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A microbiota intestinal humana tem-se tornado progressivamente mais relevante no estudo da saúde humana e de certas doenças, devido à sua ligação com o sistema imunitário e com o metabolismo humano. Um modo de modelar a microbiota intestinal é através da ingestão de prebióticos, que podem ser fermentados por bactérias benéficas presentes no cólon, resultando na produção de certos metabolitos considerados benignos, tais como os ácidos gordos de cadeia curta. O Coriolus versicolor é um cogumelo que, embora seja conhecido pelas suas propriedades imunomoduladoras e anticarcinogénicas, também foi anteriormente associado a uma potencial atividade prebiótica. No entanto, os estudos publicados focam se nas potencialidades dos extratos de C. versicolor, enquanto as propriedades da biomassa permanecem pouco estudadas. Assim, o principal objetivo do presente trabalho foi a avaliação do potencial prebiótico de um suplemento comercial de biomassa de C. versicolor, utilizando um modelo fecal in vitro. A fim de atingir o objetivo proposto, a biomassa foi primeiramente submetida a uma simulação do processo digestivo, após a qual esta foi utilizada para realizar fermentações usando fezes de cinco dadores distintos. Durante a fermentação foram recolhidas amostras às 0, 12, 24, e 48 h para realizar medições dos valores de pH e de as caracterizar relativamente à produção de ácidos orgânicos, particularmente, os ácidos gordos de cadeia curta (através de HPLC) e ao seu perfil microbiano (através de qPCR). Apesar da variabilidade intrínseca associada à microbiota intestinal humana entre indivíduos, a presença da biomassa de C. versicolor resultou num aumento do número de cópias do gene 16S rRNA de Bifidobacterium para todos os dadores, em comparação com o controlo negativo, ainda que o aumento global tenha sido inferior ao do controlo positivo (FOS). Este comportamento foi observado após 24 h (controlo negativo- 0,203 ± 0,017; controlo positivo- 0,282 ± 0,011; C. versicolor- 0,238 ± 0,008, expresso como log do número de cópias de 16S rRNA por ng de ADN) e após 48 h (controlo negativo- 0,212 ± 0,016; controlo positivo – 0,301 ± 0,027; C. versicolor- 0,268 ± 0,011, expresso como log do número de cópias de 16S rRNA por ng de ADN), mas não foram encontradas diferenças significativas entre as condições testadas após 12 h de incubação. Relativamente a outros grupos bacterianos (Firmicutes, Bacteroidetes, Bacteroides, Clostridium leptum e Lactobacillus), não foi possível estabelecer uma tendência geral, mas apenas comportamentos específicos de cada dador. De um modo geral, quer o C. versicolor quer o FOS, resultaram numa diminuição dos valores de pH, por oposição ao controlo negativo, o que confirmou a produção de ácidos, como consequência do metabolismo bacteriano. No que se refere à quantificação dos ácidos gordos de cadeia curta e do ácido láctico, no fim da fermentação, a biomassa de C. versicolor levou à produção de ácido acético (0,212 ± 0,088 mg mL-1), seguida de ácido láctico (0,032 ± 0,002 mg mL-1), e do ácido propiónico (0,018 ± 0,007 mg mL-1). Em suma, é possível concluir que a biomassa de C. versciolor teve um efeito bifidogénico, relevante na demonstração do seu potencial prebiótico.
