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

Application of MALDI-MS for characterization of fucoidan hydrolysates and screening of endo-fucoidanase activity

Brown macroalgae synthesize large amounts of fucoidans, sulfated fucose-containing polysaccharides, in the ocean. Fucoidans are of importance for their recently discovered contribution to marine carbon dioxide sequestration and due to their potential applications in biotechnology and biomedicine. However, fucoidans have high intra- and intermolecular diversity that challenges assignment of structure to biological function and the development of applications. Fucoidan-active enzymes may be used to simplify this diversity by producing defined oligosaccharides more applicable for structural refinement, characterization, and structure to function assignment for example via bioassays. In this study, we combined MALDI mass spectrometry with biocatalysis to show that the endo-fucoidanases P5AFcnA and Wv323 can produce defined oligosaccharide structures directly from unrefined macroalgal biomass. P5AFcnA released oligosaccharides from seven commercial fucoidan extracts in addition to unrefined biomass of three macroalgae species indicating a broadly applicable approach reproducible across 10 species. Both MALDI-TOF/TOF and AP-MALDI-Orbitrap systems were used, demonstrating that the approach is not instrument-specific and exploiting their combined high-throughput and high-resolution capabilities. Overall, the combination of MALDI-MS and endo-fucoidanase assays offers high-throughput evaluation of fucoidan samples and also enables extraction of defined oligosaccharides of known structure from unrefined seaweed biomass.

Relevance of the Extraction Stage on the Anti-Inflammatory Action of Fucoidans

The anti-inflammatory action of fucoidans is well known, based on both in vitro and some in vivo studies. The other biological properties of these compounds, their lack of toxicity, and the possibility of obtaining them from a widely distributed and renewable source, makes them attractive novel bioactives. However, fucoidans’ heterogeneity and variability in composition, structure, and properties depending on seaweed species, biotic and abiotic factors and processing conditions, especially during extraction and purification stages, make it difficult for standardization. A review of the available technologies, including those based on intensification strategies, and their influence on fucoidan composition, structure, and anti-inflammatory potential of crude extracts and fractions is presented.

Fucoidan Characterization: Determination of Purity and Physicochemical and Chemical Properties

Fucoidans are marine sulfated biopolysaccharides that have heterogenous and complicated chemical structures. Various sugar monomers, glycosidic linkages, molecular masses, branching sites, and sulfate ester pattern and content are involved within their backbones. Additionally, sources, downstream processes, and geographical and seasonal factors show potential effects on fucoidan structural characteristics. These characteristics are documented to be highly related to fucoidan potential activities. Therefore, numerous chemical qualitative and quantitative determinations and structural elucidation methods are conducted to characterize fucoidans regarding their physicochemical and chemical features. Characterization of fucoidan polymers is considered a bottleneck for further biological and industrial applications. Consequently, the obtained results may be related to different activities, which could be improved afterward by further functional modifications. The current article highlights the different spectrometric and nonspectrometric methods applied for the characterization of native fucoidans, including degree of purity, sugar monomeric composition, sulfation pattern and content, molecular mass, and glycosidic linkages.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: An update for 2013-2014

This review is the eighth update of the original article published in 1999 on the application of Matrix-assisted laser desorption/ionization mass spectrometry (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2014. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation, and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly- saccharides, glycoproteins, glycolipids, glycosides, and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions, and applications to chemical synthesis. © 2018 Wiley Periodicals, Inc. Mass Spec Rev 37:353-491, 2018.

Structural elucidation of polysaccharide fractions from the brown alga Coccophora langsdorfii and in vitro investigation of their anticancer activity

Laminaran, fucoidan, and alginate were isolated from the brown alga Coccophora langsdorfii collected in the Japan Sea. The structural characteristics of polysaccharides were investigated by NMR spectroscopy. The laminaran was determined as β-d-glucan, which consisted of 80% of 1,3- and 20% of 1,6-linked residues and was terminated with mannitol. The alginate was a guluronic acid-rich polysaccharide (M/G=0.85). Fucoidan, sulfated α-l-fucan, contained a linear backbone of alternating (1→3)- and (1→4)- linked α-l-fucopyranose residues with sulfate at C2 and C4 of (1→3)-α-l-fucopyranose residues. Anticancer activity of this fucoidan was investigated in comparison with activity of fucoidan having similar linear backbone from the brown alga Fucus evanescens. The fucoidan from C. langsdorfii significantly inhibited colony formation of SK-MEL-5 and SK-MEL-28 melanoma cells (the percentage of inhibition was 28 and 76, respectively) and weakly inhibited colony formation of breast adenocarcinoma cells MDA-MB-231 (the percentage of inhibition was about 5). Similar results were obtained for fucoidan from F. evanescens; the percentage of inhibition of colony formation of SK-MEL-5 and SK-MEL-28 melanoma cells was 54 and 56, respectively. The inhibition of colony formation of breast adenocarcinoma cells MDA-MB-231 was weak. We suppose that other sulfated and partially acetylated fucoidans consisting of (1→3)- and (1→4)-linked α-l-fucopyranose residues may suppress progression of melanoma cell colony formation similar to fucoidans of C. langsdorfii and F. evanescens.

