Study on the characterization of polysaccharide from Tuber sinense and its desensitization effect to β-lactoglobulin in vivo

Abstract

A water-soluble polysaccharide (TPS) with molecule weight of 77.2 kDa, was isolated and purified from Tuber sinense according to antioxygenic and antitumor properties. TPS is a homogeneous polysaccharide linked by → [4-α-D-Glcp-(1]8 → 4)-α-D-Glcp-(1 → in the main chain and α-D-Glcp-(1 → attached to the → 4)-α-D-Glcp-(1 → at O-6 position in the branch. TPS showed high binding capacity for conjugation with β-lactoglobulin (βlg) via noncovalent bonds, forming TPS-βlg conjugates. TPS decreased the β-sheet components in the secondary structure of βlg, the more changes occurred in higher pH. This decrease destroyed the conformation of immunoglobulin E (IgE) epitopes located in the β-sheet, hence impairing IgE combining potential. Moreover, animal experiments indicated TPS-βlg conjugates suppressed the allergic response and repaired the adverse changes induced by βlg. In addition, TPS enhanced 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and antitumor activity for the HeLa cells to the conjugates. This study may expand the desensitization approach to allergens.

Keywords

• Tuber sinense
• Polysaccharide
• β-lactoglobulin
• Desensitization
• Intestinal flora