Foods contaminated with pathogens are common sources of illness. Currently the most common and sensitive rapid detection methods involve the PCR. However, food matrices are complex and limit the sensitivity and thus detection limits. The use of coated activated carbon can effectively facilitate the removal of PCR inhibitors while not binding targeted bacterial cells from food samples. With activated carbon coated with the optimal amount of milk proteins a cell recovery at pH 7.0 of 95.7 ± 2.0% was obtained, compared to control uncoated activated carbon, which yielded a cell recovery of only 1.1 ± 0.8%. In addition, the milk protein coated activated carbon (MP-CAC) was able to absorb similar amounts of soluble compounds as uncoated activated carbon with the exception of bovine hemoglobin. This is evidence that the use of milk proteins to coat activated carbon should therefore serve as a suitable replacement for bentonite in the coating of activated carbon, which has previously been used for the removal of PCR inhibitors from food. The high amount of PCR inhibitors present in ground beef is a major factor that affects molecular based techniques such as the PCR for the detection of Salmonella enterica. In this study, a novel detection system was developed for eliminating PCR inhibitors and increasing the recovery of S. enterica in ground beef samples with the use of β-cyclodextrin and MP-CAC without enrichment of samples. invA, present in all Salmonella, was used as target the gene in the conventional PCR protocol. With ground beef containing 7.0, 15, and 27 % fat, treatment of stomached samples with 5.0, 10, and 15 % β-cyclodextrin respectively followed by treatment with MP-CAC, resulted in detection of 3 CFU/g which is equivalent to 75 CFU in 25 g samples. The total assay time was 4.5 hr. The methodology described in this study for the detection of S. enterica in ground beef without enrichment is rapid, sensitive, and has the potential to be applied to a number of food matrices to detect low numbers of food-borne bacterial pathogens before product is shipped to prevent costly recalls.

>Magister Scientiae - MSc / Glucose oxidase (GOx) and horseradish peroxidase (HRP) are important enzymes for the development of amperometric enzyme linked immunosensors. The selectivity of each enzyme towards its analyte deepens its importance in determining the sensitivity of the resultant immunosensor. In designing immunosensors that have customized transducer surfaces, the incorporation with FAD and iron based enzymes ensures that electron kinetics remains optimal for electrochemical measurement. Various different immobilization strategies are used to produce response signals directly proportional to the concentration of analyte with minimal interferences. The combination of self-assembled monolayers and supramolecular chemistry affords stability and simplicity in immunosensor design. In this work, two electrochemical strategies for the detection of human chorionic gonadotropin(hCG) is presented. This involves the modification of a gold surface with a thiolated β-cyclodextrin epichlorohydrin polymer (βCDPSH) to form a supramolecular inclusion complex with ferrocene (Fc)-functionalised carboxymethyl cellulose polymer (CMC). Cyclic voltammetry indicated that ferrocene is in close proximity to the electrode surface due to the supramolecular complex formed with βCDPSH. Furthermore, strategy (a) for the detection of hCG used α-antihCG labelled (HRP) as reporter conjugate. Strategy (b) maintained the CMC bifunctionalised with Fc and recognition antibody for hCG hormone. However, the system was functionalised with a HRP enzyme and detection is done by using GOx reporter conjugates for in situ production of hydrogen peroxide. The reduction of H2O2 was used for the amperometric detection of hCG by applying a potential of 200 mV. The sensitivity and limit of detection of both strategies were calculated from calibration plots. For strategy (a) the LOD was found to be 3.7283 ng/mL corresponding to 33.56 mIU/mL and a sensitivity of 0.0914 nA ng-1 mL-1. The corresponding values for strategy (b) are 700 pg/mL (6.3 mIU/mL) and 0.94 nA ng-1 mL-1.

>Magister Scientiae - MSc / Glucose oxidase (GOx) and horseradish peroxidase (HRP) are important enzymes for the development of amperometric enzyme linked immunosensors. The selectivity of each enzyme towards its analyte deepens its importance in determining the sensitivity of the resultant immunosensor. In designing immunosensors that have customized transducer surfaces, the incorporation with FAD and iron based enzymes ensures that electron kinetics remains optimal for electrochemical measurement. Various different immobilization strategies are used to produce response signals directly proportional to the concentration of analyte with minimal interferences. The combination of self-assembled monolayers and supramolecular chemistry affords stability and simplicity in immunosensor design. In this work, two electrochemical strategies for the detection of human chorionic gonadotropin(hCG) is presented. This involves the modification of a gold surface with a thiolated β-cyclodextrin epichlorohydrin polymer (βCDPSH) to form a supramolecular inclusion complex with ferrocene (Fc)-functionalised carboxymethyl cellulose polymer (CMC). Cyclic voltammetry indicated that ferrocene is in close proximity to the electrode surface due to the supramolecular complex formed with βCDPSH. Furthermore, strategy (a) for the detection of hCG used α-antihCG labelled (HRP) as reporter conjugate. Strategy (b) maintained the CMC bifunctionalised with Fc and recognition antibody for hCG hormone. However, the system was functionalised with a HRP enzyme and detection is done by using GOx reporter conjugates for in situ production of hydrogen peroxide. The reduction of H2O2 was used for the amperometric detection of hCG by applying a potential of 200 mV. The sensitivity and limit of detection of both strategies were calculated from calibration plots. For strategy (a) the LOD was found to be 3.7283 ng/mL corresponding to 33.56 mIU/mL and a sensitivity of 0.0914 nA ng-1 mL-1. The corresponding values for strategy (b) are 700 pg/mL (6.3 mIU/mL) and 0.94 nA ng-1 mL-1.

