Huprine X is a novel high-affinity inhibitor of acetylcholinesterase that is of interest for treatment of Alzheimer's disease

Pelayo Camps, Bernadette Cusack, William D. Mallender, Rachid El Achab, Jordi Morral, Diego Muñoz-Torrero, Terrone L. Rosenberry

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Abstract

Inhibitors of the enzyme acetylcholinesterase (AChE) slow and sometimes reverse the cognitive decline experienced by individuals with Alzheimer's disease. Huperzine A, a natural product used in traditional Chinese herbal medicine, and tacrine (Cognex) are among the potent AChE inhibitors used in this treatment, but the search for more selective inhibitors continues. We report herein the synthesis and characterization of (-)-12-amino-3-chloro-9- ethyl-6,7,10,11-tetrahydro-7,11-methanocycloocta[b]quinoline hydrochloride (huprine X), a hybrid that combines the carbobicyclic substructure of huperzine A with the 4-aminoquinoline substructure of tacrine. Huprine X inhibited human AChE with an inhibition constant K1 of 26 pM, indicating that it binds to this enzyme with one of the highest affinities yet reported. Under equivalent assay conditions, this affinity was 180 times that of huperzine A, 1200 times that of tacrine, and 40 times that of E2020 (donepezil, Aricept), the most selective AChE inhibitor currently approved for therapeutic use. The association and dissociation rate constants for huprine X with AChE were determined, and the location of its binding site on the enzyme was probed in competition studies with the peripheral site inhibitor propidium and the acylation site inhibitor edrophonium. Huprine X showed no detectable affinity for the edrophonium-AChE complex. In contrast, huprine X did form a ternary complex with propidium and AChE, although its affinity for the free enzyme was found to be 17 times its affinity for the propidium-AChE complex. These data indicated that huprine X binds to the enzyme acylation site in the active site gorge but interferes slightly with the binding of peripheral site ligands.

Original languageEnglish (US)
Pages (from-to)409-417
Number of pages9
JournalMolecular Pharmacology
Volume57
Issue number2
StatePublished - 2000

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Cholinesterase Inhibitors
Acetylcholinesterase
Tacrine
Alzheimer Disease
Propidium
Edrophonium
Acylation
Enzymes
Binding Sites
Dissociative Disorders
Herbal Medicine
Enzyme Inhibitors
Therapeutic Uses
Biological Products
huprine X
Catalytic Domain
Ligands
donepezil
huperzine A

ASJC Scopus subject areas

  • Pharmacology

Cite this

Camps, P., Cusack, B., Mallender, W. D., El Achab, R., Morral, J., Muñoz-Torrero, D., & Rosenberry, T. L. (2000). Huprine X is a novel high-affinity inhibitor of acetylcholinesterase that is of interest for treatment of Alzheimer's disease. Molecular Pharmacology, 57(2), 409-417.

Huprine X is a novel high-affinity inhibitor of acetylcholinesterase that is of interest for treatment of Alzheimer's disease. / Camps, Pelayo; Cusack, Bernadette; Mallender, William D.; El Achab, Rachid; Morral, Jordi; Muñoz-Torrero, Diego; Rosenberry, Terrone L.

In: Molecular Pharmacology, Vol. 57, No. 2, 2000, p. 409-417.

Research output: Contribution to journalArticle

Camps, P, Cusack, B, Mallender, WD, El Achab, R, Morral, J, Muñoz-Torrero, D & Rosenberry, TL 2000, 'Huprine X is a novel high-affinity inhibitor of acetylcholinesterase that is of interest for treatment of Alzheimer's disease', Molecular Pharmacology, vol. 57, no. 2, pp. 409-417.
Camps P, Cusack B, Mallender WD, El Achab R, Morral J, Muñoz-Torrero D et al. Huprine X is a novel high-affinity inhibitor of acetylcholinesterase that is of interest for treatment of Alzheimer's disease. Molecular Pharmacology. 2000;57(2):409-417.
Camps, Pelayo ; Cusack, Bernadette ; Mallender, William D. ; El Achab, Rachid ; Morral, Jordi ; Muñoz-Torrero, Diego ; Rosenberry, Terrone L. / Huprine X is a novel high-affinity inhibitor of acetylcholinesterase that is of interest for treatment of Alzheimer's disease. In: Molecular Pharmacology. 2000 ; Vol. 57, No. 2. pp. 409-417.
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AU - Morral, Jordi

AU - Muñoz-Torrero, Diego

AU - Rosenberry, Terrone L.

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