Thesis (Ph. D.)--Ohio University, June, 2004. / Includes bibliographical references (leaves 126-138).

Orientadores: Jose Francisco Hofling, Mary Ann Foglio / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-16T21:12:15Z (GMT). No. of bitstreams: 1 Anibal_PaulaCristina_D.pdf: 11148957 bytes, checksum: 3ec093ddc1e8ca14d584eb167334aaee (MD5) Previous issue date: 2010 / Resumo: A diversidade de produtos naturais, por muitos anos, inspirou pesquisadores para identificar novos produtos que podem ser, eventualmente, desenvolvidos para novas terapias. Extratos obtidos Punica granatum L. (romã) tem demonstrado diversas atividades, dentre elas, efeito antimicrobiano. Nas últimas duas décadas, infecções por leveduras do gênero Candida cresceram significantemente pelo mundo inteiro, em decorrência do uso prolongado de antifúngicos, ligado ao aumento da resistência a esses fármacos. Sendo assim, pesquisas por novos componentes com ação antifúngica, os quais podem estar presentes nos compostos da P. granatum, justificam este estudo. Os extratos obtidos de diferentes partes do fruto da P. granatum foram testados através da metodologia da concentração inibitória mínima (CIM) frente a dez espécies de Candida spp. e analisados por espectrometria de massas. Foi observado, também, se os extratos produziam efeitos na morfologia e estrutura das leveduras através da microscopia eletrônica de varredura e de transmissão, respectivamente. Os resultados obtidos revelaram-se promissores, pois as cepas testadas foram sensíveis aos extratos, com CIM de 125µg/mL, causando danos em sua morfologia, como irregularidades em sua superfície e em sua parede celular, e a espectrometria de massas revelou compostos de reconhecida ação antimicrobiana, dentre eles, taninos. Esses dados indicam que os compostos da Punica granatum possuem ação antifúngica, sendo que as substâncias detectadas podem ser consideradas as principais responsáveis por essa atividade. Sendo assim, substâncias da Punica granatum apresentam capacidade antimicrobiana, sendo um campo promissor para descoberta de novos fitomedicamentos para o tratamento alternativo de doenças, abrindo caminhos para pesquisas que visem explorar de forma coerente essas substâncias, manipulando-as com segurança, eficácia e qualidade padronizados / Abstract: The diversity of natural products has inspired researchers for many years to identify novel products that could eventually be developed into therapeutics. The extracts obtained from Punica granatum L. (pomegranate) have demonstrated several activities as antimicrobial affects, among others. In the last couple decades infections by yeast genus Candida increased significantly worldwide, in consequence of abuse use of antifungal, associated with increase drug resistance. There researches for new compounds with antifungal action, which may be present at P. granatum justify this study. The extracts were obtained from different parts of P. granatum fruit and tested against ten strains of Candida spp., by minimal inhibitory concentration (MIC) methodology and analyzed by mass spectrometry. Also scan and transmission electron microscopy was employed to evaluate the extracts effects on the yeast's morphology and structures. The results obtained were promising, because the tested strains demonstrated sensibility towards the extracts, with MIC of 125µg/mL, causing damage to the morphology, as irregularities on its superfaces and cell wall. The mass spectrometry analysis showed compounds with known antimicrobial action, among them, tannins. The data indicated that compounds of Punica granatum have antifungal action and the detected substances can be considered to be involved with this activity. Therefore, P. granatum extracts presented antimicrobial capacity and is a promising source for the discovery of new therapeutic agents for alternative treatment, promoting scientist to continue studies on safety, efficiency and standard quality issues for P. granatum / Doutorado / Microbiologia e Imunologia / Doutor em Biologia Buco-Dental

