Yes / There is a need to develop asymmetric routes to functionalised β-lactams, which remain the most important group of antibacterials. Here we describe biocatalytic and protein engineering studies concerning carbapenem biosynthesis enzymes, aiming to enable stereoselective production of functionalised carbapenams with three contiguous chiral centres. Structurallyguided substitutions of wildtype carboxymethylproline synthases enable tuning of their C-N and C-C bond forming capacity to produce 5-carboxymethylproline derivatives substituted at C-4 and C-6, from amino acid aldehyde and malonyl-CoA derivatives. Use of tandem enzyme incubations comprising an engineered carboxymethylproline synthase and an alkylmalonylCoA forming enzyme (i.e. malonyl-CoA synthetase or crotonyl-CoA carboxylase reductase) can improve stereocontrol and expand the product range. Some of the prepared 4,6-disubstituted-5-carboxymethylproline derivatives are converted to bicyclic β-lactams by carbapenam synthetase catalysis. The results illustrate the utility of tandem enzyme systems involving engineered crotonases for asymmetric bicyclic β-lactam synthesis.

Charles University, Pharmaceutical Faculty in Hradec Králové Department: Department of Pharmaceutical Chemistry and Pharmaceutical analysis Candidate: Martina Čečetková Supervisor: PharmDr. Jan Zitko, Ph.D. Title of Diploma Thesis: Pyrazinamide derivatives as potential antimicrobial compounds Even in 21st century, tuberculosis still remains a serious and global health threat. Tuberculosis is one of the 10 most common causes of death, the most burdened are developing countries, but this disease infects up to 1/3 of population worldwide. Due to ineffective treatment of tuberculosis in developing countries, the prevalence of tuberculosis which does not respond to standard treatment is increasing. It is necessary to develop new drugs effective against multidrug-resistant tuberculosis and prevent further spread of the disease. The design of final structures is based on previously synthesized molecule 6- chloro-N-(4-(4-fluorophenyl)thiazol-2-yl)pyrazine-2-carboxamide, which structure comes from first line antitubercular pyrazinamide (PZA) and 4-arylthiazol-2-amine scaffold with formerly identified antimycobacterial activity. This starting compound exhibits high activity against M. tuberculosis described by MIC = 0,78 µg/mL and low cytotoxicity. The object of study was to determine effect of substitution...

Orientador: Elisa Maria Aparecida Giro / Resumo: Lesões de cárie secundarias nas margens das restaurações tem sido a principal razão para a sua substituição. Portanto, o desenvolvimento de materiais com propriedades antibacterianas melhoradas e duradouras é desejável. O objetivo deste estudo foi avaliar a influência da incorporação de nanopartículas de hexametafosfato de clorexidina (NPs CLX-HMP) a um cimento de ionômero de vidro (CIV) de alta viscosidade, nas suas propriedades físico-químicas, mecânica e antibacteriana. Após a síntese e caracterização, as nanopartículas foram adicionadas ao CIV nas concentrações de 1%, 2% e 5%. O CIV sem adição de nanopartículas foi utilizado como controle. Espécimes cilíndricos (3mm x 6mm) foram confeccionados com os materiais (n=12/grupo) e mantidos em água deionizada por 30 dias. A liberação de CLX foi avaliada no eluato por espectrofotometria ultravioleta e a dosagem do flúor foi feita com auxílio de um eletrodo específico, nos períodos de 1 h e 1, 7, 15 e 30 dias. No 30º dia, os espécimes receberam uma aplicação tópica de flúor gel neutro 2% e a liberação de flúor foi reavaliada por mais 30 dias. Para avaliar a atividade antibacteriana, biofilmes polimicrobianos cresceram sobre espécimes dos materiais (n=10/grupo), utilizando um modelo de aderência ativa. Em seguida, foram coletados e inoculados em meios de cultura específicos para a quantificação de microrganismos totais, bactérias acidúricas totais e estreptococos do grupo mutans. A atividade metabólica foi analisada pelo ensaio de ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Secondary caries on the margins of restorations have been the main reason for their replacement. Therefore, the development of materials with improved and long-lasting antibacterial properties is desirable. The objective of this study was to evaluate the influence of the incorporation of chlorhexidine hexametaphosphate nanoparticles (CHX-HMP NPs) to a high viscosity glass ionomer cement (GIC) in its physicochemical, mechanical and antibacterial properties. After synthesis and characterization, the nanoparticles were added to the GIC at concentrations of 0%, 1%, 2% and 5%. Cylindrical specimens (3 mm x 6 mm) made with the materials were kept in