Thesis (M.S.) - - Andrews University, College of Arts and Sciences, 2008. / Bibliography: leaves 159-168.

Ph.d.

Thesis (Ph. D.)--School of Chemistry and Biochemistry, Georgia Institute of Technology, 2004. Directed by Katherine L. Seley. / Includes bibliographical references (leaves 113-126).

In 2010 the Florence group completed the total synthesis of the natural product chamuvarinin which, in collaboration with the Smith group, was found to be a potent inhibitor of the pathogenic parasite T. brucei. Several simplified analogues were found to maintain this inhibitory activity alongside activity against the related species T. cruzi and L. major. The mechanism of action and structural features of these compounds responsible for the observed biological activity remained elusive despite a large synthetic effort by the Florence group. With the aim of identifying protein targets in trypanosomatids to understand the mechanism of action, several photo-affinity labeling analogs have been successfully synthesised and utilised to identify a primary protein target. This protein target was fully validated and molecule docking to this protein was evaluated in-silico. This computational data was used to evaluate the mode of action and aided in the design of simplified compounds which were found to maintain the previously observed anti-parasitic activity but with decreased toxicity to mammalian cells alongside decreased synthetic complexity. The total synthesis of the natural product ascr#18 is also described alongside the synthesis of photo-affinity labeling analogs. This natural product is implicated in the modulation of pathogen resistance in plants and has potential application in crop production.

No description available.

Orientador: Rodnei Bertazzoli / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia mecanica / Made available in DSpace on 2018-08-04T08:59:38Z (GMT). No. of bitstreams: 1 Pellegrino_RosangelaRodriguesLeme_D.pdf: 3578101 bytes, checksum: e26cca52f1def178a516a716cc961293 (MD5) Previous issue date: 2004 / Resumo: o I vermectin é um agente antiparasitário muito utilizado no combate a endo e ecto parasitas em animais e em humanos. O Ivermectin é encontrado comercialmente em soluções 1% em glicerol, conhecidas como Ivomec@, Eqva1an@, Cardomec@, Mectizan@, Zimectrin@, Heartgard@, Eqvalan@. Ivermectin é uma mistura de dois homólogos contendo mais de 80% Avermectin B1a [C4sH74014], e menos 20% Avermectin Blb[C47Hn014], com massa molecular de 871,10 e 861,10 g moI, respectivamente. Como estes compostos apresentam alto peso molecular, o tratamento biológico não é eficiente para sua degradação. Este efluente pode ser tratado por incineração ou hidrólise alcalina em alta temperatura. Neste estudo utilizou-se uma amostra real de um efluente proveniente de uma industria veterinária produtora do IVOMEC@, com a finalidade de desenvolver um processo alternativo para o tratamento deste efluente. Para isso foi necessário desenvolver e otimizar um reator fotoeletroquímico em escala piloto para o estudo da degradação do I vermectin contido neste efluente. A degradação do Ivermectin foi conduzida através da eletrólise a corrente constante de um volume de 20 litros do efluente contendo aproximadamente 4 rng.L-1 de Ivermectin, por um tempo / Abstract: Ivermectin is widely used as an antiparasitic agent against endo and ectoparasites of animaIs and humans; it has a broad spectrum of activity at low dosage levels. Commercial products (Ivomec@, Eqvalan@, Cardomec@~ Mectizan~ usually contain 1% of Ivermectin in glycerol formulation. Ivermectin is a rnixture oftwo homologs containing more than 80% Avermectin B1a [C48H74014]~ and less than 20% Avermectin B1b[C47H72014], with 871.10 and 861.10 molecular weights respectively. As the compounds present high molecular weight, the conventional biological treatment is not efficient for their degradation. The current methods of Ivermectin degradation are incineration or alkaline hidrolysis at high temperatures. In this study, industrial samples of wastewater ftom a veterinary industry, containing Ivermectin, ftom the region ofCampinas were collected. The main goal ofthe present study w~ to develop and to optimize a photoelectrochemical reactor , in a pilot scale, for the treatment oj eftluent containing Ivermectin. The photoelectrochemical treatment was carried out in a flow cefi reactor, and commercia DSA@ type electrodes with nominal composition of 70Ti02/ 30Ru02~ were used as anodes, and ~ Ti screen as cathode / Doutorado / Engenharia de Materiais e Processos de Fabricação / Doutor em Engenharia Mecânica

