Abstract:A crude water-soluble polysaccharide (GC C) was obtained from Glycyrrhiza glabra L. Leaf by water extraction. DEAE-Sepharose fast flow column chromatography was used to separate and purify GC C to obtain one neutral polysaccharide (GC I) and two acidic polysaccharides (GC II and GC III). The strongest 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC) were detected in GC I, which was therefore selected for structural characterization. The molecular weight, monosaccharide composition, and glycosidic linkages of GC I were determined by high performance gel permeation chromatography (GPC), infrared spectroscopy (FT-IR), 1-phenyl-3-methyl-5-pyrazolone (PMP) precolumn derivatization-high performance liquid chromatography (HPLC), and methylation-gas chromatography mass spectrometry (GC-MS). It was found that GC I consisted of two polysaccharides with average molecular weights of 980 kDa and 20 kDa. The FT-IR spectra showed the characteristic peaks of the polysaccharides were in the frequency range of 4000-500 cm-1. Monosaccharide composition analysis indicated that GC I contained mannose, rhamnose, glucose, galactose, and arabinose, The residues of →2)-Araf-(1→, →6)-Galp-(1→ and →6)-Glcp-(1→ showed thehighest amounts in GC I.
