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During the course of our screening for squalene synthase inhibitors and Ras farnesylation inhibitors, a novel fungal culture was discovered to produce two structurally unique compounds, CP-225,917 and CP-263,114, as well as zaragozic acid A (squalestatin I). The two compounds are characterized by a bicyclo[4.3.1]dec-1,6-diene core plus two extended alkyl chains. CP-225,917 and CP-263,114 inhibit Ras farnesyl transferase from rat brain with IC50 values of 6 microM and 20 microM, respectively. CP-225,917 inhibits squalene synthase with an IC50 value of 43 microM and CP-263,114 with an IC50 of 160 microM. The producing organism, though not fully classified, exhibits the characteristics of a sterile Phoma species.

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.

Endusamycin formerly called CP-63,517 (C47H77O14Na), is a novel polycyclic ether antibiotic produced by a new strain of Streptomyces endus subsp. aureus (ATCC 39574). Recovery, fractionation and purification were achieved using standard procedures. Forms include the endusamycin free acid, mp 95 approximately 105 degrees C, lambda max 232 nm (log E 4.16), [alpha]25D +47.4 degrees (c 0.5, methanol) and a crystalline sodium salt, mp 215 approximately 220 degrees C, lambda max 232 nm, (log E 4.15), [alpha]25D +25 degrees (c 0.5, methanol). The structure is shown below, Fig. 1. Endusamycin exhibited; antibacterial activity, in vitro against Gram-positive and anaerobic bacteria, effectiveness against coccidia in poultry, and stimulation of propionic acid production in an in vitro system.