Synthesis and biological evaluation of new tetramethylpyrazine-based chalcone derivatives as potential anti-Alzheimer agents.

In the current study, a series of new ligustrazine-based chalcones was synthesized. For insertion of tetramethylpyrazine (TMP, also designated as ligustrazine) in chemical backbone of chalcone, a new ligustrazine-based aldehyde was prepared. New ketones were synthesized for inclusion of quinazolin-4-yl amino and pyrazin-2-yl amino moieties. The newly synthesized compounds were screened for acetylcholinesterase, butyrylcholinesterase, and monoamine oxidases (MAO) inhibitory activities and also for in vitro cytotoxicity on PC12 cells. The effect of these compounds against amyloid β-induced cytotoxicity and aggregation was also investigated. The synthesized compounds effectively inhibited the related enzymes and also exhibited neuroprotective effects. Most of the compounds displayed better inhibitory potencies against Aβ aggregation than reference compounds. Some compounds such as 11e and 16b showed very potent effects on multiple targets exhibiting behavior as multifunctional anti-Alzheimer agents.