Search results for " AROMA"

Use of Mechanistic Information for Adequate Metabolic Design of Genotoxicity Studies and Toxicological Interactions of Drugs and Environmental Chemic…

1995

Microorganisms as well as mammalian cells used for mutagenicity investigations have little or no activities for metabolism of premutagens and precarcinogens, i.e. of compounds ultimately leading to mutations and cancer but first requiring metabolic activation. Therefore, to such cells an exogenous activating system is added, generally the postmitochondrial supernatant fraction of the liver homogenate and a NADPH-generating system (Ames et al. 1976). In this situation enzymes requiring cofactors other than NADP(H) are unlikely to be active. Thus, this metabolic system is rather artificial. Monooxygenases are active in this system. They, for example, convert polycyclic aromatic hydrocarbons t…

Sensitive and selective determination of metabolically formed trans -dihydrodiols and phenols of benzo[ a ]pyrene in water and urine samples by HPLC …

1998

A method has been developed to separate hydroxylated metabolites of the carcinogenic polycyclic aromatic hydrocarbon benzo[a]pyrene, i. e. trans-4,5-, 7,8-, 9,10-dihydrodiol and 1-, 3-, 7-, and 9-phenol, by HPLC with amperometric detection employing an isocratic methanol/water eluent (70:30, v/v) containing 0.5 g/L sulfuric acid and 1 g/L lithium perchlorate. Compared with the usually applied fluorescence (λex = 265 nm, λem = 460 nm) and ultraviolet (λ = 265 nm) detection, the amperometric technique is about 2–12 times more sensitive for the determination of all metabolites investigated. The method was applied to the determination of the seven metabolites of benzo[a]pyrene in different wate…

Synthesis of 1,3- and 2,3-Diglycosylated Indoles as Potential Trisaccharide Mimetics

2012

Diglycosylated heteroaromatics may serve as metabolically stable mimetics of trisaccharides. Herein, the preparation of several 1,3- and 2,3-diglycosylindoles by direct C-glycosylation of monoglycosylated precursors is described.

Chemical Carcinogenesis by Polycyclic Aromatic Hydrocarbons

1982

The realization that for a vast number of toxic effects, not the given compound itself was responsible but rather a metabolite that was produced from the compound, brought about an enormous step forward in chemical carcinogenesis and in toxicology in general (1–15). In chemical mutagenesis and in chemical carcinogenesis very often coumpounds, which by themselves are chemically inert, will produce mutagenic and carcinogenic effects. A prime example of this is the polycyclic aromatic hydrocarbons, which consisting of condensed aromatic rings are chemically inert, yet do produce mutagenic and carcinogenic effects. During the last 10 to 20 years researchers have started to realize that this is …

Mammalian Xenobiotic Epoxide Hydrolases

2002

Fate of Epdxides

1982

One of the most important reactions of epoxides appears to be the covalent binding to DNA which can lead to mutagenicity and is strongly suspected to be the primary lesion ultimately leading to initiation of cancer (Miller and Miller, 1974; Oesch, 1973; Jerina and Daly, 1974; Sims and Grover, 1974; Heidelberger, 1975; Gelboin et al., 1972). This review first describes structure-activity relationships for the mutagenicity of some epoxides and then outlines some findings on the metabolic control of the concentration of such epoxides by a number of enzymes.

Isolation, separation and quantification of metabolites of the carcinogenic polycyclic aromatic hydrocarbon dibenz(a,h)anthracene

1986

Crystal structure and reactivity of 2-chloro-3,5-dinitrothiophene and of 2-phenylsulphonyl-3,5-dinitrothiophene with nucleophiles

1988

The geometry obtained by a crystal structure determination of the title compounds, as compared with that of the analogous benzene derivatives, along with results of ab initio calculations, is used to interpret the different SNAr reactivities in some thiophene and benzene compounds. The smaller rotation of the nitro groups with respect to the aromatic rings observed in thiophene derivatives should be considered a relevant factor in the higher reactivity in the thiophene series.

Increased conformational rigidity of humic substances by oxidative biomimetic catalysis

2005

A synthetic water-soluble meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate of iron(III) chloride, Fe(TDCPPS)Cl, was employed as a biomimetic catalyst in the oxidative coupling of terrestrial humic materials. High-performance size-exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance (CPMAS-(13)C NMR), electron paramagnetic resonance (EPR), and diffuse reflectance infrared spectroscopy (DRIFT) were used to follow conformational and structural changes brought about in different humic materials by the oxidative coupling. Increase in apparent weight-average molecular weight (Mw(a)) occurred invariably for all humic substances with the oxidative polymerization catalyzed …

Impact flavor compounds in cooked rice cultivars from the Camargue area (France)

2010

International audience; Rice from two scented (Aychade, Fidji) and one nonscented (Ruille) cultivars from Camargue area (France) together with one Asian scented rice (Thai) were cooked and volatile compounds were extracted by dichloromethane/pentane (1;2, v/v) solvent mixture. 40 odorous compounds were noticed during GC-O analysis of the organic extracts, amongst which oct-1-en-3-one and 2-acetyl-1-pyrroline were altmost constantly perceived. Hierarchical cluster analysis (HCA) of perceived odours enabled to distinguish the groups of rice cultivars. 60 compounds were identified and quantified by GC-MS. New odour-active components of cooked rice were detected for the first time including oct…