Submitted by Marilene Donadel (marilene.donadel@unioeste.br) on 2018-11-08T19:27:23Z No. of bitstreams: 1 Caroline_Zabotti_2018.pdf: 1717107 bytes, checksum: c78770870a13b69c262faead47da1788 (MD5) / Made available in DSpace on 2018-11-08T19:27:23Z (GMT). No. of bitstreams: 1 Caroline_Zabotti_2018.pdf: 1717107 bytes, checksum: c78770870a13b69c262faead47da1788 (MD5) Previous issue date: 2018-07-31 / Analytical methodologies for the quantification of bisphenol Metastases are analytical for the quantification of bisphenol. This monitoring if by the consumer this is the environmental pollutant which has been applied in health. In the work in question, we investigated the use of a bisphenol inclusion complex as a strategy for the determination of traffic levels of solutions by spectrofluorimetry. The use of the molecular encapsulation of β-cyclodextrin with the analyte of interest provided a high detection capacity (0.03 ppb) due to an elevation of the inclusion level, which provided higher stiffness for the bisphenol molecule response of fluorescence intensity, without interference of noise or impaired analytical signal. A simple and sensitive spectrofluorimetric method is presented. Linearity was investigated in the range of 3.85 to 26.5 ppm, the source coefficient being among the very significant variables, 0.996. The retention limit was 0.03 ppb for the β-cyclodextrin effect, and the limit of quantification was 7.5 ppm, which was a lower intensity where precision and accuracy were investigated. The method was considered accurate and accurate in the absence of the matrix, since it was verified in the sample selection, there are several unknown results present in the aqueous matrix that provoke internal filter effects. Robustness was evaluated through applications of a central rotational compound design, where the effect of the variables studied in the analytical method was analyzed. The quantification of bisphenol A by fluorescence spectroscopy proved to be a suitable method, easy to learn and fast. / Metodologias analíticas para a quantificação de bisfenol A são desenvolvidas com um objetivo em comum, que é realizar o monitoramento deste composto em diversas matrizes. Este monitoramento se faz necessário pelo fato deste composto ser um poluente ambiental que apresenta efeitos indesejáveis na saúde. No trabalho em questão, foi investigado a aplicação do complexo de inclusão de bisfenol A com βciclodextrina para determinação de níveis traço em solução aquosa por espectrofluorimetria. O uso do encapsulamento molecular da β-ciclodextrina com o analito de interesse proporcionou uma alta sensibilidade de detecção (0,03 ppb) devido a formação do complexo de inclusão, o qual proporcionou maior rigidez para a molécula de bisfenol A e consequentemente, aumento na resposta de intensidade de fluorescência, sem interferências de ruído ou sinal analítico prejudicado. É apresentado um método espectrofluorimétrico simples e sensível. A linearidade foi investigada no intervalo de concentração de 3,75 a 26,5 ppm, sendo o coeficiente de correlação entre as variáveis muito significativo, de 0,996. O limite de detecção obtido foi de 0,03 ppb devido ao efeito da β-ciclodextrina, e o limite de quantificação de 7,5 ppm, sendo esta a menor concentração onde foi investigada a precisão e exatidão. O método foi considerado exato e preciso na ausência da matriz, pois foi verificado na avaliação da seletividade, que há vários compostos desconhecidos presentes na matriz aquosa que provocam efeitos de filtro interno. A robustez foi avaliada por meio da aplicação de um delineamento composto central rotacional, onde foi avaliado o efeito das variáveis estudadas no método analítico. A quantificação de bisfenol A por espectroscopia de fluorescência mostrou-se um método adequado, fácil de realizar e relativamente rápido.