deionized water for 30 days. The CHX release was evaluated in the eluate by ultraviolet spectrophotometry and the fluoride dosage was done with the help of a specific electrode, in the periods of 1 h and 1, 7, 15 and 30 days. On the 30th day, the specimens received a topical application of neutral fluorine gel 2% and the fluoride release was reevaluated for another 30 days. To evaluate the antibacterial activity, polymicrobial biofilms grew on the specimens of the materials, using an active adherence model. The biofilms formed were collected, inoculated in specific culture media and thereafter, the quantification of total microorganisms, total acid bacteria and streptococci of mutans group was made. The metabolic activity was analyzed by the XTT assay and the biomass by violet crystal staining. Finally, it was evaluated the bond strength of the material to the sound and caries-affected dentin, after 24 h and 6 months of storage of the specimens in artificial saliva, using the microshear test. The fracture patterns were evaluated with the aid of light microscope. Adequate statistical tests were applied according to the distribution of the data and the homogeneity of variances. The level of significance was set at 5%. The synthesized nanoparticles presented ...(complete abstract electronic access below) / Doutor

Orientador: Fernando Antonio Santos Coelho / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-08-11T02:31:10Z (GMT). No. of bitstreams: 1 Rezende_Patricia_D.pdf: 4429618 bytes, checksum: 8b5bb87a85f841dc4aeabf56b44376ea (MD5) Previous issue date: 2007 / Resumo: Este trabalho teve como objetivo sintetizar e avaliar a atividade biológica de algumas 2-oxazolidinonas. As oxazolidinonas são compostos versáteis utilizados na preparação de uma série de outras classes de compostos e são largamente utilizados como auxiliares quirais em sínteses orgânicas assimétricas. Biologicamente são de grande importância por apresentarem efeitos neurolépticos, efeitos psicotrópicos, antialérgicos e antibacterianos. No que se refere a atividade antibacteriana, as oxazolidinonas, apresentam atividade notável contra muitas cepas resistentes de bactérias gram-positivas, através de um novo mecanismo de ação. As oxazolidinonas 4- e 4,5-substituídas oriundas de aldeídos alifáticos e aromáticos foram sintetizadas a partir de adutos de Morita-Baylis-Hillman (MBH), através de duas principais rotas: via rearranjo de Curtius e via reação de ozonólise do aduto de MBH, sendo esta última, resultado de estudos prévios realizados em nosso laboratório. A reprodutibilidade desta rota sintética nos possibilitou a preparação de um intermediário avançado da substância isocitoxazona, um isômero estrutural da citoxazona, uma oxazolidinona que apresenta atividade citocina moduladora sobre células Th2. A partir da rota via Rearranjo de Curtius e através de uma adaptação da mesma, sintetizamos cetonas a, b-saturadas, a partir de adutos de MBH. E finalmente, iniciamos um estudo para a síntese assimétrica de 2- oxazolidinonas, utilizando a base quiral b-isocupreidina. A mesma foi sintetizada e utilizada na reação de MBH na preparação de um aduto de MBH quiral. As oxazolidinonas sintetizadas estão sendo submetidas a ensaios para a determinação da atividade biológica frente a uma série de microorganismos / Abstract: This work has been as main purpose the synthesis and the biological evaluation of some 2-oxazolidinones. These compounds have been used as substrates for the preparation of different compounds and used as chiral auxiliary in asymmetric organic synthesis. Besides the synthetic relevance of this class of compounds, they also exhibit important biological effects, as neuroleptic, psychotropic, anti-allergenic and antibacterial. In the last years, an special attention has been paid to these compounds due to their antibacterial activity, since they show a remarkable activity against Gram-positive drugs multi-resistant strains, through a new action mechanism. In this work several 4- and 4,5-substituted oxazolidinones were synthesized from Morita-Baylis-Hillman prepared from aliphatic and aromatic commercial aldehydes, using two synthetic approaches. The first approach was based on employing a Curtius rearrangement, and the second was based on the utilization of an ozonolysis reaction of the MBH adducts. Both synthetic approaches have permitted preparing several oxazolidinones. An advanced intermediate for the total synthesis of isocytoxazone, a structural isomer of cytoxazone, was also prepared. Cytoxazone, a natural oxazolidinone, exhibits cytocine modulator activity for Th2 cells. Through an adaptation of the strategy based on Curtius rearrangement, we have also synthesized a, b-unsaturated ketones from MBH adducts. Finally, a study was started aiming at synthesizing chiral oxazolidinones, using chiral base b-isocupreidine prepared by us. Synthetic oxazolidinones prepared in this work are under biological screening for evaluating theirs antibacterial profiles / Doutorado / Quimica Organica / Doutor em Ciências

