Influence of the exopolysaccharides of polyphenol-conditioned lactic acid bacteria on gut microecology and bacterial translocation
Boubakeur Badra, Drabo M. Soungalo, Khadem Hafidha, Mullier Catherine and Tirtouil Aicha
The aim of this work was to assess in vivo prebiotic effects of exopolysaccharides produced by polyphenols extract-conditioned lactic acid bacteria. The polyphenolic content of Thymus fontanesii was extracted in water by sonication, with a yield of 41.5% and 156 mg equivalent of gallic acid/g. Gallic, caffeic, syringic, vallinic and carboxylic acids, catechin, and epicatechin were the important phenolic acids identified in the extract. Then, two dairy industrial strains Streptococcus thermophilus and Lactobacillus bulgaricus were treated at different concentrations with the extract to improve exopolysaccharides production. Streptococcus thermophilus yielded more exopolysaccharides, thrice than control (826 mg/l vs 219 mg/l), in presence of 100 μg/ml (concentration of 0.01 mg/ml) of the polyphenolic extract. Besides, polyphenols had no significant effect on Lactobacillus bulgaricus for exopolysaccharides production. Last, the effects of Streptococcus thermophilus exopolysaccharides produced in presence of the polyphenols were evaluated on gut microecology composition on some bacteria and bacterial translocation in liver, spleen, kidneys, and lungs. The molecules shaped Wistar Rat gut microbiota in favour of beneficial lactic acid bacteria and in detriment of pathogenic bacteria, and prevented bacterial translocation. Therefore, the exopolysaccharides exhibited considerable prebiotic properties.