Orientador: Francisco Benedito Teixeira Pessine / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-26T03:10:58Z (GMT). No. of bitstreams: 1 Guedes_LucianadeSouza_M.pdf: 5716470 bytes, checksum: 363ce3e7be504393ef2dcd6d349ed421 (MD5) Previous issue date: 2014 / Resumo: O Imiquimod é um fármaco com propriedades imunomodulatórias, disponível na forma de creme para tratamento tópico de certas patologias da pele como carcinoma basocelular e ceratose actínica. O contato direto do medicamento com a pele pode causar desconforto durante o tratamento. Uma das alternativas para minimizar os efeitos adversos é a utilização de sistemas carreadores que evitam o contato direto do agente com a pele. A ?-ciclodextrina foi empregada como agente carreador neste estudo e o complexo de inclusão obtido foi caracterizado em solução e no estado sólido. As técnicas espectroscópicas de absorção UV/Vis e ressonância magnética nuclear foram utilizadas para caracterizar o complexo de inclusão em solução. Essas técnicas permitiram obter a constante de equilíbrio de associação (Kc), a estequiometria do complexo formado e evidências de sua geometria. A caracterização do complexo no estado sólido foi realizada por calorimetria diferencial de varredura, termogravimetria, difração de raios X e microscopia eletrônica de varredura. Os resultados indicaram a presença de estrutura amorfa que pode ser atribuída a amorfização dos componentes devido à liofilização do complexo e também à formação do complexo de inclusão. A estrutura tridimensional do complexo obtida por modelagem molecular apresentou concordância com os resultados experimentais observados pela técnica de RMN 1H ROESY 1D. Os valores baixos de Kc e da eficiência de complexação indicam fraca interação entre o Imiquimod e a ?-ciclodextrina. Os resultados demonstram que a ?-ciclodextrina não é o sistema carreador mais adequado para aumentar a solubilidade aquosa do Imiquimod / Abstract: Imiquimod, an immune response modifier, is used for topical treatment of basal cell carcinoma and actinic keratosis. Local skin reactions can occur in the treatment area. An alternative to minimize adverse events is to use drug delivery systems which avoid drug skin contact. ?-cyclodextrin was used as drug delivery system in this study and the inclusion complex was characterized in solution and in solid state. UV/Vis absorption spectroscopy and nuclear magnetic resonance were employed to study the inclusion complex in solution. Those techniques allowed to obtain the equilibrium constant (Kc), the complex stoichiometry and insight on the geometry. The inclusion complex characterization in solid state was performed by differential scanning calorimetry, thermogravimetry, X-ray diffraction and scanning electron microscopy. The results suggest the presence of amorphous structure which can be attributed not only to components amorphization due to lyophilization but also to complex formation. The complex tridimensional geometry was obtained by molecular modeling and agrees with the experimental results observed by NMR 1H ROESY 1D experiments. The low values of Kc and complex efficiency suggest weak interaction between Imiquimod and ?-cyclodextrin. In addition to those, the results showed that ?-cyclodextrin is not the most suitable drug delivery system to improve Imiquimod aqueous solubility / Mestrado / Físico-Química / Mestra em Química

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21464号 / 工博第4539号 / 新制||工||1708(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 古賀 毅, 教授 吉崎 武尚, 教授 竹中 幹人 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Synthetic antioxidants have traditionally been added directly to food products in a single initial dose to protect against oxidation of lipids and generation of free radicals. Natural antioxidants have been shown to undergo loss of activity and become prooxidants at high concentrations; therefore, a need exists to develop active packaging which can gradually deliver antioxidants in a controlled manner. The objectives of this research were to (1) form and characterize cyclodextrin inclusion complexes with the natural antioxidants, alpha-tocopherol and quercetin, (2) incorporate cyclodextrin inclusion complexes of natural antioxidants into linear low density polyethylene (LLDPE), and (3) measure the release kinetics of inclusion complexes of natural antioxidants from LLDPE into a model food system. Cyclodextrin inclusion complexes of alpha-tocopherol and quercetin were formed by the coprecipitation method and characterized in the solid state by NMR, IR spectroscopy, and thermal analyses. Solid inclusion complex products of alpha-tocopherol:beta-cyclodextrin and quercetin:gamma-cyclodextrin had molar ratios of 1.7:1 as determined by UV spectrophotometry, which were equivalent to 18.1% (w/w) alpha-tocopherol and 13.0% (w/w) quercetin. Free and cyclodextrin complexed antioxidant additives were compounded with a twin-screw mixer into two LLDPE resin types followed by compression molding into films. Release of alpha-tocopherol and quercetin from LLDPE films into coconut oil at 30 °C was quantified by HPLC during 4 weeks of storage. The total release of alpha-tocopherol after 4 weeks was 70% from the free form and 8% from the complexed form averaged across both LLDPE resins. The mechanism by which alpha-tocopherol was released was modified due to its encapsulation inside the beta-cyclodextrin cavity within the LLDPE matrix as indicated by its diffusion coefficient decreasing by two orders of magnitude. Molecular encapsulation of natural antioxidants using cyclodextrins may be used as a controlled release mechanism within polymer food packaging to gradually deliver an effective antioxidant concentration to a food product, thereby, limiting oxidation, maintaining nutritional quality, and extending shelf life. / Ph. D.

