Bromine- and chlorine-containing aeruginosins from Microcystis aeruginosa bloom material collected in Kibbutz Geva, Israel.

Five new natural products, aeruginosins GE686 (1), GE766 (2), GE730 (3), GE810 (4), and GE642 (5), were isolated along with four known aeruginosins, 98C, 101, KY642, and DA688, from bloom material of the cyanobacterium Microcystis aeruginosa collected from a fish pond in Kibbutz Geva, Israel, in August 2007. Their structures were elucidated by a combination of various spectroscopic techniques, primarily NMR and MS, while the absolute configurations of the stereogenic centers were determined by Marfey's and chiral-phase HPLC methods. Two of the new aeruginosins, aeruginosins GE686 (1) and GE766 (2), contain the unprecedented d-m-Br-m'-Cl-p-hydroxyphenyllactic acid derivative. The structures and biological activities of the five new metabolites are described.