La tyrosinase est une métalloenzyme à cuivre de type 3 impliquée dans la biosynthèse de la mélanine. La compréhension et la modulation de cette enzyme ont plusieurs enjeux importants, notamment dans les domaines médical, cosmétique et agroalimentaire.A travers la synthèse et l'évaluation de composés actifs, sur la réaction catalysée par la tyrosinase, des relations structures activités ont pu être mises en lumière sur des tyrosinases provenant d'espèces différentes.L'ensemble des molécules analysées a permis de découvrir des inhibiteurs prometteurs de la tyrosinase mais aussi des substrats alternatifs et des activateurs hyperboliques. Cette grande variété d'activité révèle la présence d'un site allostérique sur la tyrosinase d'Agaricus bisporus.Parallèlement, la synthèse d'un analogue d'un inhibiteur compétitif de la tyrosinase (le HOPNO), marquée à l'azote 15, a été réalisée. Cette molécule sonde servira à déterminer, par RMN paramagnétique, le mode de fixation de ce fragment dans le site actif. / Tyrosinase is a copper metalloenzyme type 3 involved in the biosynthesis of melanin.Understanding and modulation of this enzyme have several important issues, including the medical, cosmetic and food .Through the synthesis and evaluation of active compounds, the reaction catalyzed by tyrosinase, structures relations activities have been highlighted on tyrosinases from different species. All molecules analyzed revealed promising inhibitors of tyrosinase but also alternative substrates and activators hyperbolic. This wide variety of activity indicates the presence of an allosteric site on tyrosinase of Agaricus bisporus. Meanwhile, the synthesis of an analogue of a competitive inhibitor of tyrosinase (the HOPNO), labeled with 15 N, was carried out. This probe molecule used to determine, by paramagnetic NMR, the binding mode of the fragment in the active site.

Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-08T13:08:54Z No. of bitstreams: 1 ligiasouzadasilveira.pdf: 3371764 bytes, checksum: 67a4072a1bdf7b995edacdda00021e31 (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: on 2016-08-08T13:56:41Z (GMT) / Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-08T14:07:53Z No. of bitstreams: 1 ligiasouzadasilveira.pdf: 3371764 bytes, checksum: 67a4072a1bdf7b995edacdda00021e31 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-08T14:10:22Z (GMT) No. of bitstreams: 1 ligiasouzadasilveira.pdf: 3371764 bytes, checksum: 67a4072a1bdf7b995edacdda00021e31 (MD5) / Made available in DSpace on 2016-08-08T14:10:22Z (GMT). No. of bitstreams: 1 ligiasouzadasilveira.pdf: 3371764 bytes, checksum: 67a4072a1bdf7b995edacdda00021e31 (MD5) Previous issue date: 2013-07-29 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O interesse pela obtenção de chalconas e suas respectivas auronas deve-se as inúmeras propriedades biológicas descritas para estes compostos como atividade antibacteriana, antiinflamatória, antifúngica, antiviral, antitumoral e principalmente pelo promissor papel nas atividades antiparasitárias. Este trabalho descreve a síntese de derivados chalcona e aurona, sendo dez compostos inéditos, a saber: três análogos de chalconas e sete análogos de auronas. Foram obtidos vinte e um análogos de chalcona através de reações de condensação de Claisen-Schimdt, pela reação de sete aldeídos alquilados e dezenove aldeídos comerciais, com a 2-hidroxi-acetofenona ou 4-flúor-2-hidroxi-acetofenona. Para a obtenção das chalconas de cadeia longa o 4-hidroxibenzaldeído foi alquilado com os haletos de alquila, 1-cloroexano, 1cloro-octano, 1-bromononano, 1-clorodecano, 1-clorododecano, 1-clorotetradecano e 1-bromo-propargila. Foram obtidas dezessete auronas pela ciclização oxidativa das chalconas previamente sintetizadas em reação com Hg(OAc)2 em piridina. Em todas as reações não foram detectadas a formação da flavona correspondente. As chalconas foram obtidas na sua configuração E, em uma conformação s-cis confirmado por difração de raio-x do composto (E)-2’-hidroxichalcona. A configuração Z para dupla ligação de auronas foi inferida por comparação com dados da literatura. As chalconas e auronas sintetizadas foram avaliadas quanto as suas atividades citotóxicas, anti-inflamatórias e antioxidantes e as mesmas estão sendo avaliadas quanto à sua atividade esquistossomicida. / The interest in obtaining chalcones and their aurones due to the numerous biological properties described for these compounds as antibacterial, anti-inflammatory, antifungal, antiviral, antitumor activities and especially the promising role in antiparasitic activities. Thus, this work describes the synthesis of chalcone and aurone derivatives, resulting in ten novel compounds being three analogues of chalcones and seven analogues of aurones. Were obtained twenty-one chalcone analogues by Claisen-Schmidt condensation by reaction of seven long chain aldehydes and nineteen commercial aldehydes with 2-hydroxy-acetophenone or 4-fluoro-2-hydroxy-acetophenone. For the obtention of long chain chalcones, the 4-hydroxybenzaldehyde was alkylated in reaction with alkyl halides, 1-chlorohexane, 1-chlorooctane, 1-bromononane, 1-chlorodecane, 1-chlorododecane, 1-clorotetradecane and 1-bromopropargyl. Were obtained seventeen aurones by oxidative cyclization from chalcones previously synthesized in reaction with Hg(OAc)2 and pyridine. In all reactions were not detected the formation of the corresponding flavone. The chalcones were obtained in E configuration in s-cis conformation. This fact was confirmed by X-ray diffraction of the compound (E)-2'-hydroxichalcone. The configuration Z for aurones was inferred by comparison with literature data. Chalcones and aurones synthesized were evaluated for their cytotoxic activities, antiinflammatory and antioxidant properties and the same are being evaluated for their activity schistosomicidal.