Abstract: Water-soluble polysaccharides tabled as NPh were separated from lotus roots pomace by hot-water extraction and ethanol precipitation and then purified by ion exchange chromatography of DEAE sepharose fast-flow.After being studied on pH values and three kinds of NaCl concentrations , the purification conditions are found as follows: 50 mmol/L acetic acid- sodium acetate as start buffer, pH value 5.0, elution buffer as 0.5mol/L NaCl mixed with start buffer,and elution rate 6.0 ml/ min.The antioxidant activities of NPh2 evaluated by 1,1-diphenyl-2 picrylhydrazyl DPPH· radical-scavenging activity and protective effects of erythrocyte hemolysis. Though the polysaccharides exhibit no notable inhibition of the DPPH·radical, but effectively inhibit the erythrocyte’s auto-oxidation and prevent the activated hemolysis by H2O2.

Key words: lotus roots, polysaccharide, purification, antioxidation