Monosaccharide composition influence and immunomodulatory effects of probiotic exopolysaccharides

Exopolysaccharides (EPSs) are metabolites of probiotics that have gained wide interest recently. A strain of Lactobacillus reuteri Mh-001 with high exopolysaccharide (EPS) production ability was isolated, identified, and were used to investigate the anti-inflammatory effects of the EPSs. Among the three unpurified EPSs, RAW246.7 murine macrophages treated with 5 ppm of EPS 1 revealed the lowest tumour necrosis factor alpha (TNF-alpha) secretion (325.32 +/- 51.10 pg/ug DNA). The second lowest TNF- alpha secretion occurred with EPS 2 (701.12 +/- 86.108 pg/ug DNA) from Mh-002. EPSs 4, 5, and 6 were further purified from EPS 1. Cells treated with 1 ppm of EPS 4 had the lowest TNF-a secretion of all (209.20 +/- 84.34 pg/ug DNA). The monosaccharide components, EPS 4 and EPS 1, had the highest galactose content (45 +/- 2.75% and 39 +/- 2.75%, respectively). The monosaccharide percentages (galactose> rhamnose > glucose) were related to the anti-inflammatory activity of the EPSs. The galactose content of EPSs enhanced their anti-inflammatory effects on the macrophages. These data indicate that EPS possesses beneficial physiological effects such as anti-inflammatory properties, and the monosaccharide content of the EPS was the factor influencing the anti-inflammatory properties. (C) 2019 Elsevier B.V. All rights reserved.