Hyperbranched Acidic Polysaccharide from Green Tea

An acidic tea polysaccharide (ALTPS), isolated from green tea (Camellia sinensis), was characterized as a hyperbranched glycoprotein containing the acidic heteropolysaccharide chains and the protein residues from the results of UV−vis, FTIR, one- and two-dimensional NMR, GC, GC-MS, and amino acid analyses. Solution properties of ALTPS were investigated by static and dynamic light scattering analyses and viscometry. The results indicated that the viscosity behavior of ALTPS exhibited a typical polyelectrolyte effect in distilled water, which may be avoided by adding salts. The low intrinsic viscosity of ALTPS in the solutions (8−15 mL/g) is attributed to its hyperbranched structure. By application of the polymer solution theory, it was revealed that ALTPS was present in a sphere-like conformation in the solutions as a result of the hyperbranched structure. The TEM image further confirmed that ALTPS existed in a spherical conformation in aqueous NaCl solution. Glucose was absorbed by ALTPS, which may be one of blood glucose lowering mechanisms of tea polysaccharides.