Huperzine A (shuangying): a promising drug for Alzheimer’s disease
An herbal supplement on the fast track for scientific recognition as a treatment for Alzheimer’s is Huperzine A, a plant extract derived from Chinese club moss. Evidence that it may revitalize memory and help improve focus and concentration is causing a stir among top scientists, including research psychiatrists at the National Institute of Mental Health and academic pharmacologists. Debasis Bagchi, Ph.D., associate professor at Creighton University School of Pharmacy, says Huperzine A holds great promise “for a wide range of memory and brain disorders, including Alzheimer’s disease.”
Huperzine has been used for centuries in Chinese folk medicine to rejuvenate memory in older people.
The “memory moss” is said to work much like prescription drugs now approved for treating Alzheimer’s. The key to both Huperzine A and such drugs is manipulation of the brain transmitter acetylcholine, known as the “memory molecule.” Acetylcholine is abnormally low in Alzheimer’ brains, because damaged nerve cells no longer synthesize it and an enzyme (acetylcholinesterase) keeps breaking down and whisking away what little is made. Huperzine A, like other memory-preserving drugs, is believed to block the enzyme from destroying acetylcholine, thus preserving more to facilitate transmission of electrical impulses between neurons. Technically, Huperzine A, like the approved Alzheimer’s drugs, is called an “acetylcholinesterase inhibitor.”
Many studies, most done in China, show that Huperzine surpassed the two major approved pharmaceutical drugs for Alzheimer’s disease, Aricept (donepezil) and Cognex (tacrine), in reversing memory deficits in aging animals. Huperzine’s activity is also reportedly long-lasting. One test in young healthy volunteers showed that Huperzine A blocked the target enzyme for 288 minutes, allowing more acetylcholine to circulate in the brain, whereas the prescription drug physotigmine inhibited the enzyme for only twenty minutes.
A recent double-blind trial at Zhejiang Medical University in Shanghai tested Huperzine on Alzheimer’s patients. Half got the real thing, half a placebo for two months. Mental cognition was measured by “gold standard” tests, including the Wechsler Memory Scale and the Mini-Mental State Examination scale. Those getting Huperzine did 36 percent better than those on placebo.
Huperzine also reportedly improved mental function in patients with multi-infarct dementia, caused by repeated mini-strokes, as well as victims of myasthenia gravis, a neuromuscular disease.
What makes Huperzine so attractive is its apparent lack of serious side effects and very low toxicity, a big plus, since approved prescription drugs with the same mechanism of action inflict brutal side effects, notably liver toxicity. Some government authorities, however, are concerned that Huperzine, a drug reportedly as potent as current prescription drugs, can be sold to treat Alzheimer’s without prescription, without FDA approval and without undergoing clinical trials in the United States. They think, at the very least, it should be used only with a doctor’s supervision.
However, Alan P. Kozikowski, director of the Drug Discovery Program at Georgetown Medical Center in Washington, D.C., who first synthesized Huperzine, says its use is not limited to those with Alzheimer’s, but benefits anyone worried about memory loss. “Anyone who is feeling some problem with memory recall will probably want it,” he has said. “I’ve tried it myself. It does make you feel more alert.”
How much? The typical dosage that benefited Alzheimer’s patients in Chinese studies is 200 micrograms twice a day. But much less may also work. Alan Mazurek, M.D., a neurologist in private practice in Rockville Center, New York, recently reported that half of a small group of Alzheimer’s patients improved in mental function after they took 100 micrograms of Huperzine A a day.
Despite Huperzine’s promising track record, the argument that it equals efficacy of current drugs may not be a sterling recommendation. New findings published in the Journal of the American Medical Association claim that current prescription drugs, designed to preserve acetylcholine, are effective only in patients with advanced Alzheimer’s, not in milder cases. If so, Huperzine might be of little or no benefit to people with mild to moderate memory disorders. More clinical trials are needed—and some are underway—to determine the memory boosting potential of Huperzine A. In the meantime, herbal authority California physician Ray Sahelian, author of numerous well-respected books on herbal remedies, advises using Huperzine A only as a treatment for Alzheimer’s and not as a way to try to boost normal memory.