Submitted by Biblioteca da Faculdade de Farmácia (bff@ndc.uff.br) on 2017-03-14T18:47:43Z No. of bitstreams: 1 Petito, Nicolly de Lima [Dissertação, 2015].PDF: 2998524 bytes, checksum: 0048771f6748f57c822ca4612196e146 (MD5) / Made available in DSpace on 2017-03-14T18:47:43Z (GMT). No. of bitstreams: 1 Petito, Nicolly de Lima [Dissertação, 2015].PDF: 2998524 bytes, checksum: 0048771f6748f57c822ca4612196e146 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Carotenoides são pigmentos naturais amplamente distribuídos na natureza, responsáveis pelas cores vermelhas, laranjas e amarelas. São substâncias amplamente estudadas por apresentarem potencial antioxidante e atividade pró-vitamina A. Devido a seu caráter lipofílico, são pigmentos naturais de difícil aplicação em alimentos como aditivos, além de apresentarem alta instabilidade frente a fatores comuns no processamento, como pH, luz, calor e oxigênio. O uso de ciclodextrinas como agentes encapsulantes é recomendado a fim de aumentar a solubilidade dos carotenoides em meio aquoso, e possivelmente, protegê-los dos fatores químicos e ambientais. Portanto, o objetivo deste trabalho foi conduzir a inclusão molecular de carotenoides de pimentão vermelho (Capsicum annuum L.) em hidroxipropil-β-ciclodextrina visando o aumento de sua solubilidade e estabilidade frente a fatores envolvidos no processamento e armazenamento de bebidas isotônicas. A extração dos carotenoides de pimentão vermelho foi realizada por meio de maceração em solvente etanol e água (9:1), seguida de partição com hexano e evaporação em baixa temperatura. O perfil de carotenoides do extrato obtido foi determinado por cromatografia líquida de alta eficiência (CLAE-UV). A inclusão do extrato de pimentão vermelho em hidroxipropil-β-ciclodextrina foi realizada por meio de sonda de ultrassom em quatro proporções (1:4, 1:6, 1:8 e 1:10 v/v). Misturas físicas nas mesmas proporções foram preparadas para efeito comparativo. O extrato de pimentão vermelho, os complexos de inclusão obtidos e as misturas físicas foram caracterizados por espectrofotometria no infravermelho (FT-IR), ressonância magnética nuclear de hidrogênio (RMN1H), calorimetria exploratória diferencial (DSC), difusão dinâmica da luz (DLS), espectrofotometria de absorção na região do UV-visível e ensaio de solubilidade. No extrato de pimentão vermelho foram identificados cinco carotenoides, a saber: β-caroteno, β-criptoxantina, 9-cis-β-caroteno, capsantina e 13-cis-β-caroteno. Observou-se que a inclusão molecular foi efetiva para as diferentes proporções de complexo ao compará-las com os resultados das misturas físicas, principalmente pelos resultados dos ensaios de solubilidade, onde foi identificado o aumento de solubilidade em até 660 vezes comparado ao do extrato isolado. Devido à relação custo-benefício, optou-se por dar continuidade aos experimentos com os complexos com proporção 1:6 (m/m). A estabilidade de cor dos complexos e do extrato de pimentão foi avaliada sob o efeito combinado das variáveis pH, tempo e temperatura. Os resultados demonstraram que se pode esperar maior retenção dos parâmetros de cor com o uso do complexo do que com o uso do extrato. A fim de avaliar a estabilidade de cor dos complexos em condições de armazenamento durante 40 dias, foram formuladas bebidas isotônicas adicionadas de complexo ou de corantes artificiais, adicionadas de conservante ou pasteurizadas, submetidas à 10 ou 25 μmol de fótons.m2.s-1, ou armazenadas na ausência de luz. Os resultados revelaram que as amostras armazenadas ao abrigo de luz apresentaram menor variação da cor, tendo as pasteurizadas apresentado melhor resultado. Em conclusão, a inclusão molecular permite o aumento da solubilidade dos carotenoides de pimentão vermelho, permitindo assim a sua aplicação em formulações alimentícias, e atribui o efeito protetor a estes carotenoides frente a fatores inerentes ao processamento de alimentos / Carotenoids are natural pigments widely distributed in nature, responsible for the red, orange and yellow colors. They are known and studied due to their antioxidant potential and pro-vitamin A activity. However, due to their lipophilic nature and high instability under influence of common processing factors, such as pH, light, heat and oxygen, it is difficult to apply them in food . Use of cyclodextrins as encapsulating agent is recommended in order to increase their aqueous solubility and protect the molecules against chemical and environmental factors. The aim of this study was to perform molecular inclusion of red bell pepper carotenoids (Capsicum annuum L.) in hydroxypropyl-β-cyclodextrin, in order to increase their solubility and stability in front of factors involved in processing and storage of food. The extraction of red bell pepper carotenoids was carried out by soaking in solvent ethanol and water (9: 1), followed by partition with hexane and evaporation at low temperature. In order to characterize the