Identification, Antioxidant and Immunomodulatory Activities of a Neutral Exopolysaccharide from DMDL 9010.

OBJECTIVES

This study investigated the properties of a neutral exopolysaccharide (EPS-LP1) with an average molecular weight of 55,637 Da, isolated from DMDL 9010 (LP9010).

RESULTS

The composition of EPS-LP1 includes galactose (Gal), glucose (Glu) and mannose (Man) in a molar ratio of 5.35:86.25:8.40. Notably, EPS-LP1 exhibits a smooth and rod-like surface along with thermal stability. Methylation combined with nuclear magnetic resonance analysis revealed that EPS-LP1 structured as t-Gal(1→, →6)-Glc(1→, 4)-Glc(1→ and →4,6)-Gal(1→), with relative molar ratio of 1.016:9.874:4.355:78.693:6.062, respectively. In the concentration range of 50 to 400 mg/mL, we observed the absence of cytotoxic effects from EPS-LP1 on RAW264.7 cells. Furthermore, EPS-LP1 demonstrated protective effects on RAW264.7 cells against oxidative damage by reducing the production of reactive oxygen species (ROS), malondialdehyde (MDA), and lactate dehydrogenase (LDH) release. Conversely, an increase in superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and concentrations of glutathione (GSH) was observed. Immunoreactivity assays indicated that EPS-LP1 can effectively reduce the production of nitric oxide (NO) and inhibit the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). Additionally, it inhibited the activation of the mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B gene binding (NF-kB) signaling pathway.

CONCLUSIONS

This research provides a foundation basis for further investigations into the neutral exopolysaccharide derived from LP9010.