title: The dietary antioxidants resveratrol and quercetin protect cells from exogenous pro-oxidative damage.
abstract: In the colorectal epithelium oxidative stress is observed endogenously in premalignant adenoma cells or induced by nutritional factors like fatty acid hydroperoxides (LOOH). Bioactive phenols like resveratrol and quercetin can quench reactive oxygen species and protect from pro-oxidative damage. Our study used colorectal adenoma and carcinoma cell lines to assess antioxidant protective effects of resveratrol and quercetin. It demonstrated that both compounds efficiently protect from oxidative stress induced by LOOH. Effective concentrations (10 microM resveratrol and 1 microM quercetin) can easily be reached in the intestinal lumen after consumption of plant foods or food supplements. Both compounds prevent LOOH-induced formation of intracellular H2O2, stimulation of cyclooxygenase-2 and vascular endothelial growth factor. For reduction of endogenous H2O2 levels in colorectal tumor cells higher antioxidant-concentrations are needed in all cell lines. Quercetin (10 microM) alone even increased H2O2 in LT97 adenoma cells and stimulated VEGF production. Resveratrol and quercetin also induced 10-30% and 40-60% cell loss respectively by apoptosis. In summary, this indicates that resveratrol and quercetin have little protective capacity in absence of exogenous stress. They are however highly efficient in protecting against nutrition induced oxidative stress damage suggesting that this constitutes the major part of their tumor protective activity.
authors.affiliation: Department of Medicine 1, Institute of Cancer Research, Medical University Vienna, Borschkegasse 8a, 1090 Vienna, Austria.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kaindl
authors.forename: Isgard
authors.initials: I
authors.lastname: Eyberg
authors.forename: Natalia
authors.initials: N
authors.lastname: Rohr-Udilova
authors.forename: Christine
authors.initials: C
authors.lastname: Heinzle
authors.forename: Brigitte
authors.initials: B
authors.lastname: Marian
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D002452:Cell Count; D002455:Cell Division / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004032:Diet; D015232:Dinoprostone / Q000096:biosynthesis / Q000235:genetics; D019073:HT29 Cells; D006801:Humans; D006861:Hydrogen Peroxide / Q000037:antagonists & inhibitors / Q000633:toxicity; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D011794:Quercetin / Q000494:pharmacology*; D012313:RNA / Q000096:biosynthesis / Q000302:isolation & purification; D000077185:Resveratrol; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013267:Stilbenes / Q000494:pharmacology*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: D000975:Antioxidants; D016877:Oxidants; D013267:Stilbenes; D042461:Vascular Endothelial Growth Factor A; D012313:RNA; D011794:Quercetin; D006861:Hydrogen Peroxide; D015232:Dinoprostone; D000077185:Resveratrol