Supplementary Materialstoxins-08-00334-s001. galacto-oligosaccharides (GOS) are able to protect epithelial cells against DON and its acetylated forms, which suggests that GOS are beneficial food additives in the protection of vulnerable segments of the human population against adverse effects of DON and its derivatives. species. Chemically, trichothecenes belong Sitagliptin phosphate distributor to the group of sesquiterpenoids and share a 9, 10 double bond and the 12, 13 epoxide group, the latter being considered to be critical for their toxicity [1,2,3] (Physique 1). The mycotoxin deoxynivalenol (DON), mainly produced by and genotypes producing all three forms (DON, 3ADON and 15ADON) have been identified . Plants in turn aim to protect their tissues, conjugating free DON to one or more molecules of glucose of which DON-3–d-glucoside (DON3G) is the most frequently measured conjugate [14,18,19]. The glycosylation changes the physico-chemical properties of DON significantly, and hence such herb glucosides have long remained undetected. They have been described as masked mycotoxins, as they escape common extraction and detection methods validated for the determination of DON [18,19,20]. The concentrations of DON3G in wheat and maize samples are highly variable, and Berthiller et al. [20,21] reported in some individual studies that DON3G concentrations Sitagliptin phosphate distributor even exceeded those of DON. Upon ingestion with food, the glucoside binding can be cleaved readily by bacterial glucosidases. Gratz et al.  reported that mixed human fecal microbiota are capable of hydrolyzing 80% of DON3G in 4 h. Comparable data for other DON glucosides are not available, but it is generally assumed that liberated DON contributes to overall human and animal exposure [14,18,19,23]. The intestinal microbiome does not only liberate DON from herb material, but is also able to convert DON to its de-epoxide, denoted DOM-1 [3,24]. Although earlier studies failed to detect significant amounts of DOM-1 in human blood samples, DOM-glucuronides have been detected in human urine samples and recently in urine samples of children as well. These findings indicate that part of the formed DOM-1 is assimilated and subsequently excreted via the kidneys . All the above mentioned derivatives and metabolites of DON are summarized in Table 1. Table 1 Deoxynivalenol (DON) and its common modified forms. 0.05, ** 0.01, *** 0.001; significantly different from control group; ^^ 0.01; significantly different from corresponding DON group. Open in a separate window Physique 3 Cytotoxic effects of DON, DON3G and DOM-1 in Caco-2 cells. Differentiated Caco-2 cells on transwell inserts were uncovered from the apical and basolateral compartment to increasing DON, DON-3- 0.01; significantly different from control group; ^ 0.05, ^^ 0.01, ^^^ 0.001 significantly different from corresponding DON group. 2.2. Comparison of Changes in Trans-Epithelial Resistance Induced by DON and Its Derivatives and Metabolites TEER is usually a commonly used marker for the integrity of the tight cellular monolayer. In the current experiments, 3ADON and 15ADON concentration-dependently decreased the TEER values in a manner comparable to DON effects at different time points (Physique 4A,C). However, 3ADON is slightly less potent in inducing a decrease in TEER values compared to DON, whereas 2.1 M 15ADON appears to be even more potent in decreasing TEER values compared to 2.1 M after 12 h of exposure. Open in a separate window Physique 4 Effects of DON and its acetylated derivatives on trans-epithelial electrical resistance (TEER) and Lucifer yellow (LY) translocation. Differentiated Caco-2 cells on transwell inserts were uncovered from the apical and basolateral compartment to increasing concentrations of DON, 3ADON (A,B) and 15ADON (C,D) for 24 h and TEER values were measured during different time points (A,C). Subsequently, LY translocation from the apical to the basolateral compartment was measured (B,D). Results are expressed as percentage of initial value (TEER PIK3C2A values) or percentage of control group (LY translocation) as mean SEM. * Sitagliptin phosphate distributor 0.05, ** 0.01, *** 0.001; significantly different from corresponding control group, ^ 0.05, ^^ 0.01, ^^^ 0.001; significantly different from corresponding DON group. In the second series of experiments, a comparison between the effects of DON and DON3G or DOM-1 was made and neither of the modified forms showed a significant effect on TEER in the tested concentration range (Physique 5A,C). However, there was a slight decrease in TEER values after exposure to 8.4 M DOM-1 for 12 and 24 h. Open in a separate window Physique 5 Effects of DON, DON3G and DOM-1 on TEER and LY.