Liang H. Huang

CP-82,009, a potent polyether anticoccidial related to septamycin and produced by Actinomadura sp.

A new polyether antibiotic CP-82,009 (C49H84O17) was isolated by solvent extraction from the fermentation broth of Actinomadura sp. (ATCC 53676). Following purification by column chromatography and crystallization, the structure of CP-82,009 was elucidated by spectroscopic (NMR and MS) methods. The absolute stereochemistry was determined by a single crystal X-ray analysis of the corresponding rubidium salt. CP-82,009 is among the most potent anticoccidial agents known, effectively controlling the Eimeria species that are the major causative agents of chicken coccidiosis at doses of 5 mg/kg or less in feed. It is also active in vitro against certain Gram-positive bacteria, as well as the spirochete, Serpulina (Treponema) hyodysenteriae.

CP-61,405, a novel polycyclic pyrrolether antibiotic produced byStreptomyces routienii Huang sp. nov.

SummaryCP-61,405 (C26H29N2O7Na) is a novel polycyclic pyrrolether antibiotic produced by a new species,Streptomyces routienii Huang sp. nov. (ATCC 39446). Recovery, fractionation and purification were achieved using standard procedures. The crystalline form includes the CP-61,405 sodium salt, m.p. 334–335°C, [α]D25°C+315°C (c=1, chloroform). The structure is shown below. CP-61,405 was co-produced with the polycyclic ether antibiotics salinomycin and epi-17-deoxy-(0–8)-salinomycin. It exhibited activity in vitro against gram-positive and anaerobic bacteria, efficacy against poultry coccidia and stimulation in vitro of propionic acid production.

Pyrenomycetes and Loculoascomycetes as sources of secondary metabolites

Over 400 secondary metabolites have been reported from members of the Pyrenomycetes and the Loculoascomycetes. Among these, members of the Hypocreaceae, the Clavicipitaceae, the Xylariaceae, the Melanosporaceae, and the Sordariaceae in the Pyrenomycetes, and those of the Pleosporaceae and the Sporormlaceae in the Loculoascomycetes have been explored frequently; and representative secondary metabolites produced by these fungi are illustrated. Many of them are reported to be phytotoxic and some of them have antibacterial or antifungal activities. Only recently were the compounds tested in screens targeted for specific enzyme inhibitors or receptoragonists/antagonists. This group of fungi are attractive for screening for novel natural products because of the diversity of species and physiology.

C-13β-ACYLOXYMILBEMYCINS, A NEW FAMILY OF MACROLIDES

A family of novel milbemycins possessing C-13 beta-acyloxy substitution was produced by Streptomyces hygroscopicus ATCC 53718. These compounds were detected by HPLC diode array analysis and possess anthelmintic and ectoparasiticidal activity. The origin of the oxygen atom at C-13 is discussed.

CP-82,996, a novel diglycoside polyether antibiotic related to monensin and produced by Actinomadura sp

SummaryA new polyether antibiotic CP-82,996 (C50H86O16) was isolated by solvent extraction from the fermentation broth ofActinomadura sp. (ATCC 63764). Following purification by silica gel column chromatography and crystallization, the structure of CP-82,996 was determined by a single crystal X-ray analysis. The structure is closely related to monensin, but is unique in that it contains two sugar groups, whereas monensin has none. The1H and13C NMR chemical shifts and assignments for CP-82, 996 were elucidated, and they were compared with those determined previously for monensin. CP-82,996 is active against certain Gram-positive bacteria, and is a very potent anticoccidial agent. It effectively controlled chicken coccidiosis caused by severalEimeria species at 5–10 ppm in feed, and is 10–20 times more potent than monensin.

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

SummaryCP-60,993, 19-epi-dianemycin, is a novel polycyclic ether antibiotic produced byStreptomyces 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 form CP-60,993 sodium salt shows the following properties: m.p. 193∼205°C, E1 cm1%=157 at 232 nm, [α]D25°C+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 againstEimeria coccidia in vivo in poultry, and stimulation in vitro of rumen propionic acid production.