title: A dramatic effect of oxygen on protection of human cells against γ-radiation by lycopene.
abstract: Reducing radiation damage is important and dietary antioxidants that can protect cells from such damage are of value. Dietary lycopene, a carotenoid found in tomatoes, protects human lymphoid cell membranes from damage by γ-radiation. We report that such protective effects are remarkably reduced as the oxygen concentration increases - near zero at 100% oxygen from fivefold protection at 20% oxygen and, dramatically, from 50-fold protection at 0% oxygen. Such huge differences imply that under higher oxygen concentrations lycopene could lead to improved cancer therapy using γ-radiation. The cells are not efficiently protected from the superoxide radical by lycopene. Noncellular studies suggest molecular mechanisms for the oxygen effect.
authors.affiliation: Photobiology Research, IHZ, Berlin, Germany.
authors.forename: Fritz
authors.initials: F
authors.lastname: Boehm
authors.affiliation: Dalton Cumbrian Facility, Westlakes Science & Technology Park, The University of Manchester, Cumbria, UK.
authors.forename: Ruth
authors.initials: R
authors.lastname: Edge
authors.affiliation: School of Physical and Geographical Sciences (Chemistry Section), Keele University, Staffordshire, UK.
authors.forename: Terence George
authors.initials: TG
authors.lastname: Truscott
authors.affiliation: Department of Pneumonology, Charité Hospital, University Medicine, Berlin, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Witt
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology; D002338:Carotenoids / Q000378:metabolism / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects / Q000528:radiation effects; D019610:Cytoprotection / Q000187:drug effects* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005720:Gamma Rays; D006801:Humans; D017665:Hydroxyl Radical / Q000378:metabolism; D000077276:Lycopene; D010100:Oxygen / Q000494:pharmacology*; D013057:Spectrum Analysis; D013481:Superoxides / Q000378:metabolism; D014801:Vitamin A / Q000031:analogs & derivatives; D014810:Vitamin E / Q000494:pharmacology
chemical_list: C487773:trans-sodium crocetinate; D013481:Superoxides; D014801:Vitamin A; D014810:Vitamin E; D017665:Hydroxyl Radical; D002338:Carotenoids; D001205:Ascorbic Acid; D010100:Oxygen; D000077276:Lycopene
keywords: cell protection; dietary lycopene; gamma radiation; lymphoid cells; oxygen effect