Synthesis, Biological Evaluation, and In Silico Characterization of Novel Imidazothiadiazole-Chalcone Hybrids as Multi-Target Enzyme Inhibitors

Abstract

Background/Objectives: The need for dual-targeted enzyme inhibitors is critical in addressing complex diseases like Alzheimer's and glaucoma. Imidazothiadiazole and chalcone moieties are known for diverse bioactivities. This study aimed to develop novel imidazothiadiazole-chalcone hybrids as potential inhibitors of acetylcholinesterase (AChE), butyrylcholinesterase (BChE), and human carbonic anhydrase isoforms (hCAs), specifically hCA I and hCA II. Methods: Four hybrid molecules (8a-8d) were synthesized and structurally confirmed via 1H NMR, 13C NMR, FT-IR, MS, and elemental analysis techniques. Their enzyme inhibitory activities were assessed using Ellman's and Verpoorte's methods. Molecular docking and 100 ns molecular dynamics (MD) simulations were conducted to examine binding interactions. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) properties were predicted using the pkCSM platform. Results: All compounds showed strong enzyme inhibition: AChE (Ki: 3.86-11.35 nM), BChE (Ki: 1.01-1.78 nM), hCA I (Ki: 45.13-81.24 nM), and hCA II (Ki: 36.08-52.45 nM). Docking analyses confirmed favorable binding, particularly with active-site residues. MD simulations demonstrated stable interactions throughout 100 ns. Compound 8a exhibited the highest cholinesterase inhibition, while compounds 8d and 8c were the most potent against hCA I and hCA II, respectively. The ADMET results showed high absorption and acceptable safety, with mild mutagenicity or cardiotoxicity concerns in select compounds. Conclusions: These findings suggest that imidazothiadiazole-chalcone hybrids are promising multi-target enzyme inhibitors. Their potent activity, structural stability, and pharmacokinetic potential support their further development for therapeutic use in neurodegenerative and ocular diseases.