Huperserines A-E, Lycopodium alkaloids from Huperzia serrata.

A phytochemical study on Huperzia serrata led to the isolation of four new 5-deoxyfawcettimine-related Lycopodium alkaloids, huperserines A-D (1-4), and one new lycodine-type alkaloid, huperserine E (5). Their structures were elucidated based on spectroscopic data, including 1D and 2D NMR techniques. 5-Carbonyl or 5-hydroxyl group is a typical characteristic of lycopodine- and fawcettimine-type alkaloids. This is the first report of the 5-deoxyfawcettimine type Lycopodium alkaloids. In vitro acetylcholinesterase (AChE) inhibitory activity assay showed that huperserine E exhibited moderate anti-AChE activity with an IC₅₀ value of 6.71 μM.