L’émergence de bactéries multirésistantes aux antibiotiques est la conséquence de leur utilisation à mauvais escient au cours de ces dernières décennies. Ce phénomène constitue un problème de santé publique majeur, et face à cette urgence sanitaire, il est nécessaire de trouver rapidement de nouveaux agents antibactériens.Les colicines, au regard de leurs propriétés antimicrobiennes intrinsèques, constituent des candidats intéressants. Naturellement produites par E. coli dans le but de tuer des souches compétitrices de la même espèce ou d’espèces apparentées, elles exercent en général leur activité cytotoxique par le biais d’une activité ionophorique ou nucléasique. Parmi les nombreuses colicines connues à ce jour, la colicine M (ColM) est la seule à interférer avec la voie de biosynthèse du peptidoglycane, macromolécule essentielle et spécifique au monde bactérien. En effet, une fois dans le périplasme de E. coli, la ColM clive le lipide II, dernier précurseur de la voie de biosynthèse du peptidoglycane, conduisant de ce fait à la lyse bactérienne. Plusieurs homologues de la ColM ont été identifiés chez d’autres genres bactériens (Pseudomonas, Pectobacterium et Burkholderia) mais aucune cytotoxicité croisée n’a été mise en évidence à ce jour, d’où un spectre d’action restreint pour les membres de cette nouvelle famille d’enzymes antibactériennes.Ce travail traite de l’étude structurale et biochimique de la ColM et de certains de ses homologues. L’étude structurale de différents variants de la PaeM, homologue issu de P. aeruginosa, a permis d’identifier une molécule d’eau conservée au sein du site actif qui joue probablement un rôle central dans le mécanisme catalytique de cette famille d’enzyme. L’expression des homologues de la ColM issus de Pseudomonas et de Pectobacterium, directement dans le périplasme de E. coli, a permis de démontrer leur activité lytique, prouvant ainsi le grand potentiel de ces bactériocines en tant qu’alternatives aux antibiotiques. Enfin, la construction de plusieurs colicines chimères entre la ColM et ses homologues, capables de dégrader le lipide II in vitro et d’induire la lyse d’E. coli suite à leur expression périplasmique, ouvre la voie à de futurs espoirs thérapeutiques. / The misuse of antibiotics during the last decades led to the emergence of multidrug resistant pathogenic bacteria. This phenomenon constitutes a major public health issue. Given that urgency, the finding of new antibacterials in the short term is crucial.Colicins, due to their antimicrobials properties, constitute good candidates. They are protein toxins produced by E. coli to kill competitors belonging to the same or related species. In most cases, they exhibit their cytotoxic activity through an ionophoric or nucleasic activity. Among the twenty colicins known to date, colicin M (ColM) is the only one known to interfere with peptidoglycan biosynthesis. It develops its lethal activity in the E. coli periplasm, in three steps deeply linked to its structural organization in three domains. Once in the periplasm, ColM degrades the lipid II, i.e. the last precursor in the peptidoglycan biosynthesis pathway, in two products that cannot be reused, thereby leading to cell lysis. Several ColM homologues have been identified in other bacterial genera, such as Pseudomonas, Pectobacterium and Burkholderia, but no cross activity has been shown to date, explaining the narrow antibacterial spectrum displayed by the members of this new family of antibacterial enzymes.This work deals with the structural and biochemical study of ColM and some of its homologues. Structural studies on several variants of PaeM, the ColM homologue from P. aeruginosa, led to identify a conserved water molecule in the active site, probably playing a central role in the catalytic mechanism of this enzyme family. Moreover, expression of ColM homologues from Pseudomonas or Pectobacterium species directly in the E. coli periplasm showed that all these homologues were able to induce E. coli cell lysis, thus demonstrating the great potential of these bacteriocins as an alternative to antibiotics. Following these results, several chimera colicins were created between ColM and its homologues, which were shown to degrade lipid II in vitro and to induce E. coli cell lysis after their periplasmic expression, opening the way to future new therapeutic options.

