Coffee, broccoli and spices are strong inducers of electrophile response element-dependent transcription in vitro and in vivo - studies in electrophile response element transgenic mice.
METHODS
Cytoprotective gene products, e.g. phase II - and antioxidant enzymes, are important in cellular redox homeostasis. A common feature of these genes is binding sites for transcription factor nuclear factor erythroid-2-related factor 2 (Nrf2), named electrophile response elements (EpREs) within their promoters.


RESULTS
To identify dietary bioactive compounds and foods with Nrf2/EpRE inducing properties in an intact organism, we utilized transgenic mice encoding luciferase under control of EpRE from the thioredoxin promoter. We found that 18 of 31 phytochemicals and 10 of 14 dietary plant extracts induced EpRE activity in liver HepG2 cells. Surprisingly, some dietary plant extracts showed profound inducing capability as compared to pure compounds indicating combinatorial effects of compounds found in whole foods. Furthermore, intraperitoneal injections of carnosol, curcumin and tert benzohydroquinine induced EpRE-dependent promoter activity in transgenic mice. In further experiments with curcumin, we found highly induced EpRE activity in intestine, liver, kidney and spleen. Finally, a combination extract made of coffee, thyme, broccoli, rosemary, turmeric and red onion fed orally, induced EpRE mediated luciferase in lung and adipose tissue.


CONCLUSIONS
These results show that plant-based foods contain compounds that can be absorbed and induce the antioxidant defence in a living organism in an organ-specific manner.
Balstad
Trude Rakel
TR
Department of Nutrition, Faculty of Medicine, University of Oslo, Oslo, Norway.
Carlsen
Harald
H
Myhrstad
Mari C W
MC
Kolberg
Marit
M
Reiersen
Hanne
H
Gilen
Lene
L
Ebihara
Kanae
K
Paur
Ingvild
I
Blomhoff
Rune
R
D045784:Abietanes / Q000494:pharmacology; D000818:Animals; D001937:Brassica / Q000737:chemistry*; D002478:Cells, Cultured; D003069:Coffee / Q000737:chemistry*; D003474:Curcumin / Q000494:pharmacology; D004032:Diet; D005260:Female; D035263:Flowering Tops / Q000737:chemistry; D017930:Genes, Reporter; D056945:Hep G2 Cells; D006801:Humans; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011802:Quinidine / Q000031:analogs & derivatives / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D017365:Spices / Q000032:analysis*; D014158:Transcription, Genetic / Q000187:drug effects*
D045784:Abietanes; D003069:Coffee; D051267:NF-E2-Related Factor 2; D010936:Plant Extracts; D012333:RNA, Messenger; C068623:carnosol; D003474:Curcumin; D011802:Quinidine