3,4,5,6,9,10-Hexahydro-14,16-dihydroxy-3-methyl-1H-2-benzoxacyclotetradecin-1,7(8H)-dione (Zearalenone)

(3S)-14,16-Dihy-droxy-3-methyl-3,4,5,6,9,10,11,12-octa-hydro-1H-2-benzoxacyclo-tetra-decine-1,7(8H)-dione (zearalanone) monohydrate

The absolute configuration of the title compound, C₁₈H₂₄O₅·H₂O, was not been determined by anomalous-dispersion effects, but has been assigned by reference to an unchanging chiral centre in the synthetic procedure. Intra­molecular O—H⋯O hydrogen bonds stabilize the mol­ecular conformation. In the crystal, O—H⋯O hydrogen bonds link the main mol­ecules and the water mol­ecules, forming an infinite three-dimensional network.

Chemical and conformational study of the interactions involved in mycotoxin complexation with beta-D-glucans

In a previous paper we reported that beta-D-glucans isolated from Saccharomyces cerevisiae could adsorb zearalenone, reduce its bioavailability in the digestive tract, and protect animals against its adverse effects. We have now investigated, in vitro, the kinetics of the interaction between other mycotoxins and beta-D-glucans from several sources at three pH values found along the digestive tract (3.0, 6.0, and 8.0). Acid and neutral conditions gave the highest affinity rates for aflatoxins B1 > deoxynivalenol > ochratoxin A and involved both the (1 --> 3)-beta-D-glucans and the (1 --> 6)-beta-D-glucans. Alkaline conditions, owing to their destructuring action on glucans, were favorable only for the adsorption of patulin. Using molecular mechanics, we found that hydroxyl, ketone, and lactone groups are involved in the formation of both hydrogen bonds and van der Waals interactions between aflatoxins B1, deoxynivalenol and patulin, and beta-D-glucans. Differences in the binding capacity of the mycotoxins are due to their specific physical and chemical characteristics.

Comprehensive Conformational Study of Key Interactions Involved in Zearalenone Complexation with β-d-Glucans

The beta-D-glucans from the cell wall of Saccharomyces cerevisiae have shown in vitro affinity for zearalenone. For this reason, their utilization as dietary adsorbent, to reduce the bioavailability of zearalenone, is of practical interest. Our study used powerful devices to elucidate the spatial conformation and molecular sites of interaction between ZEN and beta-D-glucans. In this respect, 1H NMR spectroscopy implicated the hydroxyl groups of the phenol moiety of zearalenone in the complexation by laminarin, a pure beta-(1,3)-D-glucan. X-ray diffraction determined that laminarin displays the conformation of a single-helix with six beta-D-glucopyranose residues per turn. At this stage, molecular modeling was useful to locate the interaction sites and to propose highly probable complexes of zearalenone with laminarin fragment. Interestingly, the beta-(1,3)-D-glucan chain favors a very stable intra-helical association with zearalenone, nicely stabilized by beta-(1,6)-D-glucans side chains. Both hydrogen bonds and van der Waals interactions were precisely identified in the complex and could thus be proposed as driving interactions to monitor the association between the two molecules.