Search results for "Mutagenicity"
showing 10 items of 92 documents
The effect of dietary imbalances on the activation of benzo[a]pyrene by the metabolizing enzymes from rat liver.
1987
Abstract Male Sprague-Dawley rats (70–80 g) were fed ad libitum a standard control diet (22% casein, 5% lard), or a high lipid diet (30% lard) or a low protein diet (6% casein) or a standard diet containing 50 ppm phenoclor DP6. After 6 weeks on these diets, the cytochrome P-450 microsomal content, the benzo[ a ]pyrene monooxygenase (BaP-MO) and the epoxide hydrolase (EH) were assayed. The formation of mutagenic B(a)P metabolites which covalently bind with DNA was compared. The activity of BaP-MO and of EH were increased by the high lipid diet (+27% and 106% respectively) and by the phenoclor DP6 treatment (+63% and 400% respectively), compared to the standard diet. In animals fed a low pro…
Evaluation of genotoxicity and DNA protective effects of mangiferin, a glucosylxanthone isolated from Mangifera indica L. stem bark extract.
2012
Abstract Mangiferin is a glucosylxantone isolated from Mangifera indica L. stem bark. Several studies have shown its pharmacological properties which make it a promising candidate for putative therapeutic use. This study was focused to investigate the in vitro genotoxic effects of mangiferin in the Ames test, SOS Chromotest and Comet assay. The genotoxic effects in bone marrow erythrocytes from NMRI mice orally treated with mangiferin (2000 mg/kg) were also evaluated. Additionally, its potential antimutagenic activity against several mutagens in the Ames test and its effects on CYP1A1 activity were assessed. Mangiferin (50–5000 μg/plate) did not increased the frequency of reverse mutations …
Antimutagenic effects of flavonoids, chalcones and structurally related compounds on the activity of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and…
1993
Abstract Sixty-four flavonoids were tested for their antimutagenic potencies with respect to IQ in Salmonella typhimurium TA98 and in part also towards MeIQ, MeIQx, Trp-P-2, and Glu-P-1 and in S. typhimurium TA100. Antimutagenic potencies were quantified by the inhibitory dose for 50% reduction of mutagenic activity (ID 50 ). A carbonyl function at C-4 of the flavane nucleus seems to be essential for antimutagenicity: two flavanols and four anthocyanidines were inactive. Again, five isoflavons, except biochanin A, were inactive. Within the other groups of 21 flavones, 16 flavonols and 16 flavanones the parent compounds flavone, flavonol, and flavonone possessed the highest antimutagenic pot…
Bisdihydrodiols, rather than dihydrodiol oxides, are the principal microsomal metabolites of tumorigenic trans-3,4-dihydroxy-3,4-dihydrodibenz[a,h]an…
1994
Several studies on metabolism and biological activity of tumorigenic dibenz[a,h]anthracene (DBA) and its derivatives have led to the conclusion that the M-region dihydrodiol, trans-3,4-dihydroxy-3,4-dihydro-DBA (DBA-3,4-dihydrodiol), is the precursor of the ultimate mutagenic and tumorigenic metabolite of DBA with the presumed structure of a bay-region dihydrodiol oxide. Incubations of DBA-3,4-dihydrodiol (50 microM) with the microsomal hepatic fraction of Sprague-Dawley rats pretreated with Aroclor 1254 yielded more than 13 metabolites upon separation by HPLC. anti-3,4-Dihydroxy-1,2-epoxy-1,2,3,4-tetrahydro-DBA [0.27 nmol/(nmol of P450.15 min)] could be identified for the first time by UV …
The 3,4-oxide is responsible for the DNA binding of benzo[ghi]perylene, a polycyclic aromatic hydrocarbon without a “classic” bay-region
2008
Abstract The polycyclic aromatic hydrocarbon (PAH) benzo[ghi]perylene (BghiP) lacks a “classic” bay-region and is therefore unable to form vicinal dihydrodiol epoxides thought to be responsible for the genotoxicity of carcinogenic PAHs like benzo[a]pyrene. The bacterial mutagenicity of BghiP increases considerably after inhibition of the microsomal epoxide hydrolase (mEH) indicating arene oxides as genotoxic metabolites. Two K-region epoxides of BghiP, 3,4-epoxy-3,4-dihydro-BghiP (3,4-oxide) and 3,4,11,12-bisepoxy-3,4,11,12-tetrahydro-BghiP (3,4,11,12-bisoxide) identified in microsomal incubations of BghiP are weak bacterial mutagens in strain TA98 of Salmonella typhimurium with 5.5 and 1.5…
Sulfotransferase-mediated chlorination of 1-hydroxymethylpyrene to a mutagen capable of penetrating indicator cells.
