Huperzine A | |
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(1R,9S,13E)- 1-Amino- 13-ethylidene- 11-methyl- 6-azatricyclo[7.3.1.02,7] trideca- 2(7),3,10- trien- 5-one |
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Other names
HupA |
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Identifiers | |
CAS number | 102518-79-6 ![]() |
ChemSpider | 16736021 ![]() |
DrugBank | DB01928 |
ChEMBL | CHEMBL395280 ![]() |
Jmol-3D images | Image 1 |
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Properties | |
Molecular formula | C15H18N2O |
Molar mass | 242.32 g/mol |
Melting point |
217–219 °C |
![]() ![]() ![]() Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
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Infobox references |
Huperzine A is a naturally occurring sesquiterpene alkaloid compound found in the firmoss Huperzia serrata.[1] and in varying quantities in other Huperzia species, including H. elmeri, H. carinat, and H. aqualupian.[2]
Huperzine A is also an acetylcholinesterase inhibitor, which has a mechanism of action similar to donepezil, rivastigmine, and galantamine. A pro-drug form of Huperzine A (ZT-1) is under development as a treatment for Alzheimer's disease.[3]
In the US, Huperzine A is sold as a dietary supplement for memory support. The botanical has been used in China for centuries for the treatment of swelling, fever and blood disorders. Clinical trials in China have shown it to be effective in the treatment of Alzheimer's disease[4] and enhancing memory in students.[5]
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Huperzine A is an acetylcholinesterase inhibititor[6] and NMDA receptor antagonist.[7]
Huperzine A has also attracted the attention of US medical science. It is currently being investigated as a possible treatment for diseases characterized by neurodegeneration – particularly Alzheimer's disease.[8][9] It has been found to be an inhibitor of the enzyme acetylcholinesterase.[10] The structure of the complex of huperzine A with acetylcholinesterase has been determined[11] by X-ray crystallography (PDB code: 1VOT; see the 3D structure). This is the same mechanism of action of pharmaceutical drugs such as galantamine and donepezil used to treat Alzheimer's disease. Huperzine A is also a NMDA receptor antagonist which protects the brain against glutamate induced damage, and it appears to increase nerve growth factor levels in rats.[12]
Clinical trials in China have shown that huperzine A is comparably effective to similar drugs on the market, and may even be a bit safer in terms of side effects.[4] The National Institute on Aging has completed[9] a Phase II clinical trial[13] to evaluate the safety and efficacy of huperzine A in the treatment of Alzheimer's disease in a randomized controlled trial of its effect on cognitive function. In 2008, the National Institute on Aging conducted the first controlled trial outside of China evaluating the efficacy and toxicity of huperzine A to improve cognitive function in patients with AD. In this multi-center, double-blind, placebo-controlled Phase II trial, 210 participants with mild to moderate AD received either 200 mcg of huperzine A, 400 mcg of huperzine A, or placebo twice daily for 16 weeks. While no statistical difference in cognitive scores was noted in patients in the lower dose huperzine A group compared to placebo, the higher dose (400 mcg) of huperzine A led to improved cognition and activities of daily living. However, no significant changes were noted in any of the three groups in overall change in disease or in psychiatric ratings according to the AD Assessment Scale-Cognitive (ADAS-Cog) scale. Huperzine A was safe and well tolerated in the study. (13) The same year, a Cochrane Database review examined studies evaluating the efficacy and safety of huperzine A in the treatment of AD. The review included six randomized, controlled trials involving 454 patients. Huperzine A seemed to have beneficial effects on improvement of general cognitive function, global clinical status, behavioral disturbance and function performance with no serious side effects for patients with AD.
Possible side effects include breathing problems, tightness in the throat or chest, chest pain, skin hives, rash, itchy or swollen skin, upset stomach, diarrhea, vomiting, hyperactivity and insomnia. Most adverse events were cholinergic in nature and no serious adverse events occurred. Huperzine A is a well-tolerated drug.[6]
Two scalable and efficient total syntheses of Huperzine A have been reported.[14][15]
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