Obscurumines H–P, new Lycopodium alkaloids from the club moss Lycopodium obscurum

Abstract Seven new fawcettimine-type ( 1 – 7 ) and two new lycopodine-type ( 8 and 9 ) Lycopodium alkaloids, as well as 10 known compounds, were isolated from the club moss, Lycopodium obscurum L. The structures of obscurumines H–P ( 1 – 9 ) were determined based on high-resolution MS and 1D and 2D NMR data. Compounds 1 and 2 include a new skeleton that is formed via the linkage of C-9– N -2′, which is rarely present in Lycopodium alkaloids. The in vitro acetylcholinesterase (AChE) inhibitory activity assay showed that 5 exhibited weak anti-AChE activity with an IC 50 value of 81.0 μM. Compound 8 exhibited inhibition of the secretion of IL-2 in phytohemagglutinin (PHA) and phorbol myristate acetate (PMA) stimulated Jurkat cells, and the IC 50 value was 17.2 μM.