Design,Synthesis And Activity Evaluation Of Selective Butyrylcholinesterase Inhibitor

Alzheimer’s disease（AD）is a neurodegenerative disease with insidious onset,and has become the third leading cause of death after cancer and cardiovascular disease.Although there are many kinds of drugs used in preclinical research,there are only 7 drugs approved for marketing internationally.These drugs can relieve AD to a certain extent,but are only effective for some patients and cannot prevent the progression of the disease.Its application has great limitations.Therefore,in the face of the growing population of AD patients,the development of high-efficiency,low-toxic and economical anti-AD drugs has always been an urgent problem to be solved.In recent years,most experimental studies have been carried out around the cholinergic function hypothesis.More and more experimental evidence shows that butyrylcholinesterase（BChE）has a lower hydrolysis efficiency for acetylcholine（ACh）at low concentrations,and a higher hydrolysis efficiency for ACh at high concentrations.The close spatial relationship of glial BChE would allow synergistic BChE-mediated hydrolysis to assist in the regulation of local ACh levels to permit the maintenance of normal cholinergic function.Experiments have shown that BChE can compensate for the function of acetylcholinesterase（AChE）.Therefore,selective inhibition of BChE may help reduce cholinergic deficiency.Histochemical studies have shown that some cholinergic neurons contain BChE instead of AChE.In advanced AD patients,BChE activity gradually increases,while AChE activity remains unchanged or decreases.Therefore,selective inhibition of BChE is considered to be a highly potential clinical treatment strategy for AD.In this paper,we first conducted a virtual screening of our laboratory’s compound library through molecular docking,and then obtained a moderately active BChE selective inhibitor-compound1:N-（2-（diethylamino）ethyl）-4-（（3,4-dihydroisoquinolin-2（1H）-yl）methyl）benzamide,and then the structure of compound 1 was optimized,and a series of selective BChE inhibitors were designed and synthesized.In vitro enzymatic assay results showed that compound 9:（4-（（3,4-dihydroisoquinolin-2（1H）-yl）methyl）phenyl）（pyrrolidin-1-yl）methanoneand compound 23:N-（2-bromophenyl）-4-（（3,4-dihydroisoquinolin-2（1H）-yl）methyl）benzamide shows better BChE inhibitory activity and selectivity than AChE.The binding mode of inhibitors and enzymes was explored by molecular docking methods,and further verified by molecular dynamics simulations.Kinetic analysis and molecular modeling studies showed that these derivatives can simultaneously target BChE,the catalytically active site（CAS）and the peripheral anion site（PAS）can be used as a dual-target inhibitor of BChE.In addition,the selected compounds 9 and 23 can show inhibitory activity on Aβ_1-42 aggregation in a dose-dependent manner,and has a good protective effect on SH-SY5Y nerve cell damage induced by Aβ_1-42.The selective BChE inhibitors with neuroprotective effects discovered in current experiments provide a new candidate molecule for the subsequent development of anti-AD drugs.