Natamycin is an antimycotic compound that is widely used in the cheese industry to increase the shelf life of cheeses, especially shredded cheeses, by inhibiting the growth of molds. Natamycin is applied to the surface of cheese as an aqueous suspension or as a powder. However, natamycin is not readily water soluble making it harder to distribute evenly over shredded cheese Natamycin is degraded by ultraviolet (UV) light at wavelengths of 350 nm and below. Typical packaging applications do not provide adequate UV protection causing natamycin to degrade. This work was undertaken to determine the efficacy of UV absorber film to prevent UV light degradation of natamycin on the surface of shredded cheese. Current accepted methods to determine concentration of natamycin were evaluated for appropriateness in natamycin degradation studIes. The use of cyclodextrins to increase water solubility was tested to see if a uniform distribution of natamycin over the shredded cheese could be done effectively. Furthermore, a known application of mold was performed to see how well natamycin and each of its applications could prevent visible mold growth from occurring. The International Dairy Federation recognizes two methods to quantify natamycin on shredded cheese: high performance liquid chromatography (HPLC) and spectrophotometry. Concentrations of natamycin in aqueous suspensions were determined using both methods. Results show that spectrophotometry is flawed when quantifying the amount of active natamycin because the method gives erroneously high results. The amount of active natamycin is not accurately quantified using spectrophotometric techniques because it cannot separate the active form from the inactive form of natamycin. Polymer packages containing a UV absorber (11.4% light transmission at 350 nm) allow significantly less UV-associated degradation of natamycin than those packages that lacked a UV protectant (90.0% light transmission at 350 nm) (p<0.05). Incorporating a UV absorber into a package helps protect natamycin and its various complexes from UV light degradation, which can increase the shelf life of shredded cheese. However, even with a UV absorber, natamycin is still able to degrade. Natamycin was complexed with different cyclodextrins to help better solubilize natamycin â β-cyclodextrin, hydroxy-propyl β-cyclodextrin and γ-cyclodextrin. Using cyclodextrins to apply natamycin more uniformly onto shredded cheese did not significantly increase the consistency of distribution (p<0.05). Variability was uniform throughout all treatments with the exception of HPBCD complex. After 27 days, all of the UV packages treated with each of the cyclodextrin treatments containing shredded cheese began to show visible mold growth. Those packages stored in total darkness remained mold free through the duration of the experiment ending on day 62. When untreated with natamycin and an initial concentration of 101-102 spores/gram of Penicillium roqueforti, shredded cheese remained free from visible mold growth for 24 days in total darkness at 4°C. Samples treated with one of the natamycin treatments were able to remain mold free for at least 9 more days, showing visible signs of mold growth at day 33. There was no statistical difference between the treatments of dry natamycin, aqueous suspension natamycin, β-cyclodextrin-natamycin complex, and γ-cyclodextrin-natamycin complex (p<0.05). However, there was a difference with the use of hydroxy-propyl β-cyclodextrin-natamycin complex. Hydroxy-propyl β-cyclodextrin-natamycin complex allowed the shredded cheese to last for 41 days, 17 days longer than the control sample. / Master of Science

Natamycin is an antimycotic with very low water solubility and extremely high photosensitivity, which is used to extend the shelf life of shredded cheese products. The objectives of this research are: (a) to find a new delivery system for natamycin, which increases its aqueous solubility and (b) to increase the chemical stability of natamycin so that it has a prolonged antifungal effect on the surface of the shredded cheese. Molecular inclusion complexes of natamycin were formed with β-, hydroxypropyl β-, and γ- cyclodextrins (CDs) which allowed large increases in aqueous solubility without the use of organic co-solvents or surfactants. The water solubility of natamycin was increased 16-fold, 73- fold, and 152-fold with β-CD, γ-CD, and hydroxypropyl β-CD, respectively. The natamycin:CD inclusion complexes resulted in nearly equivalent in vitro antifungal activity as natamycin in its free state. Nuclear magnetic resonance (NMR) was utilized to prove the formation of true inclusion complexes. 