Effect of gamma radiation on the citotoxicity and estrogenicity of Zearalenone

Abstract

Zearalenone (ZEA) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium mostly on cereals and corn. ZEA has a relatively low acute toxicity but it interferes strongly with estrogen receptors and, consequently, with the reproductive tract of individuals. Many methods have been used to eliminate mycotoxins from foods and feeds. Gamma radiation has been also investigated for mycotoxins detoxification showing some promising results. The purpose of present study was to evaluate the cytotoxicity of ZEA degradation products obtained after its irradiation and also to evaluate their estrogenicity. The effect of water during the irradiation process was also evaluated. Vials with 60M of ZEA at distinct moisture levels (dehydrated and in water) were irradiated with 0, 2.0 and 10.0 kGy doses. ZEA levels were determined by HPLC with fluorescence detection. Cytotoxicity of ZEA was assessed in Hep G2 cells using a battery of assays covering different modes of action including alterations of metabolic activity (AlamarBlue assay), plasma membrane integrity (CFDA-AM assay) and lysosomal function (NRU assay). The estrogenicity was assessed in HeLa 9903 cells, measuring luciferase activity. It was observed that gamma radiation is effective in reducing ZEA concentration, and that the presence of water enhanced significantly its degradation. A reduction of irradiated samples cytotoxicity related to metabolic activity and lysosomal function was also observed. ZEA didnt show any toxicity in the plasma membrane integrity. Since ZEA reduction was more effective in water samples, the reduction of cytotoxicity was also higher in this case (up to 94% in NRU assay). ZEA estrogenicity was also reduced with the increase of radiation doses. This reduction was higher in aqueous solutions (less 80%) than in dried conditions. These results point out that irradiation may contribute to reduce levels of ZEA and its toxicity on food commodities.