Hollow urchin-shaped manganese dioxide microspheres immobilized acetylcholinesterase for rapid screening inhibitors from traditional herbal medicines

Abstract

Acetylcholinesterase (AChE) is generally considered to be a valuable therapeutic target for Alzheimer's disease (AD). To rapidly screen novel AChE inhibitors from Traditional Chinese medicines (TCMs), polydopamine (PDA) coated hollow urchin-shaped manganese dioxide microspheres (h-MnO2@PDA) were fabricated in this work. AChE was immobilized onto the surface of h-MnO2@PDA for the first time, and the prepared h-MnO2@PDA immobilized AChE coupled with capillary electrophoresis (CE) was applied to AChE inhibitor screening. The enzyme catalytic activity and kinetic performances of the immobilized AChE were determined by measuring the peak areas of 5-thio-2-nitrobenzoic acid (TNB), which was produced by the reaction of thiocholine (TCh) with 5,5-dithiobis-(2-nitrobenzoic acid) (DTNB). Inhibition kinetics for the immobilized AChE was performed by employing huperzine A as model inhibitor, and its inhibition constant and IC50 were determined. The constructed AChE immobilized h-MnO2@PDA presented outstanding pH, thermal and storage stability. Ultimately, the constructed strategy was applied to screen AChE inhibitors from 7 TCMs and Schisandrae Chinensis Fructus was screened out for its superior AChE inhibitory activity. Therefore, our work not only established a platform for efficiently screening novel AChE inhibitors from TCMs, but also provided inspiration for further exploration of Schisandrae Chinensis Fructus as a potential drug for AD.