title: [Correlation Between Functional Groups and Radical Scavenging Activities of Acidic Polysaccharides from Dendrobium].
abstract: OBJECTIVE
  To compare the radical scavenging activity of five different acidic polysaccharides, and to find the correlation with the functional groups.
  
  
  METHODS
  Alkali extraction method and Stepwise ethanol precipitation method were used to extract and concentrate the five Dendrobium polysaccharides, and to determine the contents of sulfuric acid and uronic acid of each kind of acidic polysaccharides, and the scavenging activity to ABTS+ radical and hydroxyl radical. Functional group structures were examined by FTIR Spectrometer.
  
  
  RESULTS
  Five kinds of Dendrobium polysaccharides had different ability of scavenging ABTS+ free radical and hydroxyl free radical. Moreover, the study had shown that five kinds of antioxidant activity of acidic polysaccharides had obvious correlation withuronic acid and sulfuric acid. The antioxidant activity of each sample was positively correlated with the content of uronic acid, and negatively correlated with the content of sulfuric acid.
  
  
  CONCLUSIONS
  Sulfuric acid can inhibit the antioxidant activity of acidic polysaccharide but uronic acid can enhance the free radical scavenging activity. By analyzing the structure characteristics of five acidic polysaccharides, all samples have similar structures, however, Dendrobium denneanum, Dendrobium devonianum and Dendrobium officinale which had β configuration have higher antioxidant activity than Dendrobium nobile and Dendrobium fimbriatum which had a configuration.
authors.forename: Ying
authors.initials: Y
authors.lastname: Liao
authors.forename: Wen-yu
authors.initials: WY
authors.lastname: Yuan
authors.forename: Wen-ke
authors.initials: WK
authors.lastname: Zheng
authors.forename: Ao-xue
authors.initials: AX
authors.lastname: Luo
authors.forename: Yi-jun
authors.initials: YJ
authors.lastname: Fan
mesh_terms: D031667:Dendrobium / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D017665:Hydroxyl Radical; D010936:Plant Extracts / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry*; D013464:Sulfuric Acids / Q000737:chemistry; D014574:Uronic Acids / Q000737:chemistry
chemical_list: D016166:Free Radical Scavengers; D010936:Plant Extracts; D011134:Polysaccharides; D013464:Sulfuric Acids; D014574:Uronic Acids; D017665:Hydroxyl Radical; C033158:sulfuric acid