The human gut microbiota has become increasingly relevant when considering human health and disease due to its connection with the immune system and human metabolism. One way of actively modulating the gut microbiota is through the ingestion of prebiotics, that can be fermented by beneficial members of the colonic population, resulting in the production of certain metabolites regarded as beneficial, such as Short Chain Fatty Acids (SCFA). Coriolus versicolor is a mushroom that, while known for its immunomodulatory and anticarcinogenic properties has also been previously described as possessing some prebiotic potential. However, most studies focus on the potentialities of C. versicolor extracts, leaving the properties of its biomass unstudied. Hence, the main goal of the present work was to evaluate the prebiotic potential in a commercial supplement of C. versicolor biomass using an in vitro faecal model. In order to achieve the proposed goal, the biomass was first submitted to a digestion simulation after which, it was used to perform human faecal fermentations using faeces from five distinct donors. Samples were collected at 0, 12, 24 and 48 h, for pH measurements and to be characterized regarding organic acid production, with emphasis on SCFA (through HPLC), as well as characterize the microbial profile (through qPCR). Despite the intrinsic variability of the human gut microbiota between individuals, the presence of C. versicolor biomass consistently resulted in an increase in the number of Bifidobacterium’s 16S rRNA gene copies, for all donors when comparing to the negative control, although the overall increase was lower than the one registered for the positive control (i.e. FOS). This behaviour was observed after 24 h (negative control- 0.203 ± 0.017; positive control- 0.282 ± 0.011; C. versicolor- 0.238 ± 0.008, expressed in log of copy numbers of 16S rRNA per ng of DNA) and 48 h (negative control- 0.212 ± 0.016; positive control- 0.301 ± 0.027; C. versicolor- 0.268 ± 0.011, expressed in log of copy numbers of 16S rRNA per ng of DNA), but no significant differences were found between the assayed conditions after 12 h incubation. For the remaining bacterial groups characterized (Firmicutes, Bacteroidetes, Bacteroides, Clostridium leptum and Lactobacillus) it was not possible to observe a general trend but only donor specific behaviours. Overall, both C. versicolor and FOS resulted in a decrease of the pH values, in opposition to the negative control, which confirmed the production of acids as a result of bacterial metabolism. As for SCFA and lactic acid quantification, at the end of the fermentation, C. versicolor biomass led to the production of acetic acid (0.212 ± 0.088 mg mL-1), lactic acid (0.032 ± 0.002 mg mL-1) and propionic acid (0.0184 ± 0.007 mg mL-1). In sum, it is possible to conclude that C. versicolor biomass had a bifidogenic effect and, therefore, could be interesting to its establishment as a prebiotic.
The human gut microbiota has become increasingly relevant when considering human health and disease due to its connection with the immune system and human metabolism. One way of actively modulating the gut microbiota is through the ingestion of prebiotics, that can be fermented by beneficial members of the colonic population, resulting in the production of certain metabolites regarded as beneficial, such as Short Chain Fatty Acids (SCFA). Coriolus versicolor is a mushroom that, while known for its immunomodulatory and anticarcinogenic properties has also been previously described as possessing some prebiotic potential. However, most studies focus on the potentialities of C. versicolor extracts, leaving the properties of its biomass unstudied. Hence, the main goal of the present work was to evaluate the prebiotic potential in a commercial supplement of C. versicolor biomass using an in vitro faecal model. In order to achieve the proposed goal, the biomass was first submitted to a digestion simulation after which, it was used to perform human faecal fermentations using faeces from five distinct donors. Samples were collected at 0, 12, 24 and 48 h, for pH measurements and to be characterized regarding organic acid production, with emphasis on SCFA (through HPLC), as well as characterize the microbial profile (through qPCR). Despite the intrinsic variability of the human gut microbiota between individuals, the presence of C. versicolor biomass consistently resulted in an increase in the number of Bifidobacterium’s 16S rRNA gene copies, for all donors when comparing to the negative control, although the overall increase was lower than the one registered for the positive control (i.e. FOS). This behaviour was observed after 24 h (negative control- 0.203 ± 0.017; positive control- 0.282 ± 0.011; C. versicolor- 0.238 ± 0.008, expressed in log of copy numbers of 16S rRNA per ng of DNA) and 48 h (negative control- 0.212 ± 0.016; positive control- 0.301 ± 0.027; C. versicolor- 0.268 ± 0.011, expressed in log of copy numbers of 16S rRNA per ng of DNA), but no significant differences were found between the assayed conditions after 12 h incubation. For the remaining bacterial groups characterized (Firmicutes, Bacteroidetes, Bacteroides, Clostridium leptum and Lactobacillus) it was not possible to observe a general trend but only donor specific behaviours. Overall, both C. versicolor and FOS resulted in a decrease of the pH values, in opposition to the negative control, which confirmed the production of acids as a result of bacterial metabolism. As for SCFA and lactic acid quantification, at the end of the fermentation, C. versicolor biomass led to the production of acetic acid (0.212 ± 0.088 mg mL-1), lactic acid (0.032 ± 0.002 mg mL-1) and propionic acid (0.0184 ± 0.007 mg mL-1). In sum, it is possible to conclude that C. versicolor biomass had a bifidogenic effect and, therefore, could be interesting to its establishment as a prebiotic.
Descrição
Palavras-chave
Microbiota intestinal Prebióticos Biomassa de cogumelos Coriolus versicolor SCFA Gut microbiota Prebiotics Mushroom biomass