Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Azasteroids”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1975

New azasteroidal antifungal antibiotics from Geotrichum flavo-brunneum. II. Isolation and characterization.

A novel group of antibiotics, comprising microbiologically-active structurally-related factors A25822A, B, D, H, L, M and N, produced by culturing Geotrichum flavo-brunneum NRRL 3862 under submerged aerobic fermentation conditions was isolated by extraction. The individual factors were separated and purified by chromatography and crystallization. The major factor, A25822B, a 15-aza-24-methylene-D-homocholestadiene is a white crystalline compound, C25H45NO. The antibiotics are highly active against fungi and marginally active against bacteria.

Antifungal Agents↗
PubMed1975

New azasteroidal antifungal antibiotics from Geotrichum flavo-brunneum. III. Biological activity.

The A25822 antibiotic complex consists of seven biologically active factors. A comparative study of these factors determined that factor B possessed the greatest antifungal activity. The minimal inhibitory concentration of A25822B against isolates of Candida albicans was less than 0.3 similar to 5.0 mug/ml, Trichophyton mentagrophytes was inhibited at less than 0.0312 mug/ml. Other pathogenic fungi such as Cryptococcus neoformans, Histoplasma capsulatum, Blastomyces dermatitidis, Sporotrichum schenckii, and Microsporium gypseum were very susceptible to A25822B. Only limited antibacterial activity of A25822B was found. Parenteral or oral administration of 50 mg/kg of A25822B significantly extended the average survival time of mice infected with C. albicans. Doses of 20 mg/kg of A25822B caused a greater than ten-fold reduction in the number of Candida cells recovered from kidneys of infected mice. A solution of 0.5% or 0.25% A25822B applied topically was effective against an experimental dermatophyte infection on guinea pigs. A peak blood level of 3 mug/ml was achieved in mice following a 100 mg/kg dose of A25822B. Combination of A25822B with a polyene antibiotic in vitro showed antagonism.

Administration, Oral↗
PubMed1975

New azasteroidal antifungal antibotics from Geotrichum flavo-brunneum. I. Discovery and fermentation studies.

Although Geotrichum species occur ubiquitously, antibiotic production by members of this genus has not previously been reported. The antibiotic complex designated A25822, consisting of one major and six minor structurally-related components active primarily against Candida and Trichophyton, represents a new family of naturally-occurring compounds. Approximately 90% of the antibiotic activity synthesized remained associated with the fungal cell mass, from which it was recovered by multiple methanolic extractions for quantitation. Antibiotic production was enhanced by tryptophan, iron, zinc, and high levels of dextrin.

Antifungal Agents↗