title: Structure and antioxidant activity of polysaccharide POJ-U1a extracted by ultrasound from Ophiopogon japonicus.
abstract: An ultrasonic technique was employed to extract polysaccharides from Ophiopogon japonicus. The ultrasonic extracted polysaccharides (POJ-U) were purified, and POJ-U1a (a homogeneous fraction) was obtained. The structural characteristics of POJ-U1a were investigated by infrared spectra, gas chromatography, high performance liquid chromatography, periodate oxidation, Smith degradation, methylation analysis, gas chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy. The results indicated that the relative molecular weight of POJ-U1a was 4.02×10(3)Da. POJ-U1a was an α-configuration polysaccharide with a highly branched structure, and consisted of pyranoside and funanside. The backbone of POJ-U1a consisted of 1,6-α-d-glucopyranose and 1,3,6-α-d-glucofuranose in the molar ratio of 7:3, while the branched chains were mainly composed of 1,3-α-d-glucopyranose and 1-α-d-glucopyranose in the molar ratio of 1:3. The branched structure of POJ-U1a was proved intuitively by AFM. Significant antioxidant activity of POJ-U1a has been proved as shown by its DPPH radical scavenging, hydrogen radical scavenging and superoxide anion scavenging activities, which indicated that POJ-U1a showed strong antioxidant activity.
authors.affiliation: Laboratory of Biophysics and Biomedicine Engineering, College of Physics and Information Technology, Shaanxi Normal University, Xi'an 710062, China.
authors.forename: Xiao-mei
authors.initials: XM
authors.lastname: Wang
authors.forename: Run-guang
authors.initials: RG
authors.lastname: Sun
authors.forename: Jing
authors.initials: J
authors.lastname: Zhang
authors.forename: Ying-ying
authors.initials: YY
authors.lastname: Chen
authors.forename: Na-nv
authors.initials: NN
authors.lastname: Liu
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology*; D001713:Biphenyl Compounds; D031441:Ophiopogon / Q000737:chemistry*; D010851:Picrates; D018517:Plant Roots / Q000737:chemistry; D011134:Polysaccharides / Q000737:chemistry* / Q000494:pharmacology*; D013481:Superoxides / Q000737:chemistry
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; C581167:POJ-U1 polysaccharide; D010851:Picrates; D011134:Polysaccharides; D013481:Superoxides; C004931:1,1-diphenyl-2-picrylhydrazyl