Studies have been made of the reactions which take place when zirconium compounds and vegetable tannins react with chromium tanned leather, in order to elucidate the mechanisms of the reactions which occur on retannage. Statistical procedures have been used in all investigations because of the variable nature of the substrate, and computer techniques have been applied to the repetitive statistical computations. Although chromium and vegetable tannages are well understood, further information on the reaction of zirconium with collagen was necessary before attempting to interpret the results of the studies of combination tannages with chromium, and this has been obtained by a comparative study of the reactions of chromium and zirconium with modified collagen. It is concluded that the mechanism of the reaction of basic zirconium sulphate with collagen is multipoint attachment of the tanning material by residual valency forces, although charge effects with basic groups may be supplementary. Zirconyl chloride reacts with carboxyl groups but does not form satisfactory, stable cross-links with collagen. Further evidence for this theory was obtained from the investigation of the reaction of zirconium compounds with chromium tanned collagen. Zirconyl sulphate does not interfere with effective chromium tannage and therefore can have little affinity for the carboxyl groups on the protein, but it displaces chromium complexes loosely held by auxiliary valencies without reducing the shrinkage temperature of the chromium leather Zirconyl chloride, although only fixed to a limited extent, apparently forms co-ordination compounds with the carboxyl groups, disrupting the chromium tannage because there is an over-all loss of hydrothermal stability. There is no evidence that zirconium co-ordinates with, or releases acid from chromium-collagen complexes, since combination chromium/zirconium tanned leathers are stable on storage. Retannage of chromium tanned leather with vegetable tanning materials generally results in loss of strength and a product which tends to deteriorate on ageing. Lower initial strength is probably due to the increased avidity of chromium tanned pelt for vegetable tannins, resulting from the liberation of internally neutralised reactive sites which are not normally available in vegetable tannage, and from the co- ordination of vegetable tannins and non-tannins to the chromium complex with the displacement of sulphate radicals. From a study of the retannage of chromium tanned modified collagen, it appears that basic groups probably play an important part in the rapid absorption of vegetable tannin. These reactions result in overloading of the fibre and an increased number of cross-links, both of which tend to produce weak leather. Deterioration with age is primarily a hydrolytic degradation of the protein which is catalysed by acid liberated from the chromium complexes by the entry of vegetable tannins, those factors which favour the formation of acid causing greater and more rapid deterioration.

M.Sc. (Botany) / Please refer to full text to view abstract

Fireweed (Senecio madagascariensis) is a noxious and invasive weed affecting pastures in Hawaii, Australia, and South America. Fireweed contains compounds called pyrrolizidine alkaloids that are toxic to most grazing mammals. Toxic effects to cattle include irreversible damage to liver cells, hardening of the liver, and loss of liver function, which may lead to jaundice, swelling, and the accumulation of fluids in the stomach and other physiological malfunctions. External effects include rough appearance, diarrhea, low energy and dullness, photosensitization, and abnormal behavior, many of which can lead to death. Fireweed also can reduce pasture productivity by as much as 30-40%, particularly in Hawaii. As a result of these adverse effects on cattle and pasture production, people are seeking ways to manage fireweed and cattle. Condensed tannins, which are common in many forage legumes, bind with other molecules such as protein and alkaloids. Complementarities among secondary compounds such as condensed tannins and alkaloids can allow animals to consume more of plant material they would otherwise avoid due to toxicity; however, there is very little information on whether tannins actually protect animals from the toxic effect of alkaloids like the ones found in fireweed. The effects of condensed tannins on the toxicity of fireweed to cattle were examined in two stages of a research project that included studies in the lab (in vitro) and in live animals (in vivo). The in vitro studies showed that tannins bound pyrrolizidine alkaloids in cattle rumen fluid and binding was highest when mixed with tannins at 8%, with some effect at 12% as well, by weight of fireweed. The in vivo studies were inconclusive as animals from both the Fireweed and Fireweed-Tannin group demonstrated ill-effects brought on by the fireweed. The data gathered in the form of blood tests and liver tests did not identify a clear protective effect provided by having tannin in the diet, but the results likely were affected by the way we conducted the research, which involved dosing animals daily with large amounts of plant material. The findings also illustrate how strongly cattle avoid eating fireweed while grazing on pasture. In summary, management to reduce fireweed effects on cattle should focus on improving pasture diversity and resiliency, on multi-species grazing to take advantage of the innate resistance of sheep and goats to fireweed’s toxicity, and on ways to enable cattle to utilize fireweed.

Present methods for the production of leather from animal hides still depend from the most part on the use of natural tannin extracts. During the year, 1952, the amount of natural tannin extracts used by the leather industry was 560,452,119 pounds as compared to 35,793,000 pounds of synthetic tanning materials. It is not as yet possible to produce synthetic materials as economically as the natural extracts; the result being that there is still a very great demand for natural tannin extracts. The need for finding new domestic sources of tannins is apparent when the amounts of domestic and imported extracts are compared. During the period 1940-1950, only 744,394,560 pounds of natural tannin extracts were produced domestically as compared to 1,579,244,280 pounds of tannin extracts which were imported. Tannins are known to occur in various parts of plants and they are also known to occur in the majority of the members of the plant kingdom. The purpose of this research is to investigate the feasibility of utilizing parts of the walnut tree as a source of tannins.

Taken from Discussion and Summary: This investigation explores the potentialities of the bark, wood, leaves, and capsules of the Eucalyptus, Tasmanian Blue (Globulus), Longbeak (Teritocornis), Red-Ironbark (Sideroxylon), and Longbeak (Rostrata), as a domestic source of tannin. The trees were identified by Dr. Ernest E. Stanford, Professor of Botany, College of the Pacific. Results are based on hot plate dried weights and are recorded in the following Tables and Figures. Trees were chosen from the local area, Stockton, California, and from Tracy, California, to determine significant variations between localities. Analysis of the extracts followed the official methods of the American Chemists Association (1946) with no exceptions.

