Metabolic Products of Microorganisms. 234¹⁾Urdamycins, New Angucycline Antibiotics from Streptomyces Fradiae I. Isolation, Characterization and Biological Properties

The colored urdamycins A to F, six new angucycline antibiotics produced by Streptomyces fradiae strain Tu 2717, were detected by chemical screening. They are biologically active against Gram-positive bacteria and stem cells of murine LI210 leukemia. The urda-myces are glycosides and differ in their aglycones, which can be liberated by acidic hydrolysis besides the sugars D-olivose and L-rhodinose. The structure of the main compound, urda-mycin A (3b), follows from the spectroscopic and chemical data in connection with an X-ray analysis. The aglycone urdamycinone A (3a) is identical with aquayamycin. The structures of urdamycin B (4b), E (3c), F and partial structures of urdamycin C and D, will be presented in a subsequent paper. The new term “angucycline/angucyclinone” is used for an increasing group of related antibiotics.