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The mode of action of the imidazole antimycoticsNicholas, R. O. January 1984 (has links)
No description available.
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Antioxidative and Antimicrobial Activity of Casein Hydrolyzate in Cheddar Whey-Based Edible CoatingsZhang, Yin 17 August 2013 (has links)
Hydrolysis of casein using chymotrypsin results in the formation of polypeptides (CH) with a hydrophobic aromatic amino acid on one end of the chain because the enzyme selectively cleaves the adjacent peptide-bond. Due to resonance of the aromatic micro-domain, thiols become redox-sensitive and actively participate in electron transfer. These types of amphipathic peptides also tend to be membrane-lytic. The two prong approach of this investigation was to, (1) assess antibacterial effect of the CH in beef steak, and (2), to determine its antioxidative efficacy as a constituent of Cheddar whey based edible coating mix. The edible coating prevented coliform growth even at a minute concentration range of 0.15-0.2 % (w/v). Marked antioxidative efficacy of the CH, particularly at a concentration of 0.3% (w/v), was also evident from its remarkable free radical scavenging ability and extended resilience in an abusive model system saturated with peroxyl-radicals generated through controlled pyrolysis.
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Synthesis of silver doped titanium dioxide nanocomposites using tea extract from Aspalathus linearis and evaluation of their antibacterial effects.Kobese, Nokubonga January 2018 (has links)
>Magister Scientiae - MSc / Despite the wide success of antimicrobial agents against waterborne pathogens, waterborne disease continues to pose a threat to both mankind and animals. A major concern is that certain bacteria have developed resistance to antimicrobial agents, as a result of their overuse. Silver (Ag) nanoparticles are widely used for antibacterial purposes such as medical dressings. However, they are highly toxic to human cells. Hence, there is a great interest in developing next generation antibacterial nanoparticles that are as effective as Ag nanoparticles for antibacterial functions, while having less toxicity to human cells. Several methods can be used to generate these antimicrobial nanoparticles, one of which is green nanotechnology. Green nanotechnology uses natural plants such as tea to synthesise nanoparticles rather than chemicals, thus reduce human and animal harm and improve sustainability of antibacterial agents.
Silver-titanium nano-composites (Ag-TiO2 NCs) were synthesised with the hydrothermal method using a tea extract from Aspalathus linearis (Rooibos, RB), and distilled water in the presence of nitrogen. The resulting structures were characterised with high resolution transmission electron microscopy (HRTEM), energy-dispersive spectroscopy (EDS) analysis X-Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). The antibacterial characteristics of these new NCs were evaluated against 3 bacteria: Bacillus cereus, Cupriavidus metallidurans, and Escherichia coli.
The optimum processing conditions to produce 6-nm spherical NPs included maintaining the temperature at 90 °C, the pH at 4.35, and using RB extract at a concentration of 2 mg/mL. The size of silver NPs was reduced in acidic conditions, agglomerated in neutral conditions, and highly reduced in alkaline conditions. Increasing the pH decreased the particle size and narrowed the particle size distribution.
Gram-positive B. cereus showed slight resistance or tolerance to the Ag-TiO2 nanocomposite compared to the gram-negative bacteria E. coli and C. metallidurans. The treatment concentration required for total inhibition of E. coli and C. metallidurans growth was 100 mg/mL. Supported silver nanoparticles has shown to be a suitable way to obtain highly dispersed silver over higher surface area. This approach allowed Ag-TiO2 nanocomposite to be an efficient bactericide, with less silver amount employed.
