Huperzine A

Huperzine A is a naturally occurring sesquiterpene alkaloid compound found in the plant firmoss Huperzia serrata.

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.

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 and enhancing memory in students.

Pharmacological effects
Huperzine A is an acetylcholinesterase inhibititor and NMDA receptor antagonist,.

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. It has been found to be an inhibitor of the enzyme acetylcholinesterase. The structure of the complex of huperzine A with acetylcholinesterase has been solved 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.

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. The National Institute on Aging has completed a Phase II clinical trial 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.

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.