A COMPOUND first isolated from a traditional Chinese herbal medicine may lead to new therapeutic agents for Alzheimer disease (AD). Based on laboratory and x-ray crystallography studies, these agents, some researchers think, could be even better than the 2 drugs already approved for the disease. The alkaloid compound, huperzine A (HupA), was discovered in the Chinese herbal medicine Qian Ceng Ta. This traditional remedy, which is prepared from the moss Huperzia serrata, has been used in China for centuries to treat fever and inflammation. Although it has no antipyretic or antiinflammatory properties, HupA does appear to be a potent inhibitor of acetylcholinesterase (AChE). In addition to appearing more selective and possibly less toxic than the 2 AChE inhibitors currently approved for the treatment of AD, HupA has a number of other pharmacological properties of clinical interest, said Israel Silman, PhD, professor of neurobiology at the Weizmann Institute of Science, Rehovot,