Home About us Contact
|
Home About us Contact | ||
|
|
||
Heterocyclic Amines (heterocyclic + amine)
Selected AbstractsEffects of Rosemary Extracts on the Reduction of Heterocyclic Amines in Beef PattiesJOURNAL OF FOOD SCIENCE, Issue 8 2006S.Y. Tsen ABSTRACT:, The effects of rosmarinic acid and a rosemary antioxidant powder were evaluated on the reduction and mutagenicity of MeIQx, PhIP, and comutagens norharman and harman in beef patties fried at 375 °F for 5 min each side and 400 °F for 7.5 min each side. Both rosemary extracts were found to effectively decrease the formation and overall mutagenic activity of heterocyclic amines (HCAs) due to their antioxidative characteristics. At the lower temperature, rosmarinic acid was able to reduce MeIQx by up to 64% and PhIP by 48%, while rosemary powder reduced the formations of MeIQx up to 69% and PhIP up to 66%. The effects of the rosemary extracts were more dramatic when cooking temperature and time were increased, as rosmarinic acid was able to reduce MeIQx formation up to 70% and PhIP up to 64%; also, rosemary powder significantly reduced MeIQx up to 57% and PhIP up to 77%. The overall mutagenic activity was evaluated by the Ames Salmonella assay and both rosemary extracts were capable of reducing mutagenicity in beef patties at the higher cooking temperature of 400 °F. At 375 °F there was an insignificant trend of the rosemary extracts decreasing the number of Salmonella revertants. There was no significant inhibiting effect by any of the rosemary extracts on the formation of either norharman and harman as measured in this study. [source] Formation and Human Risk of Carcinogenic Heterocyclic Amines Formed from Natural Precursors in MeatNUTRITION REVIEWS, Issue 5 2005Mark G. Knize A group of heterocyclic amines that are mutagens and rodent carcinogens form when meat is cooked to medium and well-done states. The precursors of these compounds are natural meat components: creatinine, amino acids, and sugars. Defined model systems of dry-heated precursors mimic the amounts and proportions of heterocyclic amines found in meat. Results from model systems and cooking experiments suggest ways to reduce their formation and, thus, reduce human intake. Human cancer epidemiology studies related to the consumption of well-done meat products are listed and compared in this review. [source] ChemInform Abstract: Reactions of 3-(Polyfluoroacyl)chromenones with Heterocyclic Amines: Novel Synthesis of Polyfluoroalkyl-Containing Fused Pyridines.CHEMINFORM, Issue 13 2010Anton Kotljarov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Reactions of 3-(Polyfluoroacyl)chromenones with Heterocyclic Amines: Novel Synthesis of Polyfluoroalkyl-Containing Fused Pyridines.CHEMINFORM, Issue 13 2010Anton Kotljarov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Human exposure to heterocyclic amine food mutagens/carcinogens: Relevance to breast cancer ,ENVIRONMENTAL AND MOLECULAR MUTAGENESIS, Issue 2-3 2002James S. Felton Abstract Heterocyclic amines produced from overcooked foods are extremely mutagenic in numerous in vitro and in vivo test systems. One of these mutagens, 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP), induces breast tumors in rats and has been implicated in dietary epidemiology studies as raising the risk of breast cancer in humans. Efforts in our laboratory and others have centered on defining the exposure to PhIP and other dietary mutagens derived from cooked food. We accomplish this by analyzing the foods with a series of solid-phase extractions and HPLC. We have developed an LC/MS/MS method to analyze the four major human PhIP metabolites (sulfates and glucuronides) following a single meal containing 27 ,g of cooking-produced PhIP in 200 g of grilled meat. Although the intake of PhIP was similar for each of eight women, the total amount excreted in the urine and the metabolite profiles differed among the subjects. It appears that adsorption (digestion) from the meat matrix, other foods in the diet, and genetic differences in metabolism may contribute to the variation. The four major metabolites that can be routinely assayed in the urine are N2 -OH-PhIP- N2 -glucuronide, PhIP- N2 -glucuronide, 4,-PhIP-glucuronide, and N2 -OH-PhIP- N3-glucuronide. This work is suited to investigate individual exposure and risk, especially for breast cancer, from these potent dietary mutagens. Environ. Mol. Mutagen. 