title: Structural characterization and DPPH· radical scavenging activity of a polysaccharide from Guara fruits.
abstract: The crude polysaccharides were extracted from fruits of Psidium guajava Linn. by hot water. After removal of proteins, isolation and purification by DEAE-52 Cellulose chromatography and Sephadex G-75 gel filtration, a polysaccharide (GP70-2) was obtained and structurally characterized. GP70-2 has a relative molecular weight of 74 kDa and was composed of D-galactose and L-arabinose in the ratio of 1:1, with a specific optical rotation of [a]D(25) = +101°. Structural characterization of this novel polysaccharide was carried out using infrared spectroscopy, methylation analyses, and NMR studies ((1)H, (13)C, (1)H-(1)H-COSY, HMQC, and HMBC). Based on the above data, the following structure was assigned to the repeated core unit of GP70-2: [Formula: see text]. This polysaccharide showed a concentration dependent DPPH· radical scavenging activity.
authors: College of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, PR China.
authors: Dehong
authors: D
authors: Hua
authors: College of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, PR China. Electronic address: zhangdez969@163.com.
authors: Dezhi
authors: D
authors: Zhang
authors: College of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, PR China.
authors: Bing
authors: B
authors: Huang
authors: College of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, PR China.
authors: Pan
authors: P
authors: Yi
authors: College of Pharmacy, Guangdong Pharmaceutical University, Guangzhou 510006, PR China. Electronic address: ycybridge@163.com.
authors: Chunyan
authors: C
authors: Yan
mesh_terms: D001713:Biphenyl Compounds / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry*; D019906:Nuclear Magnetic Resonance, Biomolecular; D010851:Picrates / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification; D031647:Psidium / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D011134:Polysaccharides; C004931:1,1-diphenyl-2-picrylhydrazyl
keywords: DPPH· radical scavenging; Polysaccharides; Psidium guajava Linn; Structure