The effect of quercetin on genetic expression of the commensal gut microbes Bifidobacterium catenulatum, Enterococcus caccae and Ruminococcus gauvreauii

Abstract

Quercetin is one of the most abundant polyphenols found in fruits and vegetables. The ability of the gut microbiota to metabolize quercetin has been previously documented; however, the effect that quercetin may have on commensal gut microbes remains unclear. In the present study, the effects of quercetin on the commensal gut microbes Ruminococcus gauvreauii, Bifidobacterium catenulatum and Enterococcus caccae were determined through evaluation of growth patterns and cell morphology, and analysis of genetic expression profiles between quercetin treated and non-treated groups using Single Molecule RNA sequencing via Helicos technology. Results of this study revealed that phenotypically, quercetin did not prevent growth of Ruminococcus gauvreauii, mildly suppressed growth of Bifidobacterium catenulatum, and moderately inhibited growth of Enterococcus caccae. Genetic analysis revealed that in response to quercetin, Ruminococcus gauvreauii down regulated genes responsible for protein folding, purine synthesis and metabolism. Bifidobacterium catenulatum increased expression of the ABC transport pathway and decreased metabolic pathways and cell wall synthesis. Enterococcus caccae upregulated genes responsible for energy production and metabolism, and downregulated pathways of stress response, translation and sugar transport. For the first time, the effect of quercetin on the growth and genetic expression of three different commensal gut bacteria was documented. The data provides insight into the interactions between genetic regulation and growth. This is also a unique demonstration of how RNA single molecule sequencing can be used to study the gut microbiota.

Design of high specificity and sensitive sequencing primers to detect the bifidobacterial population in biological samples

“…Apart from the specificity and relative abundance, the Bif-6 primer pair was able to detect a much wider spectrum of bifidobacterial species both in human stool and breast milk samples compared with the 27f/1492r primer pair. The Bif-6 amplicons of the faecal samples comprised predominantly with the species Bifidobacterium adolescentis, Bifidobacterium catenulatum, and Bifidobacterium longum, which agreed with the results published by other reports describing the biodiversity of human bifidobacteria [6,[27][28][29]. In addition, three other commonly reported faecal bifidobacterial species (namely Bifidobacterium animalis, Bifidobacterium bifidum, and Bifidobacterium breve) [16] were also detected by using the Bif-6 primer pair.…”

Apigenin Impacts the Growth of the Gut Microbiota and Alters the Gene Expression of Enterococcus

“…Clearly, growth of L. rhamnosus GG and B.catenulatum were not affected by apigenin. This is not surprising, considering that L. rhamnosus GG is specifically used as a probiotic because it is unaffected by harsh conditions such as acid and bile [ 23 ] and B. catenulatum is unaffected by other polyphenols, such as quercetin [ 24 ]. It is possible that L. rhamnosus GG and B. catenulatum may respond to apigenin at a higher concentration, however, the low solubility of apigenin in media limits the concentration to no more than 100 µg/mL.…”

The Influence of Polyphenol Compounds on Human Gastrointestinal Tract Microbiota

“…The lack of iron suppresses the growth of sensitive bacteria, mostly aerobic microbes [72]. In Firmann et al's study [73] the influence of quercetin on intestinal commensal bacteria such as Ruminococcus gauvreauii, Bifidobacterium catenulatum and Enterococcus caccae, was evaluated. Outcome of studies show that quercetin does not influence the growth of Ruminococcus gauvreauii but mildly hinder the growth of Bifidobacterium catenulatum and Enterococcus caccae.…”