Urdamycin B is a glycoside bacterial metabolite that has been found in S. fradiae and has antibacterial and anticancer activities.1 It is active against Gram-positive and Gram-negative bacteria and inhibits proliferation of L1210 leukemia cells (IC50 = 2.4 µg/ml).
1.Drautz, H., ZÄhner, H., Rohr, J., et al.Metabolic products of microorganisms. 234. Urdamycins, new angucycline antibiotics from Streptomyces fradiae. I. Isolation, characterization and biological propertiesJ. Antibiot. (Tokyo)39(12)1657-1669(1986)