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 α (TNF-α) secretion (325.32 ± 51.10 pg/ug DNA). The second lowest TNF- α 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-α 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. •We screened twenty-eight of probiotics, and eight strains were identified based on 16S rDNA sequence and produced exopolysaccharide (EPS).•1 ppm of EPS 4 had the best anti-inflammatory activity on RAW236.7 macrophages. However, 5 ppm EPS 1 had better anti-inflammatory effects than EPS 4, EPS 5, and EPS6.•The monosaccharide percentages (galactose > rhamnose > glucose) were related to the anti-inflammatory activity of the EPSs.•EPS from probiotics possesses anti-inflammatory properties. The monosaccharide content of the EPS was the factor influencing the anti-inflammatory properties.