BCHE and Alzheimer disease: At present, the Food and Drug Administration of the United States has approved five main drugs for the clinical treatment of Alzheimer’s disease, which are cholinesterase inhibitors tacrine, galantamine, capalatine and donepezil, and N-methyl-d-aspartate receptor antagonist memantine, although these drugs have shown good efficacy in clinical trials, the actual clinical effect is less effective due to the existence of blood brain barrier.