Novel cyanobacterial metabolites, cyanopeptolin 1081 and anabaenopeptin 899, isolated from an enrichment culture dominated by Woronichinia naegeliana (Unger) Elenkin

Cyanobacteria synthesize many secondary metabolites of various chemical structures and biological activity and release them into the aquatic environment. Two new oligopeptides belonging to anabaenopeptins and cyanopeptolins were isolated from an enrichment culture dominated by Woronichinia naegeliana (Unger) Elenkin. The application of mass spectrometry and nuclear magnetic resonance spectroscopy allowed determination of their structure and identification of these compounds as cyanopeptolin 1081 and anabaenopeptin 899 with a molecular formula C52H75N9O16 and C48H65N7O10, respectively. The preliminary evaluation of their toxicity was conducted via tests based on crustacean Thamnocephalus platyurus. Although these peptides did not exert acute toxic effects at the concentration up to 40 μg ml–1, deterioration of the physiological state of the studied crustaceans, indicated by reduced mobility, was observed. Considering the limited knowledge of cyanopeptide presence in the aquatic environment, it is important to identify and characterize these compounds.