1H NMR shift titrations of N-(3 -N-dimethylaminosuccimido) natamycin with β- and γ-CDs enabled determination of the stoichiometry of both complexes as 1:1. Aqueous solutions of natamycin (20 mg/L) were found by quantitative HPLC to be completely degraded after 24 hours of exposure to 1000 lux fluorescent lighting at 4 °C. After 14 days of storage in darkness at 4 °C, 92.2% of natamycin remained in active form. Aqueous solutions of natamycin:β-CD complex and natamycin:γ-CD complex were significantly more stable (p < 0.05) than natamycin in its free state when stored in darkness at 4 °C. Clear poly(ethylene terephthalate) packaging with an ultraviolet light absorber allowed 85.0% natamycin to remain after 14 days of storage under 1000 lux fluorescent lighting at 4 °C. Such dramatic increases in water solubility and light stability will enable natamycin to function as a more effective antimycotic in the food industry. / Master of Science

Cinnamic acid (CA) is a naturally occurring organic acid that is found in some fruits and a number of spices. CA has antimicrobial activity against certain spoilage microorganisms and pathogenic bacteria. However, the acid is poorly soluble in water. Cyclodextrin molecules have a hydrophobic cavity that allows them to serve as a host for insoluble molecules in aqueous matrices. This study was conducted to determine if the aqueous solubility of cinnamic acid could be improved via complexation with α- or β-cyclodextrins, and if these complexes could be used to control bacterial pathogens in juices. Based upon phase solubility analysis, α-cyclodextrin was chosen as the host molecule for the remainder of this study. In complex with α-cyclodextrin, the solubility of cinnamic acid increased from approximately 400 mg/L to 3800 mg/L. Prepared cinnamic acid complexed with α-cyclodextrin was aseptically added (400 mg/L and 1000 mg/L) to orange juice inoculated with a Salmonella enterica (7 log CFU/mL) and apple cider inoculated with Escherichia coli O157:H7 (7 log CFU/mL). Cider and orange juice samples were extracted on day 0 and at 24 h intervals for seven days and spread plated onto Tryptic Soy Agar. Cinnamic acid was effective for reducing populations of both bacterial pathogens in juice. Populations of E. coli O157:H7 in the apple cider were significantly reduced after 7 days at 25.6 ± 0.42°C at concentrations of 400 mg/L (5-log CFU/mL reduction) and 1000 mg/L (6-log CFU/mL reduction) cyclodextrin-cinnamic acid. S. enterica counts were also reduced in orange juice at 4° C treated with 400 mg/L (2.7-log CFU/mL reduction) and 1000 mg/L (3.2-log CFU/mL reduction) complexed cinnamic acid. The much improved solubility of this compound provides food processors with greater flexibility in using cinnamic acid in their product formulations. / Master of Science

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-07-29T17:57:19Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) MMR-TESE.pdf: 16044503 bytes, checksum: 1c3b4963930b3b75a91e718bd1893e50 (MD5) / Made available in DSpace on 2016-07-29T17:57:19Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) MMR-TESE.pdf: 16044503 bytes, checksum: 1c3b4963930b3b75a91e718bd1893e50 (MD5) Previous issue date: 2016-02-29 / Facepe / Este trabalho apresenta uma metodologia in silico para o estudo de complexos de inclus o utilizados na inova o terap utica. Um complexo de inclus o formado por um host (hospedeiro), e por um guest (h spede). Neste trabalho, o host estudado a ciclodextrina (e seus derivados) e o guest, um ligante (f rmaco, em potencial), formando o complexo host:guest. O objetivo desse projeto desenvolver uma plataforma (CycloMolder) capaz de realizar estudos in silico dos complexos de inclus o de forma autom tica e precisa, fazendo uso de uma interface gr fica de usu rio. Esse objetivo foi tra ado para facilitar os estudos de modelagem molecular para este tipo de sistema qu mico, com interesse farmac utico. A plataforma composta por dois m dulos: CycloGen e CycloDock. O primeiro m dulo (CycloGen) constr i modelos com mais de uma estrutura para representar um derivado de ciclodextrina. O segundo m dulo (CycloDock) realiza o c lculo de docking molecular entre as mol culas host e guest, utilizando o programa Autodock Vina e apresenta os resultados obtidos, incluindo gr ficos que mostram a distribui o energ tica e as intera es intermoleculares do complexo. O programa CycloMolder foi testado atrav s de estudos de casos inspirados em problemas farmac uticos reais. Os testes realizados destacaram a import ncia da gera o de mais de uma configura o para representar significativamente um derivado de ciclodextrina, e tamb