Characterization of Three Deoxynivalenol Sulfonates Formed by Reaction of Deoxynivalenol with Sulfur Reagents

Abstract

Reduction of the Fusarium mycotoxin deoxynivalenol (DON) in animal feed by treatment with sodium bisulfite and sodium metabisulfite has been successfully demonstrated in several studies. All of them reported formation of one DON sulfonate of strongly reduced toxicity compared to DON. The starting point of the present work was investigation of different sulfur reagents for reduction of DON. In the course of these experiments, three different DON sulfonates termed DON sulfonate 1 (1), DON sulfonate 2 (2), and DON sulfonate 3 (3) were identified and structurally elucidated by UHPLC-HRMS/MS as well as NMR spectroscopy. Compound 1 is characterized by loss of the epoxide group, and 2 by formation of a hemiketal. Compound 3 is an equilibrating mixture of two isomers, a ketone and a hemiketal. The MS/MS pattern can be used to differentiate the three DON sulfonates, despite their same mass and molecular formula. Investigation of parameters influencing formation and stability of DON sulfonates revealed that rapid formation of 1 and 2 occurs at alkaline pH, whereas at acidic pH, slow formation of 3 takes place, irrespective of the sulfur reagent used. Whereas 1 and 2 are stable across a broad pH range, 3 decomposes to DON, 1, and 2 at alkaline pH. In addition, both 2 and 3 are unstable in solid form. The formation, characterization, and stability of three novel DON sulfonates with respect to results from previous studies are discussed, providing insights of relevance for detoxification of DON-containing animal feed.

The Fate of Mycotoxins During the Processing of Wheat for Human Consumption

“…For example, L‐cysteine, ammonium phosphate, and sodium bisulfite could cause an elevated DON loss in bread production (Boyacioğlu et al., ). Sodium bisulfite leads to the formation of DON sulfonate, which can be less toxic than DON (Young, Trenholm, Friend, & Prelusky, ; see also Schwartz et al., ). This food additive can also reduce DON in baked goods when applied to wheat grain, although part of the formed DON sulfonate is reversed back to DON during baking (Young et al., ).…”

Effects of potential detoxifying agents on growth performance and deoxynivalenol (DON) urinary balance characteristics of nursery pigs fed DON-contaminated wheat1,2

“…For pigs fed the NC + SMB treatment, DON recovery greater than 100% appears to indicate that some of the DON-sulfonate was degraded to the parent DON. Recent work by Schwartz et al (2013) revealed that 3 structurally unique forms of DON-sulfonate can be formed by the reaction of DON with sulfites, dependent on the sulfiting agent and processing conditions present. While DON-sulfonate-1 and DON-sulfonate-2 are stable across a broad pH range, DON-sulfonate-3 can decompose to DON at alkaline pH, such as those in the proximal small intestine.…”

Nucleophilic Addition of Thiols to Deoxynivalenol

“…5,10,15 Compounds 2a and 2b were isolated twice as a mixture, once in an approximate 1:1 ratio and once in a 1:5 ratio, which facilitated identification of NMR signals associated with the two components ( Figure S7 , 2a and 2b have the same skeleton and differ only in their stereochemistries at C-9 and C-10, which is reflected in the differing 3 J coupling constants for this spin system ( Table 1). The stereochemistries at C-9 and C-10 were established from ROESY ( Figure S9) and SELROESY NMR experiments ( Figure 5).…”