Molecular modeling and anticholinesterasic activity of novel 2-arylaminocyclohexyl N,N-dimethylcarbamates

This work reports a detailed theoretical and experimental study of the novel isomer series cis- and trans-2-arylaminocyclohexyl N,N-dimethylcarbamates as potential inhibitors of cholinesterases. In vitro inhibition assay by Ellman's method with human blood samples showed that the new carbamates are selective to the inhibition of enzyme butyrylcholinesterase (BuChE) with maximum inhibition of 90% and IC50 of 6 and 8 mmol L-1 for the more actives compounds of the series. Molecular modeling studies point to significant differences for the conformations of the compounds in the active sites of enzymes BuChE and acetylcholinesterase (AChE). The results show that the compounds interact more effectively with the active site of enzyme BuChE since the carbamate group is close to the key residues of the catalytic triad.O presente trabalho reporta um estudo teórico e experimental detalhado das séries inéditas de isômeros cis- e trans-N,N-dimetilcarbamatos de cicloexila 2-arilaminossubstituídos como potenciais inibidores de colinesterases. Os testes de inibição in vitro, realizados através do método de Ellman em amostras de sangue humano, mostraram que os novos carbamatos apresentaram boa seletividade frente à inibição da enzima butirilcolinesterase (BuChE), com um máximo de inibição de 90% e IC50 de 6 e 8 mmol L-1 para os compostos mais ativos da série. Os estudos de modelagem molecular apontaram significantes diferenças entre as orientações destes compostos nos sítios ativos das enzimas BuChE e acetilcolinesterase (AChE). Os resultados mostraram que os compostos interagem de forma mais efetiva com o sítio ativo da enzima BuChE, pois o grupo carbamato está próximo aos resíduos chave da tríade catalítica.17981807Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Considerations Of The Presence Of Ethyl Carbamate In Foods And Alcoholic Beverages: A Review [consideracoes Sobre A Presenca De Carbamato De Etila Em Alimentos E Bebidas Alcoolicas: Uma Revisao]

