title: Reduction and release of ferritin iron by plant phenolics.
abstract: The reductive release of ferritin iron by several naturally occurring o-diphenols was studied. The initial rate of iron release was quantified by spectrophotometric measurement of the Fe(ferrozine)3(2+) complex, which absorbs maximally at 562 nm. The initial rate of iron release was dependent upon o-diphenol concentration, but not on the concentration of the chromophoric chelating agent, ferrozine, Stoichiometric measurements resulted in a ratio of 2Fe(II) released per molecule of o-diphenol. The series of o-diphenols studied included, caffeic acid, chlorogenic acid, dihydrocaffeic acid, 3,4-dihydroxybenzoic acid, and several analogs. These reductants represent an oxidation reduction potential range of 0.38 volts. A direct correlation between reducing power of the o-diphenols and rate of ferritin iron release was observed. Superoxide dismutase, catalase, mannitol, or general radical traps had no effect on the rate of iron removal; however, EDTA and oxalate inhibited iron release. A mechanism for ferritin iron reduction and release by o-diphenols consistent with the experimental observations is discussed.
mesh_terms: D000818:Animals; D002109:Caffeic Acids / Q000494:pharmacology; D002726:Chlorogenic Acid / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D005293:Ferritins / Q000378:metabolism*; D006736:Horses; D007501:Iron / Q000378:metabolism*; D010070:Oxalates / Q000494:pharmacology; D010084:Oxidation-Reduction; D010636:Phenols / Q000494:pharmacology*; D010936:Plant Extracts / Q000494:pharmacology
chemical_list: D002109:Caffeic Acids; D010070:Oxalates; D010636:Phenols; D010936:Plant Extracts; C000995:3,4-dihydroxyphenylpropionic acid; D002726:Chlorogenic Acid; D005293:Ferritins; D004492:Edetic Acid; D007501:Iron; C040048:caffeic acid