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DOI: 10.1055/s-0033-1348813
Five Novel Metabolites from Water Bloom of Cyanobacteria
Microcystis spp. have been shown to be a rich source of unique bioactive peptides such as the micropeptins, microginins, aeruginosins, anabaenopeptins and microviridins. As part of our ongoing research on the chemical ecology of cyanobacteria from Israeli water reserves, we examined a Microcystis sp. (strain IL-405) bloom material collected from the Kishon reservoir, Israel, on the fall of 2009. The sample of the cyanobacteria was freeze-dried and extracted with 7:3 MeOH:H2O. The crude extract was separated using various chromatographic methods including flash-chromatography on an ODS column, gel-filtration on Sephadex LH-20 column and finally reversed-phase HPLC, to afford an array of pure secondary metabolites including the new microginin KR802(1), microginin KR768(2), microginin KR836(3), microginin KR639(4), microginin KR816(5) and several microcystins. The structures of the pure compounds were elucidated using 1D and 2D NMR techniques, as well as, high-resolution mass spectrometry. The isolation and structure elucidation of the seven new natural products as well as their biological activities will be presented.