39:112,118, 2002. Published 2002 Wiley-Liss, Inc. [source] Induction of Intestinal Tumors and Lymphomas in C57BL/6N Mice by a Food-borne Carcinogen, 2-Amino-l-methyl-6-phenylimidazo[4,5-b]pyridineCANCER SCIENCE, Issue 5 2002Masako Ochiai 2-Amino-l-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP) is the most abundant heterocyclic amine contained in cooked meat and fish. Although PhIP has been demonstrated to induce various types of tumors in rats, lymphomas predominated in mice using the CDF1 strain. To investigate the carcinogenic activity of PhIP on other organs in mice with a different genetic background, PhIP was administered to C57BL/6N mice. After a 40-week administration of 300 ppm of PhIP in a high-fat diet followed by continuous feeding with a high fat diet, C57BL/6N mice developed adenomas and adenocarcinomas in the small intestine, the incidences being 52% in males and 68% in females at weeks 95 and 70, respectively. Lymphomas of B-cell origin also developed in both sexes as frequently as in the CDF1 strain, incidences being 48% in males and 32% in females. Although the incidence in PhIP-treated female mice did not differ from that in the control mice, lymphomas developed significantly earlier in the PhIP-treated mice. The present study demonstrated that the intestinal tract is another potential target of PhIP-induced carcinogenesis in mice, and that the carcinogenic activity of PhIP could be affected by the genetic background of the animals. [source] Simultaneous determination of six non-polar heterocyclic amines in meat samples by supercritical fluid extraction,capillary electrophoresis under fluorimetric detectionELECTROPHORESIS, Issue 13 2010Fernando De Andrés Abstract A novel, sensitive and selective method for the separation and quantification of a group of non-polar heterocyclic amines (9H-pyrido-[3,4-b] indole, norharmane; 1-methyl-9H-pyrido-[3,4-b] indole, harmane; 2-amino-9H-pyrido-[2,3-b] indole, A,C; 2-amino-3-methyl-9H-pyrido-[2,3-b] indole, MeA,C; 3-amino-1,4-dimethyl-5H-pyrido-[4,3-b] indole, Trp-P-1 and 3-amino-1-methyl-5H-pyrido-[4,3-b] indole, Trp-P-2) in commercial meat samples has been developed. This methodology is faster than others previously described. The method is based on the combination of a supercritical fluid extraction procedure, followed by the analysis of the extracted plug by CE with fluorescence detection. The supercritical fluid extraction procedure was optimized for the clean-up of the samples and the extraction of the analytes. For the electrophoretic separation, the effect of composition, pH and concentration of buffer, organic modifier content, pressure and time of injection, capillary temperature and voltage applied were studied. A 10,mmol/L formic acid,ammonium formate,ACN (10%, v/v) solution at pH 1.5 was selected as the running electrolyte. With 5-s hydrodynamic injection, linear responses in the range from 100 to 1000,ng/mL and detection limits ranging from 15.9 to 28.1,ng/mL were obtained for different amines in less than 13,min. ACN,water (1:1 in volume) was used as a sample solvent. Fluorescence detection enhances the sensitivity and avoids interferences coming from non-fluorescent compounds present in the matrices of the sample extracts. [source] CEC separation of heterocyclic amines using methacrylate monolithic columnsELECTROPHORESIS, Issue 11 2007Elena Barceló-Barrachina Abstract Two methacrylate-based monolithic columns, one with a negatively charged group (sulfonic group) and another with a new monomer N,N -dimethylamino ethyl acrylate (DMAEA), were prepared and tested for the separation of basic compounds by CEC. This new monolithic stationary phase was prepared by the in situ polymerization of DMAEA with butyl methacrylate and ethylene dimethacrylate, using a ternary porogenic solvent consisting of water, 1-propanol and 1,4-butanediol. The performance of this column was evaluated by means of the analysis of a family of heterocyclic amines. Separation conditions such as pH, amount of organic modifier, ionic strength and elution mode (normal or counterdirectional