m mostrou o potencial anal tico do programa, proporcionado pela automa o do estudo de modelagem, execu o dos c lculos e an lise dos resultados. De forma geral, o programa CycloMolder atinge seus objetivos, automatizando e simplificando os estudos in silico dos complexos de inclus o, contribuindo desta forma para a inova o terap utica. / This work presents an in silico methodology for study of inclusion complexes used in therapeutic innovation. An inclusion complex is formed by a host and a guest. In this work, the host is the cyclodextrin and their derivatives and the guest is a potential drug, forming a host:guest complex. The goal of this work is to development a platform (CycloMolder) able to perform in silico studies of inclusion complexes in an automated and precise fashion, making use of a graphical user interface. The platform (CycloMolder) consists of two modules: CycloGen and CycloDock. The first module (CycloGen) builds models with more than one chemical structure to represent a cyclodextrin derivative. The second module (CycloDock) performs the molecular docking calculations between the host and guest molecules, using the AutoDock Vina program, and displays the results, including graphs showing the energy distribution and intermolecular interactions present in the host:guest complexes. The CycloMolder program was tested through case studies inspired by real pharmaceutical problems. The tests highlighted the importance of generating more than one chemical structure to better represent a ciclodextrin derivative, also showed the analytical potential of the program, provided by the automation of the modeling study, execution of calculations and analysis of results. Overall, the CycloMolder program achieves its goals by automating and simplifying the in silico studies of inclusion complexes, thus contributing to the therapeutic innovation.

Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2017-05-04T17:34:06Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação-31 05 2016 correções da biblioteca (atualizada).pdf: 2843933 bytes, checksum: 1003152372d1c305370bd514f8eae798 (MD5) / Made available in DSpace on 2017-05-04T17:34:06Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação-31 05 2016 correções da biblioteca (atualizada).pdf: 2843933 bytes, checksum: 1003152372d1c305370bd514f8eae798 (MD5) Previous issue date: 2016-03-09 / A β-lapachona é uma naftoquinona (3,4-dihidro-2,2-dimetil-2H-naftol[1,2-b]pirano-5,6-diona) de peso molecular 243,3 g.mol-1 presente na Tabebuia avellanedae Lor, árvore conhecida como ipê roxo ou pau d’arco roxo. Esta naftoquinona é uma substância que pode ser obtida por uma semi-síntese a partir do lapachol bem como do lomatiol. Este bioativo apresenta múltiplos efeitos farmacológicos, como antibacteriano, antifúngico, antiviral, anti-inflamatório e anti-proliferativo. Segundo o sistema de classificação biofarmacêutica, a β-lapachona (BL ou β-lap) é classificada como classe II apresentando baixa solubilidade e alta permeabilidade. Desta forma, faz necessário um estudo de incremento de solubilidade aquosa. O objetivo deste trabalho foi caracterizar físico-quimicamente os complexos propostos utilizando dois polímeros: o dendrímero bis-MPA (DEN) e a cucurbit[6]urila (CUC). O presente estudo mostra duas metodologias para a formação de complexos entre a β-lapachona /dendrímero (BLD) e β-lapachona /cucurbiturila (BLC), visando o aumento da solubilidade deste fármaco através de interações intermoleculares e suas respectivas caracterizações físico-químicas. O complexo com o dendrímero foi preparado a partir de uma relação massa/massa de 3(fármaco):1 (carreador) variando o tempo de adsorção de 1, 3 e 7 dias. Para os complexos com a cucurbiturila uma relação molar 1:1 foi estabelecida para a formação dos complexos de inclusão com BL, variando o período de adsorção em 1, 3 e 7 dias. Após o período de agitação, os complexos BLD e BLC foram evaporados e secos a temperatura ambiente para posterior caracterização. Os complexos obtidos foram caracterizados por cromatografia líquida de alta eficiência, ultravioleta na região do visível, espectroscopia de absorção vibracional na região do infravermelho, espectrometria de ressonância magnética nuclear de hidrogênio, análise termogravimétrica, análise calorimétrica diferencial, difratometria de raio-X e microscopia eletrônica de varredura. Para o complexo BLD ficou evidente que a variação no tempo de adsorção não interferiu na quantidade de produto formado ou nas propriedades do complexo obtido. Os resultados das caracterizações mostram que o BLDD1 e o BLCD1 foram formados de acordo com os dados espectroscópicos e espectrométricos