title: Protective effects of tea polyphenols against oxidative damage to red blood cells.
abstract: Tea polyphenols (TPP) from black and green teas were evaluated for their antioxidant effects on normal red blood cells (RBC) and beta-thalassemic RBC membranes challenged with exogenous oxidants in vitro. The TPP of both types protected RBC against primaquine-induced lysis; they also protected the whole cells and the membranes against H2O2-induced lipid peroxidation so that about 80% protection was reached at [TPP] = 10 microg/mL. TPP from black tea at the same concentration protected normal RBC from morphological alterations caused by the peroxide treatment. The mechanism of the effects of TPP was investigated using a chemical system generating .OH (iron + ascorbic acid). TPP from both black and green teas inhibited the .OH fluxes in a concentration-dependent manner, indicating the possibility of iron chelation by TPP. Spectrophotometric titration revealed that TPP could stoichiometrically bind ferric iron to form a redox-inactive Fe-TPP complex. Quantitative analysis suggests that one or more major catechins from the TPP preparations are the likely iron-binding compounds accounting for the antioxidant effects of TPP on RBC.
authors.affiliation: Department of Hematology, Hadassah University Hospital-Hebrew University Medical School, Jerusalem, Israel.
authors.forename: L N
authors.initials: LN
authors.lastname: Grinberg
authors.forename: H
authors.initials: H
authors.lastname: Newmark
authors.forename: N
authors.initials: N
authors.lastname: Kitrossky
authors.forename: E
authors.initials: E
authors.lastname: Rahamim
authors.forename: M
authors.initials: M
authors.lastname: Chevion
authors.forename: E A
authors.initials: EA
authors.lastname: Rachmilewitz
mesh_terms: D000975:Antioxidants / Q000494:pharmacology*; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D005290:Ferric Compounds / Q000494:pharmacology; D005419:Flavonoids; D006801:Humans; D015227:Lipid Peroxidation / Q000187:drug effects; D009571:Nitrilotriacetic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D010636:Phenols / Q000494:pharmacology*; D011108:Polymers / Q000494:pharmacology*; D059808:Polyphenols; D013662:Tea
chemical_list: D000975:Antioxidants; D005290:Ferric Compounds; D005419:Flavonoids; D010636:Phenols; D011108:Polymers; D059808:Polyphenols; D013662:Tea; D009571:Nitrilotriacetic Acid; C020326:ferric nitrilotriacetate