Laminarans and 1,3-β-D-glucanases

The laminarans are biologically active water-soluble polysaccharide (1,3;1,6-β-D-glucans) of brown algae. These polysaccharides are an attractive object for research due to its relatively simple structure, low toxicity, and various biological effects. 1,3-β-D-glucanases are an effective tool for studying the structure of laminarans, and can also be used to obtain new biologically active derivatives. This review is to outline what is currently known about laminarans and enzymes that catalyze of their transformation. We focused on information about sources, structure and properties of laminarans and 1,3-β-D-glucanases, methods of obtaining and structural elucidation of laminarans, and biological activity of laminarans and products of their enzymatic transformation. It has an increased focus on the immunomodulating and anticancer activity of laminarans and their derivatives.

The comparison of structure and anticancer activity in vitro of polysaccharides from brown algae Alaria marginata and A. angusta

Laminaran and three fucoidan fractions were obtained from the brown alga Alaria marginata. Alaria angusta, studied earlier by us, has the same polysaccharide composition. Galactofucan AmF3 from A. marginata has a main chain of →3)-α-l-Fucp-(2,4-SO3(-))-(1→residues, similar to galactofucan from A. angusta. However, the structure of the branches in fucoidan AmF3 can differ from those in the fucoidan from A. angusta. The following fragments were identified in AmF3: HexA-(1→2)-Fuc, HexA-(1→2)-Gal, Gal-(1→4)-HexA, Fuc-(1→2)-Gal-6-SO3(-), Fuc-4-SO3(-)-(1→6)-Gal, Gal-(1→2)-Gal-2-SO3(-), Gal-4-SO3(-)-(1 →6)-Gal, Gal-4-SO3(-)-(1→3)-Fuc-(1→3)-Fuc, Fuc-4-SO3(-)-(1→6)-Gal-(1→4)-Gal, Gal-(1→4)-Gal-(1→3)-Fuc, Gal-2-SO3(-)-(1→4)-Gal-(1→4)-Gal, Gal-(1→4)-Gal-6-SO3(-)-(1→2)-Gal. Chains of galactose residues (DP up to 9) were found in AmF3 fucoidan. The laminarans, galactofucans and their derivatives from both algae exhibited no cytotoxicity in vitro. Polysaccharides from A. angusta were more effective against colony formation of HT-29 cells, while those from A. marginata had a greater effect on T-47D cells. Sulfated and desulfated fucoidans possessed weak antitumor activity using SK-MEL-28 cells.

Analysis of carbohydrates and glycoconjugates by matrix-assisted laser desorption/ionization mass spectrometry: an update for 2009-2010

This review is the sixth update of the original article published in 1999 on the application of MALDI mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2010. General aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, arrays and fragmentation are covered in the first part of the review and applications to various structural typed constitutes the remainder. The main groups of compound that are discussed in this section are oligo and polysaccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Many of these applications are presented in tabular form. Also discussed are medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis.

Characterization and cytotoxic activity of sulfated derivatives of polysaccharides from Agaricus brasiliensis

Agaricus brasiliensis cell-wall polysaccharides isolated from fruiting body (FR) and mycelium (MI) and their respective sulfated derivatives (FR-S and MI-S) were chemically characterized using elemental analysis, TLC, FT-IR, NMR, HPLC, and thermal analysis. Cytotoxic activity was evaluated against A549 tumor cells by MTT and sulforhodamine assays. The average molecular weight (Mw) of FR and MI was estimated to be 609 and 310 kDa, respectively. FR-S (127 kDa) and MI-S (86 kDa) had lower Mw, probably due to hydrolysis occurring during the sulfation reaction. FR-S and MI-S presented ~14% sulfur content in elemental analysis. Sulfation of samples was characterized by the appearance of two new absorption bands at 1253 and 810 cm(-1) in the infrared spectra, related to S=O and C-S-O sulfate groups, respectively. Through (1)H and (13)C NMR analysis FR-S was characterized as a (1→6)-(1→3)-β-D-glucan fully sulfated at C-4 and C-6 terminal and partially sulfated at C-6 of (1→3)-β-D-glucan moiety. MI-S was shown to be a (1→3)-β-D-gluco-(1→2)-β-D-mannan, partially sulfated at C-2, C-3, C-4, and C-6, and fully sulfated at C-6 of the terminal residues. The combination of high degree of sulfation and low molecular weight was correlated with the increased cytotoxic activity (48 h of treatment) of both FR-S (EC₅₀=605.6 μg/mL) and MI-S (EC₅₀=342.1 μg/mL) compared to the non-sulfated polysaccharides FR and MI (EC₅₀>1500 μg/mL).