Structure and anticancer activity in vitro of sulfated galactofucan from brown alga Alaria angusta

Laminaran and three fractions of fucoidan were isolated from brown alga Alaria angusta. The laminaran AaL was characterized as a typical 1,3;1,6-β-D-glucan (ratio of bonds 1,3:1,6 = 10:1). Fucoidans AaF1 and AaF2 are sulfated heteropolysaccharides, containing fucose, galactose, mannose and xylose. The fraction AaF3 is sulfated and acetylated galactofucan with the main chain represented by a repeating unit → 3)-α-L-Fucp-(2,4-SO3(-))-(1 →. According the data of methylation analysis, AaF3 contains mainly 1,3-linked fucose, less 1,4-linked and 1,4,6-linked galactose residues. The autohydrolysis (37 °C) of fucoidan AaF3 allowed to obtain selectively 2-desulfaled polysaccharide fraction, built up of fucose only, and low molecular weight (LMW) fraction. The negative-ion tandem mass spectrometry of LMW fraction, further hydrolyzed by acid hydrolysis identified the following fragments: Gal-2-SO3(-)-(1 → 4)-Gal, Gal-4-SO3(-)-(1 → 4)-Gal, Gal-(1 → 2)-Gal-4-SO3(-), Fuc-2-SO3(-)-(1 → 4)-Gal, Gal-2-SO3(-)-(1 → 3)-Fuc-(1 → 3)-Fuc, Fuc-2-SO3(-)-(1 → 3)-Fuc-(1 → 4)-Gal. The laminaran AaL and the fucoidan AaF3 exhibited no cytotoxicity in vitro for HT 29, T-47D, and SK-MEL-28 cell lines. The AaF3 fraction suppressed colony formation of HT 29 and T-47D cells, AaL-only HT 29 cells.

Therapies from Fucoidan: An Update

Fucoidans are a class of sulfated fucose-rich polysaccharides found in brown marine algae and echinoderms. Fucoidans have an attractive array of bioactivities and potential applications including immune modulation, cancer inhibition, and pathogen inhibition. Research into fucoidan has continued to gain pace over the last few years and point towards potential therapeutic or adjunct roles. The source, extraction, characterization and detection of fucoidan is discussed.

Further studies on structure of fucoidan from brown alga Saccharina gurjanovae

A sulfated galactofucan SgF (MW 123kDa) was purified from the brown alga Saccharina gurjanovae. Polysaccharide was depolymerized by autohydrolysis at 25 and 60°C, and products were studied by mass spectrometry and (13)C NMR spectroscopy. According to results of investigation, the main chain of this polysaccharide is built of a repeating units →3)-α-L-Fucp-(2,4-OSO3(-))-(1→. Fucose chains could be sometimes terminated by (1→3)-linked galactose residues. Shorter (1→4)- and/or (1→6)-linked sulfated galactose chains are attached at positions C-2, C-3 of fucose residues. Sulfate groups can occupy positions C-2 and/or sometimes C-3 of Gal residues, but a sulfation at C-4 of the galactofucan could not be excluded. The SgF-AH25-H preparation (71kDa) was obtained by autohydrolysis of SgF at 25°C, which leaded to a selective desulfation at C-2 and, probably, to a cleavage of galactose chains, since structure of SgF-AH25-H represented a repeating unit →3)-α-l-Fucp-(4-OSO3(-))-(1→, which was definitely established by (13)C NMR spectroscopy. Galactofucan SgF and its derivative SgF-AH25-H exhibited no cytotoxic activity and leaded to about the same colony formation inhibition in colon cancer DLD-1 cells. Hence, structural simplification of SgF by lowering its molecular weight, desulfation at C-2 and removing of galactose residues by autohydrolysis at 25°C did not decrease its anticancer activity. This procedure allows obtaining standardized products which can be used as medical.