Biosynthesis of the pradimicin family of antibiotics. II. Fermentation, isolation and structure determination of metabolites associated with the pradimicins biosynthesis.

Ten metabolites produced by 4 mutants derived from Actinomadura verrucosospora subsp. neohibisca E-40, a high pradimicins producer, were isolated and their structures were determined. Strain JN-219 produced 3 novel analogs of the pradimicin A aglycone, i.e. 11-O-demethyl-7-methoxypradinone II and 11-O-demethylpradinones I and II together with a known aglycone analog, pradinone I, while the metabolites from strain JN-47 were determined to be 2 new aglycone analogs, 11-O-demethylpradimicinone I and 11-O-demethyl-7-methoxypradimicinone II and a known aglycone analog, 11-O-demethylpradimicinone II (11dM-PMN II). Products of strain JN-207 were identified as 11-O-demethyl-6-deoxypradinone I and 11dM-PMN II. Interestingly, a new pradimicin analog, 7-hydroxypradimicin A was isolated from strain JN-58 together with a new aglycone analog, pradimicinone II and 11dM-PMN II. None of these metabolites showed antifungal activity.