Transition-Metal Complexes of Bidentate Schiff-Base Ligands: In Vitro and In Silico Evaluation as Non-Classical Carbonic Anhydrase and Potential Acetylcholinesterase Inhibitors

Abstract

Schiff bases display superior features for many areas, such as significant intermediates in industrial biological, pharmacological, catalytic and optical properties, organic synthesis, and coordination chemistry. The pre-synthesized two Schiff base ligands (HL1 and HL2) and their bidentate metal complexes (Co(L-1)(2), Cu(L-1)(2), Ni(L-1)(2), Co(L-2)(2), Cu(L-2)(2), and Ni(L-2)(2)) were tested for their inhibition activities on acetylcholinesterase (AChE) and human carbonic anhydrase (hCA I and hCA II) isoforms. The transition metal complexes of bidentate Schiff base ligands displayed the potent inhibition effect with K-I constants ranging from 16.39 +/- 0.15 to 88.63 +/- 0.27 nM and 9.32 +/- 0.13 to 33.66 +/- 0.57 nM for hCA isoenzymes and AChE, respectively. The compound Cu(L-1)(2) for hCA I and Ni(L-2)(2) for AChE and hCA II had the highest inhibitory effect. Besides, the molecular docking analyses of the most active complexes (Cu(L-1)(2) and Ni(L-2)(2)) were performed to understand the binding interactions on the enzymes' binding sites. According to both in vitro and in silico analysis results, all the compounds were potential inhibitors of AChE and hCA I, II isoenzymes.