| Recently, multi‐target directed ligands have been of research interest for multifactorial
disorders such as Alzheimer's disease (AD). Since H3 receptors (H3Rs) and
cholinesterases are involved in pathophysiology of AD, identification of dual‐acting
compounds capable of improving cholinergic neurotransmission is of importance
in AD pharmacotherapy. In the present study, H3R antagonistic activity combined
with anticholinesterase properties of two previously computationally identified lead
compounds, that is, compound 3 (6‐chloro‐N‐methyl‐N‐[3‐(4‐methylpiperazin‐1‐yl)
propyl]‐1H‐indole‐2‐carboxamide) and compound 4 (7‐chloro‐N‐[(1‐methylpiperidin‐
3‐yl)methyl]‐1,2,3,4‐tetrahydroisoquinoline‐2‐carboxamide), was tested.
Moreover, molecular docking and binding free energy calculations were conducted
for binding mode and affinity prediction of studied ligands toward cholinesterases.
Biological evaluations revealed inhibitory activity of ligands in nanomolar (compound
3: H3R EC50 = 0.73 nM; compound 4: H3R EC50 = 31 nM) and micromolar
values (compound 3: AChE IC50 = 9.09 μM, BuChE IC50 = 21.10 μM; compound 4:
AChE IC50 = 8.40 μM, BuChE IC50 = 4.93 μM) for H3R antagonism and cholinesterase
inhibition, respectively. Binding free energies yielded good consistency with
cholinesterase inhibitory profiles. The results of this study can be used for lead optimization
where dual inhibitory activity on H3R and cholinesterases is needed. Such
ligands can exert their biological activity in a synergistic manner resulting in higher
potency and efficacy. |