\Huperzine A which was first isolated in the early 80's by a group of Chinese scientists from a herd used in traditional medicine, called Huperzia serrate, is a potent and selective acetylcholinesterase (AchE) inhibitors. Acetylcholinesterase breaks down acetylcholine in the synaptic cleft. Acetylcholine is involved in memory and learning. By inhibiting the enzyme that breaks it down, more acetylcholine becomes available to stimulate neurons. It is believed that Alzheimer's disease is a condition where there's a relative shortage of acetylcholine. Several studies have been done over the past few years with huperzine A, both in China and the United States. These studies have shown that huperzine A is many times more effective and selective than tacrine (one of the current cholinesterase-inhibiting drugs) in inhibiting cholinesterase. Huperzine A has been approved as a new drug in China for the treatment of Alzheimer's disease and myasthenia gravis. It's now also available in the US market, although as a food supplement.

The author presented the synthesis of several new compounds with combined feature of huperzine A and tacrine. Both the "hybrids" and "heterodimers" have increased potency and selectivity for AchE.