As a result of screening cultures of actinomycetes for metabolites having antitumor properties, we have isolated an anthracycline mixture, bohemic acid complex, from fermentations of Actinosporangium sp. strain C-36,145 (ATCC 31127). Subsequently, two pure anthracyclines, musettamycin and marcellomycin, both glycosides of e-pyrromycinone, were obtained by fractionation of the complex.