Acetylcholinesterase from

Galantamine (purity > 98%) and peptide amyloid-β (Aβ25–35, purity > 97%) were purchased from Shanghai Yuanye Biotechnology Co., Ltd. (Shanghai, China). Acetylcholinesterase (from Electrophorus electricus, 500 units/mg), all-trans astaxanthin standard (purity > 97%), acetylthiocholine iodide (purity > 98%), 5′,5-dithiobis- (2-nitrobenzoic acid) (purity > 98%), analytical grade methanol, ethyl alcohol (purity > 95%), dimethyl sulfoxide, methyl tert-butyl ether, bovine serum albumin, penicillin (100 units/mL), and streptomycin (100 μg/mL) were purchased from Sigma-Aldrich Co (St. Louis, MO, USA). PC12 cell, 3-(4,5-dimethyl-2-thiazolyl)-2,5- diphenyl-2H-tetrazolium bromide (MTT), horse serum, and bicinchoninic acid protein assay kit were purchased from Solarbio Science &Technology Co., Ltd. (Beijing, China). RPMI 1640 medium was purchased from Fisher Scientific (Waltham, MA, USA). Fetal bovine serum was purchased from Gemini Bio-Products (West Sacramento, CA, USA). Superoxide dismutase, malondialdehyde, catalase, and acetylcholinesterase (Acetylcholinesterase) kits were purchased from Nanjing Jiancheng Bioengineering Institute (Nanjing, China).

Acetylcholinesterase from electric eel type VI-S, butyrylcholinesterase from equine serum, acetylthiocholine iodide (ATCI), butyrylthiocholine iodide (BTCI), 5,5′-dithiobis[2-nitrobenzoic acid] (DTNB), bovine serum albumin (BSA), tris buffer, and galantamine were purchased from Sigma–Aldrich. The organic solvents (methanol and ethanol) and reagents used in the analysis were of analytical grades.

Acetylcholinesterase from Electrophorus electricus (Type VI-S; EC 3.1.1.7) (eelAChE), acetylcholine iodide (≥97%, ACh), choline chloride (≥99%, Ch), galanthamine hydrobromide from Lycoris sp (≥94% HPLC), 9-amino-1,2,3,4-tetrahydroacridine hydrochloride hydrate (tacrine hydrochloride, ≥99%), donepezil hydrochloride (≥98% HPLC), edrophonium chloride, caffeine, ammonium acetate, Tris hydrochloride, glutaraldehyde (25% aqueous solution), and sodium phosphate monobasic were purchased from Sigma-Aldrich (St. Louis, United States). 3-(Aminopropyl)trietoxysilane (≥99%, APTES) was purchased from Acros Organics (Geel, BE). HPLC grade methanol (MeOH), acetonitrile (ACN) and ethanol (EtOH) were acquired from Merck-Millipore (Burlington, United States). Ultrapure water was obtained with a Merck-Millipore Milli-Q^® system (Burlington, United States). Fused silica capillary (0.375 mm o. d. x 0.1 mm i. d.) was acquired from Polymicro Technologies (Phoenix, United States). All the solutions were filtered through a Merck-Millipore nylon membrane filter (0.22 μm) prior to use (Burlington, United States).