More attention has recently been paid to the chemopreventive compounds contained in food of plant origin. A large group of chemopreventive compounds are represented by flavonoids contained in many dietary supplements. One of the representatives of this group is dihydromyricetin, which is attributed to positive impact on human organism, in particular by its antioxidant, anti-inflammatory and hepatoprotective effects. Some flavonoids can act as modulators of enzymes of phase I and phase II metabolism of xenobiotics biotransformation by their inhibition or induction which can causean interference with endogenous metabolism. In first part of this present work, the effect of selected flavonoid compounds, such as biochanin A, dihydromyricetin, myricetin and their combinations on the gene expression of cytochrome P450 2E1 (CYP2E1) and sulfotransferases 1A1 (SULT1A1) in liver and small intestine of laboratory rats was studied. The small intestine was divided into three parts namely a proximal, middle and distal. At first, isolation of total RNA was made followed by conversion into cDNA using random hexamers as primers. By real-time PCR a significant decrease in gene expression of both enzymes in liver was found. The highest induction of gene expression was observed for both enzymes in proximal part of...

Submitted by MARCIA ROVADOSCHI (marciar@unifra.br) on 2018-08-16T20:20:00Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AnaJuliaFigueiroDalcin.pdf: 1880693 bytes, checksum: 994407ff94e18668a6d303e7d72b7fd6 (MD5) / Made available in DSpace on 2018-08-16T20:20:00Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Dissertacao_AnaJuliaFigueiroDalcin.pdf: 1880693 bytes, checksum: 994407ff94e18668a6d303e7d72b7fd6 (MD5) Previous issue date: 2015-08-28 / Nosocomial infections associated with biofilm formation in urinary catheters are among the leading causes of complications due to high antimicrobial resistance. An alternative is Dihydromyricetin (DHM), a flavonoid compound extracted mainly from grossedentata Ampelopsis plant, a vine of southern China, where you been widely used as a kind of healthy tea by the population. DHM has demonstrated different pharmacological properties. Among them stands out strong antimicrobial activity to various microorganisms.Therefore, the DHM has low lipid solubility consequently low biodisponibility. The nanoencapsulation can contribute to the improvement of the characteristics of drugs, as increased apparent solubility, protection against toxicity, increased drug activity and stability, sustained release and protection from degradation have been reported. The aim of this study was to evaluate the feasibility of DHM encapsulation and evaluate the influence on antimicrobial and antibiofilm activities in front of urinary catheters with Pseudomonas aeruginosa strains. The analytical method was devoloped and validated to indicate the stability of DHM and to determinaton it in polymeric nanocapsules by high-performance liquid chromatography. The developed method proved to be linear, specific, precise, accurate and robust for determining of DHM in polymeric nanocapsules. The results of the stability indicative studies demonstrated greater stability of nanocapsules than compared with free DHM, suggesting a protective the degradation of the nanostructure. The physicochemical characterization and the stability study of formulations demonstrated to be appropriate with nanometer diameter, positive zeta potential, the quantification of DHM close to the theoretical content, spherical morphology and uniform distribution of particles. The best conditions for storage of the suspensions without losing its physical and chemical characteristics during the period of 90 days was under refrigeration. The results showed that antimicrobial activity of the compound in the free form eliminate the microbial population in 12 hours while the nanocapsules containing DHM took 24 hours to remove the microbial population, extending up to 96 hours in a sustained manner. The antibiofilm activity of the formulations resulted in the eradication of biofilms both in free DHM formulations as in nanocapsules of DHM during the analyzed periods. However, within 96 hours the results of the inhibition of biofilm by DHM nanocapsules were more effective compared with free DHM, 67% of eradicating biofilm population. Thus, the formulation of nanocapsules DHM may be employed in the eradication of biofilms urinary catheters, it may be used as an innovative strategy. / As infecções