Analysis of temporal changes in growth and gene expression for commensal gut microbes in response to the polyphenol naringenin

Authors: Firrman, Jenni; Liu, Linshu; ARANGO ARGOTY, GUSTAVO - Virginia Tech; ZHANG, LIQING - Virginia Tech; Tomasula, Peggy; WANG, MINQIAN - Rutgers University; PONTIOUS, SHERRI - Temple University Medical School; KOBORI, MASUKO - Food Research Institute - Japan; XIAO, WEIDONG - Temple University Medical School

Submitted to: Microbial Insights
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/16/2018
Publication Date: 5/30/2018
Citation: Firrman, J., Liu, L.S., Arango Argoty, G., Zhang, L., Tomasula, P.M., Wang, M., Pontious, S., Kobori, M., Xiao, W. 2018. Analysis of temporal changes in growth and gene expression for commensal gut microbes in response to the polyphenol naringenin. Microbial Insights. 11:1-12. https://doi.org/10.1177/1178636118775100.
DOI: https://doi.org/10.1177/1178636118775100

Interpretive Summary: Naringenin is a nutrient, known as a flavonoid, found in many fruits and vegetables, particularly in citrus fruits and tomatoes. It is an anti-oxidant and associated with multiple health benefits. As part of the diet, naringenin is ingested and enters the human gastrointestinal tract where it comes in contact with the gut microbiota, a large community of bacteria of many species that resides in the large intestine. The goal of this study was to determine if naringenin affects the growth of individual gut microbiota species Ruminococcus gauvreauii, Bifidobacterium catenulatum, and Enterococcus caccae. Naringenin did not change the growth of Ruminococcus gauvreauii; it, slightly increased the growth of Bifidobacterium catenulatum, and severely inhibited the growth of Enterococcus caccae. This demonstrated that naringenin affected each of the bacteria in an individual manner. In addition, each bacteria reacted to naringenin through different genetic processes. These results show that naringenin is able to cause changes to the gut microbiota, which gives insight into one way that flavonoids can affect human health.

Technical Abstract: Naringenin is a polyphenol consumed as part of a healthy diet. After ingestion, naringenin enters the colon and interacts with the gut microbiota. In this study, the effect of naringenin on the growth and genetic expression of the commensal gut microbes, Ruminococcus gauvreauii, Bifidobacterium catenulatum, and Enterococcus caccae, was analyzed. The analysis of growth curves for these strains, cultured with increasing concentrations of naringenin, compared to the control, revealed that growth of Ruminococcus gauvreauii was unaffected by naringenin, growth of Bifidobacterium catenulatum was slightly enhanced by naringenin, and growth of Enterococcus caccae was severely inhibited by naringenin. Changes in genetic expression due to the presence of naringenin were determined through Single Molecule RNA Sequencing to generate gene expression profiles. Analysis revealed the following responses to naringenin: Ruminococcus gauvreauii upregulated genes involved in iron uptake; Bifidobacterium catenulatum upregulated genes involved in cellular metabolism, DNA repair and molecular transport, and downregulated genes involved in thymidine biosynthesis and metabolism; Enterococcus caccae upregulated pathways involved in transcription and protein transport and downregulated genes responsible for sugar transport and purine synthesis. For the first time, the effect of naringenin on growth and gene expression of commensal gut bacteria was documented.