The answer seems to be, "Yes". The following excerpts are taken from the American Academy of Neurology's website

"The moss extract huperzine A is a traditional Chinese medicine that acts as an acetylcholinesterase inhibitor. It may be as potent as the prescription inhibitors donepezil (Aricept ?), rivastigmine (Exelon?), and tacrine (Cognex ?). Because of their strength, huperzine A should not be used in combination with any of these FDA-approved inhibitors, as it may cause an overdose. Few studies have been done on the effectiveness of huperzine A in treating Alzheimer’s. At this time, the product is unregulated and manufactured without uniform standards."     This over-the-counter herbal extraction, available at health food stores, was touted in an Associated press article to be as effective as the currently-approved, first-generation  prescription medications for Alzheimer's disease. Of course, all medications have side-effects, whether "natural" or man-made. (Aspirin is found in the bark of the willow tree.) Caution is indicated in the use of any agent that is pharmacologically effective, regardless of how derived. And Chinese herbs, though they've been used for millenia, haven't necessarily been tested for safety.

    I have found Huperzine-A at, and only at, a local health-food store. It's expensive, at 33¢ a capsule. One of these days, Walmart will probably begin carrying it, and then its price may drop.
    One other "brain food" that may be effective is Co-Enzyme Q-10.
    "Coenzyme Q10, or ubiquinone, is a naturally occurring antioxidant that is needed for human cell reactions to take place. This compound has not been researched for its effectiveness in treating Alzheimer’s patients and not much is known about its dosage safety. Because of dosage concerns and non-regulation in manufacturing, it is recommended that individuals talk with their neurologist before treating themselves with Coenzyme Q10."
   from "Alternative Treatments for Alzheimer's Disease". Neurovista, the American Academy of Neurology.
    This article also mentions phosphatidyl serine, but says that studies carried out ten years ago didn't improve the cognitive capabilities of Alzheimer's patients.
    "Add these sites to your information-gathering list: the Alzheimer’s Association (www.alz.org) and the Alzheimer’s Disease Education and Referral Center, which is a service of the government’s National Institute on Aging (www.nic.gov)."

    Consideration of gingko biloba and of ginseng is conspicuously missing from the American Academy of Neurology's discussion above.

Hot off the Presses! This bulletin just in! Studies of gingko biloba in mice have shown that a low dose can reduce the area affected by a stroke by 30% in mice. However, a larger dose produced no effect. "This result prompted the researchers to warn that it is too early to recommend the use of gingko in humans at risk for stroke."      "In addition to reducing stroke injury, ginkgo may also be useful in improving memory following a stroke," Clark said.      Gingko biloba in the United States varies widely in its constitution. It contains antioxidants and a mild blood thinner, and must be used with caution if other blood thinners are also prescribed.     --Report - "Gingko May Protect Brain Against Stroke Damage", presented during the American Academy of Neurology's 52nd Annual Meeting in San Diego, CA, April 29 -- May 6, 2000. --from ScienceDaily, May 3, 2000.

    A discussion of "smart drugs" in a 1998 Scientific American Special Issue on Intelligence observes that the most powerful "smart drug" currently available might be a cup of coffee with sugar in it. Both caffeine and sugar temporarily boost brainpower.

    In the meantime, a number of new agents are in the FDA approval pipeline as treatments for Alzheimer's disease. Rumors making the rounds at Johns Hopkins have it that within ten years, smart drugs will be on the market that can increase a child's IQ by as much as 50 points.
    Long-term, the ability to enhance human intelligence genetically or through genetically-produced proteins must be considered to be a watershed in human affairs--a time when humans can redefine their biological selves and can transcend the limits imposed by evolution.