Isolation and Antioxidant Activity of Acidic Polysaccharide with Water-Solubility from Prunella vulgaris Linn

A new acidic polysaccharide with water-solubility from Prunella Vulgaris Linn was extracted by water, isolated and purified by sequential treatment such as alcohol precipitation, macropole adsorbent resins, and DEAE-Sepharose Fast Flow anion-exchange column chromatography. The weight-average molecular weight of acidic polysaccharide was 57234 Da. The results of FTIR, UV spectra and elemental analysis of acidic polysaccharide found it contained uronic acid and sulfate and amino acid, belonging to sulfated glycoprotein. The contents of uronic acid and sulfate group were 58.85%±0.46% and 7%±0.52% respectively. Sulfated glycoprotein showed good free radical-scavenging activity as evidenced by their low IC50 values (0.88 mg/ml for DPPH radical and 0.80 mg/ml for hydroxyl radical) with in vitro models. Scavenging abilities on DPPH radical and hydroxyl radical of sulfated glycoprotein was in concentration-dependent and reducing power manner. This suggested that the glycoprotein possessed good antioxidant properties and might be a new medicine or functional food.