CP-60,993, a new dianemycin-like ionophore produced by Streptomyces hygroscopicus ATCC 39305: fermentation, isolation and characterization.

CP-60,993, 19-epi-dianemycin, is a novel polycyclic ether antibiotic produced by Streptomyces hygroscopicus ATCC 39305. Fermentation recovery, purification and crystallization were achieved using standard procedures. CP-60,993 was characterized as a monocarboxylic acid. Elemental analysis suggested a molecular formula of C47H78O14 for the free acid and C47H77O14 Na for the sodium salt. Crystalline from CP-60,993 sodium salt shows the following properties: m.p. 193-205 degrees C, E1%(1 cm) = 157 at 232 nm, [alpha]25 degrees C(D) + 11.0 (c 1, methanol). The structure, determined by MS, PMR and CMR, differs from dianemycin only in the stereochemistry at position 19. This was confirmed by X-ray crystallography carried out on the rubidium salt of CP-60,993. It exhibited activity in vitro against Gram-positive and anaerobic bacteria, efficacy against Eimeria coccidia in vivo in poultry, and stimulation in vitro of rumen propionic acid production.