flow) were studied. At the optimal running electrolyte composition, and using the counterdirectional mode, symmetrical electrochromatographic peaks were obtained, with the number of theoretical plates up to 30,000 and a good resolution between closely related peaks. The 2-acrylamido-2-methyl-1-propane-sulfonic acid column was used for CEC-MS, taking advantage of the compatibility of its elution mode (normal flow) with the MS coupling. [source] Effects of Rosemary Extracts on the Reduction of Heterocyclic Amines in Beef PattiesJOURNAL OF FOOD SCIENCE, Issue 8 2006S.Y. Tsen ABSTRACT:, The effects of rosmarinic acid and a rosemary antioxidant powder were evaluated on the reduction and mutagenicity of MeIQx, PhIP, and comutagens norharman and harman in beef patties fried at 375 °F for 5 min each side and 400 °F for 7.5 min each side. Both rosemary extracts were found to effectively decrease the formation and overall mutagenic activity of heterocyclic amines (HCAs) due to their antioxidative characteristics. At the lower temperature, rosmarinic acid was able to reduce MeIQx by up to 64% and PhIP by 48%, while rosemary powder reduced the formations of MeIQx up to 69% and PhIP up to 66%. The effects of the rosemary extracts were more dramatic when cooking temperature and time were increased, as rosmarinic acid was able to reduce MeIQx formation up to 70% and PhIP up to 64%; also, rosemary powder significantly reduced MeIQx up to 57% and PhIP up to 77%. The overall mutagenic activity was evaluated by the Ames Salmonella assay and both rosemary extracts were capable of reducing mutagenicity in beef patties at the higher cooking temperature of 400 °F. At 375 °F there was an insignificant trend of the rosemary extracts decreasing the number of Salmonella revertants. There was no significant inhibiting effect by any of the rosemary extracts on the formation of either norharman and harman as measured in this study. [source] MgBr2 -mediated opening of 2,3-three membered heterocyclic aminesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 3 2010Giuliana Righi Regio- and stereo-controlled opening of 2,3-epoxy amines and 2,3-aziridine amines by the commercially available MgBr2 is described. As reported, this new method could represent a general and useful approach for the preparation of promising intermediates. Moreover, in particular cases, the reaction evolves toward an interesting oxazolidin-2-one structure. J. Heterocyclic Chem., (2010). [source] The cleavage of heterocyclic compounds in organic synthesis II , Use of 5-nitroisatine for synthesis of various nitrogenous heterocyclesJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 4 2004Jan Hlavá The reactions of 5-nitroisatine were studied with nucleophiles like heterocyclic amines and alkaline hydroxide. With the use of alkaline hydroxide it was converted into 2-amino-5-nitrophenylglyoxylic acid 2, with piperidine, morpholine and carbethoxypiperazine to its amides 4a-4c or by oxidation to 5-nitroanthranilic acid 7. This acid was used for synthesis of 3-hydroxy-6-nitro-2-phenyl-1H -quinolin-4-one 10. Semicarbazone of 5-nitroisatine 11 was converted to 5-(2-amino-5-nitrophenyl)-2,3,4,5-tetrahydro-1,2,4-triazine-3,5-dione 12. Cyclocondensation of this compound to afford 8-nitro-2,3-dihydro-5H -[1,2,4]triazino-[5,6- b]indol-3-one 13 was unsuccessful. [source] A new chemical method of synthesis of modified nucleoside [32P]phosphatesJOURNAL OF LABELLED COMPOUNDS AND RADIOPHARMACEUTICALS, Issue 8 2008D. V. Yanvarev Abstract A simple method of chemical phosphorylation for modified nucleosides with [32P]orthophosphoric acid in the presence of BrCN is described. The yields of 5,-[32P]nucleoside monophosphates achieved are 50,65% at nominal specific radioactivities of ca. 1000,Ci/mmol. The mechanism of phosphorylation in the presence of heterocyclic amines is studied. Copyright © 2008 John Wiley & Sons, Ltd. [source] Characterization of ring-opening polymerization of genipin and pH-dependent cross-linking reactions between chitosan and genipinJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 10 2005Fwu-Long Mi Abstract In this study, a novel chitosan-based polymeric network was synthesized by crosslinking with a naturally occurring crosslinking