Rapid mass spectrometric analysis of a novel fucoidan, extracted from the brown alga Coccophora langsdorfii.

Stanislav D Anastyuk,Tatyana N Zvyagintseva,Pavel S Dmitrenok,Tatyana I Imbs

doi:10.1155/2014/972450

Abstract

The novel highly sulfated (35%) fucoidan fraction Cf2 , which contained, along with fucose, galactose and traces of xylose and uronic acids was purified from the brown alga Coccophora langsdorfii. Its structural features were predominantly determined (in comparison with fragments of known structure) by a rapid mass spectrometric investigation of the low-molecular-weight fragments, obtained by “mild” (5 mg/mL) and “exhaustive” (maximal concentration) autohydrolysis. Tandem matrix-assisted laser desorption/ionization mass spectra (MALDI-TOF/TOFMS) of fucooligosaccharides with even degree of polymerization (DP), obtained by “mild” autohydrolysis, were the same as that observed for fucoidan from Fucus evanescens, which have a backbone of alternating (1 → 3)- and (1 → 4) linked sulfated at C-2 and sometimes at C-4 of 3-linked α-L-Fucp residues. Fragmentation patterns of oligosaccharides with odd DP indicated sulfation at C-2 and at C-4 of (1 → 3) linked α-L-Fucp residues on the reducing terminus. Minor sulfation at C-3 was also suggested. The “exhaustive” autohydrolysis allowed us to observe the “mixed” oligosaccharides, built up of fucose/xylose and fucose/galactose. Xylose residues were found to occupy both the reducing and nonreducing termini of FucXyl disaccharides. Nonreducing galactose residues as part of GalFuc disaccharides were found to be linked, possibly, by 2-type of linkage to fucose residues and were found to be sulfated, most likely, at position C-2.

Highlights

The quantity of scientific papers, concerning various biological activities [1,2,3,4] of fucoidans, sulfated polysaccharides from brown algae, is constantly growing
It was found that minor constituents of fucansulfate (Xyl, Gal, and GlcA residues) from the brown alga Fucus evanescens are incorporated into the backbone, probably, as branching points [12]. 13C NMR technique that was employed for the analysis of the same fucoidan [13] was unable to observe these fragments, just because they were rejected at purification step or the method was not sensitive enough
In some cases using known mechanisms of mass spectrometric fragmentation, it is possible to elucidate some structural features of fucoidans by mass spectrometry only

Summary

Introduction

The quantity of scientific papers, concerning various biological activities [1,2,3,4] of fucoidans, sulfated polysaccharides from brown algae, is constantly growing. In order to unambiguously establish the structure of such complex polysaccharides by powerful spectroscopic techniques, like 13C NMR, time-consuming multiple-step chemical modification procedures, coupled with purification steps, are required. These methods are offering low yields and they are requiring a large number of samples. In some cases using known mechanisms of mass spectrometric fragmentation, it is possible to elucidate some structural features of fucoidans by mass spectrometry only. In this way glycosaminoglycans and carrageenans were successfully investigated by the analysis of

Methods

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Conclusion