1990
Methylated polycyclic aromatic hydrocarbons are common in the human environment. Many of them are stronger carcinogens than their purely aromatic congeners. They may be metabolized to benzylic alcohols. We report here on biochemical and toxicological characteristics of 1-hydroxymethylpyrene (HMP), a typical representative of this class of compounds. Rat liver cytosol, fortified with 3'-phosphoadenosine-5'-phosphosulfate, converted HMP into its sulfate ester (HMPS), HMPS bound covalently to isolated DNA. In physiological buffer at 37 degrees C, HMPS had a half-life of 2 min, the major decomposition product being HMP. Thus, cyclic activation is possible. When Cl- anions were present at physio…
Assessment in vitro of cytogenetic and genotoxic effects of propolis on human lymphocytes
2012
We evaluated the genetic damage by ethanolic extract of propolis (EEP) induced to human lymphocytes which were exposed to increasing concentrations (0–2000 μg ml−1). The results indicated that EEP reduced significantly the mitotic index (MI) and proliferation index (PI) when high concentrations of EEP were used. Sister chromatid exchange (SCE) rates indicated that EEP could have genotoxic effects at high concentrations. Exposure of the cells to the amount of ethanol used as solvent did not alter either the MI and cell proliferation kinetics (CPK), or the rate of SCE. The results showed: (a) statistical increase in the percentage the cells with CAs and in the frequency of SCE at the highest …
Radioprotective activity and cytogenetic effect of resveratrol in human lymphocytes: An in vitro evaluation
2012
Trans-resveratrol is a natural occurring polyphenol, obtained from grapes and other berries. This compound has shown antioxidant, anti-inflammatory, immunostimulant or anti-carcinogenic properties. Our aim was to evaluate the radioprotective efficacy, in vitro, of trans-resveratrol against radiation-induced chromosomal damage and to study the genotoxicity and cytotoxicity of this polyphenol in cell cultures without irradiation. The study was carried out by the pre-treatment of human lymphocytes at concentrations from 0 to 219μM of trans-resveratrol. The results showed that all concentrations tested reduced radiation-induced chromosomal damage compared with cells with any treatment. Maximum …
Multiple activation pathways of benzene leading to products with varying genotoxic characteristics.
1989
Abstract Benzene and 13 potential metabolites were investigated for genotoxicity in Salmonella typhimurium and V79 Chinese hamster cells. In the presence of NADPH-fortified hepatic postmitochondrial fraction (S9 mix), benzene reverted his- S. typhimurium strains. The effect was strongest in strain TA1535. Among the potential metabolites, only the trans-1,2-dihydrodiol, in the presence of S9 mix, and the diol epoxides, in the presence and absence of S9 mix, proved mutagenic in this strain. The anti-diol epoxide was more potent than the syn-diastereomer. Both enantiomers of the anti-diastereomer showed similar activities. S9 mix did not appreciably affect the mutagenicity of the anti-diol epo…
The BIOSAFEPAPER project for in vitro toxicity assessments: preparation, detailed chemical characterisation and testing of extracts from paper and bo…
2008
International audience; Nineteen food contact papers and boards and one non-food contact board were extracted following test protocols developed within European Union funded project BIOSAFEPAPER. The extraction media were either hot or cold water, 95% ethanol or Tenax, according to the end use of the sample. The extractable dry matter content of the samples varied from 1200 to 11,800 mg/kg (0.8-35.5 mg/dm2). According to GC-MS the main substances extracted into water were pulp-derived natural products such as fatty acids, resin acids, natural wood sterols and alkanols. Substances extracted into ethanol particularly, were diisopropylnaphthalenes, alkanes and phthalic acid esters. The non-foo…