extract obtained, analysis by high performance liquid chromatography was performed (HPLC), identifying β-carotene, β-cryptoxanthin, 9-cis-β-carotene, capsanthin and 13-cis-β-carotene. Inclusion of red pepper extract in hydroxypropyl-β-cyclodextrin was performed using ultrasound probe in four different ratios (1: 4, 1: 6, 1: 8 and 1:10). Additionally, physical mixtures in the same ratios were prepared for comparative purposes. The obtained inclusion complexes, red pepper extract, hydroxypropyl-β-cyclodextrin and physical mixtures were characterized by infrared spectroscopy (FT-IR), nuclear magnetic resonance (1 H NMR), differential scanning calorimetry (DSC), dynamic light scattering (DLS), UV-visible spectroscopy and solubility assay. Molecular inclusion was effective for the different proportions of the complex, by comparing them with the results of physical mixtures, mainly the results of the solubility tests, where the increased solubility was identified up to 660 times, compared to the pure extract. Due to cost-effectiveness, it was decided to continue the experiment with the 1:6 complex. The color stability of the complex and of red bell pepper extract was evaluated under the combined effect of pH, time and temperature. Results demonstrated greater retention of color parameters using complex than the use of extract. In order to evaluate the stability of complex color storage conditions for 40 days, isotonic drinks added of artificial colors or complex were formulated, adding preservative or pasteurized, subjected to 10 or 25 micromol photons.m2.s-1 or stored in the absence of light. Results showed that the samples stored in the absence of light had less color variation, being the pasteurized the best condition. In conclusion, molecular inclusion allows increasing of solubility, thereby allowing its application in food formulations, and assigns the protective effect for carotenoids against inherent factors in food processing

Les électrodes modifiées avec cyclodextrines ayant des grandes performances analytiques représentent une alternative intéressante pour le développement de (bio)capteurs électrochimiques dans un domaine attractif de la recherche pour différentes applications, et notamment les analyses pharmaceutiques et biomédicales. Le but de cette étude a été de développer de nouvelles électrodes modifiées avec β-cyclodextrine pour des applications biomédicales et pharmaceutiques. L'influence de la β-cyclodextrine a été étudiée en solution et à la surface d’électrodes.L'influence de la β-cyclodextrine en solution aqueuse sur le comportement électrochimique de certaines substances pharmaceutiques (l’acide ascorbique, l'acide urique, la caféine, la théophylline, l'aminophylline et l'acétaminophène) a été étudiée en utilisant des méthodes électrochimiques et spectrales, mettant en évidence la formation de complexes d'inclusion.Diverses techniques ont été utilisées pour la modification des électrodes avec β-cyclodextrine: l'incorporation de la β-cyclodextrine dans la pâte de carbone et le piégeage dans des films polymères de polyéthylèneimine. Ces capteurs ont permis la détermination simultanée de l'acide ascorbique et de l'acide urique. Les électrodes modifiées ont été aussi appliquées pour le dosage de l'acide ascorbique dans deux produits pharmaceutiques et pour l’évaluation quantitative de l'acide ascorbique et de l'acide urique dans l’urine humaine avec de bonnes performances.Deux types de biocapteurs basés sur une nouvelle nanostructure de graphène ont été élaborés avec de l'oxyde réduit de graphène, de β-cyclodextrine et de tyrosinase en utilisant la méthode couche par couche et l’électropolymérisation. Les nouveaux nanocomposites ont été caractérisés par des techniques spectrales, microscopiques et électrochimiques. Les biocapteurs optimisés ont été appliquées avec succès pour la détermination du catéchol et de la dopamine dans des produits pharmaceutiques et des échantillons biologiques avec une bonne récupération.La solubilisation dans l'eau de certains nouveaux fluorophores (quatre nouvelles tétrazines) en utilisant la -cyclodextrine et de nanoparticules d'or modifiées avec β-cyclodextrine a été signalée. Les assemblages supramoléculaires redox ont été caractérisés dans l'eau par analyses électrochimiques et de fluorescence. L'immobilisation de tétrazines sur différents types d'électrodes modifiées par polypyrrole-cyclodextrine a été également réalisée et examinée par techniques électrochimiques, spectroscopiques et microscopiques.Une autre contribution originale est la combinaison de la lithographie avec de nanosphères utilisant des billes de latex avec différents diamètres (900 et 100 nm), avec l’électropolymérisation du monomère pyrrole-Ru(II). Des micro et nanostructures très organisées ont été réalisées en présentant de meilleures6propriétés pour le film photosensible de poly [Ru(II)-pyrrole]. Par ailleurs, le film de poly [Ru(II)-pyrrole] a été modifié