RESUMO
OBJECTIVE:To study the antioxidant activity in vitro of neutral polysaccharides and its graded component from 3samples of white ginseng and red ginseng. METHODS:The decoction method was used to extract the crude polysaccharides fromwhite ginseng,100 ℃ and 120 ℃ processed red ginseng;the crude polysaccharides were further separated through ion exchangecolumn to extract neutral polysaccharides;Sephadex G-75 gels filter column was used to grade the neutral polysaccharides accordingto the molecular weight,antioxidant activity in vitro of 9 samples in 3 neutral polysaccharides and were detected by DPPH andOH free radical scavenging test and reduction capacity test(FRAP value),and vitamin C was used as positive control. RESULTS:The 3 neutral polysaccharides all obtained component Ⅰ and component Ⅱ after grading. Neutral polysaccharides and its gradedcomponent showed certain antioxidant activity in vitro in a certain concentration range,and increased by concentration increasing.The activity of neutral polysaccharides and component Ⅱ from 120 ℃ processed red ginseng was the strongest,of which 50% inhibitoryconcentration(IC50)on DPPH free radical was 0.258 g/L and 0.253 g/L,on OH free radical was 7.157 g/L and 6.845g/L,FRAP values were 2.8 and 3.0 mmol/L(when concentration was 1.2 g/L),respectively. CONCLUSIONS:The antioxidant activityin vitro from 120 ℃ processed red ginseng is higher than that of 100 ℃ processed red ginseng and white ginseng,in whichcomponent Ⅱ makes important contribution to the antioxidant activity.