Title: Photolysis of Indole-Containing Mycotoxins to Fluorescent Products Author
Submitted to: Mycotoxin Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 20, 2009
Publication Date: May 5, 2009
Citation: Maragos, C.M. 2009. Photolysis of Indole-Containing Mycotoxins to Fluorescent Products. Mycotoxin Research. 25:67-75. Interpretive Summary: In this research we discovered that several toxins that cause muscle tremors could be rendered fluorescent, which facilitates their detection. Adequate methods for detection of tremorgens, a broad group of neurotoxins produced by fungi in foods and feeds, are lacking. Three tremorgens were exposed to ultraviolet light in a photoreactor, which caused them to change into fluorescent products that could be easily detected. This ability to render non-fluorescent tremorgens into fluorescent compounds will be useful in the development of sensitive methods for their detection in foods and feeds.
Technical Abstract: Photochemical reaction of the non-fluorescent mycotoxin cyclopiazonic acid (CPA) to fluorescent products was recently reported. Because CPA contains an indole moiety, believed to contribute to the fluorescence, it was of interest to determine whether the effect might be more generally applicable to indole-containing mycotoxins. Three indole-containing tremorgens (penitrem A, paxilline, verruculogen) that have not previously been reported to be fluorescent were rendered fluorescent by exposure to ultraviolet light in a photoreactor. Naturally fluorescent ergot alkaloids, which also contain an indole-moiety exhibited a diminished response after exposure. This suggests that the phenomenon may be most useful for detection of indole-containing tremorgens that are non-fluorescent, rather than for the enhancement of materials that are already fluorescent, such as the ergot alkaloids. The extent to which fluorescence enhancement was seen was strongly influenced by the reaction environment, in particular the solvent used and whether cyclodextrins were present. In an HPLC format, placement of the photoreactor post-column allowed for the fluorescence detection of penitrem A, paxilline, and verruculogen. The ability to photolyze indole-containing tremorgens and detect them by fluorescence may open up new avenues for detection of these mycotoxin alone or in combination.