que demonstram variações nos sinais de BL quando complexado. Houve uma mudança na cristalinidade da BL, a qual era bastante cristalina, para um material mais amorfo com morfologia distinta do fármaco isolado. Os resultados das caracterizações térmicas exibiram, para os complexos, uma maior estabilidade térmica da β-lap complexada (BLDD e BLCD) e menor energia de fusão, quando comparado com β-lapachona livre. Essas informações também sugerem uma diminuição na cristalinidade do complexo o que é indicativo para o incremento de solubilidade. Desta forma propôs-se a caracterização físico-química como um indício de melhoria na solubilidade da β-lapachona através da formação de complexos entre BL e dois carreadores distintos e suas contribuições para estudos de uma possível formulação farmacêutica futura. / The β-naphthoquinone lapachol is a (3,4-dihydro-2,2-dimethyl-2H-naphthol [1,2-b] pyran-5,6-dione) molecular weight of 243,3g / mol present in Tabebuia avellanedae Lor, tree known as purple ipe or pau d'purple bow. This naphthoquinone is a substance that can be obtained by semi-synthesis from lapachol well as lomatiol. This bioactive has multiple pharmacological effects such as antibacterial, antifungal, antiviral, anti-inflammatory and anti-proliferative. According to biopharmaceutical classification system, the β-lapachone (BL or β-LAP) is classified as class II presenting low solubility and high permeability. Thus, an increase aqueous solubility study is necessary. The aim of this study was to characterize chemically-physical proposed complexes using two polymers: the bis-MPA dendrimer (DEN) and cucurbit[6]uril (CUC). This study shows two methods for the formation of complexes between β-lapachone / dendrimer (BLD) and β-lapachone / cucurbituril (BLC), in order to increase the solubility of the drug through intermolecular interactions and their physicochemical characterizations. The complex with the dendrimer was prepared from a mass / mass 3 (drug): 1 (carrier) varying the time for adsorption of 1, 3 and 7 days. For cucurbituril complexes with a molar ratio of 1: 1 was established for the formation of inclusion complexes with BL varying the adsorption period at 1, 3 and 7 days. After the stirring period, the BLC and BLD complexes were evaporated and dried at room temperature for further characterization. The obtained compounds were characterized by high-performance liquid chromatography, ultraviolet into the visible region spectroscopy, vibrational absorption in the infrared, nuclear magnetic resonance spectrometry of hydrogen, thermogravimetric analysis, differential scanning calorimetry, X-ray diffraction and electron microscopy scanning. For BLD complex it was evident that the variation in the adsorption time not interfere in the amount of complex formed or the product properties obtained. The results of the characterizations show that BLDD1 and BLCD1 were formed in accordance with spectroscopic and spectrometric data showing variations in signals when complexed BL. There was a change in the crystallinity of the BL, which was very clear, to a more amorphous material with distinct morphology of the drug alone. The results showed the thermal characterizations for the complex, greater thermal stability of the complexed β-LAP (BLDD and BLCD) and less fusion energy, compared with β-lapachone free. This information also suggests a decrease in crystallinity of the complex which is an indication to increase solubility. Thus it was proposed to physicochemical characterization as a better indication of the solubility of β-lapachone by forming complexes between BL and two different carriers and their contributions to studies of possible future pharmaceutical formulation.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Toxoplasma gondii is a protozoan of great clinical importance can cause functional and biochemical changes in the host cells mainly in the central nervous system. These changes are usually associated with the inflammatory response to tissue damage and cell oxidation in immunocompetent hosts. T. gondii infection stimulate the production of high levels of cytokines such as IL-12 and IFN-γ by cells of the immune system, consisting of a main point in parasite control and disease resistance. As a potent antioxidant, resveratrol has become an important research subject due to its antioxidant and anti-inflammatory properties. However, the mechanism by which resveratrol exerts its effects are hampered by the low solubility and bioavailability. Accordingly, one way to improve the bioavailability of resveratrol is to associate with inclusion complexes. Thus, this study aimed to investigate the