Novel cinnamic acid-based N-benzyl pyridinium analogs: potent dual cholinesterase inhibitors with neuroprotective properties for Alzheimer's disease

Abstract

This study reports the design and synthesis of a novel series of cinnamic acid-based analogs bearing an N-benzyl pyridinium moiety against Alzheimer's disease (AD), aiming at dual inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), alongside neuroprotective effects. A total of 15 derivatives were synthesized, among which compound 7b exhibited the most potent dual inhibition (AChE IC₅₀ = 0.89 µM; BChE IC₅₀ = 0.11 µM), and significant neuroprotection against H₂O₂-induced oxidative stress in SH-SY5Y cells, with no cytotoxicity under the tested concentration. Structure–activity relationship (SAR) analysis revealed that small electron-withdrawing substituents (e.g. ortho-fluoro, methyl) enhanced inhibitory activity, whereas meta and para substitutions generally reduced potency. Enzyme kinetics also determined compound 7b to be a competitive inhibitor of AChE (K_i = 0.49 µM). Furthermore, molecular docking and molecular dynamics simulations identified stable binding interactions in the active sites of AChE and BChE. All these findings support the potential of these compounds as effective multi-target-directed ligands (MTDLs) for AD, displaying coordinated inhibition of cholinesterase, neuroprotection, and low toxicity.