title: Structure Elucidation of a Polysaccharide from Umbilicaria esculenta and Its Immunostimulatory Activity.
abstract: Umbilicaria esculenta has been used as a tonic food in China for several centuries owing to its pleasant flavor and health benefits. In this study, a water soluble polysaccharide, which we designated as UP2, with an average molecular weight of 3.33 × 105 Da, was isolated from U. esculenta cultivated in the Huangshan Mountain, by consecutive hot water extraction and anion-exchange chromatography. Gas chromatography analysis indicated that UP2 contained three kinds of monosaccharides, including mannose, glucose, and galactose at a molar ratio of 1.7:1.0:1.2. Linkage analysis of UP2 revealed the presence of (1 → 6)-linked glucosyl, (1 → 3,6)-linked glucosyl, t-linked galactosyl, (1 → 6)-linked galactosyl and (1 → 6)-linked mannosyl at a molar ratio of 0.7:4.6:4.1:2.2:9.1. Structural analysis determined that UP2 possessed a backbone consisting of (1 → 6)-linked β-D-glucopyranosyl and (1 → 6)-linked α-D-mannopyranosyl residues, which substituted at the O-3 position of (1 → 6)-linked β-D-glucopyranosyl residues by branches of (1 → 6)-linked α-D-galactopyranosyl and 1-linked β-D-galactopyranosyl residues. Immunostimulatory activity analysis showed that UP2 could stimulate the proliferation of RAW264.7 cells in a dose-dependent manner, and all the samples (20-500 μg/mL) were found to enhance nitric oxide production. The highest phagocytic activity of UP2 was observed at 200 μg/mL. Thus, UP2 may be a potential source of biological and pharmacological agents.
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, People's Republic of China.
authors.forename: Bi-Wei
authors.initials: BW
authors.lastname: Zhang
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, People's Republic of China.
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Xu
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, People's Republic of China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Anhui Qiangwang Flavouring Food Co., LTD, Dongcheng Development Zone, Jieshou City, Anhui, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Anhui Qiangwang Flavouring Food Co., LTD, Dongcheng Development Zone, Jieshou City, Anhui, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.affiliation: School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei, People's Republic of China.
authors.forename: Jun-Hui
authors.initials: JH
authors.lastname: Wang
mesh_terms: D000276:Adjuvants, Immunologic / Q000737:chemistry / Q000494:pharmacology; D000818:Animals; D001203:Ascomycota / Q000737:chemistry*; D002236:Carbohydrate Conformation; D049109:Cell Proliferation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D062610:Fungal Polysaccharides / Q000737:chemistry / Q000494:pharmacology; D051379:Mice; D009569:Nitric Oxide / Q000096:biosynthesis*; D000067996:RAW 264.7 Cells
chemical_list: D000276:Adjuvants, Immunologic; D062610:Fungal Polysaccharides; D009569:Nitric Oxide