Isolation and structure elucidation of secondary metabolites from a Microcystis sp. bloom material collected in southern Israel

Abstract

The hydrophilic extract of Microcystis sp. bloom material collected from Bror Hayil Reservoir in southern Israel afforded four new metabolites, (2S,3S)-3- hydeoxy-1,4-diphenylbutan-2-yl-acetate, aeruginosins BH604, BH462A and BH462B, and two known metabolites cyanopeptolins S and SS. The planar structure of 1-4 was established by analyses of their 1D and 2D NMR data and mass spectrometric data. The absolute configurations of the chiral centers of 1 were established by Mosher method and analysis of the coupling constants between H-2 and H-3, and those of 2-4 by Merfay's method and advanced Merfay's method and chiral HPLC. The compounds do not inhibit the serine proteases trypsin and thrombin.