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Isofusidienols: Novel Chromone‐3‐oxepines Produced by the Endophytic Fungus Chalara sp.
Author(s) -
Lösgen Sandra,
Magull Jörg,
Schulz Barbara,
Draeger Siegfried,
Zeeck Axel
Publication year - 2008
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200700839
Subject(s) - chromone , chemistry , bacillus subtilis , stereochemistry , candida albicans , fungus , antibacterial activity , strain (injury) , derivative (finance) , bacteria , microbiology and biotechnology , botany , medicine , genetics , financial economics , economics , biology
Four novel metabolites, named isofusidienol A, B, C, and D ( 1 – 4 ), were produced by cultures of Chalara sp. (strain 6661), an endophytic fungus isolated from Artemisia vulgaris . The unprecedented chromone‐3‐oxepine structure of the compounds was established by detailed spectroscopic analysis and in the case of isofusidienol A ( 1 ) verified by an X‐ray analysis. Additionally, two xanthones, known 5 and its 8‐chloro derivative 6 , were isolated. Presumably, 5 is the biosynthetic precursor of the isofusidienols. The isofusidienols exhibit antifungal activity against Candida albicans and antibacterial activity against gram‐positive and gram‐negative bacteria. Inhibition of Bacillus subtilis could be achieved with less than 0.625 μg of 1 on 6‐mm filter disks in plate diffusion assays. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)