title: Impact of gamma-irradiation on the antioxidative properties of sage, thyme, and oregano.
abstract: Ionizing radiation is known to stimulate the generation of oxygen radicals which destabilize organic molecules resulting in a decrease of the system's antioxidant potential. The Salmonella typhimurium (TA102) reverse mutation assay, co-incubated with t-BOOH and H(2)O(2), was used to assess the effects of gamma-irradiation (dose: 10kGy) on the antioxidant properties of sage, thyme, and oregano in chloroform and methanol extracts as well as in their mixture. In addition, measurements of the trolox equivalent antioxidative capacity (TEAC), total polyphenol content (TPC), and tocopherol equivalent (TE) were performed. For the methanol and mixed extracts, antioxidative properties in the S. typhimurium reverse mutation assay were only found when using an exogenous metabolic activation system. Generally, the greatest inhibition of mutagenicity was observed in the chloroform fractions of irradiated and of non-irradiated herbs. The relative antioxidant activities for the different herbs were as follows: TA102/t-BOOH, TEAC, TPC: thyme approximately oregano>sage. TA102/H(2)O(2): thyme approximately oregano approximately sage. TE: sage>thyme>oregano. For the majority of the investigated samples the impact of irradiation was insignificant. Therefore, gamma-irradiation at the doses tested seems to have little, if any, effect on the antioxidative capacity of the tested herbs.
authors.affiliation: Department of Nutritional Sciences, University of Vienna, Vienna, Austria. sabine.brandstetter@univie.ac.at
authors.forename: S
authors.initials: S
authors.lastname: Brandstetter
authors.forename: C
authors.initials: C
authors.lastname: Berthold
authors.forename: B
authors.initials: B
authors.lastname: Isnardy
authors.forename: S
authors.initials: S
authors.lastname: Solar
authors.forename: I
authors.initials: I
authors.lastname: Elmadfa
mesh_terms: D000818:Animals; D004338:Drug Combinations; D005519:Food Preservation; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology / Q000528:radiation effects*; D005720:Gamma Rays; D006861:Hydrogen Peroxide / Q000494:pharmacology; D031341:Origanum / Q000737:chemistry / Q000528:radiation effects; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000528:radiation effects*; D051381:Rats; D000091243:Ribosomal Protein S9; D012269:Ribosomal Proteins; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics; D027543:Salvia officinalis / Q000737:chemistry / Q000528:radiation effects; D017365:Spices / Q000032:analysis / Q000528:radiation effects*; D046930:Thymus Plant / Q000737:chemistry / Q000528:radiation effects; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
chemical_list: D004338:Drug Combinations; D016166:Free Radical Scavengers; D010936:Plant Extracts; D000091243:Ribosomal Protein S9; D012269:Ribosomal Proteins; D020122:tert-Butylhydroperoxide; D006861:Hydrogen Peroxide