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Depolymerization of Chitosan by High-Pressure Homogenization and the Effect on Antimicrobial PropertiesLyons, Deidra Shannon 01 August 2011 (has links)
The focus of this study was to look at relationship between polydispersity caused by high pressure homogenization and molecular weight dependent antimicrobial activity of chitosan. It has been shown that chitosan has antimicrobial activity against bacteria, fungi, and viruses. Chitosan is obtained by partial de-N-acetylation of chitin which, consists of a ß 1-4 copolymer of glucosamine and N-acetylglucosamine residues. In this experiment we compared chitosan of sixteen different molecular weights after being processed through a high pressure homogenizer. Processed chitosan (420 kDa average molecular weight, 30% of acetylation) was dissolved in a 1% (v/v) acetic acid in water to a final concentration of 1% (w/v) and apparent viscosity of 183 MPa. The chitosan solution was passed through a high pressure homogenizer with 0-5 passes at pressure levels 0, 100, 200, and 300 MPa. After processing, the chitosan acetate was investigated to determine the effect on polydispersity in terms of molecular weight and the antimicrobial properties of chitosan at different molecular weights. All compounds were tested against Escherichia coli K-12 to determine antimicrobial activity. There is growing interest in the application of chitosan in food industry due to its wide range of desirable properties including being non-toxic and biodegradability. However, as a hydrophobic material, it is very challenging to work with. Though chitosan is a challenge to work my findings indicated a strong antimicrobial relationship with chitosan at 1% concentration with a molecular weight of 200 kDa and lower against E. coli. In conclusion chitosan has viable application with a variety of foods and can be used as a preservative that decrease bacterial activity below detection level’s and helps to prolong shelf-stable products.
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Cinética da redução de cor ICUMSA em caldo de cana-de-açúcar por ozonização em reator RPA/CSTR para produção sulfur-free de açúcar branco / Kinetics ICUMSA color reduction in juice sugarcane by ozonation reactor in RPA/CSTR to produce sulfur-free white sugarCorrêa Nathalia Torres 11 February 2016 (has links)
A clarificação do caldo de cana-de-açúcar consiste em uma das etapas mais importantes dentro de todo o processo de produção de açúcar, isso porque, é a cor do açúcar final que determina seu preço de comercialização no mercado, bem como sua qualidade. Porém, além de ter um processo de redução de cor, que ao final apresente um açúcar de qualidade, é necessário que este processo não gere resíduos, nem para o meio ambiente, nem nenhum resíduos tóxicos que esteja presente no produto final e que venha prejudicar a saúde do consumidor. Desta forma, a busca por processos alternativos à sulfitação - que é a atual operação de clarificação do caldo de cana-de-açúcar na produção de açúcar cristal branco - tornou-se mais frequente. Tais processos são conhecidos como processos oxidativos avançados(POA) e, entre eles está o uso de ozônio. Diante deste cenário avaliaram-se as melhores condições de pH, temperatura e dosagem de ozônio para a redução da cor ICUMSA do caldo de cana-de-açúcar, obtendo como condições ótimas para pH entre 1,64 a 5,0, temperaturas de 50 a 70 °C e dosagens de ozônio entre 1,34 mg O3/min a 3,82 mg O3/min. O estudo cinético da redução da cor ICUMSA do caldo de cana-de-açúcar ozonizado permitiu observar maiores reduções de cor ICUMSA após 60 min de reação, contudo a exposição do caldo a longos períodos, em pH baixos (1,64 e 3,0) associados a altas temperaturas (50 e 70 °C) levou a hidrólise da sacarose em glicose e frutose, o que inviabilizaria o processo. As análises por espectrometria de massas permitiram observar que a redução nos teores de cor ICUMSA das amostras de caldo de cana-de-açúcar ozonizadas não está associadaà eliminação das partículas promotoras de cor, mas sim da precipitação destas partículas, uma vez que não foram identificados novos compostos nas amostras analisadas, mas sim umavariação nas concentrações destes compostos, identificados como lipídios. Além de favorecer a redução da cor ICUMSA do caldo, o ozônio também se apresentou como um agente antimicrobiano, reduzindoa presença de bactérias e fungos nas amostras de caldo tratado. Aanálise em redes neurais artificiais (RNA) mostrou um bom ajuste na maioria