Evaluation of the Prebiotic Potential of Coriolus Versicolor : Effect upon the Human Gut Microbiota

• Main Author: Costa, Célia Maria da Silva Freitas
• Format: Dissertation
• Language: English
• Published: ProQuest Dissertations & Theses 01-01-2018
• Subjects: Alcohol; Antibiotics; Bacteria; Biosynthesis; Birds; Diet; Energy; Fatty acids; Fermentation; Immune system; Immunoglobulins; Immunology; Inflammatory bowel disease; Medicine; Metabolism; Metabolites; Microbiology; Microorganisms; Nervous system; Neurosciences; Obesity; Pathogens; Pathology; Pharmaceutical sciences; Polymerase chain reaction; Public health
• ISBN: 9798381541779

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. versicolorbiomass 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. versicolorbiomass had a bifidogenic effect and, therefore, could be interesting to its establishment as a prebiotic.