Every year, millions of people contract antibiotic-resistant bacterial infections, and tens of thousands die from infection-related complications in the United States alone. Bacterial infections are one of the leading causes of death worldwide, especially in healthcare institutes such as hospitals and nursing homes where people are more susceptible to infection and complications. Bacteria can cause infections in any part of the body and often interact with sugar molecules on the surface of cells; once bacteria are attached, the cells stop functioning properly. When a bacterial infection is suspected, samples from the patient's blood or urine are taken to confirm the diagnosis. If the bacterial infection is sever enough, patients are treated with broad-spectrum antibiotics before the type of bacteria is known, and once it has been identified they are given antibiotics that target the specific bacterial strain. The high death rate associated with bacterial infections is largely due to the emergence of antibiotic-resistant bacterial strains. Although antibiotic resistance is present in some naturally occurring bacterial strains, misuse and over-prescription of antibiotics have accelerated the process. To combat the ever-growing threat of antibiotic-resistant bacteria, antibacterial polymers have been developed. Antibacterial polymers prevent bacterial infections by either killing the bacteria themselves or by preventing them from interacting with the body altogether This dissertation primarily focuses on using sugar-containing polymers to prevent bacterial growth. These materials may potentially be used as a replacement for or supplement to traditional antibiotics. / Doctor of Philosophy / All living cells possess a coating of glycomaterials on, or as critical components of their cell walls. Bacteria, including invasive bacterial pathogens, are no exception and have cell walls comprised of peptidoglycans. Glycomaterials on cell surfaces play a role in critical biological processes such as molecular recognition, cellular interaction, infection, and inflammation. Traditional antibiotic remediations are becoming less effective in treating bacterial infections due to the emergence of antibiotic-resistant strains. The formation of biofilms, an extracellular coating composed of polysaccharides, contributes to the antibiotic resistance of bacteria. The development of novel antibiotics is extremely costly and often unsuccessful, with billions in investment often producing zero new drugs. As a result, antibacterial polymers have been investigated as they are comparatively less expensive and offer unique characteristics to combat bacterial infections. Polymers with inherently antibacterial properties, or those that can be conjugated with antibacterial compounds, offer a replacement for traditional antibiotic remediation. To investigate the role of glycomaterials in antibacterial activity, a series of sugar-containing norbornene homopolymers were prepared and evaluated for their antibacterial activity. Protected glycomonomers consisting of galactose, glucose, N-acetyl glucose, and mannose were prepared in a two- or three-step synthesis by first appending an acrylate to the anomeric carbon through Koenigs-Knorr-type chemistry. After generation of the -anomer, the norbornene carboxylate was prepared by the Diels-Alder reaction of the acrylate with cyclopentadiene. Homopolymers with molecular weights ranging from 25–250 KDa were synthesized using ring-opening metathesis polymerization (ROMP) catalyzed by Grubbs 3rd generation catalyst, and subsequently deprotected to reveal the sugar-norbornene. While the galactose polymers showed no bacterial inhibition, those composed of glucose, N-acetyl glucose, or mannose prevented the growth of Escherichia coli (E. coli) and were effective at concentrations as low as 1.25 mg mL-1. Some strains of pathogenic bacteria, such as Clostridioides difficile (formerly known as Clostridium difficile), interfere with the normal cell functions by indirect means, producing toxins that adversely interact with the surrounding tissue. To sequester the toxins produced by C. difficile before they cause damage to the gastrointestinal (GI) tract, polymers containing the -gal epitope, a naturally occurring trisaccharide, were also prepared. The -gal epitope possessing a propyl azide handle at the anomeric carbon was prepared in a 15-step reaction, followed by reaction with an alkyne-functionalized polymer resin using copper-catalyzed azide-alkyne Huisgen cycloaddition. After global deprotection and thorough washing to remove residual copper from the glycomaterial, cell viability studies showed >80% cell survival. While these materials showed good cell viability, the rigorous synthesis of -Gal and the affinity of the polymer scaffolding for copper was a deterrent to further toxin-binding studies. Non-biological surfaces are also often susceptible to bacterial colonization and fouling. Although such materials may be modified to impart antimicrobial properties, their modification may also be a detriment to other key physical properties. To investigate the tradeoffs between material properties and functionalization, we synthesized a series of poly(arylene ether)s from monomers that possessed a modifiable handle and differed only in the pattern of leaving group on the aromatic ring. These polymers were further modified using post-polymerization thiol-ene reactions to evaluate the effect of the side-chains on the material's properties. The regioisomer incorporated into the polymer was found to influence its thermal properties irrespective of the installed functional group, suggesting that new functionality can be incorporated into these polymers without adversely impacting their physical properties.

