The Anticholinesterase Perspective of Dimethoxyindole Based Benzenesulfonamides: Synthesis, Biological Investigation and Molecular Docking Applications

Abstract

Due to the well-known biological potential of benzenesulfonamides for the inhibition of specific enzymes, here in, we propose to investigate anticholinesterase efficiencies of five newly synthesized benzenesulfonamides incorporating dimethoxyindole tails. The targeted compounds were synthesized through the C7 position of the methyl 4,6-dimethoxy-1H-indole-2-carboxylate via Schiff-base reaction. The biological study was directed to identify the acetylcholinesterase (ACh) and butyrylcholinesterase (BCh) enzyme inhibitions. The molecular docking studies were also carried out to determine the possible poses of ligands 8 a-e in binding sites of enzymes and ligand-residue interactions. Molecular dynamics simulations, RMSD and RMSF plots, hydrogen bond analysis, per-residue energy decomposition and MM-PB(GB)/SA calculations were carried out investigate the potentials of the compounds towards the designated enzymes. It is important to note that all the synthesized compounds were found to be selective towards the BChE inhibition with a range of efficiencies. In addition to that the compound 8 a exhibited more potency than the standard Galanthamine with the value of 87.75 % for the same enzyme. The results could be valuable for the determination of new targets which are highly selective for BChE inhibition. The formation of hydrogen bonds and hydrophobic interactions with the residues located on the compounds were responsible for the binding free energy scores. The stability of all the compounds proved by molecular dynamics simulations were also promising for the further directions of the study. Indole based benzenesulfonamides reveal selective anticholinesterase activity towards the BChE enzyme and the existence of NH2 was found to be crucial for the design of best inhibitor. The candidate 8d shows absolute selectivity with 60 % inhibition and no activity for BChE and AChE, respectively. The compound 8a demonstrates better inhibition than the standard Galanthamine for BChE enzyme. image