Assaying the antioxidant and radical scavenging properties of aliphatic mono- and di-N-oxides in superoxide dismutase-deficient yeast and in a chemiluminescence test.
The antioxidative action of amphiphilic mono-(alkanoylamino) ethyldimethylamine-N-oxides (EDA), di-N-oxides 1,1-bis {[2-(N,N-dimethylamino)ethyl]amido}alkane-di-N-oxides (MEDA) and 1,1-bis {[3-(N,N-dimethylamino)propyl]amido}alkane-di-N-oxides (MPDA) with a 12- and 14-membered acyl chain against tert-butylhydroperoxide (TBHP)-produced peroxyl and paraquat (PQ)-generated superoxide radicals was determined in superoxide dismutase-deficient mutants of Saccharomyces cerevisiae, and, in parallel, in a chemical assay based on chemiluminescence changes caused in a luminol system by peroxyl radicals generated from the azo-compound 2,2'-azobis(2-amidinopropane dihydrochloride) (AAPH). At 30 micromol/L, the shorter-chain compounds did not affect strain survival while longer-chain ones, in some cases, lowered the survival of sod2 and sod1 sod2 cells. Whether nontoxic or medium-toxic, all N-oxides protected the sod strains against the toxic effect of PQ and TBHP, the protection being stronger with the di-N-oxides. The survival was lowered only by 14-MPDA in the TBHP-exposed sod2 mutant. Membrane lipids isolated from all strains were protected against TBHP-induced peroxidation by both mono- and di-N-oxides, the protection being dependent on the alkyl chain length. Mono-N-oxides were again less active than di-N-oxides with the same alkyl chains, the antiperoxidative activity being also dependent on lipids isolated from the individual mutants. In the chemiluminescence assay, the IC50 value of the N-oxides for scavenging of radicals generated from AAPH generally decreased (i.e. the scavenging efficiency increased) with increasing chain length and was the highest in MEDA.
Krasowska
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Faculty of Biotechnology, Wrocław University, 51-148 Wrocław, Poland. aniak@microb.uni.wroc.pl
Piasecki
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Murzyn
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Sigler
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K
D000578:Amidines / Q000378:metabolism; D000975:Antioxidants / Q000494:pharmacology*; D001681:Biological Assay; D004123:Dimethylamines / Q000737:chemistry / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology*; D049449:Luminescence; D008163:Luminescent Measurements; D008165:Luminol; D009154:Mutation; D016877:Oxidants / Q000378:metabolism; D010545:Peroxides / Q000494:pharmacology; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000502:physiology; D013482:Superoxide Dismutase / Q000235:genetics*; D020122:tert-Butylhydroperoxide / Q000494:pharmacology
D000578:Amidines; D000975:Antioxidants; D004123:Dimethylamines; D016166:Free Radical Scavengers; D016877:Oxidants; D010545:Peroxides; C049375:perhydroxyl radical; D008165:Luminol; C046728:2,2'-azobis(2-amidinopropane); D020122:tert-Butylhydroperoxide; D013482:Superoxide Dismutase