Anti-Helicobacter pylori Activity of a Lactobacillus sp. PW-7 Exopolysaccharide

Helicobacter pyloriis a cause of gastric cancer. We extracted the exopolysaccharide (EPS) ofLactobacillus plajomiPW-7 for antibacterial activity versusH. pylori, elucidating its biological activity and structural characteristics. The minimum inhibitory concentration (MIC) of EPS againstH. pyloriwas 50 mg/mL. Disruption of the cell membranes of pathogenic bacteria by EPS was indicated via the antibacterial mechanism test and confirmed through electron microscopy. EPS also has antioxidant capacity. The IC50of EPS for 2,2-Diphenyl-1-picrylhydrazyl (DPPH) radical, superoxide anions, and hydroxyl radicals were 300 μg/mL, 180 μg/mL, and 10 mg/mL, respectively. The reducing power of EPS was 2 mg/mL, equivalent to 20 μg/mL of ascorbic acid. EPS is a heteropolysaccharide comprising six monosaccharides, with an approximate molecular weight of 2.33 × 104Da. Xylose had a significant effect onH. pylori. EPS fromL. plajomiPW-7 showed potential as an antibacterial compound and antioxidant, laying a foundation for the development of EPS-based foods.Keywords:Helicobacter pylori;Lactobacillus plajomi;exopolysaccharide;antibacterial activity;antioxidant activity