Tetrahydroacridine derivatives with dichloronicotinic acid moiety as attractive, multipotent agents for Alzheimer's disease treatment.

A novel series of 9-amino-1,2,3,4-tetrahydroacridine and 5,6-dichloronicotinic acid moiety were conjugated with different linkers. Afterwards new derivatives were evaluated as potential multifunctional acetylcholinesterase inhibitors (AChEIs), anti-Alzheimer's disease (AD) drug candidates. All the compounds were synthesized and tested for capacity for the inhibition of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) enzymes. Specifically, the most promising derivative 3b (IC50 = 1.02 nM) had higher inhibitory potency compared to the reference drug, tacrine. Consequently, kinetic studies of 3b compound showed a mixed-type inhibition of both AChE and BuChE. Afterwards the best potent AChE inhibitor has been examined on amyloid ß (Aß) self-induced aggregation. Furthermore, 3b compound was tested in various concentrations and had moderate activity against Aß aggregation. Inhibition of Aß aggregation was 46.63% and 19.41% at 50 µM and 5  µM concentrations, respectively. Moreover, no cytotoxicity was observed for the mentioned concentrations. Therefore, 3b compound is a promising multipotent agent for the treatment of AD.