Bifidobacterium longum subsp. longum BG-L47 boosts growth and activity of Limosilactobacillus reuteri DSM 17938 and its extracellular membrane vesicles.

The aim of this study was to identify a Bifidobacterium strain that improves the performance of Limosilactobacillus reuteri DSM 17938. Initial tests showed that Bifidobacterium longum subsp. longum strains boosted the growth of DSM 17938 during in vivo-like conditions. Further characterization revealed that one of the strains, BG-L47, had better bile and acid tolerance compared to BG-L48, as well as mucus adhesion compared to both BG-L48 and the control strain BB536. BG-L47 also had the capacity to metabolize a broad range of carbohydrates and sugar alcohols. Mapping of glycoside hydrolase (GH) genes of BG-L47 and BB536 revealed many GHs associated with plant-fiber utilization. However, BG-L47 had a broader phenotypic fiber utilization capacity. In addition, B. longum subsp. longum cells boosted the bioactivity of extracellular membrane vesicles (MV) produced by L. reuteri DSM 17938 during co-cultivation. Secreted 5'-nucleotidase (5'NT), an enzyme that converts AMP into the signal molecule adenosine, was increased in MV boosted by BG-L47. The MV exerted an improved antagonistic effect on the pain receptor transient receptor potential vanilloid 1 (TRPV1) and increased the expression of the immune development markers IL-6 and IL-1ß in a peripheral blood mononuclear cell (PBMC) model. Finally, the safety of BG-L47 was evaluated both by genome safety assessment and in a human safety study. Microbiota analysis showed that the treatment did not induce significant changes in the composition. In conclusion, B. longum subsp. longum BG-L47 has favorable physiological properties, can boost the in vitro activity of L. reuteri DSM 17938, and is safe for consumption, making it a candidate for further evaluation in probiotic studies. IMPORTANCE: By using probiotics that contain a combination of strains with synergistic properties, the likelihood of achieving beneficial interactions with the host can increase. In this study, we first performed a broad screening of Bifidobacterium longum subsp. longum strains in terms of synergistic potential and physiological properties. We identified a superior strain, BG-L47, with favorable characteristics and potential to boost the activity of the known probiotic strain Limosilactobacillus reuteri DSM 17938. Furthermore, we demonstrated that BG-L47 is safe for consumption in a human randomized clinical study and by performing a genome safety assessment. This work illustrates that bacteria-bacteria interactions differ at the strain level and further provides a strategy for finding and selecting companion strains of probiotics.

Hepatoprotective and antioxidant effects of gallic acid in paracetamol-induced liver damage in mice.

OBJECTIVES: The aim of this research paper was to investigate the hepatoprotective and antioxidant effects of gallic acid in paracetamol-induced liver damage in mice. METHODS: In the present study, the hepatoprotective and antioxidant effects of gallic acid were evaluated against paracetamol-induced hepatotoxicity in mice and compared with the silymarin, a standard hepatoprotective drug. The mice received a single dose of paracetamol (900 mg/kg body weight i.p.). Gallic acid (100 mg/kg body weight i.p.) and silymarin (25 mg/kg body weight i.p.) were administered 30 min after the injection of paracetamol. After 4 h, liver marker enzymes (aspartate transaminase, alanine transaminase and alkaline phosphatase) and inflammatory mediator tumour necrosis factor-alpha (TNF-alpha) were estimated in serum, while the lipid peroxidation and antioxidant status (superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase, glutathione-S-transferase and glutathione) were determined in liver homogenate of the control and experimental mice. KEY FINDINGS: Increased activities of liver marker enzymes and elevated TNF-alpha and lipid peroxidation levels were observed in mice exposed to paracetamol (P < 0.05), whereas the antioxidant status was found to be depleted (P < 0.05) when compared with the control group. However gallic acid treatment (100 mg/kg body weight i.p.) significantly reverses (P < 0.05) the above changes by its antioxidant action compared to the control group as observed in the paracetamol-challenged mice. CONCLUSIONS: The results clearly demonstrate that gallic acid possesses promising hepatoprotective effects.