title: Structural characterization of extracellular polysaccharides produced by the marine fungus Epicoccum nigrum JJY-40 and their antioxidant activities.
abstract: Two extracellular polysaccharides, ENP1 and ENP2, were isolated from the fermentation liquid of the marine fungus Epicoccum nigrum JJY-40 by anion-exchange chromatography and gel-filtration chromatography, and their structures were investigated using chemical and spectroscopic methods including methylation analysis and NMR spectroscopy. The results demonstrated that ENP1 was composed of mannose, glucose, and galactose in the molar ratio of 5.0:2.1:1.0, and the main chain of the polysaccharide consisted of (1 → 2)-linked mannose, (1 → 3)-linked mannose, terminal mannose, (1 → 6)-linked glucose, (1 → 4)-linked glucose, and (1 → 4)-linked galactose. ENP2 was composed of mannose, galactose, glucose, and glucuronic acid in a molar ratio of 12.4:11.2:8.3:1.0, and its glycosidic linkage patterns included terminal mannose, (1 → 6)-linked glucose, (1 → 4)-linked galactose, and (1 → 3)-linked mannose. The two polysaccharides had a partially branched structure with branch point located at C-3 position of (1 → 6)-linked glucose residue. The molecular weights of ENP1 and ENP2 were 19.2 kDa and 32.7 kDa, respectively. Antioxidant properties of the two polysaccharides were evaluated with hydroxyl, superoxide, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities and lipid peroxidation inhibition in vitro, and results showed that ENP2 and ENP1 had good antioxidant activities, especially ENP2. ENP2 could be effective as a potential antioxidant.
authors.affiliation: Key Laboratory of Marine Drugs, Ministry of Education, Institute of Marine Drug and Food, Ocean University of China, Qingdao, 266003, China.
authors.forename: Hai-Hong
authors.initials: HH
authors.lastname: Sun
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Mao
authors.forename: Jie-Ying
authors.initials: JY
authors.lastname: Jiao
authors.forename: Jia-Chao
authors.initials: JC
authors.lastname: Xu
authors.forename: Hong-Yan
authors.initials: HY
authors.lastname: Li
authors.forename: Yin
authors.initials: Y
authors.lastname: Chen
authors.forename: Xiao-Hui
authors.initials: XH
authors.lastname: Qi
authors.forename: Yan-Li
authors.initials: YL
authors.lastname: Chen
authors.forename: Jian
authors.initials: J
authors.lastname: Xu
authors.forename: Chun-Qi
authors.initials: CQ
authors.lastname: Zhao
authors.forename: Yu-Jiao
authors.initials: YJ
authors.lastname: Hou
authors.forename: Yu-Pin
authors.initials: YP
authors.lastname: Yang
mesh_terms: D000975:Antioxidants / Q000737:chemistry* / Q000378:metabolism*; D001203:Ascomycota / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D011134:Polysaccharides / Q000737:chemistry* / Q000378:metabolism*; D013055:Spectrophotometry, Infrared
chemical_list: D000975:Antioxidants; D011134:Polysaccharides