Research into Chinese herbal medicine Qian Ceng Ta may help Alzheimer’s

May 6 2004

Georgetown University Medical Center researchers today opened a new clinical trial designed to test if huperzine A, a natural product derived from a Chinese herb, can slow down or prevent cognitive decline in patients with mild to moderate Alzheimer’s Disease (AD).

Led by Paul Aisen, director of Georgetown’s Memory Disorders Program, the study follows the gold standard parameters for evaluating potential new therapies.  It is a phase two, randomized, double-blinded, placebo-controlled study.  Researchers aim to recruit 150 people from approximately 20 different sites.

Huperzine A is an alkaloid extract of the plant Huperzia serrata.  It is a component of a traditional Chinese herbal medicine, Qian Ceng Ta, used to treat fever and inflammation.  During the 1980’s, scientists in China determined that huperzine A is a potent inhibitor of acetlycholinesterase (AChE), an enzyme involved in the degradation of acetylcholine. Acetylcholine is the primary neurotransmitter involved in memory and learning. Alzheimer’s disease results in a depletion of this important chemical.

While the Chinese actively use huperzine A to treat AD, Aisen’s trial will be the first controlled clinical study outside of China testing its safety and efficacy in humans.

“Preclinical studies suggest that huperzine A may have advantages over the four AChE inhibitors currently used in the U.S. to treat the symptoms of AD,” said Aisen, MD, professor of neurology at Georgetown.  “It has good brain penetration, is relatively free of toxicity, and is highly selective for AChE in vitro.  Scientific rigor will bear out whether this natural product can be added to the arsenal of weapons used in the treatment of AD, perhaps as something even safer and more effective than the medicines currently prescribed.”

Natural huperzine A is available in health food stories as a nutriceutical, and is sold over the Internet.  It is marketed as a cognitive enhancing agent.  This concerns Aisen, who notes that no controlled studies have taken place in the U.S. to substantiate claims of preventive or curative benefit.

“As more people with and without AD take huperzine A, in the hopes of either preventing or treating AD, it is imperative we use controlled clinical trials to determine huperzine A’s safety and efficacy,” said Aisen.

Researchers for this study are looking for participants who:

• have been diagnosed with mild to moderate Alzheimer’s disease
• are age 55 or older
• are not currently taking cholinesterase inhibitors (such as Aricept, Exelon or Reminyl)
• speak English or Spanish
• have a study partner – a friend or relative who can accompany the volunteer to all clinic visits and answer questions about him or her

The study is supported by the Alzheimer’s Disease Cooperative Study at the University of California, and funded by the U.S. Government’s National Institute on Aging and by Marco Hi-Tech. For more information about this clinical trial, please call Sally Walsh at (202) 687-8323, or go to http://memory.georgetown.edu/.