Cinerubin B is an anthracycline antitumor antibiotic that has been found in Streptomyces.1,2 It inhibits RNA synthesis in, and the growth of, L1210 murine leukemia cells (IC50s = 48 and 15 nM, respectively).2
References:
[1].Silva, L.J., Crevelin, E.J., Souza, D.T., et al.Actinobacteria from Antarctica as a source for anticancer discoverySci. Rep.10(1)13870(2020).
[2].Matsuzawa, Y., Oki, T., Takeuchi, T., et al.Structure-activity relationships of anthracyclines relative to cytotoxicity and effects on macromolecular synthesis in L1210 leukemia cellsJ. Antibiot. (Tokyo)34(12)1596-1607(1981).