Evaluation of Biological Activities of Quinone-4-oxoquinoline Derivatives against Pathogens of Clinical Importance

Background: Microbial resistance has become a worldwide public health problem and may lead to morbidity and mortality in affected patients. Objectives: Therefore, this work aimed to evaluate the antibacterial activity of quinone-4-oxoquinoline derivatives. Methods: These derivatives were evaluated against Gram-positive and Gram-negative bacteria by their antibacterial activity, anti-biofilm, and hemolytic activities and in silico assays. Results: The quinone-4-oxoquinoline derivatives presented broad-spectrum antibacterial activities and, in some cases, were more active than commercially available reference drugs. These compounds also inhibited bacterial adhesion, and the assays revealed seven non-hemolytic derivatives. The derivatives seem to cause damage to the bacterial cell membrane, and those containing the carboxyl group at the C-3 position of the 4-quinolonic nucleus were more active than those containing a carboxyethyl group. Conclusion: The isoquinoline-5,8-dione nucleus also favored antimicrobial activity. The study showed that the target of the derivatives must be a non-conventional hydrophobic allosteric binding pocket on the DNA gyrase enzyme.