Elucidation of the structure of a bioactive hydrophilic polysaccharide from Cordyceps sinensis by methylation analysis and NMR spectroscopy

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• 作者：Shao-Ping Nie^a ; ^b ; Steve W. Cui^a ; ^b ; ^{cuis@agr.gc.ca} ; ^{Steve.Cui@AGR.GC.CA} ; Aled O. Phillips^c ; Ming-Yong Xie^a ; Glyn O. Phillips^d ; ^e ; Saphwan Al-Assaf^d ; ^e ; Xiao-Liang Zhang^f
• 关键词：Cordyceps sinensis ; Hydrophilic polysaccharide ; Structure ; Methylation analysis ; NMR
• 刊名：Carbohydrate Polymers
• 出版年：2011
• 出版时间：17 March 2011
• 年：2011
• 卷：84
• 期：3
• 页码：894-899
• 全文大小：626 K

文摘

The structure of a bioactive hydrophilic polysaccharide fraction from Cordyceps sinensis (CBHP) was studied using methylation analysis and 2D NMR spectroscopy. Monosaccharide composition analysis revealed that it consists mainly of glucose (95.19 % ) with trace amounts of mannose (0.91 % ) and galactose (0.61 % ). The results of methylation analysis indicated that α-1,4 linked Glcp is the main linkage type (65.7 % ), followed by t-Glcp (20.7 % ), 1,2,3,6-Glcp (4.1 % ), 1,2,4,6-Glcp (3.0 % ), 1,3,6-Glcp (2.0 % ), 1,4,6-Glcp (1.6 % ), and 1,2-Manp (1.9 % ) and 1,3-Galp (1.0 % ). Based on 1D and 2D NMR analysis, a preliminary structure is proposed: The backbone is composed of Glcp joined by 1 → 4 linkages and 1 → 3 linkages; the branching points are located at O-2 or O-6 of Glcp with α- terminal-d-Glcp as side chain. The trace amounts of 1,2-Manp and 1, 3-Galp linkages are probably located randomly in the side chains. A schematic structure is proposed as following: