Huperzine A is a naturally occurring sesquiterpene alkaloid compound found in the firmoss Huperzia serrata.and in varying quantities in other Huperzia species, including H. elmeri, H. carinat, and H. aqualupian.
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. Molecular formula C15H18N2O
