Antifungal antibiotics from Calcarisporium thermophilum: a new source of 15-azahomosterol derivatives.
Two antifungal metabolites isolated from Calcarisporium thermophilum were identified as 15-azahomosterols related to the compounds previously isolated from Geotrichum flavo-brunneum. By full spectral comparison with authentic 15-aza-24-methylene-D-homocholesta-8,14-dien-3 beta-ol (A 25822 B) from G. flavo-brunneum, the Calcarisporium metabolites were characterized as the 4 alpha-methyl- and 4,4-dimethyl-analogues of A 25822 B. Several minor members of the series were also detected, and tentatively identified by MS analysis. The 15-azahomosterols exhibited good antifungal activity towards Candida parapsiliosis, though the activities were somewhat lower than that of the 4-demethyl derivative A25822 B. Calcarisporium thermophilum is the second microorganism known to synthesize these unusual 15-azahomosterol derivatives.
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Department of Pharmaceutical Sciences, University of Nottingham, U.K.
Dewick
P M
PM
Boyle
F T
FT
D000935:Antifungal Agents / Q000302:isolation & purification* / Q000494:pharmacology; D001372:Aza Compounds / Q000302:isolation & purification / Q000494:pharmacology; D002175:Candida / Q000187:drug effects; D008401:Gas Chromatography-Mass Spectrometry; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D003904:Mitosporic Fungi; D015394:Molecular Structure; D013056:Spectrophotometry, Ultraviolet; D013261:Sterols / Q000302:isolation & purification* / Q000494:pharmacology; D013329:Structure-Activity Relationship
D000935:Antifungal Agents; D001372:Aza Compounds; D013261:Sterols