Marinocyanins, cytotoxic bromo-phenazinone meroterpenoids from a marine bacterium from the streptomycete clade MAR4.

Six cytotoxic and antimicrobial metabolites of a new bromo-phenazinone class, the marinocyanins A-F ( 1 – 6 ), were isolated together with the known bacterial metabolites 2-bromo-1-hydroxyphenazine ( 7 ), lavanducyanin ( 8, WS-9659A) and its chlorinated analog WS-9659B ( 9 ). These metabolites were purified by bioassay-guided fractionation of the extracts of our MAR4 marine actinomycete strains CNS-284 and CNY-960. The structures of the new compounds were determined by detailed spectroscopic methods and marinocyanin A ( 1 ) was confirmed by crystallographic methods. The marinocyanins represent the first bromo-phenazinones with an N -isoprenoid substituent in the skeleton. Marinocyanins A-F show strong to weak cytotoxicity against HCT-116 human colon carcinoma and possess modest antimicrobial activities against Staphylococcus aureus and amphotericin-resistant Candida albicans . [ABSTRACT FROM AUTHOR]