Scientists synthesize the drug Huperzine A from Chinese club moss. UNC researchers are testing the safety and effectiveness of Huperzine A as a treatment for Alzheimer’s disease. Photo courtesy of Ben Legler; ©2007 Endeavors.

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Occasional memory lapses may be the first signs of Alzheimer’s disease. You forget your keys or miss a meeting. Memory drifts downhill from there. But an herbal supplement found on the shelves of health stores may help fight the decline. The supplement, Huperzine A, is derived from a plant the Chinese have used for centuries to fight fever, blood disorders, and schizophrenia.

Neurologist Daniel Kaufer is leading a trial of Huperzine A at UNC to test the safety and effectiveness of 400 and 800 mg doses in more than 200 people who are affected with mild to moderate Alzheimer’s disease. Health stores sell the “brain booster” in much lower doses than those tested in the trial.

“Deciding whether to take most supplements is really haphazard in my view,” he says, “because most have not been submitted to well-controlled studies. But people take them.” Kaufer is trying to bridge the gap between herbal remedies and clinically-tested medicines. “It’s a good drug to submit to rigorous clinical trial testing because it has a track record of usefulness,” he says.

Huperzine A was first isolated by Chinese scientists in 1948. Scientists have made the drug synthetically from Chinese club moss Huperzia serrata since the mid-1980s, when the method was released without patent protection. The average content of the active ingredient — Huperzine A — in plants is only 0.011%.

Huperzine A is similar to a class of drugs — acetylcholinesterase inhibitors — already on the market to help slow the progression of symptoms of Alzheimer’s disease, Kaufer says. Alzheimer’s patients tend to have fewer neurons that make the neurotransmitter acetylcholine. This loss of acetylcholine is most pronounced in brain areas involved in memory and emotion, and least pronounced in areas controlling basic sensory and motor skills, he says.

Huperzine A and other acetylcholinesterase inhibitors block the enzyme that breaks down acetylcholine, allowing it to stay longer in the junctions between nerve cells. More acetylcholine leads to stronger communication between nerve cells, which helps memories stay intact.

Many people with the disease aren’t aware that their memories are fading. “Alzheimer’s is insidious because it affects people in the areas that are most relevant to being human,” Kaufer says. About half of people over 80 have clinically significant mental impairments, he says.

The Huperzine A trial makes experimental drug treatment available to patients, a goal Kaufer has kept in mind since he came to UNC four years ago. The study will investigate whether Huperzine A can be used safely at higher doses, but Kaufer hopes to find ways to assess the broader benefits of the drug as well as other experimental drugs. He says that standard clinical measures for cognition don’t always capture all the benefits of a treatment, such as the ability to interact with others.

“In the clinic, for example, we measure language functions, such as naming objects,” he says. “But what’s more important in day-to-day life is being able to initiate a conversation or interact socially. This is much harder to measure objectively, but it is more important to helping someone maintain their personhood.”