Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/16/1999
Publication Date: N/A
Interpretive Summary: No interpretive summary. Abstract presented at the 112th AOAC International Meeting, Montreal, Quebec, Canada, September 13-18, 1998.
Technical Abstract: Sorghum bicolor is a world-wide important cereal and forage crop. Claviceps africana has threatened the sorghum industry on a global basis by reducing production of the hybrid seed necessary for commercialization. Also, the honey-dew exudate of this fungus severely impacts mechanical harvest, predisposes the plant to other diseases, and the alkaloids produced by C. africana are a health-threat to livestock and humans. To understand the life cycle and alkaloid production by this fungus, we examined infected sorghum from Georgia for ergot alkaloid content by HPLC, TLC, and GC/MS. Infected plants were extracted and the alkaloids subjected to preparative TLC. Fractions consistent with festuclavine, pyroclavine, dihydro-elymoclavine, chanoclavine I, and dihydroergosine were collected and subjected to GC/MS analysis either neat and/or after reaction with MSTFA. The major amu(s) and fragmentation patterns for all TMS-derivatives follows the analogous patterns as that fo the parent alkaloid (EIMS, 70 eV), with the expected shift of 73 amu. Subsequent GC/MS evaluation of costaclavine, agroclavine, lysergol, elymoclavine and dihydrolysergamide proved this method unequivocal for the identification and quantitation of this class of ergot alkaloids in the nanogram range using both SCAN- and SIM-modes. Dihydroergosine was analyzed using TLC and HPLC, since GC/MS only determined fragments associated with the tricyclic-peptide portion of the alkaloid. This is the first report of using GC/MS to quantitatively determine the TMS-clavine ergot alkaloids from C. africana-infected sorghum.