Purification, structural elucidation and immunostimulatory effect of a new protein-polysaccharide conjugate produced by Nervilia fordii

Abstract

A novel protein-polysaccharide conjugate NFP-A4 was isolated and purified from water extracts of Nervilia fordii. The polysaccharide chain of NFP-A4 was found to contain D-galacturonic acid, D-galactose, D-glucose, L-arabinose, D-glucuronic acid, L-rhamnose, and D-mannose. The protein content of NFP-A4 was determined to be 12.83%, and it was bound to the polysaccharide chain via O-linkages at the serine and threonine residues. NFP-A4 was found to significantly activate macrophages and also induce immunomodulatory responses. These data suggest that NFP-A4 is a major bioactive component of N. fordii and may be responsible for many of its therapeutic properties.

Keywords:

• Immunostimulatory
• MAPK
• Nervilia fordii
• polysaccharide

Disclosure statement

The authors declare no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Additional information

Funding

This paper was financially supported by the National Natural Science Foundation of China [81260634].