title: Effect of phosphorylation on antioxidant activities of pumpkin (Cucurbita pepo, Lady godiva) polysaccharide.
abstract: Phosphorylated derivatives of pumpkin polysaccharide with different degree of substitution were synthesized using POCl3 and pyridine. Antioxidant activities and cytoprotective effects of unmodified polysaccharide and phosphorylated derivatives were investigated employing various in vitro systems. Results showed that high ratio of POCl3/pyridine could increase the degree of substitution and no remarkable degradation occurred in the phosphorylation process. Characteristic absorption of phosphorylation appeared both in the IR and (31)P NMR spectrum. The df values between 2.27 and 2.55 indicated the relatively expanded conformation of the phosphorylated derivatives. All the phosphorylated polysaccharides exhibited higher antioxidant activities. H2O2-induced oxidative damages on rat thymic lymphocyte were also prevented by the derivatives. In general, phosphorylation could improve the antioxidant activities of pumpkin polysaccharide both in vitro and in a cell system.
authors.affiliation: National Engineering Research Center for Fruits and Vegetables Processing, Beijing 100083, China; College of Agriculture and Biotechnology, China Agricultural University, Beijing 100193, China; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Song
authors.affiliation: National Engineering Research Center for Fruits and Vegetables Processing, Beijing 100083, China; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Yuanying
authors.initials: Y
authors.lastname: Ni
authors.affiliation: National Engineering Research Center for Fruits and Vegetables Processing, Beijing 100083, China; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Hu
authors.affiliation: National Engineering Research Center for Fruits and Vegetables Processing, Beijing 100083, China; College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China. Electronic address: sy587@hotmail.com.
authors.forename: Quanhong
authors.initials: Q
authors.lastname: Li
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D028464:Cucurbita / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D010084:Oxidation-Reduction / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D011134:Polysaccharides / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D017550:Spectroscopy, Fourier Transform Infrared; D060168:Thymocytes / Q000187:drug effects / Q000378:metabolism
chemical_list: D000975:Antioxidants; D010936:Plant Extracts; D011134:Polysaccharides
keywords: Antioxidant activity; Phosphorylation; Pumpkin polysaccharide