Neuroscience is in needs of new drugs to overcome risen CNS disorders because of the increasing human life expectancy [1]. Marine organisms constitute an unexplored source compared to terrestrial plants in the search of novel type of anticonvulsant natural products [2]. In the context of a screening of marine diatoms in a zebrafish epilepsy model with seizures induced by the GABAA antagonist pentylenetetrazole, the methanolic extract of Skeletonema marinoi revealed a significant activity. A bioassay-guided fractionation was undertaken by reverse phase flash chromatography after enrichment with vacuum liquid chromatography in order to isolate the bioactive compounds [3]. This rapid approach lead to the identification of the nucleoside inosine as the main active antiepileptic constituent. Inosine is known for its anticonvulsant activities but was never isolated from diatoms. Structures of isolated compounds were elucidated by spectroscopic methods including evaporative light scattering detector (ELSD), nuclear magnetic resonance (NMR) and high resolution mass spectrometry (HRMS). Additionally, the extract of Skeletonema marinoi was submitted to a metabolite profiling by UHPLC-HRMS. It reveals an interesting chemical diversity and different algal metabolites were annotated together with additional other putative compounds.
[1] Grosso C, Valentao P, Ferreres F, Andrade PB. Mar. Drugs 2014; 12: 2539-2589
[2] Montaser R, Luesch H. Future Med Chem 2011; 3(12): 1475-1489
[3] Challal S, Queiroz EF, Debrus B, Kloeti W, Guillarme D, Gupta MP, Wolfender JL. Planta Med 2015; 81: 1636-1643