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4-methylimidazole

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https://www.readbyqxmd.com/read/27822321/genotoxicity-assessment-of-4-methylimidazole-regulatory-perspectives
#1
Takeshi Morita, Chikako Uneyama
4-Methylimidazole (4-MI) is formed as a result of the Maillard reaction process, and therefore is found in many foods and beverages. It is also found in soft drinks (i.e., cola) as a by-product in the production of some caramel colors. NTP bioassays revealed clear evidence of lung carcinogenicity of 4-MI in male and female mice, but not in rats and then IARC classified 4-MI as group 2B carcinogen. Genotoxicity studies with 4-MI were negative in the Ames tests and in the erythrocyte micronucleus tests with mice or rats...
2016: Genes and Environment: the Official Journal of the Japanese Environmental Mutagen Society
https://www.readbyqxmd.com/read/27546537/the-effects-of-4-mei-on-cell-proliferation-dna-breaking-and-dna-fragmentation
#2
M Norizadeh Tazehkand, A Moridikia, O Hajipour, E Valipour, T Timocin, M Topaktas, M B Yilmaz
4-Methylimidazole (4-MEI) is a color widely found in cola drinks, roasted foods, grilled meats, coffee and other foods. This study was aimed to investigate the 4-MEI effects on the cell proliferation, purified circular DNA and DNA from cells of rats treated with the 4-MEI.In this study, mouse 3T3-L1 cell line was treated with 4-MEI at concentrations of 300, 450, 600 and 750 µg/mL for 24 hours and 48 hours periods, after that cytotoxic effect of the 4-MEI was studied by MTT test. Also, the effect of 4-MEI on purified circular DNA (pET22b) was investigated by treating of the DNA with 4-MEI concentrations of 300, 450, 600 and 750 µg/ml...
2016: Bratislavské Lekárske Listy
https://www.readbyqxmd.com/read/27353523/carcinogenic-compounds-in-alcoholic-beverages-an-update
#3
REVIEW
Tabea Pflaum, Thomas Hausler, Claudia Baumung, Svenja Ackermann, Thomas Kuballa, Jürgen Rehm, Dirk W Lachenmeier
The consumption of alcoholic beverages has been classified as carcinogenic to humans by the International Agency for Research on Cancer (IARC) since 1988. More recently, in 2010, ethanol as the major constituent of alcoholic beverages and its metabolite acetaldehyde were also classified as carcinogenic to humans. Alcoholic beverages as multi-component mixtures may additionally contain further known or suspected human carcinogens as constituent or contaminant. This review will discuss the occurrence and toxicology of eighteen carcinogenic compounds (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, glyphosate, lead, 3-MCPD, 4-methylimidazole, N-nitrosodimethylamine, pulegone, ochratoxin A, safrole) occurring in alcoholic beverages as identified based on monograph reviews by the IARC...
October 2016: Archives of Toxicology
https://www.readbyqxmd.com/read/27230278/reductive-nitrosylation-of-nickel-ii-complex-by-nitric-oxide-followed-by-nitrous-oxide-release
#4
Somnath Ghosh, Hemanta Deka, Yuvraj B Dangat, Soumen Saha, Kuldeep Gogoi, Kumar Vanka, Biplab Mondal
Ni(ii) complex of ligand ( = bis(2-ethyl-4-methylimidazol-5-yl)methane) in methanol solution reacts with an equivalent amount of NO resulting in a corresponding Ni(i) complex. Adding further NO equivalent affords a Ni(i)-nitrosyl intermediate with the {NiNO}(10) configuration. This nitrosyl intermediate upon subsequent reaction with additional NO results in the release of N2O and formation of a Ni(ii)-nitrito complex. Crystallographic characterization of the nitrito complex revealed a symmetric η(2)-O,O-nitrito bonding to the metal ion...
June 21, 2016: Dalton Transactions: An International Journal of Inorganic Chemistry
https://www.readbyqxmd.com/read/27215965/delineating-the-antigenotoxic-and-anticytotoxic-potentials-of-4-methylimidazole-against-ethyl-methanesulfonate-toxicity-in-bone-marrow-cell-of-swiss-albino-mice
#5
M Norizadeh Tazehkand, M Topaktas, M B Yilmaz, O Hajipour, E Valipour
4-Methylimidazole (4-MEI) is mostly used in beverages and coloring food, dark beers and common brands of cola drinks, which may contain more than 100 μg of this compound per 12-ounce serving. This study was aimed to investigate the antigenotoxic and anticytotoxic effects of 4-MEI (100, 130 and 160 mg/kg) against ethyl methanesulfonate (240 mg/kg) using chromosome aberrations (CAs) and Mitotic index (MI) tests in bone marrow cells of Swiss Albino Mice at 12 h and 24 h treatment periods. So, the t-test was used for the statistical analysis...
