Abstract:

The molecular characterization of the polysaccharides purified from Gentianae Radix et Rhizoma was investigated
in this study. By using orthogonal array design, the optimal extraction parameters that provided the maximum yield of
polysaccharides of 12.80% were determined as follows: extraction time 2.5 h, temperature 90 ℃, and ratio of liquid to solid
20:1 (V/m). The crude polysaccharide was purified by DEAE sepharose fast flow chromatography to obtain two fractions,
F1 and F2, with a yield of 14.1% and 63.4%, respectively. All the crude polysaccharide and purified fractions were composed
of neutral sugar, protein, sulfate and uronic acid with various ratios. Arabinose and galactose were the major monosaccharide
units along with a small portion of glucose, rhamnose, mannose and xylose. The molecular weights (Mw) and radii of gyration
(Rg) of all three samples ranged from 67.2 × 103 to 788.4 × 103 u and from 90.2 to 321.1 nm, respectively, as determined by
HPSEC-UV-MALLS-RI system. The results obtained in this study can provide the basis for further bioactivity studies.

Key words: Gentianae Radix et Rhizoma, polysaccharides, separation and purification, molecular characterization