Multifunctional tacrine-flavonoid hybrids with cholinergic, β-amyloid-reducing, and metal chelating properties for the treatment of Alzheimer's disease.

A new series of tacrine-flavonoid hybrids (13a-u) had been designed, synthesized, and evaluated as multifunctional cholinesterase (ChE) inhibitors against Alzheimer's disease (AD). In vitro studies showed that most of the molecules exhibited a significant ability to inhibit ChE and self-induced amyloid-β (Aβ₁₋₄₂) aggregation. Kinetic and molecular modeling studies also indicated compounds were mixed-type inhibitors, binding simultaneously to active, peripheral and mid-gorge sites of AChE. Particularly, compound 13k was found to be highly potent and showed a balanced inhibitory profile against ChE and self-induced Aβ₁₋₄₂ aggregation. Moreover, it also showed excellent metal chelating property and low cell toxicity. These results suggested that 13k might be an excellent multifunctional agent for AD treatment.