Orientador: Cesar Costapinto Santana / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-20T14:12:19Z (GMT). No. of bitstreams: 1 Nascimento_AnaCarolina_M.pdf: 2361694 bytes, checksum: bcd5c25d65fe1d7ac8a8666d6f13c023 (MD5) Previous issue date: 2012 / Resumo: O secnidazol corresponde à formulação 1-(hidroxipropil)-2-metil-5-nitroimidazol e possui espectro de atividade contra microorganismos anaeróbicos e eficácia no tratamento de amebíase, giardíase, tricomoníase e vaginose bacteriana. Ele é comercializado na forma racêmica, isto é, na proporção 1:1 dos seus enantiômeros R e S. Não é oficial em nenhuma farmacopeia. Estudos relatam que para alguns imidazóis o enantiômero R apresenta maior atividade biológica frente ao enantiômero S. Portanto a separação do secnidazol é importante para testes biológicos comparativos de efeitos colaterais. Inserindo-se neste contexto, foi desenvolvido este trabalho de pesquisa com o intuito de estudar a resolução enantiomérica do fármaco secnidazol pela técnica de cromatografia líquida de alta eficiência utilizando coluna recheada com fase estacionária tris(3,5-dimetilfenilcarbamato) de amilose. Experimentos de pulsos com soluções diluídas foram realizados variando a vazão de fase móvel de 1,0 a 2,5 mL/min e as temperaturas de 20 a 35°C. Os resultados mostraram alta eficiência, com número de pratos superando 1000 e fatores de separação na ordem de 7,0. Os valores negativos de 'delta'H e 'delta'S* indicam que a adsorção dos enantiômeros da fase móvel na fase estacionária é entalpicamente favorável. Experimentos a altas concentrações (condições de sobrecarga) foram realizados com a finalidade de determinar as isotermas não-lineares pelo método da análise frontal e também os perfis de eluição sob estas condições. As isotermas de adsorção apresentaram comportamento não-linear e o modelo de Langmuir foi bem correlacionado aos dados experimentais de equilíbrio no intervalo de concentração analisado. A partir da metodologia shortcut foram obtidos os parâmetros operacionais da unidade leito móvel simulado. As purezas alcançadas para as correntes de extrato e refinado foram 85,50% e 72,50%, respectivamente / Abstract: The chemical formula of secnidazole is 1-(hydroxypropyl)-2-methyl-5-nitroimidazole. It acts activity against anaerobic microorganisms and is effective in the treatment of amebiasis, giardiasis, trichomoniasis, and bacterial vaginosis. It is marketed in the racemic form, that is, proportion 1:1 of their R and S-enantiomers. It's not officially recognized by any pharmacopoeia. Studies have reported that for some imidazoles the R-enantiomer has a higher biological activity than the S-enantiomer. For this reason the separation of secnidazole is important for comparative biological tests of side effects. It is in this context that this research was developed in order to study the enantiomeric resolution of drug secnidazole by the technique of high performance liquid chromatography using stationary phase column packed with amylose tris (3, 5- dimethylphenylcarbamate). Pulse experiments with dilute solutions were conducted by varying the mobile phase flow (1.0 to 2.5 mL/min) and temperature (20 to 35 °C). The results revealed high efficiency, with number of plates overcoming 1000 and selectivities in the order of 7.0. The negative values of 'delta'H and 'delta'S* indicates that the enantiomer adsorption from the mobile phase to stationary phase is enthalpically favorable. Experiments in overloaded conditions were realized to obtain the equilibrium adsorption isotherms by frontal analysis, as well overload elution profiles. The adsorption isotherms shown a nonlinear behavior and the Langmuir model was well correlated to equilibrium experimental data in the range of investigated concentration. From the shortcut method operating parameters were obtained to the simulated moving bed unit. The purities reached for the extract and raffinate lines were 85.50% and 72.50% , respectively / Mestrado / Desenvolvimento de Processos Biotecnologicos / Mestra em Engenharia Química

Petroleum ether, dichloromethane, and 80% ethanol extracts of 15 plant species collected in Nigeria were screened for in vitro antibacterial, anti-inflammatory and antimalarial activities. Antibacterial activity was tested using the agar diffusion method, while the minimum inhibitory concentrations (MIC) of the active extracts were determined using the microtitre serial dilution method. Most antibacterial activity detected was against Gram-positive bacteria with Staphylococcus aureus being the most susceptible. The highest activity was found in petroleum ether and dichloromethane leaf extracts of Mallotus oppositifolius; petroleum ether, dichloromethane and ethanolic root extracts of Newbouldia laevis; and ethanolic root extracts of Morinda lucida and Canthium subcordatum. Against the Gram-negative bacterium Escherichia coli, the highest activity was found in dichloromethane leaf extracts of Newbouldia laevis, ethanolic root extracts of Phyllanthus amarus, Mallotus oppositifolius, and Canthium subcordatum. A total of 60 plant extracts were screened for antiplasmodial activity. A chloroquine sensitive strain of Plasmodium falciparum (D10) was used. In the assay, the parasite lactate dehydrogenase (pLDH) activity was used to measure parasite viability. About 11 extracts showed promising activity with an IC₅₀ ranging from 2.5 to 13.4 µg/ml. The petroleum ether leaf extract of Hyptis suaveolens had the highest activity (IC₅₀ = 2.5 µg/ml). The cyclooxygenase (COX-1 and COX-2) assays were used to test for anti-inflammatory activity. All the plant species, with the exception of Hedranthera barteri and Picralima nitida showed anti-inflammatory activity. Apart for a few ethanolic extracts, all the activities were recorded with petroleum ether and dichloromethane extracts. Employing bioassay-guided activity fractionation, an antibacterial anthraquinone identified as emodin was isolated from ethanolic root extract of Senna occidentalis. Although this compound had been isolated from other sources, this was the first report of isolation from Senna occidentalis. Using a similar approach a novel antimalarial diterpenoid was isolated from the petroleum ether leaves extract of Hyptis suaveolens. It had IC₅₀ of 0.1 µg/ml. This new compound is worthy of further investigation and may act as an important lead compound for future antimalarial drugs. / Thesis (Ph.D.)-University of KwaZulu-Natal, 2005.