Multifunctional Cholinesterase and Amyloid Beta Fibrillization Modulators. Synthesis and Biological Investigation

In order to identify novel Alzheimer's modifying pharmacological tools, we developed bis-tacrines bearing a peptide moiety for specific interference with surface sites of human acetylcholinesterase (hAChE) binding amyloid-beta (A beta). Accordingly, compounds 2a-c proved to be inhibitors of hAChE catalytic and noncatalytic functions, binding the catalytic and peripheral sites, interfering with A beta aggregation and with the A beta self-oligomerization process (2a). Compounds 2a-c in complex with TcAChE span the gorge with the bis-tacrine system, and the peptide moieties bulge outside the gorge in proximity of the peripheral site These moieties are likely responsible for the observed reduction of hAChE-induced A beta aggregation since they physically hamper A beta binding to the enzyme surface. Moreover, 2a was able to significantly interfere with A beta self-oligornerization, while 2b,c showed improved inhibition of hAChE-induced A beta aggregation.