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Devido à sua composição rica em compostos fenólicos, o mirtilo tem demonstrado diversos benefícios para a saúde humana, nomeadamente atividade antitumoral, anti-inflamatória e antimicrobiana, entre outras, e tendo sido mais recentemente associado à modulação da microbiota intestinal. Uma vez que anteriormente se demonstrou que um extrato de mirtilo rico em antocianinas era capaz de modular a adesão de microrganismos patogénicos num modelo in vitro de adesão intestinal, este trabalho procurou perceber o efeito do mesmo extrato sobre o metabolismo de microrganismos probióticos e como os metabolitos de fermentação dos mesmos poderiam afetar a viabilidade e modular a adesão bacteriana a células intestinais. De um ponto de vista laboratorial, foram definidas 3 etapas para possibilitar a execução do trabalho experimental. Na primeira avaliou-se o efeito de um extrato de mirtilo sobre o processo fermentativo de quatro microrganismos probióticos, e de uma mistura dos mesmos, analisando-se o número total de colónias formadas, o consumo de açúcares e a produção de ácidos orgânicos. A segunda etapa focou-se na avaliação do efeito dos metabolitos de fermentação (ocorrida na presença e ausência de extrato) sobre a viabilidade celular da linhagem de células intestinais Caco-2. Posteriormente, e mantendo-se na mesma linha investigativa, analisou-se o impacto do extrato sobre a adesão das bactérias probiótica às linhagens intestinais Caco-2 e HT29-MTX, sendo esta última produtora de muco. Os resultados relativos à fermentação do extrato, mostram que este não inibiu as contagens viáveis (embora as contagens de Lactobacillus fossem inferiores na presença de extrato relativamente às de Bifidobacterium) e que a produção de ácidos foi superior na presença do mesmo. Relativamente ao efeito dos sobrenadantes sobre a viabilidade de células Caco-2, verificou-se que estes tinham um impacto reduzido sobre o metabolismo celular, observando-se percentagens de inibição de metabolismo inferiores às dos controlos. Adicionalmente, os sobrenadantes resultantes das fermentações de Bifidobacterium animalis subsp. lactis BO na presença de extrato aparentaram promover o metabolismo celular. Finalmente, no que se refere ao impacto do extrato sobre a adesão de duas bactérias probióticas (Lactobacillus rhamnosus R11 e B. animalis subsp. lactis BB12) aos modelos celulares selecionados, verificou-se que a presença de extrato e os maiores tempos de adesão testados (nomeadamente, 120 e 180 minutos) resultavam em maiores valores de percentagem relativa, sendo Bifidobacterium o microrganismo dos dois testados com maiores valores de adesão para ambas as linhagens.
Blueberries have long been known to possess several biological properties, such as antimicrobial, antioxidant and anti-inflammatory activity, which are beneficial for human health. One of the latest additions to the list of blueberries known properties has been intestinal microbiota modulation. Considering that an anthocyanin rich blueberry extract has been previously shown to be capable of modulating pathogenic microorganisms adhesion in an in vitro adhesion model, this work sought to understand how the same extract would impact upon known probiotics’ metabolism and how these microorganisms’ metabolites would affect intestinal cell’s viability and modulate bacterial adhesion to intestinal cells. To do so, a three-step approach was drawn. In the first step, the extract’s capability to interfere in the fermentative process of four different probiotic bacteria, as well as a mixture of those, was evaluated through determination of total viable counts, organic acid production and sugar consumption. Secondly, the supernatants resulting from the fermentation in the presence or absence of extract were recovered and studied to see if they exerted any negative impact upon the viability of a cell line resembling the intestinal epithelium, namely Caco-2 cells. Lastly, and keeping in this line of thought, the effect of the extract upon probiotic bacteria (Lactobacillus rhamnosus R11 and B. animalis subsp. lactis BB12) adhesion to intestinal cells, (namely Caco-2 and the mucus producing HT29-MTX) was assayed. From a fermentation standpoint, the results obtained showed that the extract did not inhibit the growth of the bacteria tested (although the Lactobacillus tested had slightly lower viable counts in the presence of extract than the Bifidobacterium), and stimulated acid production which was significantly higher in its presence. When considering the fermentation supernatants’ impact upon Caco-2’s viability, the extract supernatants had an overall lower impact upon the cell’s metabolism, with lower metabolic inhibitions being observed. Additionally, supernatants fermented by Bifidobacterium animalis subsp. lactis BO appeared to promote cellular metabolism. Lastly, when evaluating the effect of the extract upon bacterial adhesion to the selected cellular models, it was possible to see that the presence of extract resulted in higher relative adhesion percentage values, and the Bifidobacterium tested had higher adhesion values for both cell lines in the presence of extract, which stands in accordance with reports that claim bifidogenic activity is enhanced in the presence of phenolic compounds.
Blueberries have long been known to possess several biological properties, such as antimicrobial, antioxidant and anti-inflammatory activity, which are beneficial for human health. One of the latest additions to the list of blueberries known properties has been intestinal microbiota modulation. Considering that an anthocyanin rich blueberry extract has been previously shown to be capable of modulating pathogenic microorganisms adhesion in an in vitro adhesion model, this work sought to understand how the same extract would impact upon known probiotics’ metabolism and how these microorganisms’ metabolites would affect intestinal cell’s viability and modulate bacterial adhesion to intestinal cells. To do so, a three-step approach was drawn. In the first step, the extract’s capability to interfere in the fermentative process of four different probiotic bacteria, as well as a mixture of those, was evaluated through determination of total viable counts, organic acid production and sugar consumption. Secondly, the supernatants resulting from the fermentation in the presence or absence of extract were recovered and studied to see if they exerted any negative impact upon the viability of a cell line resembling the intestinal epithelium, namely Caco-2 cells. Lastly, and keeping in this line of thought, the effect of the extract upon probiotic bacteria (Lactobacillus rhamnosus R11 and B. animalis subsp. lactis BB12) adhesion to intestinal cells, (namely Caco-2 and the mucus producing HT29-MTX) was assayed. From a fermentation standpoint, the results obtained showed that the extract did not inhibit the growth of the bacteria tested (although the Lactobacillus tested had slightly lower viable counts in the presence of extract than the Bifidobacterium), and stimulated acid production which was significantly higher in its presence. When considering the fermentation supernatants’ impact upon Caco-2’s viability, the extract supernatants had an overall lower impact upon the cell’s metabolism, with lower metabolic inhibitions being observed. Additionally, supernatants fermented by Bifidobacterium animalis subsp. lactis BO appeared to promote cellular metabolism. Lastly, when evaluating the effect of the extract upon bacterial adhesion to the selected cellular models, it was possible to see that the presence of extract resulted in higher relative adhesion percentage values, and the Bifidobacterium tested had higher adhesion values for both cell lines in the presence of extract, which stands in accordance with reports that claim bifidogenic activity is enhanced in the presence of phenolic compounds.
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Microbiota intestinal Antocianinas Compostos fenólicos Bactérias probióticas Gut microbiota Anthocyanins Phenolic compounds Probiotic bacteria