title: Preliminary screening of the inhibitory effect of food extracts on activation of the aryl hydrocarbon receptor induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin.
abstract: A preliminary screening for the inhibitory effects on the activation of the aryl hydrocarbon receptor (AhR) by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) by applying AhR-based bioassays for dioxins, the Ah-Immunoassay and CALUX assay, was attempted. Thirty-nine food extracts including vegetables, fruits, herbs, and teas were initially screened in vitro. We first examined the application of both bioassay methods using green tea extracts and (-)-epigallocatechin gallate, reported antagonists of the AhR, since the results could reveal an inhibitory effect versus the control in both assays. Food extracts were then tested. Among the herbs, extracts of sage, among the vegetables, green leafy ones such as spinach, and among the fruit, citrus showed inhibitory effects on AhR activation by TCDD, although some tested samples did not show parallel behavior in both assays. Sage had a remarkable inhibitory effect (79% in the CALUX assay and 83% in the Ah-Immunoassay compared with control) and its effects were dose dependent. The results suggest that these assays might be applicable to the preliminary screening of antagonist activity against the AhR. Moreover, based on these results, the potential benefit of factors that function as dietary ligands of the AhR and are present in several foodstuffs is indicated.
authors.affiliation: Division of Foods, National Institute of Health Sciences, Tokyo, Japan. amakura@nihs.go.jp
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Amakura
authors.forename: Tomoaki
authors.initials: T
authors.lastname: Tsutsumi
authors.forename: Masafumi
authors.initials: M
authors.lastname: Nakamura
authors.forename: Hiroko
authors.initials: H
authors.lastname: Kitagawa
authors.forename: Junko
authors.initials: J
authors.lastname: Fujino
authors.forename: Kumiko
authors.initials: K
authors.lastname: Sasaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshida
authors.forename: Masatake
authors.initials: M
authors.lastname: Toyoda
mesh_terms: D000818:Animals; D005638:Fruit; D051379:Mice; D010936:Plant Extracts / Q000494:pharmacology*; D000072317:Polychlorinated Dibenzodioxins / Q000037:antagonists & inhibitors* / Q000633:toxicity; D018336:Receptors, Aryl Hydrocarbon / Q000187:drug effects*; D013662:Tea; D014407:Tumor Cells, Cultured; D014675:Vegetables
chemical_list: D010936:Plant Extracts; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D013662:Tea