Huperzine A is extracted from Huperzia serrata. It is a reversible acetylcholinesterase inhibitor and NMDA receptor antagonist that crosses the blood-brain barrier. The structure of the complex of huperzine A with acetylcholinesterase has been determined by X-ray crystallography (PDB code: 1VOT; see the 3D structure).
For some years, huperzine A has been investigated as a possible treatment for diseases characterized by neurodegeneration, particularly Alzheimer’s disease. A 2013 meta-analysis found that huperzine A may be efficacious in improving cognitive function, global clinical status, and activities of daily living for individuals with Alzheimer’s disease. However, due to the poor size and quality of the clinical trials reviewed, huperzine A should not be recommended as a treatment for Alzheimer’s disease until further high quality studies confirm its beneficial effects.
Huperzine A is also marketed as a dietary supplement with claims made for its ability to improve memory and mental function.Huperzine A has also been postulated as a potential treatment for myasthenia gravis.
Huperzine A may present with mild cholinergic side effects such as nausea, vomiting, and diarrhea.
The use of huperzine A during pregnancy and lactation is not recommended due to the lack of sufficient safety data.