avec d'autres types de dérivés de pyrrole qui présentent de propriétés de complexation utiles pour l’immobilisation des biomolécules à la surface de l'électrode. / The cyclodextrin modified electrodes with enhanced analytical performances represent an attractive promise for the future development of electrochemical (bio)sensors and remain a very active field of research for a wide range of applications in many areas, including pharmaceutical and biomedical analysis. The aim of this study was to develop novel cyclodextrin modified electrodes for pharmaceutical and biomedical applications. The β-cyclodextrin influence was investigated both in solution and immobilized at the electrode surface.The influence of β-cyclodextrin on the electrochemical behavior of some pharmaceuticals (ascorbic acid, uric acid, caffeine, theophylline, aminophylline, and acetaminophen) in aqueous solutions was studied by using electrochemical and spectral methods, which highlighted the inclusion complexes formation.Various techniques were used for the electrode modification with β-cyclodextrin, such as: the incorporation in carbon paste and the entrapment in polymeric films (polyethylenimine). These sensors allowed the simultaneous determination of ascorbic and uric acids. The modified electrodes were also applied for the dosage of ascorbic acid in two pharmaceutical products and for the ascorbic and uric acids quantification in human urine with good performances.Two types of biosensors based on a new nanostructured graphene framework were developed with reduced graphene oxide, β-cyclodextrin and tyrosinase by using either layer by layer method or electropolymerization. These new nanocomposites were characterized by spectral, microscopic and electrochemical techniques. The optimized biosensors were successfully applied for catechol and dopamine determination in pharmaceutical products, serum and urine samples with good recoveries.The solubilization in water of some new fluorophores (four new synthesized tetrazines) by using -cyclodextrin and gold nanoparticles modified with β-cyclodextrin was reported. The redox supramolecular assemblies were characterized in water by electrochemical and fluorescence measurements. The immobilization of tetrazines onto various types of electrodes modified with polypyrrole-cyclodextrin was also achieved and examined by electrochemical, microscopic and spectroscopic techniques.Another original contribution is the combination of nanosphere lithography by using latex beads with different diameters (900 and 100 nm), with the electropolymerization of a Ru(II)-pyrrole monomer. The achievement of highly organized micro and nanostructures showed enhanced features for the photosensitive electrogenerated poly-[RuII-pyrrole] films. Furthermore, poly-[RuII-pyrrole] film was modified with other types of pyrrole derivatives presenting complexation properties in order to immobilize biomolecules at the electrode surface.

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / The essential oils (EOs) are compounds extracted from plants that have a great variety of biological activities reported in the literature. In this class, carvone, an unsaturated ketone monoterpene, is found in nature under two enantiomeric forms: S-(+)-carvone and R-(-)-carvone. Carvone has several pharmacological properties such as anticancer, anticonvulsant, anxiolytic, antidepressant and anti-inflammatory. R-(-)-carvone has some physico-chemical characteristics that limit its use, such as low solubility in water, high volatilization and easy oxidation. In this perspective, the formation of inclusion complexes (ICs) with cyclodextrins (CDs) have been one of the main strategies to increase the solubility in water of poorly soluble drugs, bypassing their physico-chemical limitations. In this way, the present study aimed to prepare the R-(-)-carvone/β-CD complexes in the 1: 1 molar ratio by different complexation methods: physical mixture (PM), paste complex (PC), slurry complex (SC), ultrasound (US) and freeze drying (FD), characterized by differential scanning calorimetry (DSC), thermogravimetry/derivative thermogravimetry (TG/DTG), Karl Fischer Moisture Determination (KF), Fourier transform infrared spectrophotometry (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). In addition, the analytical method for quantification of R-(-)-carvone was developed by high performance liquid chromatography (HPLC) and complexation efficiency (CE%) was determined from this method. DSC and TG/DTG curves of the SC and FD methods showed, respectively, the disappearance of the R-(-)-carvone melting characteristic event, and the considerable reduction of mass loss in the first step (Δm1 6.87% and 5.18% between 34-150 °C), indicating the complexation. XRD results of the ICs (PC, SC and FD) showed the disappearance of spectral characteristic lines of β-CD and the emergence of new peaks, suggesting a change of β-CD crystalline