title: Rapid and repeatable redox cycling of an insoluble dietary antioxidant: electrochemical analysis.
abstract: There are many unresolved questions concerning the health benefits of dietary antioxidants due in part to the complexity of the materials and mechanisms of action. We applied a new electrochemical method and report new observations for one of the richest sources of dietary antioxidants. We observed that the insoluble fraction of clove is redox-active and can be rapidly and repeatedly switched between oxidized and reduced states. Also, the radical scavenging antioxidant properties of insoluble clove are largely independent of this reversible redox activity, which is similar to observations made with the natural phenolic melanin. In contrast to melanin, insoluble clove was observed to have little pro-oxidant activity (as measured by H2O2 generation) irrelevant to whether it was poised in an oxidized or reduced state. These results suggest that dietary antioxidants, even when insoluble and nonabsorbed, can undergo important redox interactions in the intestinal tract.
authors.affiliation: Fischell Department of Bioengineering, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Morgan E
authors.initials: ME
authors.lastname: Lee
authors.forename: Eunkyoung
authors.initials: E
authors.lastname: Kim
authors.forename: Yi
authors.initials: Y
authors.lastname: Liu
authors.forename: John C
authors.initials: JC
authors.lastname: March
authors.forename: William E
authors.initials: WE
authors.lastname: Bentley
authors.forename: Gregory F
authors.initials: GF
authors.lastname: Payne
mesh_terms: D000975:Antioxidants / Q000032:analysis* / Q000737:chemistry / Q000494:pharmacology; D048271:Chitosan / Q000737:chemistry; D004563:Electrochemistry / Q000379:methods*; D006861:Hydrogen Peroxide / Q000378:metabolism; D010084:Oxidation-Reduction; D012995:Solubility; D027842:Syzygium / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D048271:Chitosan; D006861:Hydrogen Peroxide
keywords: antioxidant; chitosan; clove; electrochemistry; pro-oxidant; redox activity; redox cycling