CP-91,243 and CP-91,244, novel diglycoside polyether antibiotics related to UK-58,852 and produced by mutants of Actinomadura roseorufa.

Interest in polyether antibiotics has remained at a high level for over 20 years, owing largely to the commercial importance of this class of drugs in veterinary medicine. For example, monensin1*, lasalocid1} and salmomycin2) are marketed as anticoccidial agents for poultry, and are used as growth permittants in cattle or swine. Narasin1} and maduramicin3) are also used as anticoccidial agents. Following the discovery of the attractive, semisynthetic anticoccidial ionophore semduramicin4'5) (UK-61,689), a mutation program was undertaken that was designed to produce this polyether antibiotic by direct fermentation6*. The producing culture of the antibiotic UK-58,852, was chosen as the parental strain to be mutagenically treated to induce a semduramicin producing mutant7'8). The two compounds differ from each other in that the A-ring glycone of UK-58,852 has been replaced by a hydroxyl group in semduramicin (Fig1).