Les polyphénols contenus dans les petits fruits ont été confirmés par des recherches antérieures pour avoir des effets bénéfiques sur la santé humaine. On pense en particulier aux effets des proanthocyanidines (PACs) qui permettent d'améliorer les paramètres cardiométaboliques, ainsi qu'aux ellagitanins, qui eux-mêmes après une intense dégradation microbienne, libéreront des urolithines qui sont responsables des effets bénéfiques contre les maladies tels que le cancer, le diabète. Ce mémoire de maîtrise focalise donc principalement sur ces tanins, que contiennent la viorne trilobée et les akènes de fraises. Les objectifs sont d'optimiser les paramètres d'extraction des PACs et des ellagitanins de la viorne trilobée et d'akènes de fraise respectivement, et de caractériser ces composés phénoliques. Dans cette étude, le solvant utilisé est l'éthanol, car il est caractérisé GRAS (Generally Recognized as Safe), et peut donc être utilisé dans les produits alimentaires. La méthode de surface de réponse de Box Behnken a été utilisée pour déterminer les effets des autres paramètres d'extraction, à savoir la température, la concentration d'éthanol et l'acidification du milieu extractif. Les plages suivantes ont été testées : température entre 20 et 60°C, concentration en éthanol de 40 à 80 % et acidité du milieu extractif de 0 à 1 %. Les résultats obtenus ont montré que le meilleur paramètre d'extraction des PACs était une concentration de 80% d'éthanol, les autres paramètres ont eu peu d'effets. Lors de l'analyse par la méthode de chromatographie liquide à haute performance, des monomères, des dimères, un certain nombre d'oligomères, entre DP3- DP10, ainsi que des polymères de PACs de DP>10 ont été identifiés dans les extraits de la viorne trilobée. Rappelons que le DP ou le degré de polymérisation est le nombre d'unités de monomères contenu dans un polymère. En comparaison avec la canneberge, qui est un fruit riche en PACs, la viorne trilobée s'est avérée être plus riche en PACs, les teneurs en PACs totaux étaient respectivement de 7346 mg éq épicatéchine/100g MS et de 4478mg éq épicatéchine/100g MS pour la viorne et la canneberge, respectivement. Quant aux akènes de fraises, les conditions optimales d'extraction des composés phénoliques étaient une température de 60°C, une concentration en éthanol de 68%, l'acidification du milieu extractif a eu peu d'effet. Lors de la quantification des ellagitanins des akènes de fraise par la méthode de chromatographie liquide ultra haute performance couplée à la spectrométrie de masse à temps de vol (UPLC-QToF-MS), nous avons trouvé qu'ils contenaient des ellagitanins dont la teneur était de 799 mg/100g MS. Les ellagitanins étaient la catégorie de composés phénoliques majoritaires dans les akènes de fraises, car ils représentaient 82% des polyphénols totaux, qui étaient de 977 mg/100g de matière sèche. Lorsque nous avons identifié ces ellagitanins à l'aide de la méthode de chromatographie liquide à ultra haute performance couplée à la spectrométrie de masse à trappe orbitale. Cette méthode nous a permis d'identifier les ellagitanins à un niveau d'identification 3, selon la classification de (Sumner et al., 2007). Les ellagitanins suivants ont été potentiellement retrouvés: la sanguiine H6, l'agrimoniine, la fragariine A, la sanguiine H2, la casuarictine, des isomères de la pédunculagine, la tellimagrandine I et des isomères d'isostricitine, dont la présence avait déjà été rapportée dans les akènes et les fruits de fraises, et l'acide chébulagique et la géraniine dont la présence potentielle a été rapportée pour la première fois dans la fraise. Cette étude a permis de comprendre que les akènes de fraises peuvent être valorisés en extraits d'ellagitanins. Aussi, d'avoir un aperçu que les composés présents dans les akènes de fraises sont probablement plus diversifiés que les composés présents dans le réceptacle. Ces composés spécifiques aux akènes suscitent alors de nouvelles études sur la caractérisation des métabolites des akènes de fraises, ainsi que leurs effets sur le microbiote intestinal.

No description available.

