Biotransformation of Rutin in In Vitro Porcine Ileal and Colonic Fermentation Models.

Quercetin, a polyphenol antioxidant, is widely distributed in food in the form of glycoside rutin, which is not readily absorbed in the gastrointestinal tract. The microbiota of the colon is known to biotransform rutin, generating quercetin aglycones that can be absorbed. We investigated the role of the ileal and colonic microbiota in rutin biotransformation using established in vitro fermentation models. Overall, a higher rate of rutin biotransformation was observed during colonic fermentation compared with ileal fermentation. The colonic microbiome showed higher potential for rutin conversion to quercetin through an increased abundance of α-rhamnosidase- and ß-glucosidase-encoding genes compared to the ileal microbiome. Nonetheless, rutin metabolism occurred rapidly during ileal fermentation (∼20% rutin disappearance after 1 h). The appearance of quercetin varied depending on the ileal inoculum and correlated with an increased abundance of Firmicutes, suggesting that quercetin absorption could be improved via modulation of the ileal microbiota.

A Diet Enriched with Lacticaseibacillus rhamnosus HN001 and Milk Fat Globule Membrane Alters the Gut Microbiota and Decreases Amygdala GABA a Receptor Expression in Stress-Sensitive Rats.

Brain signalling pathways involved in subclinical anxiety and depressed mood can be modulated via the gut brain axis (GBA), providing the potential for diet and dietary components to affect mood. We investigated behavioural, physiological and gut microbiome responses to the Lacticaseibacillus rhamnosus strain HN001 (LactoB HN001™), which has been shown to reduce postpartum anxiety and depression, and a milk fat globule membrane-enriched product, Lipid 70 (SurestartTM MFGM Lipid 70), which has been implicated in memory in stress-susceptible Wistar Kyoto rats. We examined behaviour in the open field, elevated plus maze and novel object recognition tests in conjunction with the expression of host genes in neuro-signalling pathways, and we also assessed brain lipidomics. Treatment-induced alterations in the caecal microbiome and short-chain fatty acid (SCFA) profiles were also assessed. Neither ingredient induced behavioural changes or altered the brain lipidome (separately or when combined). However, with regard to brain gene expression, the L. rhamnosus HN001 + Lipid 70 combination produced a synergistic effect, reducing GABAA subunit expression in the amygdala (Gabre, Gat3, Gabrg1) and hippocampus (Gabrd). Treatment with L. rhamnosus HN001 alone altered expression of the metabotropic glutamate receptor (Grm4) in the amygdala but produced only minor changes in gut microbiota composition. In contrast, Lipid 70 alone did not alter brain gene expression but produced a significant shift in the gut microbiota profile. Under the conditions used, there was no observed effect on rat behaviour for the ingredient combination. However, the enhancement of brain gene expression by L. rhamnosus HN001 + Lipid 70 implicates synergistic actions on region-specific neural pathways associated with fear, anxiety, depression and memory. A significant shift in the gut microbiota profile also occurred that was mainly attributable to Lipid 70.