The protective effect of the olive oil polyphenol (3,4-dihydroxyphenyl)-ethanol counteracts reactive oxygen metabolite-induced cytotoxicity in Caco-2 cells.
We investigated the injurious effects of reactive oxygen metabolites on the intestinal epithelium and the possible protective role played by two olive oil phenolic compounds, (3,4-dihydroxyphenyl)ethanol and (p-hydroxyphenyl)ethanol, using the Caco-2 human cell line. We induced oxidative stress in the apical compartment, either by the addition of 10 mmol/L H2O2 or by the action of 10 U/L xanthine oxidase in the presence of xanthine (250 micromol/L); after the incubation, we evaluated the cellular and molecular alterations. Both treatments produced significant decreases in Caco-2 viability as assessed by the neutral red assay. Furthermore, we observed a significant increase in malondialdehyde intracellular concentration and paracellular inulin transport, indicating the occurrence of lipid peroxidation and monolayer permeability changes, respectively. The H2O2-induced alterations were completely prevented by preincubating Caco-2 cells with (3,4-dihydroxyphenyl)ethanol (250 micromol/L); when the oxidative stress was induced by xanthine oxidase, complete protection was obtained at a concentration of polyphenol as small as 100 micromol/L. In contrast, (p-hydroxyphenyl)ethanol was ineffective up to a concentration of 500 micromol/L. Our data demonstrate that (3,4-dihydroxyphenyl)ethanol can act as a biological antioxidant in a cell culture experimental model and that the ortho-dihydroxy moiety of the molecule is essential for antioxidant activity. This study suggests that dietary intake of olive oil polyphenols may lower the risk of reactive oxygen metabolite-mediated diseases such as some gastrointestinal diseases and atherosclerosis.
Manna
C
C
Institute of Biochemistry of Macromolecules, Medical School, Second University of Naples, Italy.
Galletti
P
P
Cucciolla
V
V
Moltedo
O
O
Leone
A
A
Zappia
V
V
D000975:Antioxidants / Q000494:pharmacology*; D018938:Caco-2 Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D004042:Dietary Fats, Unsaturated / Q000494:pharmacology*; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology / Q000187:drug effects; D007444:Inulin / Q000378:metabolism; D015227:Lipid Peroxidation; D008315:Malondialdehyde / Q000032:analysis; D000069463:Olive Oil; D016877:Oxidants / Q000633:toxicity; D018384:Oxidative Stress; D010626:Phenylethyl Alcohol / Q000031:analogs & derivatives* / Q000494:pharmacology; D010938:Plant Oils / Q000737:chemistry / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D019820:Xanthine; D014969:Xanthine Oxidase / Q000378:metabolism; D014970:Xanthines / Q000494:pharmacology
D000975:Antioxidants; D004042:Dietary Fats, Unsaturated; D000069463:Olive Oil; D016877:Oxidants; D010938:Plant Oils; D017382:Reactive Oxygen Species; D014970:Xanthines; C005975:3,4-dihydroxyphenylethanol; C011867:4-hydroxyphenylethanol; D019820:Xanthine; D008315:Malondialdehyde; D007444:Inulin; D006861:Hydrogen Peroxide; D014969:Xanthine Oxidase; D010626:Phenylethyl Alcohol