dos casos apresentados e indicou que a variável Brix%caldo apresentou maior influência na redução da cor ICUMSA e o tempo a variável que apresentou a menor influência. / Clarification of the sugarcane juice is one of the most important steps within the entire sugar production process, so why is the color of the final sugar that determines its trading price in the market as well as its quality. However, besides having a color reduction process, which ultimately makes a quality sugar, it is necessary that this process does not generate waste or to the environment, and no toxic residues are present in the final product and that may harm consumer health. Thus, the search for alternative processes to sulfite - which is the current operating clarification of sugarcane juice in white crystal sugar production - has become more frequent. Such processes are known as advanced oxidation processes (AOP), and among them is the use of ozone. In this scenario evaluated the best conditions of pH, temperature and ozone dosing for reducing ICUMSA color of sugarcane juice, optimal conditions for obtaining such pH between 1.64 to 5.0, temperatures from 50 at 70 °C and ozone O3 dosages between 1.34 mg/min to 3.82 mg O3/min. The kinetic study of the reduction of ICUMSA color of sugarcane juice ozonized allowed to observe greater reductions ICUMSA color after 60 min of reaction, however the exposure of the juice long periods at low pH (1.64 and 3.0) associated with high temperatures (50 to 70 °C) led to hydrolysis of sucrose to glucose and fructose, which would make the process. Analysis by mass spectrometry allowed to observe that the reduction in ICUMSA color content of sugarcane ozonated juice samples not associated with the elimination of promoting particles color, but the precipitation of these particles, since they were not novel compounds identified in the samples, but a variation in concentration of these compounds, identified as lipids. In addition to further reduce the ICUMSA color of juice, ozone is also presented as an antimicrobial agent, reducing the presence of bacteria and fungi on the treated juice samples. The analysis on artificial neural networks (ANN) showed good fit in most cases presented and indicated that the variable Brix%juice showed greater influence in reducing ICUMSA color and time the variable that had the least influence.
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Cinética da redução de cor ICUMSA em caldo de cana-de-açúcar por ozonização em reator RPA/CSTR para produção sulfur-free de açúcar branco / Kinetics ICUMSA color reduction in juice sugarcane by ozonation reactor in RPA/CSTR to produce sulfur-free white sugarCorrêa Nathalia Torres 11 February 2016 (has links)
A clarificação do caldo de cana-de-açúcar consiste em uma das etapas mais importantes dentro de todo o processo de produção de açúcar, isso porque, é a cor do açúcar final que determina seu preço de comercialização no mercado, bem como sua qualidade. Porém, além de ter um processo de redução de cor, que ao final apresente um açúcar de qualidade, é necessário que este processo não gere resíduos, nem para o meio ambiente, nem nenhum resíduos tóxicos que esteja presente no produto final e que venha prejudicar a saúde do consumidor. Desta forma, a busca por processos alternativos à sulfitação - que é a atual operação de clarificação do caldo de cana-de-açúcar na produção de açúcar cristal branco - tornou-se mais frequente. Tais processos são conhecidos como processos oxidativos avançados(POA) e, entre eles está o uso de ozônio. Diante deste cenário avaliaram-se as melhores condições de pH, temperatura e dosagem de ozônio para a redução da cor ICUMSA do caldo de cana-de-açúcar, obtendo como condições ótimas para pH entre 1,64 a 5,0, temperaturas de 50 a 70 °C e dosagens de ozônio entre 1,34 mg O3/min a 3,82 mg O3/min. O estudo cinético da redução da cor ICUMSA do caldo de cana-de-açúcar ozonizado permitiu observar maiores reduções de cor ICUMSA após 60 min de reação, contudo a exposição do caldo a longos períodos, em pH baixos (1,64 e 3,0) associados a altas temperaturas (50 e 70 °C) levou a hidrólise da sacarose em glicose e frutose, o que inviabilizaria o processo. As análises por espectrometria de massas permitiram observar que a redução nos teores de cor ICUMSA das amostras de caldo de cana-de-açúcar ozonizadas não está associadaà eliminação das partículas promotoras de cor, mas sim da precipitação destas partículas, uma vez que não foram identificados novos compostos nas amostras analisadas, mas