hospitalares associadas à formação de biofilmes em cateteres urinários estão entre as principais causas de complicações devido à alta resistência antimicrobiana. Uma alternativa é a Dihidromiricetina (DHM), um composto flavonóide extraído principalmente da planta Ampelopsis grossedentata, uma videira do Sul da China, a qual te sido amplamente utilizada como uma espécie de chá saudável pela população. DHM tem demonstrado diferentes propriedades farmacológicas. Dentre elas destaca-se forte atividade antimicrobiana a diferentes microrganismos. Porém a DHM, possui baixa solubilidade lipídica, consequentemente baixa biodisponibilidade. A nanoencapsulação pode contribuir para a melhora das características de fármacos, pois aumento da solubilidade aparente, proteção contra toxicidade, aumento da atividade farmacológica e estabilidade, liberação sustentada e proteção contra degradações têm sido relatada. O objetivo do presente estudo foi avaliar a viabilidade da encapsulação e verificar sua influência sobre atividade antimicrobiana e antibiofilme em cateteres urinários frente a cepas de Pseudomonas aeruginosa. Foi desenvolvido e validado um método analítico indicativo de estabilidade para quantificação de DHM em nanocápsulas através de cromatografia líquida de alta eficiência. O método desenvolvido demonstrou-se linear, específico, preciso, exato e robusto para determinação de DHM em nanocápsulas poliméricas. Os resultados do estudo indicativo de estabilidade nas condições testadas demonstraram uma maior estabilidade da formulação de nanocápsulas de DHM quando comparada com DHM livre, sugerindo uma proteção da nanoestrutura frente às degradações. A caracterização físico-química e o estudo de estabilidade das formulações demonstraram-se adequadas com diâmetro nanométrico, potencial zeta positivo, teor próximo ao teórico, morfologia esférica e distribuição de partícula uniforme. A melhor condição para o armazenamento das suspensões sem perder suas características físico-químicas durante o período de 90 dias foi sob refrigeração. Os resultados da atividade antimicrobiana revelaram que o composto na forma livre eliminou a população microbiana em 12 horas enquanto as nanocápsulas contendo DHM levaram 24 horas para eliminar a população microbiana, estendendo-se até 96 horas de forma sustentada. A atividade antibiofilme das formulações resultou na erradicação dos biofilmes tanto nas formulações de DHM livre quanto nas nanocápsulas de DHM durante os períodos analisados. No entanto, em 96 horas os resultados da inibição do biofilme pelas nanocápsulas de DHM foram mais efetivos quando comparados com DHM livre, erradicando 67% da população do biofilme. Sendo assim, a formulação de nanocápsulas de DHM poderá ser empregada na erradicação de biofilmes em cateteres urinários, podendo ser utilizado como uma estratégia inovadora.

Oxidation limits the shelf life of many food products. Adding antioxidants to foods is the most common way to solve this problem. Reports on safety issues of synthetic food additives have raised consumer interest in "all natural" foods, without added antioxidants or with synthetic replaced with natural antioxidants. The natural antioxidants now in use are much more expensive and less potent than the synthetic antioxidants. Thus, effective and economical natural antioxidants are of great interest to researchers. Teng Cha is a type of herbal tea found in China that has reported high levels of antioxidants. Antioxidant activity of Teng Cha extract and its major component dihydromyricetin has been reported, but no studies have provided clear evidence for the antioxidant effectiveness of Tech Cha extracts. The goal of this study was to measure the antioxidant activity of Teng Cha extract and dihydromyricetin (DHM), a major component of Tech Cha extract. The DPPH assay was conducted and antioxidant activities of the crude extract and dihydromyricetin were evaluated in soybean oil based on the peroxide value, anisidine value, Totox value, headspace volatiles and headspace oxygen. Antioxidant effectiveness was also evaluated in a cooked beef model system. DHM was more potent than BHA in preventing soybean oil oxidation. The crude extract was not as effective as BHA and DHM, possibly because it contained transition metals. In cooked beef, DHM and the crude extract showed lower activity than BHA, possibly due to their low solubility. Overall, Teng Cha extract and DHM are potential natural food antioxidants for future applications. / Master of Science in Life Sciences