Chemiluminescent high-throughput microassay for evaluation of acetylcholinesterase inhibitors

Current drug therapies for Alzheimer's disease (AD) are mainly based on acetylcholinesterase (AChE) inhibitors. However, such inhibitors may possess non-optimal pharmacological properties or cause adverse effects, therefore research for the development of new drugs is still in progress. In this paper, a rapid and simple chemiluminescent (CL) assay for the in vitro evaluation of AChE inhibitors in which the activity of AChE is measured through a series of coupled enzymatic reactions leading to light emission is described. The assay is performed in microtiter plates, both in the 96- and 384-well formats. In the latter format up to 30 compounds can be simultaneously analyzed in a very short time (the chemiluminescence measurement lasts 5 min) and using small volumes of samples and reagents (the assay volume is less than 60 μL), thus allowing high-throughput screening (HTS). The assay proved to be reliable, as demonstrated by the analysis of known AChE inhibitors, and the reproducibility of the results was satisfying for a screening assay (CV% in the order of 20%). It could therefore represent a valuable alternative to other methods for the preliminary evaluation of new potential AChE inhibitors.