Synthesis, biochemical and computational evaluations of novel bis-acylhydrazones of 2,2'-(1,1'-biphenyl)-4,4'-diylbis(oxy))di(acetohydrazide) as dual cholinesterase inhibitors

Abstract

A series of twenty-seven bis(acylhydrazones) were successfully synthesized with high yields through a multistep process, which entailed the esterification of hydroxyl groups, hydrazination with an excess of hydrazine hydrate, and subsequent reactions with various carbonyl moieties (aldehydes). In the final stage of synthesis, different chemical species including aromatic, heterocyclic, and aliphatic compounds were integrated into the framework. The resulting compounds were characterized using several spectroscopic techniques (¹H NMR, ¹³C NMR, and mass spectrometry). Their anticholinesterase activities were assessed in vitro by examining their interactions with two cholinesterase enzymes: acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). Among the synthesized hits, compounds 3, 5, 6, 9-12, and 14 exhibited good to moderate inhibition of AChE. Specifically, 10 (IC₅₀ = 26.3 ± 0.4 μM) and 11 (IC₅₀ = 28.4 ± 0.5 μM) showed good inhibitory activity against AChE, while 9, 12, 3, and 6 exhibited significant inhibition potential against AChE with IC₅₀ values ranging from 35.2 ± 1.1 μM to 64.4 ± 0.3 μM. On the other hand, 5 (IC₅₀ = 22.0 ± 1.1 μM) and 27 (IC₅₀ = 31.3 ± 1.3 μM) displayed significant, and 19 (IC₅₀ = 92.6 ± 0.4 μM) showed moderate inhibitory potential for BChE. Notably, 5 and 27 exhibited dual inhibition of AChE and BChE, with greater potency than the standard drug galantamine. The binding patterns of these molecules within the binding cavities of AChE and BChE were anticipated by molecular docking which showed good correlation with our in vitro findings. Further structural optimization of these molecules may yield more potent AChE and BChE inhibitors.

Keywords: 4,4ʹ-Bisphenol; Acetylcholinesterase; Aldehydes; Bis(acylhydrazones); Butyrylcholinesterase; Molecular docking.