New anthracycline metabolites from mutant strains of Streptomyces galilaeus MA144-M1. I. Isolation and characterization of various blocked mutants

During genetic study on obtaining high-yield variants of aclacinomycin A-producer, a variety of blocked mutants were isolated from Streptomyces galilaeus MA144-M1 and were characterized. The isolated mutants included those which accumulated only specific components of parental glycosides, those which produced new aklavinone glycosides devoid of parental rhodosamine or both rhodinose and cinerulose, those which produced non-glycosidic aglycones, and antibiotic-negative mutants, some of which were able to glycosidate exogenous aklavinone. By biotransformation with the aglycone feeding culture, the precursor activity of new aglycones was also tested. From the results and in relation to the characterization of isolated mutants, the biosynthetic pathway of aclacinomycin A and related antibiotics is discussed.

Reverse phase high speed liquid chromatography of antibiotics. III. Use of ultra high performance columns and ion-pairing techniques

Improved methods for the separation and quantitation of cephalosporin, penicillin, aminoglycoside and anthracycline antibiotics are presented. The use of ultra high performance 5 micrometer phase columns combined with the added dimension of ion-pairing greatly increases the ease of separation and speed of analysis of complex antibiotic mixtures. Antibiotics in a variety of dosage forms and in fermentation broths have been examined in order to provide the maximum data on impurities to meet regulatory requirements for drug safety, purity and efficacy. Mixtures of antibiotics have been analyzed to demonstrate the improved separations, increased efficiency and shortened analysis times possible with ultra thin performance columns. Under these improved conditions, the danger of multiple components in a single peak are markedly reduced.

High performance liquid chromatographic determination of aclacinomycin A and its related compounds. I. Normal phase HPLC for monitoring fermentation and purification processes

A normal phase high performance liquid chromatographic method is presented for the separation and quantitative determination of aclacinomycin A (ACM) and its related compounds classified as anthracycline antibiotics. The sensitive, reliable and reproducible chromatography was achieved on a mu-Porasil column with a mobile phase consisting of chloroform-methanol-acetic acid-water-triethylamine (68:20:10:2:0.01, v/v). By use of MA144 M1, one of the ACM analogues, as an internal standard, selectivity of the HPLC method could be retained by virtue of the adjustment of the detecting wavelength to 436 nm. The HPLC method was applicable to monitoring the fermentation and purification processes.

New anthracycline glycosides from Micromonospora. II. isolation, characterization and biological properties

Four glycosides, designated A, B, C and D, are the main components of the anthracycline complex produced by cultures of Micromonospora sp. nov. They were extracted by solvent partition, separated by column chromatography and characterized by chemical and physical methods as 11-deoxy analogues of daunorubicin. Among these new anthracyclines, displaying antibacterial and cytotoxic activity in vitro, 11-deoxydaunorubicin and 11-deoxydoxorubicin are also active against P388 leukemia in mice.

New anthracycline antibiotics produced by interspecific recombinants of streptomycetes. III. Isolation and structure of iremycin

The structure of the anthracycline antibiotic iremycin isolated from Streptomyces violaceus subspecies iremyceticus has been elucidated as 10-(alpha-L-rhodosaminyl)-gamma-rhodomycinone (I) on the basis of spectroscopic analyses and chemical reactions.

Production of rhodomycins in Streptomyces griseoruber 4620

The strain Streptomyces griseoruber 4620 produces, besides the anthracycline antibiotics beromycins, some other anthracyclines of the rhodomycin type. Twelve isolates exhibiting a higher antibiotic activity (up to 2.5X), as compared to the parent strain, were obtained after a spontaneous selection. The following species were isolated from the hydrolysate of mycelial extract: beta-rhodomycinone, beta-isorhodomycinone, alpha 2-rhodomycinone, epsilon-rhodomycinone and 10-deoxy-beta-rhodomycinone, which has not yet been described.

Isolation, characterization and biological activities of verotetrone from a mutant strain of Streptomyces aureofaciens

A new metabolite denoted as verotetrone was isolated from the mycelium of the mutant strain Streptomyces aureofaciens NMG-2. Interpretations of physical data concerning verotetrone and its triacetate and, the determination of its degradation product indicate that verotetrone belongs to pretetramide-type metabolites. Verotetrone exhibits neither antibacterial nor antifungal activity. In vitro it inhibits the synthesis of nucleic acids as well as proteins in Ehrlich ascites carcinoma cells. Both verotetrone and its triacetate interfere in vivo with the metabolism of tumour and lymphoid cells, exhibiting antitumour or immunosuppressive activity. This activity, which is more intense with verotetrone than with its triacetate, is detectable in a dose which is already toxic in some animals.

Antitumor agents from bohemic acid complex, III. The isolation of marcellomycin, musettamycin, rudolphomycin, mimimycin, collinemycin, alcindoromycin, and bohemamine

Six anthracycline antitumor agents, marcellomycin, musettamycin, rudolphomycin, alcindoromycin, collinemycin, and mimimycin, have now been isolated from bohemic acid complex. This has been achieved by classical column chromatography with Sephadex LH-20 and ammonia-neutralized silica and by analytical and prepatative hplc techniques with normal phase systems containing aqueous ammonia.

New anthracycline antibiotics

A number of anthracycline antibiotics have been found in Streptomyces cultures. Among them, adriamycin and daunomycin have been studied most in detail, because these compounds have exhibited a strong antitumor activities 1, 2). However, their clinical usefuleness is limited by side effects, particularly by bone marrow suppression and cumulative dose-dependent cardiac toxicity. 3 approximately 5) By the collaboration with Prof. H. UMEZAWA and Dr. T. TAKEUCHI, Institute of Microbial Chemistry, for the studies to find out new anthracycline antibiotics that may have lower cardiac toxicity and the same degree of the antitumor activity, we found 32 new anthracycline compounds in Streptomyces cultures and aclacinomycin A is under the phase II clinical study. Anthracycline compounds can be classified depending on the structures of their aglycones as shown in Table 1. These compounds have a linear tetracyclic polyhydroxy anthracyclines, and can be grouped into seven groups. Biologically active anthracycline antibiotics have various sugar moieties at C-7 and/or C-10 position of the anthracyclinones. In 1951, H. BROCKMANN6) discovered rhodomycins A and B in the culture of a new species of Streptomyces purpurascens. Since then, he found numerous anthracycline compounds such as rhodomycin-, isorhodomycin- and pyrromycin-types in Streptomyces and elucidated their structures. All of these anthracyclines are red pigments. In 1964 and 1969 new group of orange-red anthracycline antibiotics: daunomycin10) and adriamycin11) was reported by DiMARCO and F. ARCAMONE. Moreover, aklavin12, 13) which has yellow aklavinone as aglycone and citromycinone aglycone14) which is also yellow have been isolated in the Streptomyces cultures. Aclacinomycin A15), which we found in Streptomyces galilaeus MA144-M1, has aklavinone aglycone and is becoming more interesting in its low cardiac toxicity.