Orientador: Lidiane Nunes Barbosa / Resumo: Combinações entre antimicrobianos, a exemplo de nisina (bacteriocina) e fármacos antibacterianos tradicionais, podem amenizar o problema da resistência bacteriana, pois o possível efeito sinérgico se torna estratégico, possibilitando o uso de doses menores no tratamento de doenças infecciosas com redução nos custos e na toxicidade, além de ter potencial na prevenção do surgimento das linhagens resistentes. No entanto, os mecanismos envolvidos na ação antibacteriana são importantes para pesquisas de novos fármacos. O objetivo do estudo foi investigar como a nisina, alguns fármacos antibacterianos e respectivas combinações interferem no metabolismo de Staphylococcus aureus Meticilina Resistente (MRSA) e Pseudomonas aeruginosa, através de ensaios de estresse oxidativo bacteriano, análises morfológicas por microscopia eletrônica de transmissão (MET) e análise do perfil de proteínas expressas nas bactérias quando expostas aos antimicrobianos e suas combinações em concentrações subletais. Inicialmente foram realizados ensaios visando obter os valores de concentração inibitória mínima (CIM) e concentração subletal máxima (CSM) para nisina e fármacos como tetraciclina, ciprofloxacina, vancomicina, polimixina B, oxacilina e cefalotina para ambas bactérias. Na sequencia, foram realizados ensaios para verificação de sinergismo entre nisina e antibacterianos utilizando metodologia da curva de sobrevivência, sendo escolhidas para ensaios posteriores, as combinações com demostração de sine... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Combinations of antimicrobials, such as nisin (bacteriocin) and traditional antibacterial drugs, may assuage the problem of bacterial resistance because the possible synergistic effect becomes interesting, allowing the use of smaller doses in the treatment of infectious diseases and reduction in costs and toxicity , besides having potential in the prevention of the emergence of resistant strains. However, the mechanisms involved in antibacterial action are important for research on new drugs. The aim of this study was to investigate how nisin, antibacterial drugs and their combinations interfere in the metabolism of Methicillin Resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, verified in bacterial oxidative stress assays, morphological analyzes by transmission electron microscopy (TEM) and analysis of the protein profile expressed in bacteria when exposed to antimicrobials and combinations in sublethal concentrations. Initially, assays were performed to obtain the minimum inhibitory concentration (MIC) and maximum sublethal concentration (MSC) for nisin and drugs such as tetracycline, ciprofloxacin, vancomycin, polymyxin B, oxacillin and cephalothin for both bacteria. Subsequently, assays were performed to verify the synergism between nisin and antibacterials using time kill curve methodology and the combinations with demonstration of synergism (reduction in final bacterial count above 2 logs of CFU / mL in relation to initial inoculum) were chosen for later... (Complete abstract click electronic access below) / Doutor

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2017-03-14T17:41:15Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertação Darla Silveira Volcan Maia.pdf: 1194381 bytes, checksum: b604e15daa48092534ea10a3647416c8 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2017-03-17T22:15:15Z (GMT) No. of bitstreams: 2 Dissertação Darla Silveira Volcan Maia.pdf: 1194381 bytes, checksum: b604e15daa48092534ea10a3647416c8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-17T22:15:15Z (GMT). No. of bitstreams: 2 Dissertação Darla Silveira Volcan Maia.pdf: 1194381 bytes, checksum: b604e15daa48092534ea10a3647416c8 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2017-02-01 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / A demanda por alimentos livres de conservantes químicos sintéticos tem aumentado. Nos últimos anos, vários estudos foram realizados a fim de se obter compostos antimicrobianos naturais. Alguns estudos foram realizados com frutas nativas do Brasil, no entanto, não existem estudos avaliando o potencial antibacteriano do butiá. O objetivo deste estudo foi prospectar a atividade antibacteriana de extratos de butiá (Butia odorata) com diferentes polaridades e caracterizar quimicamente o extracto com a melhor atividade. Um extrato hexânico e um metanólico de butiá foram avaliados quanto à sua atividade antibacteriana contra três bactérias Gram-positivas (Listeria monocytogenes, Staphylococcus aureus e Bacillus cereus) e três bactérias Gram-negativas (Salmonella Typhimurium, Escherichia coli O157:H7 