Synthesis, characterization and in vitro inhibition of metal complexes of pyrazole based sulfonamide on human erythrocyte carbonic anhydrase isozymes I and II

Abstract

Sulfonamides represent an important class of biologically active compounds. A sulfonamide possessing carbonic anhydrase (CA) inhibitory properties obtained from a pyrazole based sulfonamide, ethyl 1-(3-nitrophenyl)-5-phenyl-3-((5-sulfamoyl-1,3,4-thiadiazol-2-yl)carbamoyl)-1 H-pyrazole-4-carboxylate ( 1), and its metal complexes with the Ni(II) for ( 2), Cu(II) for ( 3) and Zn(II) for ( 4) have been synthesized. The structures of metal complexes ( 2– 4) were established on the basis of their elemental analysis, ¹H NMR, IR, UV–Vis and MS spectral data. The inhibition of two human carbonic anhydrase (hCA, EC 4.2.1.1) isoenzymes I and II, with 1 and synthesized complexes ( 2– 4) and acetazolamide (AAZ) as a control compound was investigated in vitro by using the hydratase and esterase assays. The complexes 2, 3 and 4 showed inhibition constant in the range 0.1460–0.3930 µM for hCA-I and 0.0740–0.0980 µM for hCA-II, and they had effective more inhibitory activity on hCA-I and hCA-II than corresponding free ligand 1 and than AAZ.