The contamination of foods and alcoholic beverages by ethyl carbamate (EC), as well as its mechanism of formation are discussed in this review. EC induces mutagenic, teratogenic and carcinogenic effects in animals and has been considered as a potential carcinogenic substance for humans. In order to alert about the health risk due to the EC exposure, this paper deals about the occurrence of this contaminant in foods and alcoholic beverages, as well as its physical and chemical properties and analytical and toxicological aspects.1313142Allen, J.W., Stoner, G.D., Pereira, M.A., Backer, L.C., Sharief, Y., Hatch, G.G., Campbell, J.A., Nesnow, S., Tumorigenesis and genetoxicity of ethyl carbamate and vinyl carbamate in rodentcells1 (1986) Cancer Res., 46 (10), pp. 4911-4915. , BaltimoreAlmy, J., Ough, C.S., Urea analysis for wines (1989) J. Agric. Food Chem., 37 (4), pp. 968-970. , WashingtonAndrey, D., A simple gas chromatography method for the determination of ethyl carbamate in spirits (1987) Z. Lebensm. Unters.-Forsch., 185 (1), pp. 21-23. , HeidelbergAylott, R.I., McNeish, A.S., Walker, D.A., Determination of ethyl carbamate in distilled spirits using nitrogen specific and mass spectrometric detection (1987) J. Inst. Brew., 93 (5), pp. 382-386. , LondonBailey, R., North, D., Myatt, D., Determination of ethyl carbamate in alcoholic beverages by methylation and gas chromatography with nitrogen-phosphorus thermionic detection (1986) J. Chromatogr., 369 (1), pp. 199-202. , AmsterdamBalestrieri, F., Flori, A., Marini, D., Etilcarbammato in bevande alcoliche: Determinazione analitica (1991) Industrie delle Bevande, 20 (113), pp. 187-189. , PineroloBateman, A.J., The mutagenic action of urethane (1976) Mut. Res., 39 (1), pp. 75-96. , AmsterdamBattaglia, R., Conacher, H.B.S., Page, B.D., Ethyl carbamate (urethane) in alcoholic beverages and foods: A review (1990) Food Add. Contam., 7 (4), pp. 477-496. , LondonBoscolo, M., Lima-Neto, B.S., Franco, D.W., Determination of ethyl carbamate in brazilian sugar cane spirit and mandioca spirit by melti-dimensional HRGC-FID (1998), p. 37. , I Brazilian Meeting on the Chemistry of Food and Beverages, USP, Sao Carlos, SP, 1998Boyland, E., Nery, R., The metabolism of urethane and related compounds (1965) Biochem. J., 94, pp. 198-208. , LondonBrumley, W.C., Canas, B.J., Perfetti, G.A., Mossoba, M.M., Sphon, J.A., Corneliussen, P.E., Quantitation of ethyl carbamate in whiskey, sherry, port, and wine by gas chromatography/Tandem Mass Spectrometry using a triple quadrupole mass spectrometer (1988) Anal. Chem., 60 (10), pp. 975-978. , WashingtonBudavari, S., (1996) The Merck Index: An encyclopedia of chemicals, drugs, and biologicals, p. 1684. , Merck and CO., Inc., Whitehouse Station, 12(th) edCai, J., Myers, S.R., Hurst, H.E., Measurement of the Hemoglobin N-(2-oxoethyl)valine adduct in ethyl carbamate-treated mice1 (1995) Toxicol. App. Pharmacol., 131 (1), pp. 73-79. , New YorkCairns, T., Siegmund, E.G., Luke, M.A., Soose, G.M., Residue levels of ethyl carbamate in wines and spirits by gas chromatography and mass spectrometry/mass spectrometry (1987) Anal. Chem., 59 (17), pp. 2055-2059. , WashingtonCanas, B.J., Havery, D.C., Joe F.L., Jr., Rapid gas chromatographic method for determining ethyl carbamate in alcoholic beverages with thermal energy analyzer detection (1988) J. Assoc. Off. Anal. Chem., 71 (3), pp. 509-511. , WashingtonCanas, B.J., Havery, D.C., Joe F.L., Jr., Determination of ethyl carbamate in alcoholic beverages and soy sauce by gas chromatography with mass selective detection: Collaborative study (1994) J. Assoc. Off. Anal. Chem., 77 (6), pp. 1530-1536. , WashingtonCanas, B.J., Joe F.L., Jr., Diachenko, W., Burns, G., Ethyl carbamate in selected fermented foods and beverages (1989) J. Assoc. Off. Anal. Chem., 72 (6), pp. 873-876. , WashingtonChoy, W.N., Black, W., Mandakas, G., Mirro, E.J., Black, H.E., A pharmacokinetic study of ethanol inhibition of micronuclei induction by urethane in mouse bone marrow erythrocytes (1995) Mut. Res., 341 (4), pp. 255-263. , AmsterdamClegg, B.S., Frank, R., Ripley, B.D., Chapman, N.D., Braun, H.E., Sobolov, M., Wright, S.A., Contamination of alcoholic products by trace quantities of ethyl carbamate (urethane) (1988) Bull. Environ. Contam. Toxicol., 41 (6), pp. 832-837. , New YorkClemente, I.M., Il problema dell'uretano nelle bevande alcoliche (1990) Industrie delle Bevande, 19 (105), pp. 6-8. , Pinerolo, febConacher, H.B.S., Page, B.D., Ethyl carbamate in alcoholic beverages: A Canadian case history (1986) Proceedings of Euro Food Tox II, Interdisciplinary Conference on Natural Toxicants in Food, Zurich, pp. 237-242Conacher, H.B.S., Page, D., Lau, B.P.Y., Lawrence, J.F., Bailey, R., Calway, P., Hanchay, J.P., Mori, B., Capillary column gas chromatographic determination of ethyl carbamate in alcoholic beverages with confirmation by gas chromatography/mass spectrometry (1987) J. Assoc. Off Anal. 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Toxicol. Environm. Health, 15 (5), pp. 635-654. , WashingtonFunch, F., Lisbjerg, S., Analysis of ethyl carbamate in alcoholic beverages (1988) Z. Lebensm. Unters.-Forsch., 186 (1), pp. 29-32. , HeidelbergGuengerich, F.P., Kim, D.H., Enzymatic oxidation of ethyl carbamate to vinil carbamate and its role as an intermediate in the formation of 1,N6-ethenoadenosine (1991) Chem. Res. Toxicol., 4 (4), pp. 413-421. , WashingtonGuengerich, F.P., Kim, D.H., Iwasaki, M., Role of human cytochrome P-450 IIE1 in the oxidation of many low molecular weight cancer suspects (1991) Chem. Res. 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Japan, 28 (5), pp. 330-335. , TokyoLeithauser, M.T., Liem, A., Stewart, B.C., Miller, E.C., Miller, J.A., 1,N6-Ethenoadenosine formation, mutagenicity and murine tumor induction as indicators of the generation of an electrophilic epoxide metabolite of the closely related carcinogens ethyl carbamate (urethane) and vinyl carbamate (1990) Carcinogenesis, 11 (3), pp. 463-473. , OxfordLofroth, G., Gejvall, T., Diethyl pyrocarbonate. Formation of urethane in treated beverages (1971) Science, 174, pp. 1248-1250. , WashingtonLutz, W.K., Schlatter, J., Chemical carcinogens and overnutrition in diet-related cancer (1992) Carcinogenesis, 13 (12), pp. 2211-2216. , OxfordMartindale, (1982) The extra pharmacopoeia. 28(th) edition, p. 230. , The Pharmaceutical Press, LondonMatsudo, T., Aoki, T., Abe, K., Fukuta, N., Higuchi, T., Sasaki, M., Uchida, K., Determination of ethyl carbamate in soy sauce and its possible precursor (1993) J. Agric. 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Cholinesterases Inhibition by Novel cis

