Integrated analytical approaches towards toxic algal natural products discovery
Thomas Ostenfeld Larsen1, Silas Anselm1, Nikolaj Gedsted Andersen2, Hannah Blossom2, Carsten
Christophersen1, Per Juel Hansen2 & Kristian Fog Nielsen1
1
Center for Microbial Biotechnology (CMB), Department of Systems Biology, Technical University of
Denmark, DK-2800 Kgs. Lyngby, Denmark
2
Marine Biological Section, University of Copenhagen, DK-3000 Helsingør, Denmark
Microalgae are known to produce toxins which affect the marine ecosystems. This include
compounds active against competitors, grazers and in many cases also fish (1,2). Many strategies
can be followed for discovery of novel bioactive secondary metabolites from marine sources. We
have previously demonstrated that phenotypic based chemotaxonomy can be successfully used as
the intial step in selection of talented strains for testing in various bioassays, using multivariate
methods for clustering of whole profiles of metabolites. The second and very important step in the
discovery process is dereplication, where we use explorative solid-phase extraction (E-SPE), and
UHPLC-state-of-the-art high resolution mass spectrometry (<1 ppm mass accuracy and accurate
isotope pattern) in combination with comprehensive compound databases in order to ensure not to
waste time isolating and elucidating the structures of already known compounds (3). When likely
unknown compounds have been identified, we use E-SPE results (4) to predict a fast and optimal
purification strategy towards the pure novel compounds for NMR characterization. This
presentation will highlight our integrated analytical approaches and present some of the initial
results that we have gained looking into the chemistry of Alexandrium and Prymnesium in the new
larger Danish strategic project: “Harmful algal blooms and fish kills”(5).
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Jakobsen R, Hansen PJ, Daugbjerg N, Andersen NG (2012). The fish-killing dictyochophyte
Pseudochattonella farcimen: Adaptations leading to bloom forrmation during early spring in Scandinavian
waters. Harmful Algae 18: 84-95
Blossom H, Daugbjerg N, Hansen PJ (2012) Toxic mucus traps: a novel mechanism that mediates prey uptake
in the mixotrophic dinoflagellate Alexandrium pseudogonyaulax. Harmful Algae 17: 40-53
Nielsen, K.F., Månsson, M., Rank, J., Frisvad, J.C. & Larsen, T.O. (2011). Dereplication of microbial natural
products by LC-DAD-TOFMS: Experiences gained from an inhouse database of 719 mycotoxins and fungal
metabolites. Journal of Natural Products, 74, 2338-2348.
Månsson, M., Phipps, R.K., Gram, L., Munro, M.H.G., Larsen, T.O. & Nielsen, K.F. (2010). Explorative
Solid-Phase Extraction (E-SPE) for accelerated microbial natural product discovery, dereplication and
purification. Journal of Natural Products, 73, 1126-1132.
We acknowledge support from the Programme Committee for Food, Health and Welfare under the Danish
Strategic Research Council.