Prooxidant activity of β-carotene under 100% oxygen pressure in rat liver microsomes |
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Authors: | Paola Palozza Gabriella Calviello Gianna Maria Bartoli |
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Institution: | a Institute of General Pathology, Catholic University, Rome, Italy b Department of Biology, Tor Vergata University, Rome, Italy |
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Abstract: | The effects of the partial pressure of oxygen (pO2 on antioxidant efficiency of β-carotene in inhibiting 2,2′-azobis(2-amidinopropane) (AAPH)-induced lipid peroxidation are investigated in rat liver microsomal membranes. The rate of peroxyl radicals generated by thermolysis of AAPH at 37°C is markedly higher at 150 than 760 mm Hg pO2. At 150 mm Hg pO2 β-carotene acts as an antioxidant, inhibiting 2,2′-azobis(2-amidinopropane) (AAPH)-induced Malondialdehyde (MDA) formation. At 760 mm Hg pO2, it loses its antioxidant activity and shows a prooxidant effect, increasing lipid peroxidation products, -Tocopherol prevents the prooxidant effect of β-carotene in a dose-dependent manner. Our data provide the first evidence of a prooxidant effect of β-carotene under 100% oxygen pressure in a biological membrane model and point out the existence of cooperative interactions between β-carotene and -tocopherol. |
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Keywords: | Free radicals Oxygen β-carotene Lipid peroxidation Rat liver |
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