phase. SEM images of ICs exhibited relevant changes in morphology compared to free β-CD and PM, showing a decrease in particle size, especially in the US and FD methods. FTIR results showed that there were displacements and reduction in the intensity of the R-(-)-carvone characteristic bands in the ICs spectra. HPLC analysis showed that the higher CE% were obtained by SC and FD methods (70.93% and 84.26%). Thus, it is concluded that the SC and FD complexation methods presented the best host-guest interaction profiles, suggesting IC's formation between R-(-)-carvone and β-CD. / Os óleos essenciais (OEs) são compostos extraídos de plantas que dispõem de uma grande variedade de atividades biológicas relatadas na literatura. Nessa classe, destaca-se a carvona, monoterpeno cetônico insaturado, encontrado na natureza sob duas formas enantioméricas, a S-(+)-carvona e R-(-)-carvona. A carvona possui diversas propriedades farmacológicas tais como: anticancerígena, anticonvulsivante, ansiolítica, antidepressiva e anti-inflamatória. A R-(-)-carvona apresenta algumas características físico-químicas que limitam sua utilização, como por exemplo, baixa solubilidade em água, elevada volatilização e fácil oxidação. Nessa perspectiva, a formação de complexos de inclusão (CIs) com ciclodextrinas (CDs) têm sido uma das principais estratégias para aumentar a solubilidade em água de fármacos fracamente solúveis contornando suas limitações físico-químicas. Dessa forma, o presente estudo teve como objetivo preparar os complexos R-(-)-carvona/β-CD na razão molar 1:1 por diferentes métodos de complexação: mistura física (MF), malaxagem (MA), coevaporação (CE), ultrassom (US) e liofilização (LF) caracterizando-os por calorimetria exploratória diferencial (DSC), termogravimetria /termogravimetria derivada (TG/DTG), determinação de umidade por Karl Fischer (KF), espectrofotometria de absorção na região do infravermelho com transformada de Fourier (FTIR), difração de raios X (DRX) e microscopia eletrônica de varredura (MEV). Além disso, o método analítico para quantificação da R-(-)-carvona foi desenvolvido por cromatografia líquida de alta eficiência (CLAE) e a eficiência de complexação (EC%) foi determinada a partir desse método. As curvas DSC e TG/DTG dos métodos de CE e LF mostraram respectivamente, o desaparecimento do evento característico de fusão da R-(-)-carvona, e a redução considerável de perda de massa na primeira etapa (Δm1 6,87% e 5,18% entre 34-150 °C), indicando a complexação. Os resultados de DRX dos CIs (MA, CE e LF) apresentaram o desaparecimento de linhas espectrais características da β-CD e o surgimento de novos picos, sugerindo mudanças na fase cristalina da β-CD. As imagens de MEV dos CIs exibiram mudanças relevantes na morfologia em comparação com a β-CD livre e a MF, apresentando uma diminuição no tamanho das partículas, principalmente nos métodos US e LF. Os resultados de FTIR demonstrou que houve deslocamentos e redução na intensidade das bandas características da R-(-)-carvona nos espectros dos CIs. As análises de CLAE demonstraram que as maiores EC% foram obtidas pelos métodos de CE e LF (70,93% e 84,26%). Assim, conclui-se que os métodos de complexação CE e LF apresentaram os melhores perfis de interação hóspede-hospedeiro, sugerindo a formação dos CIs entre a R-(-)-carvona e a β-CD. / São Cristóvão, SE

Quinones have been the subject of much interest due to their various biological activities, mainly as antitumor and as trypanocidal agents. Quinones are cytotoxic by two main mechanisms: the generation of ROS resulting in oxidative stress and alkylation of cellular nucleophiles, such as DNA and some enzymes such as topoisomerases. Their activity depends on bioreduction, similarly to what happens to nitroaromatic compounds. They also catalyze electron transfer reactions in biological processes and, after reduction generate radical anions (semiquinone radical anion and nitro), which depending on stability, can furnish their free electrons to acceptor molecules. In the present study, compounds with mixed functionalities derived from nor-β-lapachone, including a nitroaniline group were electrochemically studied in protic (acetate buffer) and aprotic (DMF+TBABF4, DMSO+TBAP and Acetonitrile+TBABF4) media, using glassy carbon and mercury as working electrodes. The compounds showed a complex redox behavior and the mechanism was elucidated using electron spin resonance. The electroreduced products of nor-β-lapachone and of the nitroquinones reacted with oxygen, indicative of the generation of reactive oxygen species, reactivity in the order of 2 > nor-β-lapachone > 3 > 1. We investigated their interaction with DNA, which was shown to be positive for nitroquinones and negative for the precursor nor-β-lapachone, in agreement with biological assays which had also shown that the nitroquinones cause DNA damage. The stability of the nitrosemiquinones, their half-life times were measured