Une étude expérimentale a été menée afin de protéger des attaques biologiques des contreplaqués faits d'essences non durables (hêtre et peuplier), et ce, avec un faible impact environnemental. Des produits de protection à base de tannins et de bore, nouvellement développés afin de réduire le lessivage du bore, ont été sélectionnés pour ce but. Ce système a été utilisé pour protéger les contreplaqués selon deux approches : (1) au niveau de la colle pour remplacer les adhésives à base de formaldéhyde et coller les plis, (2) en traitement des plis avec des formulations plus diluées, les plis étant collés avec des adhésifs mélamine-urée-formaldéhyde. Les données expérimentales de cette thèse peuvent être classées en trois grands groupes : essais chimiques et thermomécaniques des colles tannin-bore, mesure des propriétés physiques et mécaniques, de la résistance biologique avant et après vieillissement des différents panneaux. Les essais chimiques sur les colles tannin/hexamine ont montré que l'addition de bore sous forme d'acide borique peut contribuer à plus de liaisons inter-flavonoids et à ouvrir les cycles pyranes ce qui accélère les réactions de polymérisation. Des analyses thermomécaniques sur les colles contenant des tannins de mimosa et de quebracho ont confirmé que l'addition d'acide borique (1) abaissait le temps et la température de prise, et (2) augmentait les valeurs du module d'élasticité de la colle. L'addition d'une quantité optimale d'acide borique dans la colle à base de tannin augmente les propriétés physiques et la résistance au cisaillement. Une charge excessive d'acide borique (10%) dans la colle est la cause de pertes de propriétés mécaniques et physiques. Bien qu'en faible quantité, l'introduction de l'acide borique dans la colle de tannin amène une protection efficace contre l'attaque fongique, même après un lessivage selon l'EN 1250-2. Les résultats des essais termites montrent que l'acide borique contenu dans la colle cause le plus faible taux de survie des insectes et de perte de masse, mais présentent un fort degré d'attaque selon une cotation visuelle. Aucune amélioration n'a été obtenue lors d'un essai de choix après lessivage. Les contreplaqués faits de plis traités par des solutions tannin-bore ont montré des résistances au cisaillement plus faibles, mais toujours dans les gammes requises pour des applications en atmosphère humide. Des résultats satisfaisants ont été obtenus par les réseaux polymères de tannins, même après une lessivage sévère, vis-à-vis de l'attaque fongique. Les contreplaqués faits de plis traités à l'acide borique seul ont présenté une sensibilité importante à l'attaque biologique après un lessivage. Les résultats des essais termites ont montré un faible taux de survie des insectes et de perte de masse, même après un lessivage sévère, pour les contreplaqués avec des plis traités par des systèmes tannin-bore. Les résultats d'un essai de choix a montré que les termites préféraient se nourrir des témoins quand l'alternative proposée était des échantillons traités avec des systèmes tannin-bore. / An experimental investigation was conducted to protect plywood panels made of perishable wood species (beech and poplar) against biological attacks with low environmental impact. The newly developed tannin-boron preservative which was proposed to reduce the leaching of borates was selected for this purpose. This system was used to protect plywood with two approaches: (1) in the glue line to replace formaldehyde based adhesives and gluing wood veneers, (2) pretreatment of wood veneers with the diluted formulations and bonded with melamine-urea-formaldehyde resin The research data in this thesis were obtained from three main groups of experiments: chemicals and thermomechanical testing on the tannin-boron resin, measuring physical and mechanical properties, and different biological tests before and after leaching processes. The chemicals testing on the tannin/hexamine adhesive showed that the addition ofboron, in the form of boric acid, can contribute more inter-flavonoid linkages and the opening of pyran rings which leads to the acceleration of polymerization reactions. Thermomechanical analysis on the adhesives of mimosa and quebracheo tannins confirmed that the addition of boric acid (1) lowered time and temperature of hardening, (2) and increased modulus of elasticity values of the adhesive. The addition of optimal boric acid into the tannin adhesive upgraded physical properties and tensile shear strength. An excess loading of boric acid (10%) in the glue line caused imperfect physical and mechanical features. Despite the low uptake of boric acid but its addition into the tannin glue provided effective resistance against fungal attack even after mild leaching test according to the EN 1250-2. The results of termites test showed that increase in the boric acid content of the adhesive caused the lower survival rate and the weight loss but samples underwent the high level of attack. No improvement against termite attack was obtained after leaching by a choice feeding test. The plywoods made of pretreated veneers by tannin-boron solutions showed partially lower tensile shear strength but still in the range of standards requirements for the humid applications. The satisfactory results were obtained even after severe leaching test against fungal attack with a strong polymeric network of tannin. The control plywoods made of pretreated veneers with boric acid alone solutions presented significant sensitivity against biological attack after leaching test. The results of termite tests showed the lower survival rate and the weight loss even after severe leaching test for the plywoods made of pretreated veneers with tannin-boron systems. The results of choice feeding test showed that termites preferred feeding from the controls when alternative samples were treated with the tannin-boron system. In general the evidence from this study suggests that tannin-boron system can significantly slow down the leaching of boron and it rendered high potential to preserve plywood.