sim umavariação nas concentrações destes compostos, identificados como lipídios. Além de favorecer a redução da cor ICUMSA do caldo, o ozônio também se apresentou como um agente antimicrobiano, reduzindoa presença de bactérias e fungos nas amostras de caldo tratado. Aanálise em redes neurais artificiais (RNA) mostrou um bom ajuste na maioria dos casos apresentados e indicou que a variável Brix%caldo apresentou maior influência na redução da cor ICUMSA e o tempo a variável que apresentou a menor influência. / Clarification of the sugarcane juice is one of the most important steps within the entire sugar production process, so why is the color of the final sugar that determines its trading price in the market as well as its quality. However, besides having a color reduction process, which ultimately makes a quality sugar, it is necessary that this process does not generate waste or to the environment, and no toxic residues are present in the final product and that may harm consumer health. Thus, the search for alternative processes to sulfite - which is the current operating clarification of sugarcane juice in white crystal sugar production - has become more frequent. Such processes are known as advanced oxidation processes (AOP), and among them is the use of ozone. In this scenario evaluated the best conditions of pH, temperature and ozone dosing for reducing ICUMSA color of sugarcane juice, optimal conditions for obtaining such pH between 1.64 to 5.0, temperatures from 50 at 70 °C and ozone O3 dosages between 1.34 mg/min to 3.82 mg O3/min. The kinetic study of the reduction of ICUMSA color of sugarcane juice ozonized allowed to observe greater reductions ICUMSA color after 60 min of reaction, however the exposure of the juice long periods at low pH (1.64 and 3.0) associated with high temperatures (50 to 70 °C) led to hydrolysis of sucrose to glucose and fructose, which would make the process. Analysis by mass spectrometry allowed to observe that the reduction in ICUMSA color content of sugarcane ozonated juice samples not associated with the elimination of promoting particles color, but the precipitation of these particles, since they were not novel compounds identified in the samples, but a variation in concentration of these compounds, identified as lipids. In addition to further reduce the ICUMSA color of juice, ozone is also presented as an antimicrobial agent, reducing the presence of bacteria and fungi on the treated juice samples. The analysis on artificial neural networks (ANN) showed good fit in most cases presented and indicated that the variable Brix%juice showed greater influence in reducing ICUMSA color and time the variable that had the least influence.
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Modifikace parametrů nanočástic z polyesterů alifatických hydroxykyselin. / Modification of parameters of nanoparticles prepared from aliphatic hydroxyacids polyesters.Křivková, Marie January 2017 (has links)
Charles University Faculty of Pharmacy in Hradec Králové Department of Pharmaceutical Technology Consultant: doc. RNDr. Milan Dittrich, CSc. Student: Marie Křivková Title of Thesis: Modification of parameters of nanoparticles prepared from aliphatic hydroxyacids polyesters Polyesters of aliphatic α-hydroxyacids are mentioned in the theoretical part. A significant part of it is mostly devoted to the polyester PLGA. Physicochemical properties, the process of biodegradation and biodistribution are described there. Subsequently, some examples of PLGA utilization in pharmacy and medicine are mentioned. The theoretical part deals also with the method of diffusion used for nanoparticles preparation, which was used in the experimental part, and the principles of size and surface charge measurements of these nanoparticles. The crucial part of this master thesis is based upon an experiment. It is focused on various approaches to the formulation of nanoparticles out of aliphatic polyester carriers with variable molecular constitution. Polymer PLGA with linear molecule and polymers containing PLGA branched on tripentaerythritol and polyacrylic acid were used. Using the diffusion method, nanoparticles were prepared out of these carriers. The outer water-based phase was modified by use of cetrimide of different...
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Complexation to 5-Chloro-8-Hydroxyquinoline Can Improve the Antibacterial Activity of Iron Against Staphylococcus aureusAlidrees, Amjad Idrees 18 November 2022 (has links)
No description available.
