Selective acetylcholinesterase inhibitors derived from muscle relaxant dantrolene.

Dantrolene, the only therapeutic agent for malignant hyperthermia, is known to have not only a muscle relaxant effect, but also a neuroprotective effect and Alzheimer's disease improving effect. Recently, it has been reported that dantrolene has a weak inhibitory effect on acetylcholinesterase (AChE), which is a therapeutic drug target for Alzheimer's disease. Thus, we focused on developing of AChE inhibitors with benzylpiperidine/piperazine moieties that are based on the dantrolene skeleton. Several derivatives showed an inhibitory activity. Among them, ortho-nitro derivative 8c showed the most potent inhibitory activity with the IC50 value of 34.2 nM. Furthermore, Lineweaver-Burk plot analysis indicated that 8c is AChE-selective inhibitor, which shows only a weak inhibitory effect on butyrylcholinesterase (BuChE) and a non-competitive inhibition.