Effects of six flavonoid compounds addition on short-chain fatty acids production and human fecal microbial community change during in vitro fermentation

Abstract

Flavonoid has been proposed to have beneficial effects on human health, including antimicrobial activity. To clarify whether the flavonoid addition has an impact on the volatile fatty acids (VFA) production and the composition of the human fecal microbiota, six flavonoid compounds including baicalin, quercetin, icraiin, luteolin, amygdalin, naringin were investigated using a batch-culture fermentation system. 16S ribosomal RNA (rRNA) gene based polymerase chain reaction- denaturing gradient gel electrophoresis (PCR-DGGE) and real-time PCR were used to monitor the changes in the composition of microbiota after the flavonoid addition. The results showed that incubation of six flavonoids compounds (40 or 160 mg/L) with faecal bacteria, led to a general increase in TVFA production (except baicalin), and improved the acetate, propionate (except baicalin and aringin) and butyrate (except baicalin) production. The analysis of DGGE profiles revealed that fingerprints of the fecal bacteria communities had a similarity of >89% between the control and the flavonoid treatment. As compared with the control, icraiin addition improved the Shannon index of diversity, while no significant differences were observed with baicalin, quercetin, luteolin, amygdalin or naringin addition, the Q-PCR results showed that the numbers of the total bacteria was increased by the naringin addition, and there is a tendency for increased in the bacteria number with the quercetin addition, while no any significant changes were observed on the bacteria number with the baicalin, icraiin, luteolin or amygdalin addition. These observations suggest that the consumption of i¬‚ava-onid-rich foods may support gut health through their ability to exert prebiotic actions, but this flavonoid induced effect may depend on the type of the flavonid. Future human intervention studies will provide further insight into the potential of flavonoid monomers to act as prebiotics in the human large intestine in vivo. Key words: Flavavonid, prebiotics, faecal microi¬‚ora, Microbial diversity, polymerase chain reaction- denaturing gradient gel electrophoresis (PCR-DGGE).