Novel benzenesulfonamide derivatives linked to diaryl pyrazole tail as potential carbonic anhydrase II/VII inhibitors with anti-epileptic activity

Two new series of 1,2,3-triazole benzenesulfonamide derivatives 16a-f and imino-thiazolidinone benzenesulfonamide derivatives 19a-f with diaryl pyrazole tail were synthesized as carbonic anhydrase (CA) II, VII inhibitors and assessed for antiepileptic activity. All compounds were tested in vitro for their inhibition activity against the human (h) carbonic anhydrase I, II, and VII isoforms. Among these series, compounds 16b, 16d, 19b, and 19d exhibited exceptional inhibitory activity against hCA II, with K_i 10.9–47.1 nM, and hCA VII, with K_i 8.4–23.6 nM, while the two series did not show significant activity against hCA I. Furthermore, 16b, 16d, 19b, and 19d were tested against in vivo pilocarpine-induced seizure model, and they showed excellent neuroprotective activity; they delayed seizure onset, reduced seizure severity, and improved survival rates compared to the pilocarpine group, which highlighted their efficacy in regulating neuronal excitability through CA inhibition and chloride homeostasis. Also, hippocampal levels of KCC2 and mTOR were analyzed, as these markers are critical in regulating neuronal excitability and are closely linked to epilepsy. Noteworthy, Compounds 16d and 19b surpassed the standard anti-convulsant valproic acid in key parameters, underscoring their superior efficacy. In addition, they do not show any significant neurotoxic effects or alterations in liver and kidney function. Moreover, the results of in vitro cytotoxicity of compounds 16d and 19b against Vero cells indicate their safety at the doses given (IC₅₀ = 59.7, 71.9 μM respectively) compared to acetazolamide (IC₅₀ = 32.3 μM). Finally, molecular docking of sulfonamide derivatives with hCA II (PDB code: 2h4h) and hCA VII (PDB code: 3ml5) was performed.