benefits of resveratrol associated with sulfamethoxazole-trimethoprim (ST) in the treatment of experimentally infected mice with T. gondii. For the study, 60 mice were divided into two groups: non-infected (n = 24) and infected with T. gondii (n = 36). The two groups were divided into subgroups and treated with resveratrol (free and inclusion complex 2-hydroxypropyl-β-cyclodextrin) isolated and associated with ST. The groups A to D composed by healthy mice and groups E to J consisting of animals infected by T. gondii (VEG strain). The treatment started 20 days post-infection for 10 consecutive days with oral doses of 0.5 mg kg-1 of ST (groups B and F), 100 mg kg-1 of free resveratrol (groups C and G) and inclusion complex of resveratrol (inclusion complex containing resveratrol) (groups D and H), as well as with an association of both drugs (groups I and J). Groups A and E were used as control, untreated. Behavioral tests (memory, anxiety and locomotion) were performed after treatment. Blood samples, liver and brain fragments were collected to evaluate the cytokine profile, pathological changes, brain cysts counts, as well as oxidant/antioxidant profile. Infected animals showed behavioral changes such as anxiety and memory loss. The combination ST and resveratrol was able to restore time latência in passive avoidance task. A reduction of the number of brain cyst was observed on animals treated with the combination of drugs. Infected animals show an increase in pro-inflammatory cytokines and reduction of anti-inflammatory cytokine (IL-10), as well as increased protein oxidation in liver and brain tissue. The combination of resveratrol and ST with free inclusion complex in increased the total antioxidant capacity (TAC) and ferric reducing antioxidant power (FRAP) levels in liver and brain that can be interpreted by the protective effect of resveratrol. In addition, resveratrol in inclusion complex form when combined with ST improved therapeutic effect of ST reducing oxidative damage in liver and brain, reducing the number of cysts in the treatment of mice infected with T. gondii. Therefore, it is possible to suggest that the ST with resveratrol on treatment of infected mice can exerts a protective effect on host cells. The resveratrol in inclusion complex form was the best treatment option, for controlled tissue and serum immune responses, as well as oxidative stress in mice infected with T. gondii. / O Toxoplasma gondii é um protozoário de grande importância clínica capaz de ocasionar alterações bioquímicas e funcionais nas células do hospedeiro, principalmente no sistema nervoso central. Essas alterações, geralmente estão associadas à resposta inflamatória com danos teciduais e oxidação celular em hospedeiros imunocompetentes. A infecção por T. gondii estimula a produção de altos níveis de citocinas, tais como IL-12 e IFN-γ, pelas células do sistema imunológico, consistindo em um ponto principal no controle do parasito e resistência à doença. Como um potente antioxidante, o resveratrol tem se tornado um importante alvo de pesquisas graças a suas propriedades antioxidantes e anti-inflamatórias. No entanto, os mecanismos pelo qual o resveratrol exerce seu efeito são prejudicados pela baixa solubilidade e biodisponibilidade. Nesse sentido, uma forma de melhorar a biodisponibilidade do resveratrol é associá-lo a um complexo de inclusão. Desta maneira, os objetivos deste estudo foram investigar os benefícios do resveratrol associado a sulfamethoxazol-trimetropin (ST) no tratamento de camundongos infectados experimentalmente com T. gondii. Para o estudo, 60 camundongos foram divididos em dois grupos: não-infectados (n=24) e infectados com T.gondii (n=36). Os dois grupos foram subdivididos em subgrupos (n= 10) e tratados com resveratrol (livre e em complexo de inclusão 2- hidroxipropil-β-ciclodextrina) isolado e associado com ST. Os grupos A-D foram compostos por animais saudáveis; grupos E-J consistiram de animais infectados por T. gondii (cepa VEG). O tratamento foi iniciado 20 dias após a infecção e manteve-se por 10 dias consecutivos nas doses orais de 0.5 mg kg-1 de ST (grupos B e F), 100 mg kg-1 de resveratrol livre (grupos C e G) e na forma de complexo de inclusão (grupos D e H), bem como na associação de ambas drogas (grupos I e J). Grupos A e E foram usados como controles, não tratados. Testes comportamentais (memória, ansiedade e locomoção) foram avaliados após o tratamento. Amostras de sangue, fragmentos de fígado e cérebro foram coletados a fim de avaliar os níveis de citocinas, alterações histopatológicas, contagem de cistos cerebrais, como também perfil oxidativo/antioxidante. Animais infectados