Studies on Chemical and Biological Assays of Fusarenon-X and Diacetoxyscirpenol in Cereal Grains

To establish the method for detection of mycotoxins from grains contaminated by Fusarium, the recovery study of fusarenon-X (Fu-X) or diacetoxyscirpenol (DAS) added to rice powder was carried out. Fu-X or DAS was extracted from hexane-washed rice powder with methanol-NaCl and transfered into chloroform by liquid-liquid partition, and the extracts were analyzed by silica gel TLC. The toxins were detected on a thin-layer chromatogram by spraying with sulfuric acid or p-anisaldehyde and determined quantitatively by densitometry in the range of 0.25-2μg/spot. Quantitative analysis of DAS were also studied by the fluorometric method with the detection limit of 0.05μg per spot. The same samples extracted were assayed biologically using the inhibitory activity of these mycotoxins on the growth of mouse leukemia cells in vitro. The limit of determination ranged 0.04-0.15μg and 0.003-0.01μg for Fu-X and DAS, respectively. Recovery of added Fu-X and DAS calculated from these two assay methods averaged approximately 85%. These results suggest that the combination of the chemical and biological assay method is very effective for the examination of scirpene mycotoxins.