Chemical properties and antioxidant activity of a water-soluble polysaccharide from Dendrobium officinale

• Published in: International journal of biological macromolecules Vol. 89; pp. 219 - 227
• Main Authors: Luo, Qiu-lian, Tang, Zhuan-hui, Zhang, Xue-feng, Zhong, Yong-hong, Yao, Su-zhi, Wang, Li-sheng, Lin, Cui-wu, Luo, Xuan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2016
• Subjects: 2,2-diphenyl-1-picrylhydrazyl; anion exchange chromatography; Antioxidant activity; Antioxidants - chemistry; Antioxidants - isolation & purification; arabinose; Arabinose - chemistry; Biphenyl Compounds - antagonists & inhibitors; Carbohydrate Conformation; Chromatography, Gel; Chromatography, Ion Exchange; Dendrobium - chemistry; Dendrobium officinale; Dendrobium officinale polysaccharide; ethanol; galacturonic acid; glucose; Glucose - chemistry; Glycosides - chemistry; Hexuronic Acids - chemistry; hydroxyl radicals; in vitro studies; mannose; Mannose - chemistry; Molecular Weight; nuclear magnetic resonance spectroscopy; Picrates - antagonists & inhibitors; Plant Extracts - chemistry; Plant Stems - chemistry; polymerization; polysaccharides; Polysaccharides - chemistry; Polysaccharides - isolation & purification; Solid Phase Extraction; stems; Structure characterization; Dendrobium officinale polysaccharide; Antioxidant activity; Structure characterization
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2016.04.067

•Structural characterization of Dendrobium officinale polysaccharide.•Mannose and glucose are the main constituent.•The polysaccharide possesses antioxidant property. In this report, a water-soluble polysaccharide was obtained from the dried stems of Dendrobium officinale Kimura et Migo by hot-water (70–75°C) extraction and 85% ethanol precipitation, and successively purification by DEAE-cellulose anion-exchange chromatography and gel-permeation chromatography. The D. officinale polysaccharide (DOP) has a molecular weight of 8500Da. Monosaccharide composition analysis reveals that DOP is composed of mannose, glucose, and arabinose with a trace of galacturonic acid in a molar ratio of 6.2:2.3:2.1:0.1. Periodate oxidation–smith degradation and 1D and 2D NMR spectroscopy analysis suggest the predominance of mannose and glucose, and it contains a 2-O-acetylglucomannan and (1→4)-linked-β-d-mannopyranosyl and (1→4)-linked-β-d-glucopyranosyl residues. Atomic force microscope shows that DOP mainly exists as rod-shaped chains, supporting high degrees of polymerization. The antioxidant activities of the polysaccharide in vitro assay indicate that DOP has good scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, higher scavenging activity of hydroxyl radical, and metal chelating activities.