com T. gondii apresentaram alterações comportamentais como ansiedade e perda de memória. A combinação com ST e resveratrol foi capaz de restaurar o tempo de latência no teste de esquiva inibitória. Uma redução na contagem de cistos foi observada nos animais tratados com a associação de drogas assim como redução das lesões teciduais. Animais infectados apresentam aumento de citocinas pró-inflamatórias e redução da citocina anti-inflamatória (IL-10), assim como maior oxidação proteica em tecido hepático e cerebral. A combinação de ST com resveratrol livre e em complexo de inclusão aumentou os a capacidade antioxidante total (TAC) e os produtos de redução férrica (FRAP) em fígado e cérebro que pode ser interpretado pelo efeito protetor do resveratrol. Além disso, o resveratrol na forma de complexo de inclusão quando combinado à ST melhorou o efeito terapêutico da ST reduzindo os danos oxidativos, lesões hepáticas e número de cistos cerebrais no tratamento de camundongos infectados com T. gondii. Portanto, é possível sugerir que a combinação de ST com resveratrol em camundongos infectados parece exercer um efeito protetor nas células hospedeiras. O resveratrol na forma de complexo de inclusão foi a melhor opção terapêutica, pois controlou as respostas imunológicas séricas e teciduais, assim como o estresse oxidativo em camundongos infectados com T. gondii.

In this thesis, density functional theory is employed in the study of two kinds of systems that can be considered to be biomimetic in their own ways. First, three binuclear metal complexes, synthesized by the group of Prof. Ebbe Nordlander, have been investigated. The complexes are designed to resemble the active sites of phosphatase enzymes and have been examined in complexes where either two Zn(II) ions or one Fe(III) and one Mn(II) ion are bound. These dinuclear compounds were studied as catalysts for the hydrolysis of bis(2,4-dinitrophenyl) phosphate and the transesterification of 2-hydroxypropyl p-nitrophenyl phosphate, which are model systems for the same reactions occurring in DNA or RNA. It was found that the two reactions take place in similar ways: a hydroxide ion that is terminally bound to one of the metal centers acts either as a nucleophile in the hydrolysis reaction or as a base in the transesterification. The leaving groups depart in an effectively concerted manner, and the formed catalyst-product complexes are predicted to be the resting states of the catalytic cycles. The rate-determining free energy barriers are identified from the catalyst-product complex in one catalytic cycle to the transition state of nucleophilic attack in the next. Another type of biomimetic modeling is made with an aim of imitating the conceptual features of selective binding of guests and screening them from solute-solvent interactions. Such features are found in so-called nanocontainers, and this thesis is concerned with studies of two capsules synthesized by the group of Prof. Julius Rebek, Jr. First, the cycloaddition of phenyl acetylene and phenyl azide has experimentally been observed to be accelerated in the presence of a capsule. Computational studies were herein performed on this system, and a previously unrecognized structure of the capsule is discovered. Two main factors are then identified as sources of the rate acceleration compared to the uncatalyzed reaction, namely the reduction of the entropic component and the selective destabilization of the reactant supercomplex over the transition state. In the second capsule study, the alkane binding trends of a water-soluble cavitand was studied. It is found that implicit solvation models fail severely in reproducing the experimental equilibrium observed between binding of n-decane by the cavitand monomer and encapsulation in the capsule dimer. A mixed explicit/implicit solvation protocol is developed to better quantify the effect of hydrating the cavitand, and a simple correction to the hydration free energy of a single water molecule is proposed to remedy this. The resulting scheme is used to predict new hydration free energies of the cavitand complexes, resulting in significant improvement vis-à-vis experiments. The computational results presented in this thesis show the usefulness of the quantum chemical calculations to develop understanding of experimental trends observed for substrate binding and catalysis. In particular, the methodology is shown to be versatile enough such that experimental observations can be reproduced for such diverse systems as studied herein. / <p>At the time of the doctoral defense, the following paper was unpublished and had a status as follows: Paper 5: Manuscript.</p>