NEW YORK (Reuters Health) - An extract from Chinese club moss shows promise as a treatment for people with Alzheimer's disease, researchers report after analyzing combined data from multiple trials conducted in China.

However, there is insufficient evidence to currently support routine use of the extract, known as Huperzine A, for Alzheimer's patients, report in The Cochrane Library, a publication of the Cochrane Collaboration, an international organization that evaluates medical research.

Huperzine A is an extract of Huperzia serrata, a traditional Chinese medicine plant commonly referred to as Chinese club moss.

Other research has suggested Huperzine A may have some benefit in the management of Alzheimer's disease, the investigators note, but previous multiple-study reviews involved only English-language research.

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To gain a better understanding of the effects of Huperzine A in Alzheimer's disease, Hongmei Wu, of Sichuan University in Chengdu, China, and colleagues performed an all-language multiple-study review. They analyzed 6 randomized controlled trials that assessed the efficacy and safety of Huperzine A in a total of 454 patients with Alzheimer's disease.

The data suggest, the researchers report, that compared with placebo or usual care, Huperzine A may improve measures of thinking and memory, behavior disturbances, and Alzheimer's disease patients' performance of daily functions. However, the trials were of low "methodological" quality, they point out.

The researchers did not identify obvious adverse effects among patients treated with Huperzine A, but they note that many of the studies did not sufficiently report adverse effects.

While data from studies to date do not support the current use of Huperzine A for Alzheimer's disease, findings from this and other studies warrant further research in large randomized, controlled trials of adequate duration and that sufficiently follow patient groups for adverse events and outcomes, the investigators conclude.

"These findings are based on a small number of trials, but the data indicate that it would be well worth setting up some more high quality assessments of this interesting drug," Wu added in a statement issued by The Cochrane Library.

SOURCE: The Cochrane Library, April 2008