title: Epigallocatechin-3-gallate and epicatechin-3-gallate from green tea decrease plasma non-transferrin bound iron and erythrocyte oxidative stress.
abstract: Beta-thalassemia patients suffer from secondary iron overload caused by increased iron absorption and multiple blood transfusions. Excessive iron catalyzes free-radical formation, causing oxidative tissue damage. Non-transferrin bound iron (NTBI) detected in thalassemic plasma is highly toxic and chelatable. Desferrioxamine and deferiprone are used to treat the iron overload, but many side effects are found. Epigallocatechin gallate (EGCG) and epicatechin gallate (ECG) in green tea (GT) show strong antioxidant properties. We separated the EGCG and ECG from GT extract using an HPLC, and examined their iron-binding and free-radical scavenging activities. They bound Fe(3+) rapidly to form a complex with a predominant absorption at 560 nm. EGCG and ECG bound chemical Fe(3+) and chelated the NTBI in a time- and dose dependent manner. They also decreased oxidative stress in iron-treated erythrocytes. In conclusion, EGCG and ECG could be natural iron chelators that efficiently decrease the levels of NTBI and free radicals in iron overload.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand.
authors.forename: C
authors.initials: C
authors.lastname: Thephinlap
authors.forename: S
authors.initials: S
authors.lastname: Ounjaijean
authors.forename: U
authors.initials: U
authors.lastname: Khansuwan
authors.forename: S
authors.initials: S
authors.lastname: Fucharoen
authors.forename: J B
authors.initials: JB
authors.lastname: Porter
authors.forename: S
authors.initials: S
authors.lastname: Srichairatanakool
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives* / Q000302:isolation & purification / Q000494:pharmacology; D002478:Cells, Cultured; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D016166:Free Radical Scavengers; D006801:Humans; D007501:Iron / Q000097:blood / Q000378:metabolism*; D007502:Iron Chelating Agents / Q000302:isolation & purification / Q000494:pharmacology*; D019190:Iron Overload / Q000188:drug therapy; D018384:Oxidative Stress / Q000187:drug effects*; D013662:Tea / Q000737:chemistry; D017086:beta-Thalassemia
chemical_list: D016166:Free Radical Scavengers; D007502:Iron Chelating Agents; D013662:Tea; D002392:Catechin; C062669:epicatechin gallate; C045651:epigallocatechin gallate; D007501:Iron