Glucomannan polysaccharides derived from Pediococcus pentosaceus: From molecular characteristics to inhibition on...

Extracellular polysaccharides (EPS) from Pediococcus pentosaceus were obtained, followed by investigation of their structural and functional properties. Current results indicated the polysaccharides belonged to glucomannans, which mainly consisted of mannose and glucose with a molecular weight of 2248.71 kDa. NMR analysis suggested that the backbone of EPS-2 fraction included 1,2-α-Manp, 1,3-α-Manp, 1,2,6-α-Manp, 1,6-α-Glcp and 1,4-α-Glcp, whereas its side chain consisted of T-α-Manp residues. Importantly, the EPS demonstrated a hyperbranched glucomannan structure, in which its side chains were linked to the backbone via α-1,2- and α-1,6- glycosidic bonds. Furthermore, cell model results demonstrated the existence of ESP-2 fraction depressed HCT116 proliferation but had no side-effect on normal intestinal epithelial cells (doses applied from 50 μg/mL to 1000 μg/mL). Flow cytometry analysis showed that the fraction induced the cell cycle arrest at mid-mitosis and increased the rate of apoptosis. Importantly, transcriptomic data revealed that EPS-2 fraction prevented cancer cell proliferation via enriched IL-17 pathway and enhanced gene expression associated with NF-κB and TNF at a dose of 600 μg/mL. This study might highlight a novel approach for providing a new type of lactic acid bacterial derived exopolysaccharides with the function of attenuating colonic inflammatory responses.