title: Preparation and characterization of guluronic acid oligosaccharides degraded by a rapid microwave irradiation method.
abstract: Guluronic acid oligosaccharides (GOS) with degree of polymerization (DP) ranging from 1 to 10 were prepared by a rapid microwave degradation method. Polyguluronic acid, fractionated from alginate hydrolysate, was dissolved in dilute ammonia water at a concentration of 20 mg/mL (pH 5) and then hydrolyzed under microwave irradiation (1600 W) at 130°C for 15 min to produce GOS mixture. The GOS mixture was separated by a Bio-Gel P6 column and ten fractions were obtained. Each GOS fraction was further characterized by electrospray ionization mass spectrometry, (1)H NMR, (13)C NMR, and 2D NMR spectroscopy techniques. The data showed that the GOS fractions were saturated oligoguluronates with general molecular formula C(6n)H(8n+2)O(6n+1) (n=1-10). This microwave degradation method was not only convenient, less time consuming, and environment-friendly, but also produced GOS with high yield (71%) and eliminating a desalting procedure compared to conventional acid hydrolysis method.
authors.affiliation: Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China.
authors.forename: Ting
authors.initials: T
authors.lastname: Hu
authors.forename: Chunxia
authors.initials: C
authors.lastname: Li
authors.forename: Xia
authors.initials: X
authors.lastname: Zhao
authors.forename: Guangsheng
authors.initials: G
authors.lastname: Li
authors.forename: Guangli
authors.initials: G
authors.lastname: Yu
authors.forename: Huashi
authors.initials: H
authors.lastname: Guan
mesh_terms: D006603:Hexuronic Acids; D006868:Hydrolysis; D009682:Magnetic Resonance Spectroscopy; D008872:Microwaves; D008970:Molecular Weight; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization
chemical_list: D006603:Hexuronic Acids; D009844:Oligosaccharides; C007896:guluronic acid