Abstract
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•Pyrazoline-linked benzenesulfonamides with CA inhibitory activity were synthesized.•Some synthesized compounds inhibit hCA I, II, IX and XII isoforms comparable to AAZ.•Compounds 18–25 showed potent inhibitory hCA I greater than AAZ.•Compounds 19, 21–23, 26, 28–30 and 32 revealed potent CAIS against hCA IX.•Compounds 20–22, and 30 exerted hCA XII inhibition similar to AAZ.
Carbonic anhydrases (CA, EC 4.2.1.1) are Zinc metalloenzymes and are present throughout most living organisms. Among the catalytically active isoforms are the cytosolic CA I and II, and tumor-associated CA IX and CA XII. The carbonic anhydrase (CA) inhibitory activities of newly synthesized pyrazoline-linked benzenesulfonamides 18–33 against human CA (hCA) isoforms I, II, IX, and XII were measured and compared with that of acetazolamide (AAZ), a standard inhibitor. Potent inhibitory activity against hCA I was exerted by compounds 18–25, with inhibition constant (KI) values of 87.8–244.1 nM, which were greater than that of AAZ (KI, 250.0 nM). Compounds 19, 21, 22, 29, 30, and 32 were proven to have inhibitory activities against hCA IX with KI values (5.5–37.0 nM) that were more effective than or nearly equal to that of AAZ (KI, 25.0 nM). Compounds 20–22, and 30 exerted potent inhibitory activities (KIs, 7.1–10.1 nM) against hCA XII, in comparison with AAZ (KI, 5.7 nM).