Bacteroides thetaiotaomicron Starch Utilization Promotes Quercetin Degradation and Butyrate Production by Eubacterium ramulus

Abstract

Consumption of flavonoids has been associated with protection against cardiovascular and neurodegenerative diseases. Most dietary flavonoids are subjected to bacterial transformations in the gut where they are converted into biologically active metabolites that are more bioavailable and have distinct effects relative to the parent compounds. While some of the pathways involved in the breakdown of flavonoids are emerging, little it is known about the impact of carbon source availability and community dynamics on flavonoid metabolism. This is relevant in the gut where there is a fierce competition for nutrients. In this study, we show that metabolism of one of the most commonly consumed flavonoids, quercetin, by the gut-associated bacterium Eubacterium ramulus is dependent on interspecies cross-feeding interactions when starch is the only energy source available. E. ramulus can degrade quercetin in the presence of glucose but is unable to use starch for growth or quercetin degradation. However, the starch-metabolizing bacterium Bacteroides thetaiotaomicron , which does not metabolize quercetin, stimulates degradation of quercetin and butyrate production by E. ramulus via cross-feeding of glucose and maltose molecules released from starch. These results suggest that dietary substrates and interactions between species modulate the degradation of flavonoids and production of butyrate, thus shaping their bioavailability and bioactivity, and likely impacting their health-promoting effects in humans.

An acetate‐yielding diet imprints an immune and anti‐microbial programme against enteric infection

“…Our proteomic data showed altered proteins involved in acetate production and starch degrading associated with Bacteroides thetaiotaomicron and Parabacteroides distasonis , a commensal member of the gut microbiota, supporting bacteria functional changes. As such B. thetaiotaomicron can degrade starches and produce butyrate 62 . Although Bacteroides can have beneficial effects in health, 63 it has been reported that interaction between B. thetaiotaomicron and the enteric pathogens can enhance virulence and infection progression 64,65 .…”

“…As such B. thetaiotaomicron can degrade starches and produce butyrate. 62 Although Bacteroides can have beneficial effects in health, 63 it has been reported that interaction between B. thetaiotaomicron and the enteric pathogens can enhance virulence and infection progression. 64,65 Furthermore, HAMSA feeding increased the proportion of an unknown Alphaproteobacteria in the faecal microbiota, similar to what has been observed in pigs fed a resistant starch diet.…”

Gut-derived Flavonifractor species variants are differentially enriched during in vitro incubation with quercetin

“…Human fecal samples were used for in vitro incubations with quercetin. Samples from 9 subjects kept in frozen straws were aliquoted (~50 mg) on dry ice, weighted, and resuspended at 0.5 mg ml -1 final concentration with heavy vortexing in anaerobic 7N minimal medium supplemented with 20 mM sodium acetate (filter-sterilized through a 0.22-m pore diameter) [ 19 ]. Quercetin dihydrate, 97% w/w (Alfa Aesar) concentration was 0.125 mg ml -1 (0.4 mM) in the corresponding medium.…”

“…Samples were processed as previously described [ 19 ]. Briefly, 200 μl samples were mixed with 1000 μl HPLC-grade methanol plus 20 μM genistein as internal standard, the suspension was bead beaten (2 min), heated (56°C for 20 min) and spun (10 min at 18, 000 g ).…”

Bacteroides thetaiotaomicron Fosters the Growth of Butyrate-Producing Anaerostipes caccae in the Presence of Lactose and Total Human Milk Carbohydrates

“…The primary HMOS degraders could drive the microbial community in the infant gut via cross-feeding. As such, the intermediate breakdown products by one bacterial species serve as the substrate to support the growth of other microbes in the environment, resulting in indirect benefits for all species involved [ 11 , 12 , 13 , 14 ]. For instance, Bifidobacterium spp.…”