Synthesis, Characterization, and Conformational Analysis of DNA Adducts from Methylated Anilines Present in Tobacco Smoke

Abstract

The ability of a series of aromatic amines present in tobacco smoke (2-, 3-, and 4-methylaniline, 2,3- and 2,4-dimethylaniline) to bind to DNA has been investigated by reacting N-(acyloxy)arylamines with dG, dG nucleotides, and DNA. The predominant products from reactions with dG and the nucleotides were characterized as N-(deoxyguanosin-8-yl)arylamines by spectroscopic and HPLC methods. HPLC and spectroscopic analyses of the modified DNA indicated the same adducts. Analyses of the 1H and 13C NMR spectra suggested that the adducts containing a methyl substituent ortho to the arylamine nitrogen had a higher percentage of syn conformers. This observation was supported by theoretical simulation studies that indicated substantial percentages of low energy syn conformers, increasing with the substitution pattern in the order para < meta < ortho < ortho,para < ortho,meta. The results demonstrate that, although single-ring arylamines are considered weak carcinogens, their electrophilic N-acetoxy derivatives, which are plausible metabolic intermediates, react with DNA to yield covalent adducts structurally identical to those derived from carcinogenic polyarylamines, such as 2-aminofluorene and 4-aminobiphenyl. Furthermore, the conformational perturbation induced in DNA by the formation of the monoarylamine-DNA adducts, especially those with an ortho substituent, may contribute to the biological activities of these compounds.

Assessment of the Medicines Lidocaine, Prilocaine, and Their Metabolites, 2,6-Dimethylaniline and 2-Methylaniline, for DNA Adduct Formation in Rat Tissues

“…Metabolic activation of DMA and MA is thought to involve N-hydroxylation and possible subsequent esterification with sulfate. These esters are highly reactive intermediates (Marques et al, 1996;Beland et al, 1997). In the present studies, the detected DNA adducts formed in rats and those obtained by reaction of the synthetic N-hydroxy derivatives with CT-DNA in vitro were chromatographically identical.…”

“…The crystals were washed with cold hexane, dried, and stored at Ϫ70°C until use. The mp were: N-hydroxy-DMA obs 92 to 95°C, lit 97 to 99°C (Bamberger and Rising, 1901b;Marques et al, 1997), and N-hydroxy-MA obs 40 to 42°C, lit 42 to 44°C (Bamberger and Rising, 1901a;Marques et al, 1996).…”

Effect of Substitution Site upon the Oxidation Potentials of Alkylanilines, the Mutagenicities of N-Hydroxyalkylanilines, and the Conformations of Alkylaniline−DNA Adducts

“…N-(Deoxyguanosin-8-yl)arylamines. dG-C8-Ar adducts were prepared by reacting dG with each N-acetoxy-or N-(pivaloyloxy)arylamine as detailed in Marques et al (21). Briefly, N-acetoxy-and N-(pivaloyloxy)arylamines were generated in situ in THF solution by low-temperature (-30 to -40°C ) reaction of their N-hydroxyarylamine precursors with acetyl cyanide and pivaloyl cyanide, respectively.…”

Differentiation of isomeric C8-substituted alkylaniline adducts of guanine by electrospray ionization and tandem quadrupole ion trap mass spectrometry

“…The C8-substituted guanine adducts were enriched by solid phase extraction and isolated by HPLC using a water:methanol gradient [7]. The concentrations of the guanine adducts were estimated from their UV absorbance using the max and values of the corresponding C8-substituted deoxyguanosine adducts [9,10]. The yields for the eight different dimethyl and ethyl aniline adducts synthesized in this study varied from 3-7%.…”