title: Benzopyrone coumarin leads to an inhibition of ochratoxin biosynthesis in representatives of Aspergillus and Penicillium spp. via a type of feedback response mechanism.
abstract: Growth and mycotoxin biosynthesis of the ochratoxin-producing fungal strains Aspergillus carbonarius, Aspergillus steynii, Penicillium verrucosum, and Penicillium nordium were analyzed on standard laboratory growth medium supplemented with different amounts of coumarin, an organic compound of the benzopyrone class. Neither the growth nor the phenotypic morphology of the filamentous fungi analyzed was affected by using coumarin concentrations equivalent to 2.5 to 25 μg/ml of medium. In contrast, the ochratoxin biosynthesis was strongly inhibited in both strains of the Aspergillus species and nearly completely inhibited in both Penicillium strains at coumarin concentrations above 8.75 μg/ml. Analyzing the transcriptional activity of the otapksPN polyketide synthase gene in P. nordicum using real-time PCR revealed a strong concentration-dependent decrease in gene expression. Taken together, the data show that ochratoxin biosynthesis in representative strains of the genera Aspergillus and Penicillium could be effectively inhibited by coumarin in a concentration-dependent manner. It could be suggested that the molecular background behind this inhibition is some kind of feedback response mechanism, based on the structural similarity of coumarin to the benzopyrone moiety of the ochratoxin molecule.
authors.affiliation: Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruits and Vegetables, Haid-und-Neu-Strasse 09, Karlsruhe 76131, Germany.
authors.forename: L S L
authors.initials: LS
authors.lastname: Mayer
authors.affiliation: Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruits and Vegetables, Haid-und-Neu-Strasse 09, Karlsruhe 76131, Germany.
authors.forename: D A
authors.initials: DA
authors.lastname: Stoll
authors.affiliation: Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruits and Vegetables, Haid-und-Neu-Strasse 09, Karlsruhe 76131, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Geisen
authors.affiliation: Max Rubner-Institut, Federal Research Institute of Nutrition and Food, Department of Safety and Quality of Fruits and Vegetables, Haid-und-Neu-Strasse 09, Karlsruhe 76131, Germany. Markus.Schmidt-Heydt@mri.bund.de.
authors.forename: M
authors.initials: M
authors.lastname: Schmidt-Heydt
mesh_terms: D000935:Antifungal Agents / Q000494:pharmacology*; D001230:Aspergillus / Q000187:drug effects* / Q000378:metabolism; D003374:Coumarins / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D009793:Ochratoxins / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D010407:Penicillium / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000935:Antifungal Agents; D003374:Coumarins; D009793:Ochratoxins; C030123:coumarin