|Zeringue Jr, Hampden|
Submitted to: Phytochemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/1999
Publication Date: N/A
Citation: Interpretive Summary: Aflatoxins are highly toxic compounds produced by the mold, Aspergillus flavus. Aflatoxin contamination of cottonseed reduces both the quality and economic value of the crop and is a potential health problem to both man and animal. In our study of the process of contamination of cottonseed with toxic aflatoxin, the bright-greenish-yellow-fluorescence (BGY-F) substance that is observed on cotton lint in cotton bolls associated with aflatoxin contamination in cottonseed was identified. The substance was subjected to structural analyses and was found to be a dimer of kojic acid (two kojic acid molecules linked together). Kojic acid, a product of the fungus, together with reactants found on cotton lint, results in the formation of the BGY-F substance (the kojic acid dimer). The observation of this reaction and the BGY-F substance may suggest an initial defense mechanism initiated by the plant. This information would be beneficial to molecular biologists who are looking for disease (aflatoxin) resistant traits to decrease the incident of aflatoxin contaminated cottonseed.
Technical Abstract: In order to characterize the structure of the bright-greenish-yellow fluorescence(BGY-F) compound on cotton lint associated with aflatoxin contamination in cotton seed, various in vitro and in vivo natural BGY-F reaction products were prepared. Under similar high pressure liquid chromatography separation with variable wavelength and programmable fluorescence detection (HPLC-UV/FL), combined with atmospheric pressure ionization and mass spectral determinations, it was found that the BGY-F reaction products prepared from three preparations: (a) kojic acid (KA) plus peroxidase (soybean peroxide or horseradish type VI and type II) plus H2O2, or (b) detached fresh cotton locules plus KA plus H2O2, or (c) attached field cotton locules that were treated with a spore suspension of aflatoxigenic Aspergillus flavus, all resulted in identical chromatographic characteristics. Also these three reaction products exhibited a molecular weight of 282 for the BGY-F compound. Further characterization of the BGY-F reaction product with 1H and 13C NMR analysis indicated that it was a dimer of 2 KA linked at the C-6 positions.