Structural insights into Arylidenehydrazinyl Benzenesulfonamides as potent mycobacterial carbonic anhydrase inhibitors

Aims To design, synthesize, and assess novel sulfonamide hydrazone derivatives as selective inhibitors of Mycobacterium tuberculosis carbonic anhydrase. Materials and methods Two series of 4-(arylidenehydrazinyl)benzenesulfonamides ( 5a-r ) and N-arylidene-4-methylbenzenesulfonohydrazides ( 6a-h ) were synthesized and evaluated against recombinant MtCA isoforms 1 and 3, and human carbonic anhydrase isoforms I and II by enzyme inhibition assays. Molecular docking and molecular dynamics simulations assessed the binding stability and coordination with the active-site zinc ion. Anti-mycobacterial activity was determined by minimum inhibitory concentrations (MICs) against M. tuberculosis. Time-kill kinetics and cytotoxicity assays evaluated the bactericidal potential and selectivity of the compound toward mammalian cells. Results The compounds showed potent inhibition of MtCA 3 and hCA II, with moderate activity against MtCA 1 and hCA I. Notably, compounds 3e and 3f exhibited K i values of 0.0931 µM and 0.0984 µM, respectively, surpassing acetazolamide (K i = 0.104 µM). Docking and simulations confirmed stable zinc coordination. MIC values ranged from 4 to 128 µg/mL. Time-kill and cytotoxicity studies confirmed rapid bactericidal activity and low mammalian toxicity. Conclusion These sulfonamide hydrazone derivatives demonstrate potent, selective MtCA inhibition, robust antimycobacterial efficacy, and favorable safety profiles, representing promising scaffolds for novel tuberculosis therapies with a novel mode of action.