First-in-class nonsteroidal anti-inflammatory drug and carbonic anhydrase inhibitor hybrid compounds as effective antimycobacterial agents

We investigated the in vitro effects of nonsteroidal anti-inflammatory drug-carbonic anhydrase inhibitor hybrids (NSAID-CAIs) on β-carbonic anhydrases 1-3 expressed by Mycobacterium tuberculosis, as well as their antimycobacterial efficacy in a zebrafish infection model. The primary aims were to investigate whether these enzymes represent valid therapeutic targets and whether NSAID-CAIs constitute potential drug candidates for tuberculosis. In vitro inhibition activity against the carbonic anhydrases was evaluated with a CO₂-hydration assay. Antimycobacterial properties of the NSAID-CAIs were assessed via screening assays based on bioluminescence and colony-forming units. Larval and adult zebrafish were used for in vivo experiments. NSAID-CAIs strongly inhibited Mycobacterium tuberculosis β-carbonic anhydrase 2 and human carbonic anhydrases IX and XII in vitro. They exhibited high efficacy against Mycobacterium marinum and attenuated Mycobacterium tuberculosis in biofilm environments, outperforming their coadministered constitutive fragments. Compounds 11, 19, and 24 showed bactericidal properties against Mycobacterium marinum, and 12 was able to potentiate the effects of rifampicin. The experimental data provides solid in vitro evidence for the use of NSAID-CAIs as antimycobacterial agents by means of Mycobacterium tuberculosis β-carbonic anhydrase inhibition along with the possible suppression of the host immune response through the induction of host-directed therapeutic effects.