e Pseudomonas aeruginosa), pelo método de difusão em ágar, Concentração Inibitória Mínima (CIM) e Concentração Bactericida Mínima (CBM). Ambos extratos apresentaram atividade antibacteriana, entretanto, o extrato hexânico (EHB) apresentou desempenho superior, portanto realizou-se a caracterização química por CG-MS deste extrato. Interessantemente, o EHB apresentou maior atividade contra bactérias Gram-negativas, sendo E. coli O157:H7, a mais sensível (CBM 5 µL.mL-1 ). Entre as bactérias Gram-positivas, S. aureus (CBM 20 μL.mL-1 ) foi a mais sensível. Os fitoesteróis representaram 51% do EHB, sendo gama-sitosterol o composto predominante, constituindo 22% do extrato. / Demand for synthetic chemical preservative free foods has increased. In recent years several studies have been conducted in order to obtain natural antimicrobial compounds. Some studies were performed with native fruit from Brazil, however there are no studies evaluating the potential antibacterial of jelly palm fruits (butiá). The objective of the study was exploring the antibacterial activity of butiá (Butia odorata) extracts with different polarities and chemically characterize the extract with the best activity. A hexane and a methanol extract of butiá were evaluated for their antibacterial activity against three Grampositive (Listeria monocytogenes, Staphylococcus aureus, and Bacillus cereus) and three Gram-negative bacteria (Salmonella Typhimurium, Escherichia coli O157:H7, and Pseudomonas aeruginosa) by the agar diffusion method, Minimal Inhibitory Concentration (MIC), Minimal Bactericidal Concentration (MBC). Both extracts showed antibacterial activity, however of hexane extract (BHE) showed superior performance, therefore the chemical characterization by CG-MS for this extract. Interestingly, the BHE higher activity against Gram-negative bacteria, and E. coli O157:H7 was the most sensitive (MBC 5 μL.mL-1 ). Of the Gram-positive bacteria, S. aureus (MBC 20 μL.mL-1 ) was the most sensitive. Phytosterols represented 51% of the BHE and gamma-sitosterol was the predominant compound constituting 22% of the extract.

Le marché de la cosmétique est l’un des marché les plus porteur actuellement dans le monde. La population française utilise énormément ces produits pour son hygiène quotidienne. Ce sont les shampoings ou autre crème de soins. Pour protéger ces produits, depuis maintenant de nombreuses années, les fabricants ajoutent des agents conservateurs pour augmenter la durée de conservation, ou encore éviter certaines contaminations microbiennes après les contacts avec la peau. Ces dernières années ont également vu les mentalités des consommateurs évoluer et actuellement, ces derniers souhaiteraient des produits cosmétiques le plus naturel possible, sans ajouts de conservateurs. Dans ce contexte, il semble intéressant de travailler sur la protection de ces produits par d’autres moyens. En premier lieu, nous vient immédiatement à l’esprit, la protection par l’emballage. L’idée est de modifier les emballages actuels pour leur conférer des activités antimicrobiennes et ainsi les rendre protecteurs. L’étude présentée s’intéresse à certaines possibilités de mises en oeuvre et modifications de polymères pour apporter une activité antimicrobienne. Deux voies de fabrications ont été étudiées dans cette thèse. Une première a consisté en la réalisation de revêtements antimicrobiens et protecteurs à basse température. Cette technique a montré la possibilité de créer des couches antimicrobiennes par photo-polymérisation à partir de monomères méthacrylates renfermant les agents antimicrobiens. C’est cette couche finale qui va venir s’ajouter à certaines zones spécifiques des emballages finaux pour assurer la protection antimicrobienne du contenu.La seconde voie d’action a étudié une fabrication plus industrielle à haute température. Cette technologie a permis de créer par extrusion des granulés antimicrobiens avec des introductions d’actifs de différentes natures. Ceux sont ces granulés qui sont par la suite injectés sous la forme d’emballages. Pour cette voie d’action, l’idée n’est plus de protéger l’emballage via une couche antimicrobienne, mais de substituer certaines pièces de l’emballage constituées de polymères naturellement antimicrobiens. Ces travaux ont permis la réalisation d’une large gamme de matériaux antimicrobiens. Les différentes solutions étudiées ont également permis de réaliser des prototypes d’emballages, ceci en collaboration avec certaines entreprises partenaires du projet. Tous ces prototypes seront prochainement testés en conditions réelles d’utilisations, c’est-à-dire par des essais de mises en contact avec le consommateur d’un système