Zearalenone (ZEN), also known as RAL and F-2 mycotoxin, is a potent estrogenic metabolite produced by someFusarium and Gibberella species.Particularly is produced by Fusarium graminearum, Fusarium culmorum,Fusarium cerealis, Fusarium equiseti, Fusarium verticillioides, and Fusarium incarnatum
Zearalenone is heat-stable and is found worldwide in a number of cereal crops, such as maize, barley, oats,wheat, rice, and sorghum.
Chemical and physical properties
Zearalenone is a white crystalline solid. It exhibits blue-green fluorescence when excited by long wavelength ultraviolet (UV) light (360 nm) and a more intense green fluorescence when excited with short wavelength UV light (260 nm). In methanol, UV absorption maxima occur at 236 (e = 29,700), 274 (e = 13,909) and 316 nm (e = 6,020). Maximum fluorescence in ethanol occurs with irradiation at 314 nm and with emission at 450 nm. Solubility in water is about 0.002 g/100 mL. It is slightly soluble in hexane and progressively more so in benzene,acetonitrile, methylene chloride, methanol, ethanol, and acetone. It is also soluble in aqueous alkali.
Dermal exposure
Zearalenone can permeate through the human skin. However, no significant hormonal effects are expected after dermal contact in normal agricultural or residential environments.
In common with other mycotoxins, sampling food commodities for zearalenone must be carried out to obtain samples representative of the consignment under test. Commonly used extraction solvents are aqueous mixtures of methanol, acetonitrile, or ethyl acetate followed by a range of different clean-up procedures that depend in part on the food and on the detection method in use. Thin-layer chromatography (TLC) methods and high-performance liquid chromatography(HPLC) are commonly used. HPLC alone is not sufficient, as it may often yield false positive results. Today, HPLC-MS/MS analysis is used to quantify and confirm the presence of zearalenone.
The TLC method for zearalenone is: normal phase silica gel plates, the eluent: 90% dichloromethane, 10% v/v acetone; or reverse phase C18 silica plates; the eluent: 90% v/v methanol, 10% water. Zearalenone gives unmistakable blue luminiscence under UV.
