Black tea extract suppresses transformation of aryl hydrocarbon receptor induced by dioxin

Issue title: The Proceedings of the 3rd International Conference on Food Factors (ICoFF 03)

Article type: Research Article

Authors: Fukuda, Itsuko | Sakane, Iwao | Yabushita, Yoshiyuki | Sawamura, Shin-ichi | Kanazawa, Kazuki | Ashida, Hitoshi

Affiliations: Laboratory of Food and Nutritional Chemistry, Faculty of Agriculture, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan | Central Research Institute, Ito En, Ltd., 21 Megami, Sagara-cho, Haibara-gun, Shizuoka 421-0516, Japan

Note: [] Corresponding author.: Tel./Fax: +81 78 803 5878; E-mail: [email protected]

Abstract: Dioxins cause various adverse effects through binding to an aryl hydrocarbon receptor (AhR) and transformation of the receptor. In this study, we investigated whether black tea extract suppresses AhR transformation. Dried black tea leaves were extracted with 75% ethanol, and the extract was pretreated to the rat liver cytosol fraction 10 min prior to addition of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Transformed AhR was detected by electrophoretic gel mobility shift assay. Black tea extract suppressed AhR transformation in a dose-dependent manner, and the IC_{50} value against 1 nM TCDD-induced AhR transformation was 8.9 μg/ml. The result suggests that intake of black tea has a potential to suppress the AhR transformation, leading protection from dioxin toxicity.

Keywords: black tea, dioxin, aryl hydrocarbon receptor, rats

Journal: BioFactors, vol. 21, no. 1-4, pp. 367-369, 2004