other hand, these drugs did not affect any of the ROS examined in the xanthine-xanthine oxidase system. Balofloxacin showed no significant effect on ROS generated by either system. The present study indicates that ofloxacin and ciprofloxacin may exert an anti-inflammatory action by reducing the potent ROS species excessively generated by neutrophils at the sites of inflammation.