Combining β2-AR agonism with butyrylcholinesterase inhibition, a synergistic neuroprotective action against Alzheimer's disease

Abstract

Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder for which the current treatments remain largely symptomatic. Pleiotropic prodrug strategies offer a promising approach to address this complexity, combining complementary pharmacological mechanisms within a single molecular entity. In this study, we report the design, synthesis, and biological evaluation of novel carbamate-based pleiotropic prodrugs that combine butyrylcholinesterase (BuChE) inhibition and β₂-adrenergic receptor (β₂-AR) agonism. Seven salmeterol-derived carbamates were synthesized and evaluated for their cholinesterase inhibitory activity, β₂-AR activity, and neuroprotective potential. Several derivatives exhibited potent and selective inhibition of human BuChE in the nanomolar range, revealing a clear structure-activity relationship driven by carbamate substitution and amine protection. Kinetics and LC-MS analyses demonstrated a pseudo-irreversible covalent inhibition mechanism associated with rapid enzyme reactivation, thereby enabling controlled salmeterol release. While carbamates behaved as inactive prodrugs at the β₂-AR level, selected compounds displayed significant neuroprotective effects in a cellular model of amyloid-β-induced toxicity. Collectively, these findings validate salmeterol-derivated carbamates as innovative pleiotropic prodrugs and support the potential of combining BuChE inhibition and β₂-AR agonism as a disease-modifying strategy for Alzheimer’s disease.