The present study describes the synthesis, assessment of the anticholinesterase activity and the inhibition type of novel cis- and trans-3-arylaminocyclohexyl N,N-dimethylcarbamates. In vitro inhibition assay by Ellman's method with human blood samples showed that carbamates were selective for butyrylcholinesterase (BuChE) with compound concentration that inhibits 50% of enzyme activity (IC50) between 0.11 and 0.18 mmol L-1. cis- and trans-3-(4-Methoxyphenylamino)cyclohexyl N,N-dimethylcarbamate hydrochloride were the most active for BuChE, showing that the presence of methoxyl group enhanced the anticholinesterase activity. The enzyme kinetics studies indicate a noncompetitive inhibition against acetylcholinesterase (AChE) and mixed type inhibition for BuChE. Molecular modeling studies confirm the ability of carbamates to bind both the active and peripheral sites of the BuChE

Identification of Aspergillus flavus isolates as potential biocontrol agents of aflatoxin contamination in crops

Aspergillus flavus, a haploid organism found worldwide in a variety of crops, including maize, cottonseed, almond, pistachio, and peanut, causes substantial and recurrent worldwide economic liabilities. This filamentous fungus produces aflatoxins (AFLs) B1 and B2, which are among the most carcinogenic compounds from nature, acutely hepatotoxic and immunosuppressive. Recent efforts to reduce AFL contamination in crops have focused on the use of nonaflatoxigenic A. flavus strains as biological control agents. Such agents are applied to soil to competitively exclude native AFL strains from crops and thereby reduce AFL contamination. Because the possibility of genetic recombination in A. flavus could influence the stability of biocontrol strains with the production of novel AFL phenotypes, this article assesses the diversity of vegetative compatibility reactions in isolates of A. flavus to identify heterokaryon self-incompatible (HSI) strains among nonaflatoxigenic isolates, which would be used as biological controls of AFL contamination in crops. Nitrate nonutilizing (nit) mutants were recovered from 25 A. flavus isolates, and based on vegetative complementation between nit mutants and on the microscopic examination of the number of hyphal fusions, five nonaflatoxigenic (6, 7, 9 to 11) and two nontoxigenic (8 and 12) isolates of A. flavus were phenotypically characterized as HSI. Because the number of hyphal fusions is reduced in HSI strains, impairing both heterokaryon formation and the genetic exchanges with aflatoxigenic strains, the HSI isolates characterized here, especially isolates 8 and 12, are potential agents for reducing AFL contamination in cropsConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CAPES (Coordenação de Aperfeiçoamento de Pessoal de Nível Superior

Maize (Zea Mays L) landraces from the southern region of Brazil: contamination by Fusarium sp, zearalenone, physical and mechanical characteristics of the kernels

This work had as objectives the study of the physical and mechanical characteristics of maize kernels in relation to the contamination by Fusarium sp and by zearalenone in twenty landraces of maize from the southern region of Brazil. From the analyzed samples, 60 % has been considered to have a hard endosperm type and 40 % an intermediary one. A correlation between the physical and mechanical variables was observed as an indication that the higher is the proportion of hard endosperm, more dense will be the kernel and more force for its rupture will be necessary. The level of contamination by Fusarium sp was between 5.5 and 24.75% among the analyzed grains, correlating positively with the flotation index, indicating that the landraces of maize with a softer endosperm can present a higher contamination by this genus. The presence of zearalenone was verified in 75 % of the samples, in concentrations varying from 50 to 640 µg kg-1.<br>Este trabalho teve por objetivos verificar as características físicas, mecânicas, contaminação por Fusarium sp e por zearalenona e suas relações, em vinte variedades crioulas de milho da região sul do Brasil. Verificou-se que das amostras analisadas, 60% foram consideradas como possuidoras de endosperma do tipo duro e 40% com endosperma do tipo intermediário. As variáveis físicas e mecânicas se correlacionaram, indicando que quanto maior a proporção de endosperma vítreo, mais denso e maior a força necessária até a ruptura do grão. A contaminação por Fusarium sp esteve entre 5,5% e 24,75% nos grãos analisados, correlacionando-se positivamente com o índice de flotação, indicando que as variedades crioulas de milho com uma maior proporção de endosperma macio podem apresentar uma maior contaminação por Fusarium sp, sugerindo-se a utilização de variedades crioulas com a textura do endosperma predominantemente vítrea. A presença de zearalenona foi verificada em 75% das amostras, em concentrações que variaram de 50 a 640 µg kg-1