agent,genipin. The results showed that the crosslinking reactions were pH-dependent. Under basic conditions, genipin underwent a ring-opening polymerization prior to crosslinking with chitosan. The crosslink bridges consisted of polymerized genipin macromers or oligomers (7 , 88 monomer units). This ring-opening polymerization of genipin was initiated by extracting proton from the hydroxyl groups at C-1 of deoxyloganin aglycone, followed by opening the dihydropyran ring to conduct an aldol condensation. At neutral and acidic conditions, genipin reacted with primary amino groups on chitosan to form heterocyclic amines. The heterocyclic amines were further associated to form crosslinked networks with short chains of dimmer, trimer, and tetramer bridges. An accompanied reaction of nucleophilic substitution of the ester group on genipin by the primary amine group on chitosan would occur in the presence of an acid catalysis. The extent in which chitosan gels crosslinked with genipin was significantly dependent on the crosslinking pH values: 39.9 ± 3.8% at pH 5.0, 96.0 ± 1.9% at pH 7.4, 45.4 ± 1.8% at pH 9.0, and 1.4 ± 1.0% at pH 13.6 (n = 5, p < 0.05). Owing to the different crosslinking extents and different chain lengths of crosslink bridges, the genipin-crosslinked chitosan gels showed significant difference in their swelling capability and their resistance against enzymatic hydrolysis, depending on the pH conditions for crosslinking. These results indicated a direct relationship between the mode of crosslinking reaction, and the swelling and enzymatic hydrolysis properties of the genipin-crosslinked chitosan gels. The ring-opening polymerization of genipin and the pH-dependent crosslinking reactions may provide a novel way for the preparation and exploitation of chitosan-based gels for biomedical applications. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1985,2000, 2005 [source] Correlations of dietary patterns with prostate healthMOLECULAR NUTRITION & FOOD RESEARCH (FORMERLY NAHRUNG/FOOD), Issue 1 2008Maria Stacewicz-Sapuntzakis Abstract Both genetic and environmental influences may be involved in etiology of prostate health and prostate cancer. These include ethnic origin, family history, smoking, and diet. Adiposity and excess energy intake are potentially distinct risk factors and positive associations with prostate cancer risk for both were observed among case-control and cohort studies. Some epidemiological studies support an association between dietary fat, particularly saturated or animal fats, and prostate cancer risk. Of these, several suggest reduced risk with low-fat diets high in n-3 fatty acids and increased risk with high-fat diets rich in n-6 fatty acids. Others suggested association with higher meat intake, possibly due to heterocyclic amines and polycyclic aromatic hydrocarbons, produced during grilling or frying. Positive association of prostate cancer risk with dairy intake could involve ,-methylacyl-CoA racemase activity (required for ,-oxidation of phytanic acid present in dairy products and red meat) or the suppression of vitamin D activity by calcium. Inverse associations were observed with dietary intake of plant foods. These include cereals, soy products, and fruit and vegetable sources of carotenoids. Numerous plant constituents may act synergistically in the prevention and inhibition of prostate disorders. These diet-risk associations may lead to future individualized diet recommendations based upon genetic polymorphisms. [source] Formation and Human Risk of Carcinogenic Heterocyclic Amines Formed from Natural Precursors in MeatNUTRITION REVIEWS, Issue 5 2005Mark G. Knize A group of heterocyclic amines that are mutagens and rodent carcinogens form when meat is cooked to medium and well-done states. The precursors of these compounds are natural meat components: creatinine, amino acids, and sugars. Defined model systems of dry-heated precursors mimic the amounts and proportions of heterocyclic amines found in meat. Results from model systems and cooking experiments suggest ways to reduce their formation and, thus, reduce human intake. Human cancer epidemiology studies related to the consumption of well-done meat products are listed and compared in this