title: DNA cleavage by metabolites of butylated hydroxytoluene.
abstract: The effect of butylated hydroxytoluene (BHT) and its metabolites on DNA cleavage in vitro was studied with supercoiled plasmid DNA, pUC18, by agarose gel electrophoresis. Among several BHT metabolites, 2,6-di-t-butyl-p-benzoquinone (BHT-quinone) caused cleavage of supercoiled DNA (form I) at a concentration as low as 1 x 10(-6) M. The relative amount of linear form (form III) was increased with increasing concentration of BHT-quinone. 2,6-Di-t-butyl-4-hydroperoxy-4-methyl-2,5-cyclohexadienone (BHT-peroxyquinol) and 3,5-di-t-butyl-4-hydroxybenzaldehyde (BHT-CHO) also cleaved DNA, but to a lesser extent than BHT-quinone. No DNA cleavage was detected by BHT, 2,6-di-t-butyl-4-hydroxymethyl phenol (BHT-OH), 3,5-di-t-butyl-4-hydroxybenzoic acid (BHT-COOH), 2,6-di-t-butyl-4-hydroxy-4-methyl-2,5-cyclohexadienone (BHT-quinol) or 2,6-di-t-butyl-4-methylene-2,5-cyclohexadienone (BHT-quinone methide). The DNA cleavage by BHT-quinone was inhibited by oxygen radical scavengers including superoxide dismutase (SOD), catalase, polyethylene glycol, t-butyl alcohol, dimethyl sulfoxide, sodium azide, sodium benzoate, bovine serum albumin and methionine, while it was enhanced by the addition of FeCl2. The production of superoxide radical in a solution of BHT-quinone was confirmed by cytochrome c reduction assay. Superoxide was not produced by BHT or other BHT metabolites except for BHT-quinone. These results suggest that BHT-quinone, one of the principal metabolites of BHT, cleaves DNA strands via its generation of oxygen radicals.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Toxicology, Tokyo Metropolitan Research Laboratory of Public Health, Japan.
authors.forename: F
authors.initials: F
authors.lastname: Nagai
authors.forename: K
authors.initials: K
authors.lastname: Ushiyama
authors.forename: I
authors.initials: I
authors.lastname: Kano
mesh_terms: D002084:Butylated Hydroxytoluene / Q000378:metabolism / Q000633:toxicity*; D002712:Chlorides; D003574:Cytochrome c Group / Q000378:metabolism; D004249:DNA Damage; D004278:DNA, Superhelical / Q000187:drug effects*; D004587:Electrophoresis, Agar Gel; D005290:Ferric Compounds / Q000494:pharmacology; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase / Q000494:pharmacology; D013481:Superoxides / Q000378:metabolism
chemical_list: D002712:Chlorides; D003574:Cytochrome c Group; D004278:DNA, Superhelical; D005290:Ferric Compounds; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D013481:Superoxides; D002084:Butylated Hydroxytoluene; D013482:Superoxide Dismutase; C024555:ferric chloride