Huperzine A's therapeutic uses
Huperzine A is a natural compound derived from the club moss Huperzia serrata, known for its potential therapeutic uses, particularly in treating age-related memory loss, Alzheimer's disease, and other forms of dementia. It functions by inhibiting the enzyme acetylcholinesterase, which breaks down acetylcholine, a neurotransmitter essential for cognitive function. By preventing this breakdown, Huperzine A may enhance memory and mental performance, making it popular as a supplement for individuals seeking cognitive improvements, even in those without dementia. Clinical studies, primarily conducted in China, have shown varied results; some trials indicate significant benefits for individuals with Alzheimer's, while others report no substantial differences compared to placebo. Despite promising findings, the overall evidence remains mixed, particularly regarding its efficacy for healthy individuals and other cognitive disorders like vascular dementia. Huperzine A is generally well-tolerated but can cause side effects such as nausea and gastrointestinal issues, and its use should be supervised by a healthcare professional, especially for those with pre-existing health conditions. While marketed as a dietary supplement in some regions, it is important to approach its use cautiously, given its potent effects and potential interactions with other medications.
Huperzine A's therapeutic uses
DEFINITION: Natural plant products used to treat specific health conditions.
PRINCIPAL PROPOSED USES: Age-related memory loss, Alzheimer’s disease, and other forms of dementia
Overview
Huperzine A (HupA) is a potent chemical derived from a particular type of club moss (Huperzia serrata [Thunb.] Trev.), though HupA may be more practically derived from endophytic fungi. Like caffeine and cocaine, huperzine A is a medicinally active, plant-derived chemical that belongs to the class known as alkaloids. It was first isolated in 1948 by Chinese scientists. This substance is really more a drug than an herb, but it is sold over the counter as a dietary supplement for memory loss and mental impairment.
Studies in animals suggested that huperzine A could improve memory skills. These findings led to human trials and the subsequent marketing of huperzine A as a treatment for Alzheimer’s disease and related conditions. It is also sold as a “brain booster” for enhancing memory and mental function in people without Alzheimer’s disease.
Huperzine A inhibits the enzyme acetylcholinesterase. This enzyme breaks down acetylcholine, a substance that plays an important role in mental function. When the enzyme that breaks it down is inhibited, acetylcholine levels in the brain tend to rise. Drugs that inhibit acetylcholinesterase (such as tacrine and donepezil) improve memory and mental functioning in people with Alzheimer’s and other severe conditions.
The research on huperzine A indicates that it works in much the same way. The chemical action of huperzine A is very precise and specific. It “fits” into a niche on the enzyme where acetylcholine is supposed to attach. Because huperzine A is in the way, the enzyme cannot grab and destroy acetylcholine. This mechanism has been demonstrated by considerable scientific work, including sophisticated computer modeling of the shape of the molecule. Huperzine A may also help protect nerve cells from damage.
While huperzine A is sold as a dietary supplement, in all essential ways, it is simply a typical drug. Huperzine A is highly purified in a laboratory and is just a single chemical. It is not much like an herb. Herbs contain hundreds or thousands of chemicals. Huperzine A resembles drugs such as digoxin, codeine, Sudafed, and vincristine (a chemotherapy drug), which are also highly purified chemicals taken from plants. If huperzine A is called a “natural” treatment, it would also be necessary to call these drugs, and dozens of other standard drugs, “natural.”
Therapeutic Dosages
Huperzine A is a highly potent compound with a recommended dose of only 100 to 200 micrograms twice a day for age-related memory loss. Individuals should use it only under a doctor’s supervision.
Scientific Evidence
Most clinical trials of huperzine were performed in China and reported in Chinese. A double-blind, placebo-controlled study evaluated 103 people with Alzheimer’s disease who received either huperzine A or placebo twice daily for eight weeks. About 60 percent of the treated participants showed improvements in memory, thinking, and behavioral functions compared to 36 percent of the placebo-treated group, and the difference was significant. Benefits were also seen in an earlier double-blind trial using injected huperzine in 160 individuals with dementia or other memory disorders.
