title: Biocontrol of aflatoxins B1, B2, G1, G2, and fumonisin B1 with 6,7-dimethoxycoumarin, a phytoalexin from Citrus sinensis.
abstract: Phytoalexins (stress-induced compounds) from Citrus sinensis cultivar Valencia were screened for antifungal and antimycotoxic activity against a test organism (Cladosporium cladosporoides) and mycotoxin-producing fungi Fusarium verticillioides and Aspergillus parasiticus. The active compound, a member of the coumarin family of compounds, has antifungal and antimycotoxic activities and was chemically identified. High-performance liquid chromatography results indicated that Valencia oranges contain a trace amount (0.36 microg/g) of scoparone in untreated fruit, but concentrations increased in UV-irradiated fruit (15.2 microg/g). Infection with Penicillium digitatum, a natural spoilage mold of citrus fruit, caused a 35.51-microg/g increase in the phytoalexin. UV absorption, infrared absorption, and 1H nuclear magnetic resonance spectroscopy revealed that this phytoalexin is identical to 6,7-dimethoxycoumarin. This is the first report indicating that the stress-induced compound, 6,7-dimethoxycoumarin, isolated from P. digitatum-infected Valencia fruit confers resistance against the mycotoxigenic fungi A. parasiticus and F. verticillioides and causes a reduction in production of fumonisin B1 and aflatoxins G1, G2, B1, and B2.
authors.affiliation: Department of Biological Sciences, M. L. Sultan Campus, Durban Institute of Technology, Durban 4000, South Africa.
authors.forename: Viresh
authors.initials: V
authors.lastname: Mohanlall
authors.forename: Bharti
authors.initials: B
authors.lastname: Odhav
mesh_terms: D016604:Aflatoxin B1 / Q000037:antagonists & inhibitors; D000348:Aflatoxins / Q000037:antagonists & inhibitors*; D002851:Chromatography, High Pressure Liquid; D032084:Citrus sinensis / Q000737:chemistry*; D003257:Consumer Product Safety; D003374:Coumarins / Q000494:pharmacology*; D005514:Food Irradiation; D005519:Food Preservation / Q000379:methods*; D037341:Fumonisins / Q000037:antagonists & inhibitors*; D006801:Humans; D010572:Pest Control, Biological / Q000379:methods*; D010936:Plant Extracts / Q000494:pharmacology*; D012717:Sesquiterpenes; D013729:Terpenes; D014466:Ultraviolet Rays; D000094162:Phytoalexins
chemical_list: D000348:Aflatoxins; D003374:Coumarins; D037341:Fumonisins; D010936:Plant Extracts; D012717:Sesquiterpenes; D013729:Terpenes; C027955:aflatoxin G1; C029754:aflatoxin G2; C056933:fumonisin B1; C029753:aflatoxin B2; D016604:Aflatoxin B1; C018145:scoparone; D000094162:Phytoalexins