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Formulação à base de um extrato do chá verde desenvolvida para uso bucal: avaliação da atividade antimicrobiana e da alteração de cor dental / Formulation based of green tea extract developed for oral use: Evaluation of antimicrobial activity and dental color changeVilela, Marina Moscardini 27 November 2015 (has links)
Atualmente o digluconato de clorexidina (CHX) constitui o agente antimicrobiano de uso bucal mais utilizado na Odontologia devido ao seu amplo espectro de ação contra bactérias, fungos e vírus e efeito residual. No entanto, este agente apresenta efeitos colaterais quando utilizado por longo período, podendo causar coloração extrínseca nos dentes e restaurações, alteração no paladar, sensibilidade na língua e descamação das mucosas. Estes efeitos adversos conduzem à pesquisa de novas formulações. Entretanto, até o momento, nenhum agente antimicrobiano substituiu a clorexidina. Assim, o objetivo deste estudo foi desenvolver uma nova formulação antimicrobiana à base de um extrato de planta derivado do chá verde, a epigalocatequina-3-galato (EGCG), avaliar sua ação antimicrobiana contra microrganismos cariogênicos, in vitro e in vivo, e a possibilidade de alteração de cor dental, in vitro. A atividade antimicrobiana in vitro contra S. mutans, S. sobrinus e L. casei foi avaliada por meio da determinação da concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM), e, posteriormente sua concentração antimicrobiana de uso clínico foi determinada in vivo, após seu uso por crianças com alto risco e atividade da doença cárie. A concentração de microrganismos cariogênicos foi determinada na saliva das crianças, antes e após a realização do bochecho em diferentes concentrações, até se obter a máxima ação antimicrobiana. A clorexidina a 0,12% (Periogard®) e a água destilada foram utilizadas como controle positivo e negativo, respectivamente. A possível alteração de cor dental foi avaliada na coroa de dentes decíduos e permanentes humanos anteriores recém-extraídos, por meio de espectrofotometria (Easy Shade) e obtenção dos valores absolutos de L*, a* e b* (Sistema CIELab). Foi determinada a cor inicial e após a realização de 1, 5, 10 e 30 simulações de bochechos com cada solução testada durante 1 minuto. Os resultados dos ensaios de CIM e CBM in vitro mostraram que a formulação de EGCG inibiu o crescimento de todos os microrganismos cariogênicos avaliados. A CIM de EGCG contra S. mutans, S. sobrinus e para o L. casei foi obtida nas concentrações de 125, 750 e 750 μg/mL, respectivamente. A CBM de EGCG contra o S. mutans, S. sobrinus e para o L. casei foi verificada nas concentrações de 250, 1000 e 1000 μg/mL, respectivamente. A CBM em comum entre os 3 microrganimos foi utilizada como concentração inicial para a avaliação da atividade antimicrobiana in vivo. A partir desse valor a concentração foi sendo dobrada até atingir o valor de 4000 μg/mL, que foi considerada a concentração de EGCG de uso clínico que causou redução da microbiota salivar cariogênica (86,48%) que mais se assemelhou à clorexidina (89,89%). A simulação de bochechos com a formulação de EGCG desenvolvida (4000 μg/mL) causou alteração no valor absoluto das coordenadas L*, a* e b* em dentes decíduos e permanentes, de forma semelhante à causada pela solução de clorexidina. A alteração dos valores absolutos de L* e b* foram reversíveis após a realização de profilaxia dental. Com base nas metodologias e nos resultados obtidos no presente estudo pode-se concluir que a formulação desenvolvida, à base de EGCG, apresenta efeito antimicrobiano contra microrganismos cariogênicos, in vitro e in vivo, e causa alteração de cor dental reversível. / Currently the digluconate of chlorhexidine (CHX) is the antimicrobial agent for oral use most often used in dentistry due to its broad spectrum of activity against bacteria, fungi and viruses, and residual effect. However, this agent has side effects when used for long periods, and may cause extrinsic staining on teeth and restorations, change in taste, tenderness in the language and peeling of the mucous membranes. These adverse events lead to research into new formulations. However, to date, no antimicrobial agent has replaced the chlorhexidine. The objective of this study was to develop a new antimicrobial formulation based of green tea extract, epigallocatechin-3-gallate (EGCG), evaluate their antimicrobial activity against cariogenic microorganisms in vitro and in vivo, and possibility of dental color change in vitro. The in vitro antimicrobial activity against S. mutans, S. sobrinus e L. casei