Structural, antioxidant, and immunomodulatory activities of an acidic exopolysaccharide from Lactiplantibacillus plantarum DMDL 9010

Abstract

This study investigated the structural, antioxidant, and immunomodulatory activities of acidic exopolysaccharide (EPS-LP2) isolated from Lactiplantibacillus plantarum DMDL 9010. EPS-LP2 is composed of fucose (Fuc), arabinose (Ara), galactose (Gal), glucose (Glc), mannose (Man), and D-fructose (Fru) with a molar ratio of 0.13: 0.69: 8.32: 27.57: 62.07: 0.58: 0.46, respectively. Structural analysis of EPS-LP2 exhibited a smooth irregular lamellar surface, rod-like structure with swollen ends and slippery surfaces, and good thermal stability. Based on the methylation and NMR analysis, sugar residues including t-Manp, t-Glcp, 2-Manp, 6-Galp, 6-Glcp, and 4-Glcp were found to exist in EPS-LP2. In the 50∼400 μg/ml range, EPS-LP2 showed negligible neurotoxicity to RAW264.7 cells. Moreover, EPS-LP2 could protect RAW264.7 cells from oxidative injury by lowering the generation of reactive oxygen species (ROS), malondialdehyde (MDA), and the secretion of lactate dehydrogenase (LDH). In contrast, an increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and the concentrations of glutathione (GSH) were observed. Immunoreactivity assays showed that EPS-LP2 could suppress the expression of NO, tumor necrosis factor-α (TNF-α), and interleukin 6 (IL-6) and inhibit the activation of the mitogen-activated protein kinase (MAPK)/nuclear factor-κB-gene binding (NF-κB) cell pathway. Conclusively, EPS-LP2 could be a potential natural antioxidant and immunomodulatory agent in functional foods and medicines.

Bacterial Exopolysaccharides: From Production to Functional Features

“…In the presence of EPS-LP2, ROS, MDA, and LDH contents were reduced in a dose-dependent manner. EPS-LP2 could also protect cells against H2O2-induced oxidative stress by improving SOD, CAT, and GSH-Px activities [150] .…”

“…These findings suggest that the EPS obtained from L. plantarum C88 could enhance both enzymatic and non-enzymatic antioxidant activities as well as mitigate lipid peroxidation. It was reported that acidic exopolysaccharide (EPS-LP2) isolated from Lactiplantibacillus plantarum DMDL 9010 improved the enzymatic antioxidant activity, alleviated the reduction of antioxidant substances, and enhanced the non-enzymatic antioxidant system, leading to a reduction of the cell damage [150] . In the presence of EPS-LP2, ROS, MDA, and LDH contents were reduced in a dose-dependent manner.…”