A phytochemical study on Lycopodium casuarinoides has led to the isolation of two new C16N2-type Lycopodium alkaloids, casuarine A (1), a cage-like structure featured with a fused 6/6/6/6/6 pentacyclic ring system, and casuarine B (2). Their structures were elucidated based on the spectroscopic data and further confirmed by X-ray analysis. In vitro acetylcholinesterase (AChE) inhibitory activity assay showed that compound 2 exhibited moderate anti-AChE activity with IC50 46.40 mu M. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.