Activation of the Ah Receptor by Extracts of Dietary Herbal Supplements, Vegetables, and Fruits
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- 作者：Anoek Jeuken ; Bart J. G. Keser ; Elaine Khan ; Abraham Brouwer ; Jan Koeman ; and Michael S. Denison
- 刊名：Journal of Agricultural and Food Chemistry
- 出版年：2003
- 出版时间：August 27, 2003
- 年：2003
- 卷：51
- 期：18
- 页码：5478 - 5487
- 全文大小：241K
- 年卷期：v.51,no.18(August 27, 2003)
- ISSN：1520-5118
文摘
The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that can be activatedby a structurally diverse range of synthetic and natural chemicals, and it mediates the toxic andbiological effects of environmental contaminants such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).The spectrum of chemicals that bind to and activate the AhR signal transduction pathway and theidentity of materials containing AhR active chemicals is only now being defined. Utilizing AhR-dependent gel retardation and reporter gene bioassays, the screening of extracts of 22 dietary herbalsupplements and 21 food products (vegetables and fruits) was performed to identify those containingAhR agonists. Several herbal extracts (ginseng, Fo-Ti, white oak bark, licorice, ginkgo biloba, andblack cohosh) stimulated AhR DNA binding and gene expression to levels between 20 and 60% ofthat produced by TCDD. Although some food extracts (corn, jalapeño pepper, green bell pepper,apple, Brussels sprout, and potato) were relatively potent activators of AhR DNA binding (30-50%of TCDD), only corn and jalapeño pepper extracts induced AhR-dependent luciferase reporter geneexpression. However, dilution of corn, jalapeño pepper, bell pepper, and potato extracts dramaticallyincreased their ability to induce luciferase activity, suggesting that these extracts contained AhRantagonists whose effectiveness was overcome by dilution. Overall, these results demonstrate thatdietary products can be a major source of naturally occurring AhR ligands to which animals andhumans are chronically exposed.Keywords: Ah receptor; 2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD; natural ligands; herbs; vegetables;fruits; natural products