Deoxynivalenol (DON) is a potent mycotoxin produced by Fusarium moulds and affects intestinal nutrient absorption and barrier function in experimental and farm animals. Free DON and the plant metabolite DON-3-ß-D-glucoside (D3G) are frequently found in wheat and maize. D3G is stable in the upper human gut but some human intestinal bacteria release DON from D3G in vitro. Furthermore, some bacteria derived from animal digestive systems degrade DON to a less toxic metabolite, de-epoxy deoxynivalenol (DOM-1). The metabolism of D3G and DON by human microbiota has not been fully assessed. We therefore conducted in vitro batch culture experiments, assessing the activity of the human fecal microbiota to release DON from D3G.We also studied detoxification of DON to DOM-1 by microbiota and its potential effect on urinary DON excretion in humans. Fecal slurry from five volunteers was spiked with DON or D3G and incubated anaerobically (1 hour - 7 days) and mycotoxins were extracted into acetonitrile. Mycotoxins were detected in fecal extracts and urine using LC-MS/MS. Fecal microbiota released DON from D3G very efficiently with hydrolysis peaking after 4-6 hours. Fecal microbiota from one volunteer transformed DON to DOM-1. Urine from the same volunteer also contained DOM-1 (4.7% of DON) whereas DOM-1 was not detectable in urine from other volunteers. Our results confirm that fecal microbiota release DON from its glycosylated form, hence increasing the toxic burden in exposed individuals. Furthermore, this is first evidence that human fecal microbiota of one volunteer detoxifies DON, resulting in the appearance of DOM-1 in urine.
Gratz, S. W., Duncan, G., & Richardson, A. J. (2013). Human fecal microbiota metabolize deoxynivalenol and deoxynivalenol-3-glucoside and may be responsible for urinary de-epoxy deoxynivalenol. Applied and Environmental Microbiology, 79(6), 1821-1825. https://doi.org/10.1128/AEM.02987-12