title: Molecular properties and antioxidant activities of polysaccharides isolated from alkaline extract of wild Armillaria ostoyae mushrooms.
abstract: This study aims to discover novel and bioactive polysaccharides (PS) from wild Armillaria ostoyae, a honey mushroom species. Two PS designated AkPS1V-1 (66.6 kDa) and AkPS1V-2 (15.3 kDa) were isolated and fractionated by anion ion exchange (IEC) and size exclusion chromatography (SEC) from the alkaline extract of A. ostoyae mushrooms. AkPS1V-1 was a glucan composed of solely glucose residues and AkPS1V-2 a heteropolysaccharide composed of glucose and galactose at 6:1 molar ratio. AkPS1V-2 exhibited higher antioxidant activities than AkPS1V-1 based on reducing power, radical scavenging and metal chelating assays. The structure of AkPS1V-2 was further analyzed and elucidated as a branched galactoglucan with a backbone composed of (1→6)-β-D-glucopyranosyl, (1→3)-β-D-glucopyranosyl, (1→3)-α-D-galactopyranosyl and (1→3,6)-β-D-glucopyranosyl residues at 3:1:1:1 ratio, and side chain of (1→3)-β-D-glucopyranosyl residue. This is the first report on a pure PS structure and its antioxidant activities from this mushroom species.
authors.affiliation: Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Ka-Chai
authors.initials: KC
authors.lastname: Siu
authors.affiliation: College of Agricultural Resource and Environment, Heilongjiang University, 15000 Harbin, China.
authors.forename: Lijian
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong.
authors.forename: Xia
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Applied Biology & Chemical Technology, State Key Laboratory of Chinese Medicine and Molecular Pharmacology in Shenzhen, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong. Electronic address: jian-yong.wu@polyu.edu.hk.
authors.forename: Jian-Yong
authors.initials: JY
authors.lastname: Wu
mesh_terms: D000363:Agaricales / Q000737:chemistry*; D000468:Alkalies / Q000737:chemistry; D000975:Antioxidants / Q000737:chemistry*; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D011134:Polysaccharides / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000468:Alkalies; D000975:Antioxidants; D011134:Polysaccharides
keywords: Antioxidant activity; Armillaria ostoyae; Extraction; Fractionation; Polysaccharides; Structure