was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and subsequently its antimicrobial concentration was determined in clinical use, after its use for children at high risk and activity of caries. The concentration of cariogenic microorganisms was determined in the saliva of children before and after performing the mouthwash at different concentrations to obtain maximum antimicrobial activity. The chlorhexidine 0.12% (Periogard®) and distilled water were used as positive and negative controls, respectively. The possible dental color change was evaluated on the crown of deciduous and permanent teeth freshly extracted human anterior by means of spectrophotometry (Easy Shade) and obtaining the absolute values of L *, a * and b * (CIELab system). The color was determined in the beginning and after the completion of 1, 5, 10 and 30 mouthwash simulations for 1 minute of each solution tested. In vitro results of MIC and CBM tests showed that formulation EGCG inhibited the growth of all cariogenic microorganisms evaluated similarly to chlorhexidine. The MIC of EGCG against S. mutans, S. sobrinus and L. casei was observed at concentrations of 125, 750 and 750 μg/ml, respectively. EGCG MBC against S. mutans, S. sobrinus and L. casei was observed at concentrations of 250, 1000 and 1000 μg/ml, respectively. The common CBM between the three microbes was used as initial concentration for the evaluation of the antimicrobial activity in vivo. From this value the concentration was being folded up to the value of 4000 μg/mL, which was considered the concentration of EGCG clinical use which caused reduction in salivary microbiota cariogenic (86.48%) that most resembled the chlorhexidine (89.89%). The simulation of mouthwash with the developed formulation EGCG (4000 μg/ml) caused change in the absolute value of the coordinates L *, a * and b * in deciduous and permanent teeth, similar to that caused by chlorhexidine . The changes of the absolute values of L* and b* were reversible after performing dental prophylaxis. Accordance with the procedures and the results obtained in this study it can be concluded that the formulation developed, based on EGCG, has antimicrobial effect against cariogenic microorganisms in vitro and in vivo, and causes reversible change dental color.
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Formulação à base de um extrato do chá verde desenvolvida para uso bucal: avaliação da atividade antimicrobiana e da alteração de cor dental / Formulation based of green tea extract developed for oral use: Evaluation of antimicrobial activity and dental color changeMarina Moscardini Vilela 27 November 2015 (has links)
Atualmente o digluconato de clorexidina (CHX) constitui o agente antimicrobiano de uso bucal mais utilizado na Odontologia devido ao seu amplo espectro de ação contra bactérias, fungos e vírus e efeito residual. No entanto, este agente apresenta efeitos colaterais quando utilizado por longo período, podendo causar coloração extrínseca nos dentes e restaurações, alteração no paladar, sensibilidade na língua e descamação das mucosas. Estes efeitos adversos conduzem à pesquisa de novas formulações. Entretanto, até o momento, nenhum agente antimicrobiano substituiu a clorexidina. Assim, o objetivo deste estudo foi desenvolver uma nova formulação antimicrobiana à base de um extrato de planta derivado do chá verde, a epigalocatequina-3-galato (EGCG), avaliar sua ação antimicrobiana contra microrganismos cariogênicos, in vitro e in vivo, e a possibilidade de alteração de cor dental, in vitro. A atividade antimicrobiana in vitro contra S. mutans, S. sobrinus e L. casei foi avaliada por meio da determinação da concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM), e, posteriormente sua concentração antimicrobiana de uso clínico foi determinada in vivo, após seu uso por crianças com alto risco e atividade da doença cárie. A concentração de microrganismos cariogênicos foi determinada na saliva das crianças, antes e após a realização do bochecho em diferentes concentrações, até se obter a máxima ação antimicrobiana. A clorexidina a 0,12% (Periogard®) e a água destilada foram utilizadas como controle positivo e negativo, respectivamente. A possível alteração de cor dental foi avaliada na coroa de dentes decíduos e permanentes humanos anteriores recém-extraídos, por meio de espectrofotometria (Easy Shade) e obtenção dos valores absolutos de L*, a* e b* (Sistema CIELab). Foi determinada a cor inicial e após a realização de 1, 5, 10 e 30 simulações de bochechos com cada solução testada durante 1 minuto. Os resultados dos ensaios de CIM e CBM in vitro