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Polyketide Skeletons from the Marine Alga‐Derived Fungus Coniothyrium cereale
Author(s) -
Elsebai Mahmoud Fahmi,
Nazir Mamona,
Kehraus Stefan,
Egereva Ekaterina,
Ioset Karine Ndjoko,
Marcourt Laurence,
Jeannerat Damien,
Gütschow Michael,
Wolfender JeanLuc,
König Gabriele M.
Publication year - 2012
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.201200700
Subject(s) - polyketide , fungus , chemistry , stereochemistry , diketopiperazines , enzyme , microbiology and biotechnology , botany , biochemistry , biology , biosynthesis
The fungus Coniothyrium cereale was isolated from the Baltic Sea alga Enteromorpha sp. Upon cultivation in saline medium, C. cereale produced the structurally unprecedented isoindole pseudoalkaloid conioimide ( 1 ) and the polyketide cereoanhydride ( 2 ). Because of the very limited amount of compounds isolated, the structures of 1 and 2 were established from extensive NMR spectroscopic and mass spectrometric analyses, and in the case of 1 , the structural analysis was completed by NMR shielding calculations. Conioimide and cereoanhydride represent new structural types of polyketides. Experiments with 13 C‐labeled acetate proved the polyketide nature of the major and known C. cereale metabolite (–)‐trypethelone ( 3 ), which is proposed to be the precursor of cereoanhydride. Conioimide has prominent and selective inhibitory activity towards the protease human leukocyte elastase (HLE), an enzyme involved in many inflammatory diseases, with an IC 50 (half maximal inhibitory concentration) value of 0.2 μg mL –1 .