Increase daccumulation of enoxacin is consistent with interference with NorA. As such, it is clear that compound 1 is a NorA inhibitor. Use of concentrations that surpassed the MIC of compound 1 for SA-1199B was not problematic based on time–kill assays, which revealed no effect of compound 1 at 50M on the viability of SA-1199B over 60min. The pharmacophore of compound 1 may provide a starting point towards the development of a more effective inhibitor, and its weak cytotoxic activity towards cancer and mammalian cell lines suggests that this class of compound may have potential in a topical formulation or, if antibacterial activity in the presence of blood can be enhanced through iterative chemistry, as a lead in the development of a new class of systemic antibiotics. Compounds that are antibacterial and can inhibit efflux processes of bacteria could have potential to treat infections due to multidrug-resistant strains.
Funding:TheHeptagonFundandUnionLifeSciencesfundedthis work. Competing interests: None declared. Ethical approval: Not required.