Planta Med 2008; 74 - PB53
DOI: 10.1055/s-0028-1084398

Alkaloid content of the Icelandic club moss Lycopodium annotinum – acetylcholinesterase inhibitory activity in vitro

ES Halldorsdottir 1, ES Olafsdottir 1, JW Jaroszewski 2
  • 1University of Iceland, Faculty of Pharmacy, Hagi, Hofsvallagata 53, IS-107 Reykjavik, Iceland
  • 2Faculty of Pharmaceutical Sciences, University of Copenhagen, Department of Medicinal Chemistry, Universitetsparken 2, DK-2100 Copenhagen, Denmark

Plant species belonging to the club moss genera Lycopodium and Huperzia are known to produce a variety of alkaloids with condensed polycyclic structures [1]. The club moss Huperzia serrata, which has long been used in traditional Chinese medicine, produces huperzine A, a potent acetylcholinesterase inhibitor that has a potential as an anti-Alzheimer drug [2]. Over 500 species of club mosses grow all around the world, but only five of them are represented in Iceland [3].

The aim of this study was to explore the alkaloid content of an Icelandic subspecies of Lycopodium annotinum and to determine the ability of the alkaloids to inhibit the enzyme acetylcholinesterase in vitro.

The plant extract was subjected to usual fractionation assisted by acetylcholinesterase-inhibition assay based on Ellman's method [4], and structures of the purified alkaloids were determined by 2D NMR. This led to structure elucidation of twelve alkaloids where one of them is new. Seven alkaloids exhibited moderate acetylcholinesterase-inhibitory activity, showing IC50 of 250–2000µM. These results encourage further research on designing analogues in order to increase the affinity towards acetylcholinesterase.

Aknowledgement: Icelandic Research Fund, University of Iceland Research Fund, The Icelandic Research Fund for Graduate Students, Pharmaceutical Society of Iceland Fund, Th. Scheving Thorsteinsson Fund.

References: 1. Ma, X., Gang, DR. (2004) Nat. Prod. Rep. 21:752–772. 2. Liu et al. (1986) Can. J. Chem. 64: 837–839. 3. Kukkonen, I. (2000) Flora Nordica. The Royal Swedish Academy of Sciences. Stockholm, Sweden. 4. Ellman, GL. et al. (1961) Biochem. Pharmacol. 7: 88–95.