Intestinal hydrolysis and microbial biotransformation of diacetoxyscirpenol-α-glucoside, HT-2-β-glucoside and N-(1-deoxy-d-fructos-1-yl) fumonisin B₁ by human gut microbiota in vitro

Abstract

Fusarium mycotoxins are common contaminants in cereals and often co-occur with plant-derived mycotoxin sugar conjugates. Several of these modified mycotoxins are not degraded in the small intestine and hence carried through to the large intestine where microbial transformation may occur. This study aims to assess the gastrointestinal stability of the trichothecenes HT-2 toxin (HT-2), HT-2-β-glucoside (HT-2-Glc), diacetoxyscirpenol (DAS), DAS-α-glucoside (DAS-Glc) and fumonisin B1 (FB₁), N-(1-deoxy-d-fructos-1-yl) fumonisin-B₁ (NDF-FB₁). All tested modified mycotoxins were stable under upper gastrointestinal (GI) conditions. In faecal batch culture experiments, HT-2-Glc was hydrolysed efficiently and no further microbial biotransformation of HT-2 was observed. DAS-Glc hydrolysis was slow and DAS was de-acetylated to 15-monoacetoxyscripenol. NDF-FB₁ was hydrolysed at the slowest rate and FB₁ accumulation varied between donor samples. Our results demonstrate that all tested modified mycotoxins are stable in the upper GI tract and efficiently hydrolysed by human gut microbiota, thus potentially contributing to colonic toxicity. Hence the microbial biotransformation of any novel modified mycotoxins needs to be carefully evaluated.

Keywords:

• Diacetoxyscirpenol-α-glucoside
• HT-2-β-glucoside
• N-(1-deoxy-d-fructos-1-yl) fumonisin B1
• human faecal microbiota
• masked mycotoxins
• release

Acknowledgements

In Peoria, the following colleagues were involved in the preparation of the modified mycotoxins: S McCormick, C Maragos, K Sieve, K Wetterhorn.

Disclosure statement

No potential conflict of interest was reported by the authors.

The authors have full control of all primary data and allow the journal to review their data if requested.

Additional information

Funding

This study was funded by Scottish Government Rural, and Environment Science, and Analytical Services Division (RESAS) [RG13488-33]. ND was supported by an Elphinstone PhD scholarship by the University of Aberdeen.