However, not all studies have been positive. Another double-blind trial of sixty individuals with Alzheimer’s disease found no significant difference in symptoms between the treated group and the placebo group. Such contradictory results are common when a treatment is only modestly effective, as may be the case here. In a 2008 detailed review of six randomized controlled trials, researchers concluded that, on balance, huperzine A appears to have some beneficial effects. However, the variable quality of these studies suggests that the evidence to date is not strong. Huperzine is also promoted for improving memory in healthy individuals, but the supporting evidence for this claim appears to be limited to one small, poorly designed trial.
Huperzine A may also be effective in treating vascular dementia, which is a condition where issues with the blood vessels in the brain affect cognition and memory. Studies have been contradictory; however, a 2014 meta-analysis of several studies of huperzine A showed it did provide some benefit. Huperzine A may also increase anticholinesterase activity and provide antiglutamate, antioxidant, and neuroprotective effects. Small studies have also expanded to look into its effectiveness against Parkinson’s, epilepsy, and schizophrenia. Similar studies continue to show mixed results for huperzine A's efficacy in treating vascular dementia. Large-scale reviews of these studies conducted in 2016 and 2022 revealed that huperzine A has a generally positive effect on health and quality of life for individuals with Alzheimer’s disease, but the studies contained construction bias that may indicate that the researchers simply found the result they wanted to find.
Safety Issues
Common side effects of huperzine A include nausea, diarrhea, vomiting, muscle spasms, dry mouth or excessive salivation, constipation, sweating, slurred speech, and blurred vision. Other individuals experienced a slowed heart rate, increased severity of existing seizure disorders, gastrointestinal or urinary tract blockage, stomach ulcers, and worsened asthma or chronic obstructive pulmonary disease. Huperzine A increases the body’s acetylcholine levels, a neurotransmitter critical in many brain functions, which may decrease the effectiveness of anticholinergic and cholinergic drugs, like those used for glaucoma and Alzheimer’s disease. Huperzine A is an approved prescription medication in China, where most drug studies have been undertaken, and the US Food and Drug Administration recognizes it as a dietary ingredient. Children, pregnant or nursing women, and those with high blood pressure or severe liver or kidney disease should not take huperzine A except on a doctor’s recommendation.
Bibliography
Cheng, D. H., and X. C. Tang. “Comparative Studies of Huperzine A, E2020, and Tacrine on Behavior and Cholinesterase Activities.”Pharmacology, Biochemistry, and Behavior vol. 60, 1998, pp. 377-86.
Chennai, Hind Yassmine, et al. “Identification of Potent Acetylcholinesterase Inhibitors as New Candidates for Alzheimer Disease via Virtual Screening, Molecular Docking, Dynamic Simulation, and Molecular Mechanics-Poisson-Boltzmann Surface Area Calculations.” Molecules (Basel, Switzerland), vol. 29, no. 6, 10 Mar. 2024, doi:10.3390/molecules29061232.
Fan, Fangcheng, et al. “The Efficacy and Safety of Alzheimer's Disease Therapies: An Updated Umbrella Review.” Journal of Alzheimer's Disease, vol. 85, no. 3, 2022, pp. 1195-1204. doi:10.3233/JAD-215423.
Ghassab-Abdollahi, Nafiseh, et al. “The Effects of Huperzine A on Dementia and Mild Cognitive Impairment: An Overview of Systematic Reviews.” Phytotherapy Research: PTR, vol. 35, no. 9, 2021, pp. 4971-87. doi:10.1002/ptr.7126.
“Huperzine A Uses, Benefits & Dosage.” Drugs.com, 2023, www.drugs.com/npp/huperzine-a.html. Accessed 27 Aug. 2023.
Phan, Ross. “Huperzine A Uses, Benefits, & Side Effects.” Verywell Health, 13 Apr. 2023, www.verywellhealth.com/the-benefits-of-huperzine-a-89464. Accessed 20 Sept. 2024.
Sun, Q. Q., et al. “Huperzine-A Capsules Enhance Memory and Learning Performance in Thirty-Four Pairs of Matched Adolescent Students.” Zhongguo Yao Li Xue Bao vol. 20, 1999, pp. 601-03.