Structural studies of a heteroxylan from Plantago major L. seeds by partial hydrolysis, HPAEC-PAD, methylation and GC-MS, ESMS and ESMS/MS.
The seed mucilage from Plantago major L. contains acidic heteroxylan polysaccharides. For further structural analysis, oligosaccharides were generated by partial acid hydrolysis and then isolated by high-pH anion-exchange chromatography (HPAEC). Each HPAEC fraction was shown by ESMS to contain one major oligosaccharide and several minor components. Partial structures of the oligosaccharides were determined using GC-MS, ESMS and ES tandem mass spectrometry (ESMS/MS). A (1-->4)-linked xylan trisaccharide and (1-->3)-linked xylan oligosaccharides with DP 6-11 suggested that the backbone of the heteroxylan polysaccharide consisted of blocks of (1-->4)-linked and (1-->3)-linked Xylp residues. A (1-->2)-linked Xylp disaccharide and a branched tetrasaccharide were also found, revealing that single Xylp residues are linked to the O-2 of some of the (1-->4)-linked Xylp residues in the backbone. In addition, our results confirm the presence of side chains consisting of the disaccharide GlcpA-(1-->3)-Araf.
Samuelsen
A B
AB
School of Pharmacy, Department of Pharmacognosy, University of Oslo, Norway. a.b.samuelsen@farmasi.uio.no
Cohen
E H
EH
Paulsen
B S
BS
Brüll
L P
LP
Thomas-Oates
J E
JE
D002240:Carbohydrate Sequence; D002852:Chromatography, Ion Exchange / Q000379:methods*; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006868:Hydrolysis; D013058:Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D010943:Plantago / Q000737:chemistry*; D010946:Plants, Medicinal; D013997:Time Factors