Novel donepezil-chalcone-rivastigmine hybrids as potential multifunctional anti-Alzheimer's agents: Design, synthesis, in vitro biological evaluation, in vivo and in silico studies.

Alzheimer's disease (AD) is a chronic, progressive brain neurodegenerative disorder. Up to now, there is no effective drug to halt or reverse the progress of AD. Given the complex pathogenesis of AD, the multi-target-directed ligands (MTDLs) strategy is considered as the promising therapy. Herein, a series of novel donepezil-chalone-rivastigmine hybrids was rationally designed and synthesized by fusing donepezil, chalone and rivastigmine. The in vitro bioactivity results displayed that compound 10c was a reversible huAChE (IC50 = 0.87 μM) and huBuChE (IC50 = 3.3 μM) inhibitor. It also presented significant anti-inflammation effects by suppressing the level of IL-6 and TNF-α production, and significantly inhibited self-mediated Aβ1-42 aggregation (60.6%) and huAChE-mediated induced Aβ1-40 aggregation (46.2%). In addition, 10c showed significant neuroprotective effect on Aβ1-42-induced PC12 cell injury and activated UPS pathway in HT22 cells to degrade tau and amyloid precursor protein (APP). Furthermore, compound 10c presented good stabilty in artificial gastrointestinal fluids and liver microsomes in vitro. The pharmacokinetic study showed that compound 10c was rapidly absorbed in rats and distributed in rat brain after intragastric administration. The PET-CT imaging demonstrated that [11C]10c could quickly enter the brain and washed out gradually in vivo. Further, compound 10c at a dose of 5 mg/kg improved scopolamine-induced memory impairment, deserving further investigations.