using mercury electrode, and the reaction rates for the electrochemical process-following-up-isproportionation reaction were measured. From these studies, a lower stability for the meta-substituted nitrophenylaniline (k2 = 5.188 x 103 L mol-1 s-1 and t1/2 = 0.06 s) was evidenced. Upon spectroelectrochemical reduction studies of the nitroquinones, the generation of radicalar intermediates (semiquinone radical anion and nitro radical anion) was observed, with differences between o- and m-derived compounds and the p-substituted one. To increase the solubility of the nitroquinones, in order to allow in vivo studies, the formation of inclusion complexes with β-cyclodextrin were evaluated. Positive results were obtained, leading to a viable formulation alternative for further biological studies with the compounds. / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Quinonas despertam muito interesse devido às suas diversas atividades biológicas, principalmente como agentes antitumoral e tripanossomicida. A citotoxicidade de quinonas decorre de dois mecanismos principais: geração de EROs resultando no estresse oxidativo e alquilação de nucleófilos celulares, como o DNA e algumas enzimas, como as topoisomerases. Sua atividade depende de biorredução, similarmente ao que acontece com compostos nitroaromáticos. Eles também catalisam reações de transferência de elétrons biológicas e, após a redução geram ânions radicais (ânions radicais semiquinona e nitro), que dependendo da estabilidade, podem transferir seus elétrons livres a moléculas aceptoras. Neste trabalho, compostos de funcionalidade mista derivados da nor-β-lapachona, com um grupo nitroanilina, foram estudados eletroquimicamente nos meios prótico (tampão acetato) e aprótico (DMF + TBABF4, DMSO + TBAP e acetonitrila + TBABF4), utilizando carbono vítreo e mercúrio como eletrodos de trabalho. Os compostos apresentaram um comportamento redox complexo e o mecanismo elucidado por espectroeletroquímica. Os produtos da eletro-redução da nor-β-lapachona e nitroquinonas reagiram com oxigênio, indicativo da geração de EROs, na ordem de reatividade 2 > nor-β-lapachona > 3 > 1. Foi investigada a interação com DNA, que se mostrou positiva para as nitroquinonas e negativa para o precursor nor-β-lapachona, concordantes com ensaios biológicos que também evidenciou que as nitroquinonas causam dano ao DNA. A estabilidade do nitrosemiquinona, tempos de meia-vida e as taxas reacionais referentes à reação química de desproporcionamento acoplada ao processo eletroquímico para cada derivado foram determinadas usando eletrodo de mercúrio. A partir desses estudos, foi evidenciada a menor estabilidade para o nitrofenilamina meta-substituída (k2 = 15,188 x 103 L mol-1 s-1 and t1/2 = 0,06 s). Nos estudos por espectroeletroquímica das nitroquinonas, observou-se a geração de intermediários radicalares (ânions radicais semiquinona e nitro), com diferenças entre os nitroderivados o- e m-, assim como para o p- derivado. Com objetivo de aumentar a solubilidade das nitroquinonas, para posteriores estudos in vivo, foi avaliada a formação de complexos de inclusão com β-ciclodextrina. Foram obtidos resultados positivos, refletindo em alternativa viável para formulações posteriores com estes compostos e ensaios biológicos.

Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / The development of polymers with the ability to transport and release drugs and bioactives has been growing rapidly because of their unique properties in protecting and enhancing solubilization of drugs in physiological media. In this work, polyesters derived from β-cyclodextrin were developed in two different systems: The former consisted of cyclodextrin cross-linked with citric acid and subsequently functionalized with glutamic acid. The latter was obtained from β-cyclodextrin esterified with gluthamic acid. The polyesters were characterized by Fourier Transform Infrared Spectroscopy (FTIR), Solid-state Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13C–NMR) and Thermogravimetric Analysis (TGA) for the confirmation of the formation of polymers and the esterification of glutamic acid with β-cyclodextrin molecules. The formation of inclusion complex of the polymers in solution with orange methyl was evaluated to verify the activation of β-cyclodextrin cavities. The polymers were used as reducer and stabilizer in the synthesis of silver nanoparticles (AgNPs). The characterization of the AgNPs was performed by UV-Vis spectroscopy, and bands between 350-500 nm evidenced of the obtainment of silver nanoparticles. Analyses by transmission electron microscopy revealed AgNPs with spherical morphology and diameter around ~ 5 to ~60 nm, corroborating with the results of UV-Vis. / O desenvolvimento de polímero com a capacidade de transportar e liberar fármacos e compostos bioativos vem crescendo rapidamente, devido suas propriedades únicas em proteger e aumentar a solubilização em meios