کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1383285 | 1500637 | 2015 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Structural studies of an arabinan from the stems of Ephedra sinica by methylation analysis and 1D and 2D NMR spectroscopy Structural studies of an arabinan from the stems of Ephedra sinica by methylation analysis and 1D and 2D NMR spectroscopy](/preview/png/1383285.png)
• Structure of a new arabinan from Ephedra sinica was reported for the first time.
• GC–MS, 2D-NMR and AFM were used for characterization of this polysaccharide.
• The repeating unit was characterized by a much longer linear (1→5)-α-Araf backbone.
Plant arabinan has important biological activity. In this study, a water-soluble arabinan (Mw ∼ 6.15 kDa) isolated from the stems of Ephedra sinica was found to consist of (1→5)-Araƒ, (1→3,5)-Araƒ, T-Araƒ, (1→3)-Araƒ and (1→2,5)-Araƒ residues at proportions of 10:2:3:2:1. A tentative structure was proposed by methylation analysis, nuclear magnetic resonance (NMR) spectroscopy (1H NMR, 13C NMR, DEPT-135, 1H–1H COSY, HSQC, HMBC and ROESY) and literature. The structure proposed includes a branched (1→5)-α-Araf backbone where branching occurs at the O-2 and O-3 positions of the residues with 7.7% and 15.4% of the 1,5-linked α-Araf substituted at the O-2 and O-3 positions. The presence of a branched structure was further observed by atomic force microscopy. This polymer was characterized as having a much longer linear (1→5)-α-Araf backbone as a repeating unit. In particular, the presence of α-Araf→3)-α-Araf-(1→3)-α-Araf-(1→ attached at the O-2 is a new finding. This study may facilitate a deeper understanding of structure–activity relationships of biological polysaccharides from the stems of E. sinica.
Journal: Carbohydrate Polymers - Volume 121, 5 May 2015, Pages 449–456