mostraram que a formulação de EGCG inibiu o crescimento de todos os microrganismos cariogênicos avaliados. A CIM de EGCG contra S. mutans, S. sobrinus e para o L. casei foi obtida nas concentrações de 125, 750 e 750 μg/mL, respectivamente. A CBM de EGCG contra o S. mutans, S. sobrinus e para o L. casei foi verificada nas concentrações de 250, 1000 e 1000 μg/mL, respectivamente. A CBM em comum entre os 3 microrganimos foi utilizada como concentração inicial para a avaliação da atividade antimicrobiana in vivo. A partir desse valor a concentração foi sendo dobrada até atingir o valor de 4000 μg/mL, que foi considerada a concentração de EGCG de uso clínico que causou redução da microbiota salivar cariogênica (86,48%) que mais se assemelhou à clorexidina (89,89%). A simulação de bochechos com a formulação de EGCG desenvolvida (4000 μg/mL) causou alteração no valor absoluto das coordenadas L*, a* e b* em dentes decíduos e permanentes, de forma semelhante à causada pela solução de clorexidina. A alteração dos valores absolutos de L* e b* foram reversíveis após a realização de profilaxia dental. Com base nas metodologias e nos resultados obtidos no presente estudo pode-se concluir que a formulação desenvolvida, à base de EGCG, apresenta efeito antimicrobiano contra microrganismos cariogênicos, in vitro e in vivo, e causa alteração de cor dental reversível. / Currently the digluconate of chlorhexidine (CHX) is the antimicrobial agent for oral use most often used in dentistry due to its broad spectrum of activity against bacteria, fungi and viruses, and residual effect. However, this agent has side effects when used for long periods, and may cause extrinsic staining on teeth and restorations, change in taste, tenderness in the language and peeling of the mucous membranes. These adverse events lead to research into new formulations. However, to date, no antimicrobial agent has replaced the chlorhexidine. The objective of this study was to develop a new antimicrobial formulation based of green tea extract, epigallocatechin-3-gallate (EGCG), evaluate their antimicrobial activity against cariogenic microorganisms in vitro and in vivo, and possibility of dental color change in vitro. The in vitro antimicrobial activity against S. mutans, S. sobrinus e L. casei was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), and subsequently its antimicrobial concentration was determined in clinical use, after its use for children at high risk and activity of caries. The concentration of cariogenic microorganisms was determined in the saliva of children before and after performing the mouthwash at different concentrations to obtain maximum antimicrobial activity. The chlorhexidine 0.12% (Periogard®) and distilled water were used as positive and negative controls, respectively. The possible dental color change was evaluated on the crown of deciduous and permanent teeth freshly extracted human anterior by means of spectrophotometry (Easy Shade) and obtaining the absolute values of L *, a * and b * (CIELab system). The color was determined in the beginning and after the completion of 1, 5, 10 and 30 mouthwash simulations for 1 minute of each solution tested. In vitro results of MIC and CBM tests showed that formulation EGCG inhibited the growth of all cariogenic microorganisms evaluated similarly to chlorhexidine. The MIC of EGCG against S. mutans, S. sobrinus and L. casei was observed at concentrations of 125, 750 and 750 μg/ml, respectively. EGCG MBC against S. mutans, S. sobrinus and L. casei was observed at concentrations of 250, 1000 and 1000 μg/ml, respectively. The common CBM between the three microbes was used as initial concentration for the evaluation of the antimicrobial activity in vivo. From this value the concentration was being folded up to the value of 4000 μg/mL, which was considered the concentration of EGCG clinical use which caused reduction in salivary microbiota cariogenic (86.48%) that most resembled the chlorhexidine (89.89%). The simulation of mouthwash with the developed formulation EGCG (4000 μg/ml) caused change in the absolute value of the coordinates L *, a * and b * in deciduous and permanent teeth, similar to that caused by chlorhexidine . The changes of the absolute values of L* and b* were reversible after performing dental prophylaxis. Accordance with the procedures and the results obtained in this study it can be concluded that the formulation developed, based on EGCG, has antimicrobial effect against cariogenic microorganisms in vitro and in vivo, and causes reversible change dental color.
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