Study on the Activity of Scavenging Free Radicals of Nostoc flagelliforme Polysaccharides

[Objective] The study aimed to provide scientific foundation for developing medicament and food from Nostoc flagelliforme polysaccharide. [Method] The scavenging effects of N. flagelliforme polysaccharides on free radicals were studied by spectrophotometry. [Result] The extracellular and capsular polysaccharides in N. flagelliforme had some scavenging ability on DPPH radical. When the addition of polysaccharides was 312 μg, the scavenging rate of extracellular polysaccharide (12.8%) on DPPH radical was higher than that of capsular polysaccharide (11.2%). The scavenging effect of extracellular polysaccharide in N. flagelliforme on hydroxyl radical was more significant and the maximum scavenging rate of capsular polysaccharide on hydroxyl radical was 37.7% in the experimental concn. range. The scavenging effects of extracellular and capsular polysaccharides in N. flagelliforme on superoxide radical were more significant and when the polysaccharide was 125 μg/ml, the scavenging rate of extracellular polysaccharide (42.6%) on superoxide radical was a little higher than that of capsular polysaccharide (41.5%). [Conclusion] The extracellular and capsular polysaccharides in N. flagelliforme had scavenging abilities on DPPH, hydroxyl and superoxide anion radicals and in a certain concn. range, their scavenging effects showed positive correlation with polysaccharide concn. The effect of extracellular polysaccharide was stronger than that of capsular polysaccharide.