Detection of DNA adducts originating from 1-methoxy-3-indolylmethyl glucosinolate using isotope-dilution UPLC-ESI-MS/MS.

1-Methoxy-3-indolylmethyl (1-MIM) glucosinolate, present at substantial levels in several food crops (e.g., broccoli and cabbage), forms DNA adducts in vitro and is mutagenic to bacterial and mammalian cells after activation by the plant enzyme myrosinase.

Synthesis, absolute configuration, and bacterial mutagenicity of the 8 stereoisomeric vicinal diol epoxides at the terminal benzo ring of carcinogenic dibenz[a,h]anthracene.

The synthesis of the 8 possible stereoisomeric diol epoxides (DEs) at the terminal benzo ring of carcinogenic dibenz[a,h]anthracene (DBA) is reported. trans-3,4-Dihydroxy-3,4-dihydro-DBA (1) afforded the 4 bay region DEs: the enantiomeric pairs of the anti diastereomers (+)-3/(-)-3 and of the syn diastereomers (-)-4/(+)-4, respectively. trans-1,2-Dihydroxy-1,2-dihydro-DBA (2) served as precursor of the 4 reverse DEs: the enantiomeric pairs of the anti diastereomers (+)-5/(-)-5 and of the syn diastereomers (-)-6/(+)-6, respectively.

DNA repair and replication influence the number of mutations per adduct of polycyclic aromatic hydrocarbons in mammalian cells.

Polycyclic aromatic hydrocarbons (PAH) are an important class of environmental contaminants many of which require metabolic activation to DNA-reactive bay or fjord region diolepoxides (DE) in order to exert their mutagenic and carcinogenic effects. In this study, the mutagenicity of the bay region diolepoxides (+)-anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) and (±)-anti-1,2-dihydroxy-3,4-epoxy-1,2,3,4-tetrahydrodibenzo[a,h]anthracene (DBADE) and the fjord region diolepoxides (±)-anti-11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydrodibenzo[a,l]-pyrene (DBPDE) and (±)-anti-3,4-dihydroxy-1,2-epoxy-1,2,3,4-tetrahydrobenzo[c]-phenanthrene (BPhDE) was compared in nucleotide excision repair (NER) proficient and deficient hamster cell lines. The (32)P-postlabelling assay was applied to analyze DNA adduct levels and the Hprt gene mutation assay for monitoring mutations.

Structural requirements for mutation formation from polycyclic aromatic hydrocarbon dihydrodiol epoxides in their interaction with food chemopreventive compounds.

Chinese hamster V79 cells were used to investigate the protective effect of four known antimutagens present in food, chlorophyllin (CHL), ellagic acid (EA), epigallocathechingallate (EGCG) and benzylisothiocyanate (BITC), against potent mutagenic polycyclic aromatic hydrocarbon diol epoxides (PAH-DE) derived from benzo[a]pyrene (BP), dibenzo[a,h]anthracene (DBA), dibenzo[a,l]pyrene (DBP), and benzo[c]phenanthrene (BPh) known to be deposited on crops from polluted ambient air or formed during food processing. As fjord-region PAH-DE are more toxic and mutagenic than bay-region PAH-DE, we adjusted the concentrations of PAH-DE to induce approximately the same levels of adducts. The studies were performed using an assay indicating toxicity in terms of reduced cell proliferation together with the V79 Hprt assay for monitoring mutant frequencies.

1-Methoxy-3-indolylmethyl glucosinolate; a potent genotoxicant in bacterial and mammalian cells: Mechanisms of bioactivation.

1-Methoxy-3-indolylmethyl (1-MIM) glucosinolate, contained in many Brassica vegetables, is strongly mutagenic in Salmonella typhimurium TA100 when activated by myrosinase. Here, we describe the synthesis and evaluation of two breakdown products, 1-MIM nitrile and 1-MIM alcohol. 1-MIM nitrile was not mutagenic and 1-MIM alcohol showed low direct mutagenicity in TA100, indicating that other breakdown products mediated the mutagenicity of 1-MIM glucosinoate/myrosinase in this strain.

Probenecid, an inhibitor of transmembrane organic anion transporters, alters tissue distribution of DNA adducts in 1-hydroxymethylpyrene-treated rats.

1-Methylpyrene (1-MP), an abundant alkylated polycyclic aromatic hydrocarbon, is activated by side-chain hydroxylation to 1-hydroxymethylpyrene (1-HMP) and subsequent sulfo-conjugation to electrophilic 1-sulfooxymethylpyrene (1-SMP). In rats, this activation mainly occurs in liver. 1-SMP may react with hepatic DNA or be exported into the blood circulation to reach other tissues, in particular kidneys.

Renal organic anion transporters OAT1 and OAT3 mediate the cellular accumulation of 5-sulfooxymethylfurfural, a reactive, nephrotoxic metabolite of the Maillard product 5-hydroxymethylfurfural.