complet, à savoir le produit cosmétique conditionné dans des emballages protecteurs. Ces tests devront permettre de vérifier si les solutions proposées pourraient aboutir à une adaptation sur une chaine industrielle pour une utilisation à grande échelle / Today the cosmetic market is one of the most popular in the world. French people use many these products everyday as for examples, creams or shampoos. In order to protect the cosmetic products, the manufacturers introduced during these last year additives or conservative agents in cosmetic products to increase the shelf life or avoid a microbial contamination after a direct contact with the skin of consumers. However, recent years have also revealed that the consumer mindsets evolve and now, they would like cosmetics more natural, without addition of additives. In this context, it was interesting to work on the cosmetics protection by other ways. Firstly, we think immediately to the protection by use of packaging. The objective is to modify the current packaging to bring an antimicrobial activity and protect the cosmetics. This work presents different technologies of fabrication and modification of polymers to get an antimicrobial activity. For this, two techniques were studied. A first technology has consisted to develop antimicrobial coating at low temperature. This way has demonstrated possibilities of creation by photo-polymerization under UV radiations. Initially, the antimicrobial agents were introduced in liquid monomers before the polymerization and the fabrication of polymer networks. The final coatings were finally destiny to be added on specific areas of packaging, generally in contact with the consumers and prevent all risks of microbial contaminations from the products. The second technology has studied a way of polymer fabrication more industrial at high temperature. The technique has consisted to create antimicrobial pellets by extrusion with introductions of different natures of additives. The obtain pellets were injected at the end to fabricate certain pieces of the final packaging. This work has allowed the realization of a large range of antimicrobial materials. All the studied solutions have been used to fabricate prototype packaging in collaboration with partner companies of the project. All these prototypes will be tested by antimicrobial tests in real conditions of uses. If these tests prove successful, it will be possible to envisage an industrialization step

Submitted by Cristhiane Guerra (cristhiane.guerra@gmail.com) on 2017-02-03T15:51:13Z No. of bitstreams: 1 arquivototal.pdf: 2439266 bytes, checksum: 852d348e101a0679a14c24845b557b1e (MD5) / Made available in DSpace on 2017-02-03T15:51:13Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2439266 bytes, checksum: 852d348e101a0679a14c24845b557b1e (MD5) Previous issue date: 2015-07-31 / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Phenolic compounds, among them the flavonoids, are holders of antimicrobial, antioxidant and anti-inflammatory effects, but not free from toxicity and/or adverse effects, that's why research in this area, whether they are in silico, in vitro and/or in vivo approach have been intensified to ensure the safe use of these molecules. Thus, the aim of this study was to investigate the probable pharmacological activities, toxicity and antibacterial and antioxidant effects of flavonoid flavone and its hydroxy derivatives: 3-hydroxyflavone, 5-hydroxyflavone and 6-hydroxyflavone, tracing a structure-activity relationship of such substances. It was investigated the pharmacological, pharmacokinetics and theoretical toxicological characteristics of flavonoids using in silico testing with the PASS online and Osiris softwares; the cytotoxicity on human erythrocytes of blood types A, B and O positive and negative Rh factor, running the models of hemolysis and Erythrocyte Osmotic Fragility (EOF); was analysed the antimicrobial activity in front of Gram-positive (B. subtilis CCT 0516, S. aureus ATCC 25619 and S. aureus ATCC 25925) and Gram-negative, including clinical importance (P. aeruginosa ATCC 8027, P. aeruginosa ATCC 23243, E. coli ATCC 2536, E. coli 101, E. coli 103, E. coli 104, E. coli 105 and E. coli 108); assessed the oxidant and antioxidant potential of these molecules in the presence of Reactive Oxygen Species (ROS - H2O2) and phenylhydrazinium (Ph) and, finally, the genotoxicity using the micronucleus test. The results obtained revealed numerous probable pharmacological activities to the flavonoids, as integrity agonists and membrane permeability inhibitors, anaphylatoxin receptor antagonists, inhibitors of kinase and peroxidase, antimutagenic potential and