2016: Bratislavské Lekárske Listy
https://www.readbyqxmd.com/read/27214063/azole-anion-based-aprotic-ionic-liquids-functional-solvents-for-atmospheric-co2-transformation-to-various-heterocyclic-compounds
#6
Zhimin Liu
The chemical transformation of atmospheric CO2 is of great significance and challenge. Herein azole anion-based aprotic ionic liquids (ILs) were designed via deprotonating weak proton donors (e.g., 2-methylimidazole, 4-methylimidazole, 2,4-dimethylimidazole) with tetrabutylphosphonium hydroxide ([Bu4P][OH]). It was found that these ILs, e.g., [Bu4P][2-MIm], could activate atmospheric CO2 through forming carbamates. The resultant carbamate intermediates could further react with various kinds of substrates including propargylic alcohols, 2-aminobenzonitriles, o-phenylenedimines and 2-aminothiophenol, producing α-alkylidene cyclic carbonates, quinazoline-2,4(1H,3H)-diones, benzimidazolones, benzothiazoline, respectively, in moderate to good yields...
May 23, 2016: Chemistry, An Asian Journal
https://www.readbyqxmd.com/read/26765635/evaluation-of-4-methylimidazole-in-the-ames-salmonella-test-using-induced-rodent-liver-and-lung-s9
#7
Carol Beevers, Richard H Adamson
4-methylimidazole (4-MeI) is formed by the interaction of ammonia with reducing sugars and low levels have been identified as a by-product in coffee, soy sauce, wine, dark beers, soft drinks, and caramel colors. The 4-MeI has been reported to induce alveolar/bronchiolar tumors in mice but not rats. Its mechanism of action is unlikely to be due to genotoxicity as 4-MeI does not induce mutation in Salmonella typhimurium and does not induce micronuclei in rodent peripheral erythrocytes or bone marrow cells. However, the question of whether genetically reactive intermediates could be formed via lung-specific metabolism has not previously been addressed...
January 2016: Environmental and Molecular Mutagenesis
https://www.readbyqxmd.com/read/26722899/proton-transport-in-imidazoles-unraveling-the-role-of-supramolecular-structure
#8
Tyler Cosby, Adam Holt, Philip J Griffin, Yangyang Wang, Joshua Sangoro
The impact of supramolecular hydrogen bonded networks on dynamics and charge transport in 2-ethyl-4-methylimidazole (2E4MIm), a model proton-conducting system, is investigated by broadband dielectric spectroscopy, depolarized dynamic light scattering, viscometry, and calorimetry. It is observed that the slow, Debye-like relaxation reflecting the supramolecular structure in neat 2E4MIm is eliminated upon the addition of minute amounts of levulinic acid. This is attributed to the dissociation of imidazole molecules and the breaking down of hydrogen-bonded chains, which leads to a 10-fold enhancement of ionic conductivity...
October 1, 2015: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/26692921/cytotoxic-effects-of-4-methylimidazole-on-bone-marrow-mesenchymal-stem-cells-in-vitro
#9
Fan Bu, Tao Li, Yanling Ding, Lingxian Sun, Tao Tu, Fangfang Zhou, Wenkai Qi, Xinyi Jiang, Jie Fang, Jiabo Hu, Wei Zhu, Xiaochun Sun
4-Methylimidazole (4-MI) is found in a great number of food products. The National Toxicology Program (NTP) revealed that 4-MI is carcinogenic and can also cause anemia and weight loss. Mesenchymal stem cells (MSCs) are able to support hematopoiesis and migrate to the site of tumors. To investigate whether 4-MI has an impact on MSCs, we have measured the ability of cell (osteoblast, adipocyte) proliferation, apoptosis, cell cycle, gene expression, migration and differentiation between control group and the 4-MI group...
2015: American Journal of Translational Research
https://www.readbyqxmd.com/read/26634952/assessment-of-chromosomal-aberration-in-the-bone-marrow-cells-of-swiss-albino-mice-treated-by-4-methylimidazole
#10
Mostafa Norizadeh Tazehkand, Mehmet Topaktas, Mehmet Bertan Yilmaz
4-Methylimidazole (4-MEI) is formed during the production of certain caramel coloring agents used in many food and drink products. It may also be formed during the cooking, roasting, or other processing of some foods and beverages. So it was unintentionally consumed in worldwide. This study was aimed to investigate the genotoxic and cytotoxic effects of 4-MEI using chromosome aberration (CA) and mitotic index (MI) in Swiss Albino mice. In this research, CA and MI of the mouse bone marrow cells were analyzed after treating the animals with 4-MEI (100, 130 and 160 mg/kg) for 12 h and 24 h treatment times...
