Design and synthesis of piperazine-based 3,5-disubstituted-1,2,4-oxadiazole derivatives as dual AChE and BChE inhibitors: In vitro and in silico studies

In this study, ten original 3,5-disubstituted-1,2,4-oxadiazole derivatives were successfully synthesized and characterized by mass spectrometry and ¹H and ¹³C NMR spectroscopy. The potential of these compounds to inhibit butyrylcholinesterase (BChE) and acetylcholinesterase (AChE) was assessed, and the results were reported as IC50 and Kᵢ values. The compounds' Ki values ranged from 21.82 ± 7.87 to 83.67 ± 22.16 nM against BChE and from 9.52 ± 2.10 to 34.99 ± 11.33 nM against AChE. Consequently, it was found that all compounds, except 4f, demonstrated more effective inhibitory action against BChE than donepezil, and that 4g, 4e, and 4i demonstrated more effective inhibitory activity against AChE than donepezil. All compounds were subjected to molecular docking against AChE and BChE, and hydrogen bonding and π-interactions between the compounds and the enzymes were observed. Stabilities of enzyme-compound complexes generated from the docking were investigated by molecular dynamics (MD) simulation. The generated complexes were determined to be stable during the simulation period. To further deepen our understanding, computational DFT analysis revealed key insights into the structures, electronic properties, and reactivity of these materials. To broaden our research, absorption, distribution, metabolism, excretion, and toxicity (ADMET) calculations of the compounds were also carried out.