The use of Huperzia species for the treatment of Alzheimer's disease.

Alzheimer's disease (AD), which relates to nervous degeneration, is the most popular form of memory loss. The pathogenesis of AD is not fully understood, and there are no therapies for this disorder. Some drugs have been used in clinical applications for preventing and treating AD, but they have significant adverse reactions. Therefore, there is a need to develop treatment for AD. Traditional medicine has used many medicinal plants to alleviate the symptoms of AD. Medicinal plants may reduce neurodegenerative disorders with fewer side effects than chemical drugs, and they are promising drug candidates for AD therapy. This review is the summary of the pathogenesis and treatments of AD and includes information about the chemistry and bioactivities of some medicinal plants from the Huperzia species, such as Huperzia saururus, Huperzia selago, Huperzia phlegmaria, Huperzia fargesii, Huperzia serrata, Huperzia reflexa and Huperzia quadrifariata, that are used for the treatment of AD. We searched literature, including Medline, Embase, Google Scholar and PubMed database, and did a bibliographic review of relevant articles. Key words included Huperzia species, huperzine, huperin, Huperzia and Alzheimer's disease. We found that the main bioactive compounds of the Huperzia species are alkaloids, which have shown significant effects on preventing the development of AD. They are new promising compounds against AD due to their antioxidant, anti-inflammatory and acetylcholinesterase inhibitory activities in the neural system. Our conclusion from this review is that the Huperzia species are potential source containing various pharmaceutical compounds for the treatment of AD.