2016: Drug and Chemical Toxicology
https://www.readbyqxmd.com/read/26605856/identification-of-new-and-distinctive-exposures-from-little-cigars
#11
Theodore P Klupinski, Erich D Strozier, David A Friedenberg, Marielle C Brinkman, Sydney M Gordon, Pamela I Clark
Little cigar mainstream smoke is less well-characterized than cigarette mainstream smoke in terms of chemical composition. This study compared four popular little cigar products against four popular cigarette products to determine compounds that are either unique to or more abundant in little cigars. These compounds are categorized as new or distinctive exposures, respectively. Total particulate matter samples collected from machine-generated mainstream smoke were extracted with methylene chloride, and the extracts were analyzed using two-dimensional gas chromatography-time-of-flight mass spectrometry...
February 15, 2016: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/26456664/evaluation-of-the-mode-of-action-of-mouse-lung-tumors-induced-by-4-methylimidazole
#12
George Cruzan, Jack R Harkema, Hiromi Hosako, Jennifer M Wasil, F Jay Murray
4-Methylimidazole (4-MEI) occurs in certain foods and beverages as a product of browning reactions. An increased incidence of lung tumors was reported in mice, but not rats, exposed to levels of 4-MEI in their diet that far exceed human dietary intake. This investigation evaluated the hypothesis that 4-MEI induces mouse lung tumors by the same mode of action (MOA) as styrene: CYP2F2 metabolic activation and increased BrdU labeling. Using styrene (200 mg/kg/day by gavage) as a positive control, histopathology and DNA synthesis (measured by BrdU incorporation) in the bronchiolar region were evaluated in: (1) a 5-day comparative toxicity study in C57BL/6 "wild type" and CYP2F2 "knock out" (KO) mice given 4-MEI at the same dietary concentrations used in the NTP cancer bioassay, and (2) a 13-week comparative toxicity study of C57BL/6 and B6C3F1 mice receiving 0, 1250 or 2500 ppm of 4-MEI in the diet for 6, 15, 34 and 91 days...
November 2015: Regulatory Toxicology and Pharmacology: RTP
https://www.readbyqxmd.com/read/26409957/short-communication-study-on-the-formation-of-2-methylimidazole-and-4-methylimidazole-in-the-maillard-reaction
#13
Xinlan Wu, Minghui Huang, Fansheng Kong, Shujuan Yu
2-Methylimidazole (2-MI) and 4-methylimidazole (4-MI) can be formed via the Maillard reaction during dairy thermal treatment. In this study, different reactions between α-dicarbonyl compounds (methylglyoxal, glyoxal) and aldehydes (formaldehyde, acetaldehyde) in the presence of ammonium sulfate were performed to investigate the formation of 2-MI and 4-MI. Two formation pathways of 2-MI and 4-MI were proposed. One pathway is that α-dicarbonyl compound reacts with equivalent ammonia to form an intermediate, while aldehyde reacts with equivalent ammonia to form another intermediate, then the 2 intermediates react together to generate 2-MI or 4-MI...
December 2015: Journal of Dairy Science
https://www.readbyqxmd.com/read/26363948/determination-of-imidazole-derivatives-by-micellar-electrokinetic-chromatography-combined-with-solid-phase-microextraction-using-activated-carbon-polymer-monolith-as-adsorbent
#14
Yung-Han Shih, Stephen Lirio, Chih-Keng Li, Wan-Ling Liu, Hsi-Ya Huang
In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed...
January 8, 2016: Journal of Chromatography. A
https://www.readbyqxmd.com/read/26312411/comparative-study-of-the-effect-of-glucosamine-and-free-ammonium-on-4-methylimidazole-formation
#15
COMPARATIVE STUDY
Pei Yu, Xian-Bing Xu, Shu-Juan Yu
The effect of glucosamine analogues (glucosamine and acetylglucosamine) and free ammonium on the formation of 4-methylimidazole (4-MeI) was investigated in the caramel model reaction systems. Methylglyoxal (MGO) was detected after derivatization by high-performance liquid chromatography with a diode array detector (HPLC-DAD). 4-MeI in the Maillard reaction was tested using a high-performance cation exchange chromatography coupled with APCI-MS (HPCEC-MS). The levels of pyrazines tested by gas chromatography (GC) coupled with MS were applied to mark the condensation reaction between dicarbonyls and free ammonium...
