Virtual Screening and Biological Evaluation of Piperazine Derivatives as Human Acetylcholinesterase Inhibitors

Table 2

Comparisons of free energy of binding and inhibition constants of the derivatives on both PAS and catalytic site.

Drug (ligand) molecule	PAS site			Catalytic site
	Estimated free energy of binding (Δ𝐺), kcal/mol	Estimated inhibition constant (𝐾𝑖) μM	Total intermolecular energy, kcal/mol	Estimated free energy of binding (Δ𝐺), kcal/mol	Estimated inhibition constant, (𝐾𝑖) μM	Total intermolecular energy, kcal/mol
1-(1,4-Benzodioxane-2-carbonyl)piperazine-K	−8.15	1.06	−8.45	−7.33	4.27	−7.62
4-(4-Methyl)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine-S1	−9.90	0.05578	−10.79	−4.33	672.74	−5.22
4-Benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine-S4	−9.79	0.06643	−10.69	−6.65	13.45	−7.54
4-(2,5-Dichloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine-S7	−11.42	0.00426	−12.02	−11.42	0.00424	−12.02
4-(4-Chloro)-benzenesulfonyl-1-(1,4-benzodioxane-2-carbonyl) piperazine-S3	−9.97	0.04881	−10.87	−4.05	1080	−4.94