System isolation and purification of Isatidis Radix polysaccharides and determination of their compositions / 中草药

ABSTRACT

Objective: To isolate and purify the polysaccharides (glycoproteins) from IsatidisRadix (Banlangen) systematically and to study the composition of them. Methods: Crude polysaccharides precipitated by 80% ethanol from thewater extract of IsatidisRadix, which has theanti-viral activity, were fractionated by DEAE-Sepharose Fast Flow, Sephacryl-200, and high gel chromatography system sequentially. The composition of monosaccharides and amino acids of polysaccharides (glycoproteins) was then determined by HPLC with pre-column derivatization using 1-phenyl-3-methyl-5-pyrazolone (PMP) and o-phthalaldehyde (OPA), respectively. Results: Two of homogeneous polysaccharides named IRPS1A and IRPS1B and two of homogeneous glycoproteins named IRPS2A and IRPS3A were obtained from IsatidisRadix by systematical separation and purification. The monosaccharide composition of IRPS1A and IRPS1B was of arabinose, mannose, galactose, and glucose. IRPS2A contained galacturonic acid, glucose, galactose, and arabinose. While IRPS3A contained mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose. The amino acid compositions of IRPS2A and IRPS3A were 14 kinds of amino acid residues including Asp, Glu, Ser, His, Gly, Thr, Arg, Ala, Cys, Val, Phe, Iso, Leu, and Lys. Besides all, IRPS2A also contained Tyr. Conclusion: This strategy can be used for the isolation and purification of homogeneouspolysaccharides/glycoproteins from IsatidisRadixwhich provides a possible support for the elucidation of the structure and the pharmacologic action of IsatidisRadixpolysaccharides (glycoproteins).