Design, synthesis and biological evaluation of novel coumarin-N-benzyl pyridinium hybrids as multi-target agents for the treatment of Alzheimer's disease.

Combining N-benzyl pyridinium moiety and coumarin into in a single molecule, novel hybrids with ChE and MAO-B inhibitory activities were designed and synthesized. The biological screening results indicated that most of compounds displayed potent inhibitory activity for ChE and Aβ (1-42) self-aggregation, and clearly selective inhibition to MAO-B over MAO-A. Of these compounds, compound 7f was the most potent inhibitor for hMAO-B, and it was also a good and balanced inhibitor to ChEs and hMAO-B (0.0373 μM for eeAChE; 2.32 μM for eqBuChE; 1.57 μM for hMAO-B). Molecular modeling and kinetic studies revealed that compound 7f was a mixed-type inhibitor, which bond simultaneously to CAS and PAS of AChE, and it was also a competitive inhibitor, which occupied the active site of MAO-B. In addition, compound 7f with no toxicity on PC12 neuroblastoma cells, showed good ability to inhibit Aβ (1-42) self-aggregation and cross the BBB. Collectively, all these results suggested that compound 7f might be a promising multi-target lead candidate worthy of further pursuit.