Molecular properties and antioxidant activities of polysaccharides isolated from alkaline extract of wild Armillaria ostoyae mushrooms. (10th February 2016)

• Record Type: Journal Article
• Authors: Siu, Ka-Chai; Xu, Lijian; Chen, Xia; Wu, Jian-Yong
• Is Part Of: Carbohydrate polymers. Volume 137(2016)
• Page Start: 739
• Page End: 746
• Publication Date: 2016-02-10
• Subjects: Armillaria ostoyae -- Polysaccharides -- Extraction -- Fractionation -- Structure -- Antioxidant activity; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2015.05.061
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: Polysaccharides (PS) were isolated from alkaline extract of Armillaria ostoyae . AkPS1V-1 was a 66.6 kDa glucan and AkPS1V-2 a 15.3 kDa galactoglucan. AkPS1V-2 was composed of 6:1 Glc/Gal and O -3-linked Glc p branches. AkPS1V-2 showed higher antioxidant activities than AkPS1V-1. 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.