Suppressive effects of flavonoids on dioxin toxicity

Article type: Research Article

Authors: Hitoshi Ashida,

Affiliations: Department of Biofunctional Chemistry, Faculty of Agriculture, Kobe University, Nada-ku, Kobe 657-8501, Japan. Fax: +81 78 803 5879

Abstract: Dioxin type chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) cause a variety of toxicity. Most of the toxicity of TCDD has been attributed to a mechanism by which TCDD is bound to aryl hydrocarbon receptor (AhR) and transforms the receptor. Thus, suppression of the AhR transformation by food factors can suppress the dioxin toxicity. In this study, flavonoids at various concentrations were treated to a rat cytosolic fraction containing AhR before adding 1 nM TCDD. The transformed AhR was detected by an electrophoretic mobility shift assay with a DNA oligonucleotide consensus to dioxin response element. As the results, flavones and flavonols at dietary levels act as the antagonists for AhR and suppress the transformation. The antagonistic IC_{50} values were in a range between 0.14 and 10 \muM, which are close to the physiological levels in human. These results suggest that a plant-based diet can prevent the dioxin toxicity.

Keywords: dioxin, Ah receptor, flavonoid, hepatocytes

Journal: BioFactors, vol. 12, no. 1-4, pp. 201-206, 2000