September 16, 2015: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/26073294/determination-of-2-methylimidazole-4-methylimidazole-and-2-acetyl-4-1-2-3-4-tetrahydroxybutyl-imidazole-in-licorice-using-high-performance-liquid-chromatography-tandem-mass-spectrometry-stable-isotope-dilution-analysis
#16
Marion Raters, Paul W Elsinghorst, Stephanie Goetze, Anna Dingel, Reinhard Matissek
A quick and selective analytical method was developed for the simultaneous quantitation of 2-methylimidazole, 4-methylimidazole, and 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl)imidazole, which are known to be formed by Maillard reactions. The methodology reported here employs stable-isotope dilution analysis (SIDA) using 4-methylimidazole-d6 and [(13)C6]-2-acetyl-4-(1,2,3,4-tetrahydroxybutyl)imidazole as internal standards. It was successfully applied in a model assay to show that the addition of ammonium chloride during the manufacture of licorice promotes imidazole formation depending on the added amount of ammonium chloride without the well-known impact of present caramel food colorings...
July 1, 2015: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/25832559/2-acetyl-4-tetrahydroxybutylimidazole-and-4-methylimidazole-in-caramel-colours-vinegar-and-beverages-in-china
#17
Liying Wang, Beibei Ren, Yinping Liu, Yang Lu, Fengqi Chang, Lixin Yang
A survey of 2-acetyl-4-tetrahydroxybutylimidazole (THI) and 4-methylimidazole (4-MeI) concentrations in caramel colours, vinegar and beverages from the Chinese market were performed by ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). In total, 117 samples, 78 caramel colour samples, 23 vinegar samples and 16 beverage samples, were investigated. The results indicated that 4-MeI was found in all samples. THI was found in a part of the samples and also the level range was lower compared to 4-MeI...
2015: Food Additives & Contaminants. Part B, Surveillance
https://www.readbyqxmd.com/read/25693062/caramel-color-in-soft-drinks-and-exposure-to-4-methylimidazole-a-quantitative-risk-assessment
#18
Tyler J S Smith, Julia A Wolfson, Ding Jiao, Michael J Crupain, Urvashi Rangan, Amir Sapkota, Sara N Bleich, Keeve E Nachman
Caramel color is added to many widely-consumed beverages as a colorant. Consumers of these beverages can be exposed to 4-methylimidazole (4-MEI), a potential carcinogen formed during its manufacture. California's Proposition 65 law requires that beverages containing 4-MEI concentrations corresponding to exposures that pose excess cancer risks > 1 case per 100,000 exposed persons (29 μg 4-MEI/day) carry warning labels. Using ultrahigh-performance liquid chromatography-tandem mass spectrometry, we assessed 4-MEI concentrations in 12 beverages purchased in California and a geographically distant metropolitan area (New York) in which warning labels are not required...
2015: PloS One
https://www.readbyqxmd.com/read/25688483/probing-peptide-cation-radicals-by-near-uv-photodissociation-in-the-gas-phase-structure-elucidation-of-histidine-radical-chromophores-formed-by-electron-transfer-reduction
#19
Huong T H Nguyen, Christopher J Shaffer, František Tureček
Electron transfer reduction of gas-phase ions generated from histidine-containing peptides forms stable cation-radicals that absorb light at 355 nm, as studied for AAHAR, AAHAK, DSHAK, FHEK, HHGYK, and HHSHR. Laser photodissociation of mass-selected cation-radicals chiefly resulted in loss of H atoms, contrasting dissociations induced by slow collisional heating. The 355 nm absorption was due to new chromophores created by electron transfer and radical rearrangements in the cation-radicals. The chromophores were identified by time-dependent density functional theory calculations as 2H,3H-imidazoline and 2H-dihydrophenol radicals, formed by hydrogen atom transfer to the histidine and tyrosine side chain groups, respectively...
March 12, 2015: Journal of Physical Chemistry. B
https://www.readbyqxmd.com/read/25671465/light-activated-protein-inhibition-through-photoinduced-electron-transfer-of-a-ruthenium-ii-cobalt-iii-bimetallic-complex
#20
Robert J Holbrook, David J Weinberg, Mark D Peterson, Emily A Weiss, Thomas J Meade
We describe a mechanism of light activation that initiates protein inhibitory action of a biologically inert Co(III) Schiff base (Co(III)-sb) complex. Photoinduced electron transfer (PET) occurs from a Ru(II) bipyridal complex to a covalently attached Co(III) complex and is gated by conformational changes that occur in tens of nanoseconds. Reduction of the Co(III)-sb by PET initiates displacement of the inert axial imidazole ligands, promoting coordination to active site histidines of α-thrombin. Upon exposure to 455 nm light, the rate of ligand exchange with 4-methylimidazole, a histidine mimic, increases by approximately 5-fold, as observed by NMR spectroscopy...
March 11, 2015: Journal of the American Chemical Society
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