fisiológicos. Neste trabalho, foram desenvolvidos poliésteres derivado de β-ciclodextrina em dois sistemas distintos. O primeiro sistema foi obtido a partir de β-ciclodextrina reticulado com ácido cítrico e posteriormente funcionalizado com ácido glutâmico. O segundo foi a partir de β-ciclodextrina esterificada com ácido glutâmico. Os poliésteres foram caracterizados por espectroscopia na região do infravermelho com transformada de Fourier (FTIR), ressonância magnética nuclear no estado sólido sob polarização cruzada e rotação com ângulo mágico (RMN 13C CP/MAS) e análise termogravimétrica (TG), para a confirmação da formação dos polímeros e a esterificação do ácido glutâmico com as moléculas de β-ciclodextrina. A formação de complexo de inclusão dos polímeros com o alaranjado de metila foi avaliada em solução, comprovando-se a ativação das cavidades de β-ciclodextrina. Os polímeros foram testados quanto a habilidade de promover a formação/estabilização de nanopartículas de prata (AgNPs) a partir de nitrato de prata em solução. A caracterização das AgNPs foi realizada por espectroscopia de UV-Vis, e as bandas observadas entre 350-500 nm são evidências da presença de nanopartículas de prata. As imagens de microscopia eletrônica de transmissão revelaram AgNPs de morfologia esférica com diâmetro em torno de ~5 a ~60 nm, corroborando com os resultados de UV-Vis. / São Cristóvão, SE

Le but de ce travail était la préparation de dérivés cyclobutaniques du GABA optiquement purs et leur utilisation dans la préparation de γ/α-peptides pouvant adopter une structure tridimensionnelle bien définie. Pour cela, deux stratégies ont été développées. La première consistait en l’utilisation de la β-Cyclodextrine comme hôte supramoléculaire chirale lors de cyclizations photochimiques énantiosélectives. La tentative de cyclisation [2+2] intramoléculaire du N-allyl-N-(4-methoxyphenyl)acrylamide n’a conduit qu’à un δ-lactame issu d’une électrocyclisation 6π. L’électrocyclisation de la 1,3-dihydro-2H-azepin-2-one nous a permis d’obtenir le γ-latame bicyclique précurseur du (+)-cis-3,4CB-GABA avec un excès énantiomérique de 45%. La deuxième stratégie était basée sur une synthèse racémique du N-Boc-cis-3,4CB-GABA suivi d’une séparation des deux énantiomères par CLHP semi-préparative avec une colonne chirale. Les (-) et (+)-cis-3,4CB-GABA optiquement purs ont ainsi été obtenu à l’échelle du gramme. Ces deux énantiomères (-) et (+)-cis-3,4CB-GABA ont ensuite été utilisés pour la préparation de deux séries de peptides mixtes γ/α, diastéréoisomères [(S,S/R) et (R,R/R)] à courtes chaines contenant alternativement le cis-3,4CB-GABA et le D-Alanine. L'analyse des conformations des dipeptides des deux séries par Diffraction des Rayons X, n'a montré aucune interaction intramoléculaire mais plutôt un assemblage de liaisons d'hydrogène intermoléculaires entre les molécules du dipeptide. D'autre part, les études RMN 1D et 2D (en solution) ont montré que le tétrapeptide des séries (S,S/R) pourraient avoir une structure hélicoïdale 12/10, tandis que son analogue diastéréoisomères des séries (R,R/R), a montré, en solution, une nouvelle structure sous forme de ruban 7/9. / This work revolves around the synthesis of ennatiomerically pure cyclobutane derivatives of GABA, and their use in the preparation of hybrid γ/α-peptides that could adopt a well-defined three dimensional secondary structure. In this aim we developed two strategies. The first one employed native β-Cyclodextrin as a supramolecular chiral host to achieve enantiodifferentiating photochemical cyclizations. Attempting to perform an intramolecular [2+2] cyclization of N-allyl-N-(4-methoxyphenyl)acrylamide, we only obtained a δ-lactam resulting from a 6π electrocyclization, whereas the electrocyclization of 1,3-Dihydro‑2H‑azepin-2-one allowed access to a 45% enantiomerically enriched bicyclic γ-lactam precursor of (+)-cis-3,4CB-GABA. The second strategy was based on a racemic synthesis of N-Boc-cis-3,4CB-GABA followed by a separation of the two enantiomers using a semi-preparative HPLC fitted with a chiral column. This allowed access to optically pure (-) and (+)-cis-3,4CB-GABA, on a gram scale. Furthermore, the enantiomerically pure (-) and (+)-cis-3,4CB-GABA, were used to synthesize, and fully characterize two series [the (S,S/R) and the (R,R/R)] of short diasteriomeric hybrid γ/α-peptides composed of alternating cis-3,4CB-GABA and D-Alanine. Analysis of the conformational behavior of the dipeptides from both series by X-Ray diffraction on a single crystal, showed no intramolecular interactions but rather an array of intermolecular hydrogen bonding between the dipeptide molecules. On the other hand, a series of 1D and 2D NMR experiments showed that the tetrapeptide of the (S,S/R)-series could attain a 12/10 helical structuration, whereas its diasteriomeric analog of the (R,R/R)-series, displayed evidence of an unprecedented 7/9 folding pattern in solution.