Discovery of novel benzenesulfonamides incorporating 1,2,3-triazole scaffold as carbonic anhydrase I, II, IX, and XII inhibitors

Sulfonamides are among the most promising potential inhibitors for carbonic anhydrases (CAs), which are pharmaceutically relevant targets for treating several disease conditions. Herein, a series of benzenesulfonamides bearing 1,2,3-triazole moiety as inhibitors of human (h) alpha-CAs (hCAs) were designed using the tail approach. The design method combines a benzenesulfonamide moiety with a tail of oxime and a zinc-binding group on a 1,2,3triazole scaffold. Among the synthesized derivatives, the naphthyl (6m, KI of 68.6 nM, SI of 10.3), and methyl (6a, KI of 56.3 nM, SI of 11.7) derivatives (over hCA IX) and propyl (6c, KI of 95.6 nM, SI of 2.7), and pentyl (6d, KI of 51.1 nM, SI of 6.6) derivatives (over hCA XII) displayed a noticeable selectivity for isoforms hCA I and II, respectively. Meanwhile, derivative 6e displayed a potent inhibitory effect versus the cytosolic isoform hCA I (KI of 47.8 nM) and tumor-associated isoforms hCA IX and XII (KIs of 195.9 and 116.9 nM, respectively) compared with the reference drug acetazolamide (AAZ, KIs of 451.8, 437.2, and 338.9 nM, respectively). Derivative 6b showed higher potency (KI of 33.2 nM) than AAZ (KI of 327.3 nM) towards another cytosolic isoform hCA II. Nevertheless, substituting the lipophilic large naphthyl tail to the 1,2,3-triazole linked benzenesulfonamides (6an) raised inhibitory effect versus hCA I and XII and selectivity towards hCA I and II isoforms over hCA IX. Evaluation of the cytotoxic potential of the synthesized derivatives was conducted in L929, MCF-7, and Hep-3B cell lines. Several compounds in the series demonstrated significant antiproliferative activity and minimal cytotoxicity. In the molecular docking study, the sulfonamide moiety interacted with the zinc-ion and neatly fit into the hCAs active sites. The extension of the tail was found to participate in diverse hydrophilic and hydrophobic interactions with adjacent amino acids, ultimately influencing the effectiveness and specificity of the derivatives.