Activation of antioxidant response element (ARE)-dependent genes by roasted coffee extracts.
Coffee beans contain numerous bioactive components that exhibit antioxidant capacity when assessed using both chemical, cell free, and biological, cell-based model systems. However, the mechanisms underlying the antioxidant effects of coffee in biological systems are not totally understood and in some cases vary considerably from results obtained with simpler in vitro chemical assays. In the present study, the physicochemical characteristics and antioxidant activity of roasted and non-roasted coffee extracts were investigated in both cell free (ORAC(FL)) and cell-based systems. A profile of antioxidant gene expression in cultured human colon adenocarcinoma Caco-2 cells treated with both roasted and non-roasted coffee extracts, respectively, was investigated using Real-Time polymerase chain reaction (PCR) array technology. Results demonstrated that the mechanisms of the antioxidant activity associated with coffee constituents assessed by the ORAC(FL) assay were different to those observed using an intracellular oxidation assay with Caco-2 cells. Moreover, roasted coffee (both light and dark roasted) extracts produced both increased- and decreased-expressions of numerous genes that are involved in the management of oxidative stress via the antioxidant defence system. The selective and specific positive induction of antioxidant response element (ARE)-dependent genes, including gastrointestinal glutathione peroxidase (GPX2), sulfiredoxin (SRXN1), thioredoxin reductase 1 (TXNRD1), peroxiredoxin 1 (PRDX1), peroxiredoxin 4 (PDRX4) and peroxiredoxin 6 (PDRX6) were identified with the activation of the endogenous antioxidant defence system in Caco-2 cells.
Food Chemistry and Toxicology Laboratory, Food Science, Nutrition and Health, University of British Columbia, BC, Canada.
Liu
L
Yazheng
David D
DD
Kitts
D061745:Antioxidant Response Elements / Q000235:genetics*; D000975:Antioxidants / Q000032:analysis* / Q000494:pharmacology; D018938:Caco-2 Cells; D002110:Caffeine / Q000032:analysis; D055598:Chemical Phenomena; D002726:Chlorogenic Acid / Q000032:analysis; D040503:Coffea / Q000737:chemistry; D003069:Coffee / Q000737:chemistry*; D041981:Gastrointestinal Tract / Q000166:cytology / Q000201:enzymology / Q000473:pathology; D005979:Glutathione Peroxidase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000235:genetics / Q000378:metabolism; D054465:Peroxiredoxin VI / Q000235:genetics / Q000378:metabolism; D054464:Peroxiredoxins / Q000235:genetics / Q000378:metabolism; D010936:Plant Extracts / Q000032:analysis* / Q000494:pharmacology; D060888:Real-Time Polymerase Chain Reaction; D054481:Thioredoxin Reductase 1 / Q000235:genetics / Q000378:metabolism
D000975:Antioxidants; D003069:Coffee; D010936:Plant Extracts; D002726:Chlorogenic Acid; D002110:Caffeine; C515940:PRDX1 protein, human; C515980:PRDX4 protein, human; C515977:PRDX6 protein, human; D054465:Peroxiredoxin VI; D054464:Peroxiredoxins; D005979:Glutathione Peroxidase; D050862:Oxidoreductases Acting on Sulfur Group Donors; D054481:Thioredoxin Reductase 1; C504024:SRXN1 protein, human