5-Hydroxymethylfurfural (HMF) is formed when sugars are acidified or heated. It is present at high levels in numerous foods. HMF is inactive in standard genotoxicity tests, but can be metabolized to a chemically reactive intermediate, 5-sulfooxymethylfurfural (SMF), which is mutagenic and carcinogenic.

Conversion of the common food constituent 5-hydroxymethylfurfural into a mutagenic and carcinogenic sulfuric acid ester in the mouse in vivo.

5-Hydroxymethylfurfural (HMF), formed by acid-catalyzed dehydration and in the Maillard reaction from reducing sugars, is found at high levels in numerous foods. It was shown to initiate colon aberrant crypt foci in rats and skin papillomas and hepatocellular adenomas in mice. HMF is inactive in in vitro genotoxicity tests using standard activating systems but is activated to a mutagen by sulfotransferases.

Time course of hepatic 1-methylpyrene DNA adducts in rats determined by isotope dilution LC-MS/MS and 32P-postlabeling.

The alkylated polycyclic aromatic hydrocarbon 1-methylpyrene is a carcinogen in rodents and has been detected in various environmental matrices and foodstuffs. It is activated metabolically by benzylic hydroxylation to 1-hydroxymethylpyrene followed by sulfoconjugation to yield electrophilic 1-sulfooxymethylpyrene (1-SMP) that is prone to form DNA adducts. An LC-MS/MS method using multiple reaction monitoring (MRM) of fragment ions has been developed for specific detection and quantification of N (2)-(1-methylpyrenyl)-2'-deoxyguanosine (MP-dGuo) and N (6)-(1-methylpyrenyl)-2'-deoxyadenosine (MP-dAdo) formed in DNA in the presence of 1-SMP.

Detoxification of promutagenic aldehydes derived from methylpyrenes by human aldehyde dehydrogenases ALDH2 and ALDH3A1.

Methylated polycyclic aromatic hydrocarbons can be metabolically activated via benzylic hydroxylation and sulpho conjugation to reactive esters, which can induce mutations and tumours. Yet, further oxidation of the alcohol may compete with this toxification. We previously demonstrated that several human alcohol dehydrogenases (ADH1C, 2, 3 and 4) oxidise various benzylic alcohols (derived from alkylated pyrenes) to their aldehydes with high catalytic efficiency.

Directing role of organic anion transporters in the excretion of mercapturic acids of alkylated polycyclic aromatic hydrocarbons.

Excretion of mercapturic acids of a xenobiotic is a good indicator for the formation of electrophilic intermediates. However, the route of excretion, urine or feces, is important for usage of a given mercapturic acid as a biomarker in humans. In the present study we investigated the excretion routes of 1-methylpyrenyl mercapturic acid (MPMA) and 1,8-dimethylpyrenyl mercapturic acid (DMPMA) formed from the corresponding benzylic alcohols in rats.

Formation of estrogenic metabolites of benzo[a]pyrene and chrysene by cytochrome P450 activity and their combined and supra-maximal estrogenic activity.

Metabolism of polycyclic aromatic hydrocarbons (PAHs) has been studied intensively, and potential metabolites with estrogenic activity have been identified previously. However, little attention has been paid to the metabolic pathways in mammalians and to the combined effect of individual metabolites. Several hydroxylated metabolites of benzo[a]pyrene (BaP) and chrysene (CHN) were formed by rat liver microsomal cytochrome P450 (CYP) activity, some of which possess estrogenic activity.

Activation of 3-nitrobenzanthrone and its metabolites by human acetyltransferases, sulfotransferases and cytochrome P450 expressed in Chinese hamster V79 cells.

3-nitrobenzanthrone (3-NBA) is a potent mutagen and suspected human carcinogen identified in diesel exhaust and ambient air pollution. 3-aminobenzanthrone (3-ABA), 3-acetylaminobenzanthrone (3-Ac-ABA) and N-acetyl-N-hydroxy-3-aminobenzanthrone (N-Ac-N-OH-ABA) have been identified as 3-NBA metabolites. Recently we found that 3-NBA and its metabolites (3-ABA, 3-Ac-ABA and N-Ac-N-OH-ABA) form the same DNA adducts in vivo in rats.

Microsomal activation of dibenzo[def,mno]chrysene (anthanthrene), a hexacyclic aromatic hydrocarbon without a bay-region, to mutagenic metabolites.

Metabolically formed dihydrodiol epoxides in the bay-region of polycyclic aromatic hydrocarbons are thought to be responsible for the genotoxic properties of these environmental pollutants. The hexacyclic aromatic hydrocarbon dibenzo[def,mno]chrysene (anthanthrene), although lacking this structural feature, was found to exhibit considerable bacterial mutagenicity in histidine-dependent strains TA97, TA98, TA100, and TA104 of S. typhimurium in the range of 18-40 his(+)-revertant colonies/nmol after metabolic activation with the hepatic postmitochondrial fraction of Sprague-Dawley rats treated with Aroclor 1254.