vase-protecting capacity; do not present significant theoretical toxicity risks and have good oral bioavailability. The 4 flavonoids have shown moderate hemolysis at concentrations of 500 and 1000 μg/mL, the example of 3-hydroxyflavone which induced 20.2 % and 53 % of hemolysis, respectively, in blood type A, Rh+; the flavonoids hydroxylated protected cells types A and O from osmotic stress. All flavonoids exhibited moderate antibacterial activity against Gram-positive strains and Gram-negative, being the flavone bactericide in the concentration of 200 μg/mL to the strains of P. aeruginosa ATCC 8027, S. aureus ATCC 25619 and E. coli 104, while other flavonoids have bacteriostatic action. It did not promote oxidation of erythrocyte and behaved as scavengers and antioxidants of H2O2 and phenylhydrazinium and finally the flavone did not show genotoxicity compared to cyclophosphamide, a proven genotoxic agent. It is concluded that the flavone, 3-hydroxyflavone, 5-hydroxyflavone and 6- hydroxyflavone have different pharmacological activities, good bioavailability and low theoreticals toxicity, reduced cytotoxicity, absence of genotoxicity as well as being moderate antibacterial and antioxidant, showing, with this study, the importance of the inclusion of computational chemistry techniques for targeting evaluation protocols of the biological effects of the molecules. / Compostos fenólicos, dentre eles os flavonoides, são detentores de efeitos antimicrobiano, antioxidante e anti-inflamatório, porém não isentos de toxicidade e/ou efeitos adversos, por isso pesquisas nesta área, sejam elas com uma abordagem in silico, in vitro e/ou in vivo têm se intensificado para que se garanta a segurança no uso dessas moléculas. Assim, o presente estudo se propôs a investigar as prováveis atividades farmacológicas, a toxicidade e os efeitos antibacteriano e antioxidante do flavonoide flavona e de seus derivados hidroxilados: 3-hidroxiflavona, 5-hidroxiflavona e 6-hidroxiflavona, traçando uma relação estrutura-atividade das referidas substâncias. Para tanto, investigou-se as características farmacológica, farmacocinética e toxicológica teóricas dos flavonoides utilizando ensaios in silico com os softwares PASS online e Osíris; a citotoxicidade sobre eritrócitos humanos dos tipos sanguíneos A, B e O e fator Rh positivo e negativo, executando-se os modelos de hemólise e Fragilidade Osmótica Eritrocitária (FOE); analisou-se a atividade antimicrobiana frente a bactérias Gram-positivas (B. subtilis CCT 0516, S. aureus ATCC 25619 e S. aureus ATCC 25925) Gram-negativas, inclusive de importância clínica (P. aeruginosa ATCC 8027, P. aeruginosa ATCC 23243, E. coli ATCC 2536, E. coli 101, E. coli 103, E. coli 104, E. coli 105 e E. coli 108); avaliou-se o potencial oxidante e antioxidante das referidas moléculas na presença de Espécies Reativas de Oxigênio (EROs - H2O2) e da fenilhidrazina (Ph) e, por último, a genotoxicidade por meio do teste do micronúcleo. Os resultados obtidos revelaram numerosas prováveis atividades farmacológicas para os flavonoides, como agonistas da integridade e inibidores da permeabilidade membranar, antagonistas do receptor de anafilatoxina, inibidores de quinase e peroxidase, potencial antimutagênico e capacidade vasoprotetora; não apresentam significativos riscos teóricos de toxicidade e detêm uma boa biodisponibilidade oral. Os 4 flavonoides demonstraram moderada hemólise nas concentrações de 500 e 1000 μg/mL, a exemplo da 3-hidroxiflavona que induziu 20,2 e 53 % de hemólise, respectivamente, no sangue tipo B,Rh-; os flavonoides hidroxilados protegeram os eritrócitos tipos A e O do estresse osmótico. Todos os flavonoides exibiram moderada atividade antibacteriana contra cepas Gram-positivas e Gram-negativas, sendo a flavona bactericida na concentração de 200 μg/mL para as linhagens de P. aeruginosa ATCC 8027, S. aureus ATCC 25619 e E. coli 104, enquanto que os demais flavonoides têm ação bacteriostática. As substâncias não promoveram oxidação dos eritrócitos e comportaram-se como sequestradores e antioxidantes de H2O2 e fenilhidrazina e, por fim, a flavona não apresentou genotoxicidade quando comparado com a ciclofosfamida, um comprovado agente genotóxico. Conclui-se que flavona, 3-hidroxiflavona, 5-hidroxiflavona e 6-hidroxiflavona possuem variadas atividades farmacológicas, boa biodisponibilidade e baixa toxicidade teóricas, reduzida citotoxicidade, ausência de genotoxicidade, além de serem moderadamente antibacterianos e antioxidantes, evidenciando-se, com este estudo, a importância da inserção de técnicas de química computacional para o direcionamento de protocolos de avaliação de efeitos biológicos de moléculas.