title: In vivo imaging of free radicals produced by multivitamin-mineral supplements.
abstract: BACKGROUND
  Redox active minerals in dietary supplements can catalyze unwanted and potentially harmful oxidations.
  
  
  METHODS
  To determine if this occurs in vivo we employed electron paramagnetic (EPR) imaging. We used 1-hydroxy-3-carboxy-2,2,5,5-tetramethylpyrrolidine (CPH) as a reporter for one-electron oxidations,e.g. free radical-mediated oxidations; the one-electron oxidation product of CPH, 3-carboxy-2,2,5,5-tetramethyl-1-pyrrolidinyloxy (CP•), is a nitroxide free radical that is relatively persistent in vivo and detectable by EPR. As model systems, we used research formulations of vitamin mineral supplements (RVM) that are typical of commercial products.
  
  
  RESULTS
  In in vitro experiments, upon suspension of RVM in aqueous solution, we observed: (1) the uptake of oxygen in the solution, consistent with oxidation of the components in the RVM; (2) the ascorbate free radical, a real-time indicator of ongoing oxidations; and (3) when amino acid/oligosaccharide (AAOS; glycinate or aspartate with non-digestible oligofructose) served as the matrix in the RVM, the rate of oxidation was significantly slowed. In a murine model, EPR imaging showed that the ingestion of RVM along with CPH results in the one-electron oxidation of CPH by RVM in the digestive system. The resulting CP•distributes throughout the body. Inclusion of AAOS in the RVM formulation diminished the oxidation of CPH to CP•in vivo.
  
  
  CONCLUSIONS
  These data demonstrate that typical formulations of multivitamin/multimineral dietary supplements can initiate the oxidation of bystander substances and that AAOS-complexes of essential redox active metals,e.g. copper and iron, have reduced ability to catalyze free radical formation and associated detrimental oxidations when a part of a multivitamin/multimineral formulation.
authors.affiliation: Research & Development, Melaleuca Inc, 4609 West 65th South, Idaho Falls, ID 83402, USA.
authors.forename: Alexander B
authors.initials: AB
authors.lastname: Rabovsky
authors.affiliation: Free Radical and Radiation Biology, The University of Iowa, Iowa City, IA, USA.
authors.forename: Garry R
authors.initials: GR
authors.lastname: Buettner
authors.affiliation: Noxygen Science Transfer & Diagnostics GmbH, Elzach, Germany.
authors.forename: Bruno
authors.initials: B
authors.lastname: Fink
keywords: Ascorbate; Electron paramagnetic resonance; Free radical; Imaging; Minerals; Oxidation; Vitamins