Initial Source: Harvested from the club moss Huperzia serrata.

Primary medical role: Huperzine A has been used in China for centuries to treat fever and inflammation. The compound exhibits anticholinesterase activity and is now under investigation as potential Alzheimer disease medication. Currently approved for AD treatment in China.

Role in Alzheimer's disease: Huperzine A is a reversible and selective acetylcholinesterase inhibitor, similar to but potentially more potent than tacrine or donepezil. Animal studies have shown it to be beneficial on memory deficits in cases of amnesia. In nonhuman primate studies, Huperzine A displayed long term improvement in the mnemonic performance requiring working memory.