review. [source] Synthesis, structure and cytotoxicity of organoammonium selenites,APPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2002Edmunds Lukevics Abstract New selenites of different organic bases have been prepared by the reaction of selenium dioxide with aliphatic and heterocyclic amines in an aqueous medium. Their structure was confirmed by 1H, 13C and 77Se NMR data and, in the case of triethanolammonium hydroselenite [HN+(CH2CH2OH)3 HSeO3], by X-ray analysis. Most of these selenites have an expressed cytotoxic activity on theMG-22A (mouse hepatoma), HT-1080 (human fibrosarcoma), B16 (mouse melanoma), and Neuro 2A (mouse neuroblastoma) cell lines. The substances studied were also active in vivo against sarcomaS-180. Copyright © 2002 John Wiley & Sons, Ltd. [source] DNA Adduct Levels and Intestinal Lesions in Congenic Rapid and Slow Acetylator Syrian Hamsters Administered the Food Mutagens 2-Amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP) or 2-Amino-3-methylimidazo[4,5- f]quinoline (IQBASIC AND CLINICAL PHARMACOLOGY & TOXICOLOGY, Issue 6 2000Inger-Lise Steffensen Epidemiological studies indicate that rapid acetylators with a high intake of well-done red meat have an increased risk of colorectal cancer. Arylamine N -acetyltransferase enzymes (E.C. 2.3.1.5) activate carcinogenic heterocyclic amines found in the crust of fried meat via O -acetylation of their N -hydroxylamines to reactive intermediates that bind covalently to DNA and produce mutations. Syrian hamsters as well as humans express two N -acetyltransferase isozymes (NAT1 and NAT2) which differ in substrate specificity and genetic control. Nucleic acid substitutions in the NAT2 gene segregate individuals into rapid, intermediate and slow acetylator phenotypes. In the present paper, we examined the role of the polymorphic NAT2 acetylator genotype in carcinogenesis induced by the food mutagens 2-amino-1-methyl-6-phenylimidazo[4,5- b]pyridine (PhIP) or 2-amino-3-methylimidazo[4,5- f]quinoline (IQ) by comparing Syrian hamster lines congenic at the NAT2 locus. No differences were found between rapid and slow acetylator congenic hamsters in levels of intestinal PhIP-DNA adducts. In contrast to previous studies in rats, no carcinogen-related induction of the preneoplastic lesions aberrant crypt foci or tumors was found in the intestines of rapid and slow acetylator congenic Syrian hamsters administered PhIP or IQ. [source] Antioxidant and antigenotoxic activities of Angelica keiskei, Oenanthe javanica and Brassica oleracea in the Salmonella mutagenicity assay and in HCT116 human colon cancer cellsBIOFACTORS, Issue 4 2006Daejoong Kwon Abstract Epidemiological studies indicate that consumption of green-yellow vegetables rich in chlorophyll, vitamin C, vitamin E, and carotenoids reduce the risk of cancer. We sought to examine the antigenotoxic and antioxidant properties of chlorophyll-rich methanol extracts of Angelica keiskei, Oenanthe javanica, and Brassica oleracea (kale). In the Salmonella mutagenicity assay, A. keiskei caused dose-dependent inhibition against three heterocyclic amine mutagens in the presence of S9, O. javanica was antimutagenic only at the highest concentration in the assay (2 mg/plate), and B. oleracea showed no consistent inhibitory activity at non-toxic levels. None of the extracts were effective against three direct-acting mutagens in the absence of S9. Extracts of A. keiskei and, to a lesser extent O. javanica, inhibited two of the major enzymes that play a role in the metabolic activation of heterocyclic amines, based on ethoxyresorufin-O-deethylase and methoxyresorufin-O-demethylase assays in vitro. All three plant extracts were highly effective in assays which measured ferric reducing/antioxidant power, oxygen radical absorbance capacity, and Fe2+/H2O2 -mediated DNA nicking. Finally, using the ,comet' assay, all three plant extracts protected against H2O2 -induced genotoxic damage in human HCT116 colon cancer cells. These findings provide support for the antigenotoxic and antioxidant properties of chlorophyll-rich extracts of A. keiskei, O. javanica, and B. oleracea, through mechanisms that include inhibition of carcinogen activation and scavenging of reactive oxygen species. [source] | ||||||||||||||||