Water-soluble sulfated polysaccharides from the red seaweed Chaetangium fastigiatum. Analysis of the system and the structures of the α-d-(1 → 3)-linked mannans

The water-soluble polysaccharides from Chaetangium fastigiatum were fractionated with cetrimide. The complexed material was subjected to fractional solubilization in solutions of increasing sodium chloride concentration and seven fractions were separated and analyzed. Two of the fractions were subjected to methylation and desulfation-methylation analyses. The results indicate that this seaweed contains a system of sulfated polysaccharides consisting in part of a galactan and an α-d-(1 → 3)-linked mannan, 2- and 6-sulfated, and having single stubs of β-(1 → 2)-linked d-xylose. Composition dispersity of the mannan is produced by variation of the amount and disposition of the sulfate groups and of the content of the xylose side-chains.     

Sulfated xylomannans isolated from red seaweeds Chondrophycus papillosus and C. flagelliferus (Ceramiales) from Brazil

Sulfated xylomannans were isolated from two species of genus Chondrophycus by aqueous extraction followed by KCl fractionation. Structural determination of the native, desulfated and Smith-degraded KCl-precipitated polysaccharides carried out by composition and methylation analysis and NMR spectroscopy (1D and 2D experiments) showed the following general structure: [see text] These xylomannans present different degrees of branching (15-25%) by beta-D-Xylp (70-80%) and beta-D-Manp-2-S (20-30%) and molecular weights (33-222kDa). This is the first report of the presence of a sulfated xylomannan in species of order Ceramiales.     

ESIMS analysis of fucoidan preparations from Costaria costata, extracted from alga at different life-stages

Four fucoidan fractions from brown alga Costaria costata, collected at different life-stages: vegetative, May (5F2 and 5F3) and generative, July (7F1 and 7F2) collections were characterized. It was found that seaweed synthesizes different set of fucoidans - one with high fucose content and substantial percentage of hexoses and uronic acid and lower sulfate content (7F1, 5F2 and 5F3) and other - highly sulfated galactofucan (7F2). Structural features of fractions 7F2 and 5F3 were predominantly determined by mass spectrometric analysis of low-molecular-weight (LMW) oligosaccharide fragments, obtained by autohydrolysis of 7F2 and mild acid hydrolysis of 5F3 fucoidans. It was found that oligosaccharides from 7F2 fractions were mainly built up of sulfated at C-2 and/or at C-2/C-4 (1→3)-linked α-l-fucopyranose residues. d-Galactose residues, sulfated either at C-2 or C-6, were found as parts of mixed di- and trisaccharides at both termini and, probably, internal. Fucose residues in 5F3 fucoidan fragments were sulfated at C-2 and sometimes at C-4. Galactose residues were sulfated at C-4 and less frequently at C-2. Resistant to hydrolysis fraction was probably a core, built up with fucose, mannose and glucuronic acid. Presumably, oligosaccharide fragments were branches at C-4 of GlcA. They were sulfated at C-2 and sometimes at C-4 (1→3)- and/or (1→4)-linked fucooligosaccharides (sometimes terminated with (1→3)-linked galactose) and sulfated at C-4 or C-2 (1→4)- or, probably, (1→6)-linked galactooligosaccharides, probably, with own branches, formed by (1→2)-linked galactose residues. Unsulfated xylose residues were probably terminal in chains built up of fucose. It was confirmed, that monosaccharide content and structure of fucoidans of vegetative algae changed following its life stage. Generative alga in general produced highly sulfated galactofucan having lower MW along with less sulfated mannoglucuronofucan with higher MW, which was extensively synthesized by vegetative algae.     

Comparative study of carrageenans from reproductive and sterile forms of <Emphasis Type="Italic">Tichocarpus crinitus</Emphasis> (Gmel.) Rupr (Rhodophyta,Tichocarpaceae)

A comparative study of the structure and properties of the sulfated polysaccharides (carrageenans) isolated from the vegetative and reproductive forms of the red alga Tichocarpus crinitus was performed. The polysaccharides were separated into the gelling (KCl-insoluble) and non-gelling (KCl-soluble) fractions by precipitation with 4% KCl. The total content of polysaccharides extracted from the reproductive form of the alga was 1.8-fold more than that extracted from the vegetative form, and in the first case, the gelling polysaccharides mostly accumulated. The gelling polysaccharides from the vegetative form have the highest molecular weight (354 kD). According to the results of FT-IR and 13C-NMR spectroscopy, the gelling polysaccharide fractions from both forms are kappa/beta carrageenans. The differences concern the content of the kappa- and beta-disaccharide units and the presence of a small content of the sulfated disaccharide segments (precursors of the kappa-carrageenans) in the polysaccharide from the reproductive form of the alga. The non-gelling polysaccharide fractions from both forms of the plant are mixtures of sulfated galactans with a low content of 3,6-anhydrogalactose.     

In vitro anti-herpetic activity of sulfated polysaccharide fractions from Caulerpa racemosa

A sulfated polysaccharide fraction was isolated from the hot water extract of the green alga Caulerpa racemosa and designated HWE. This polymer, which contained galactose, glucose, arabinose and xylose as the major component sugars, had [alpha](D)(30) + 46.2 degrees in water and contained 9% sulfate hemiester groups. Sugar linkage analysis indicates that HWE was branched and mainly contained 1,3- and 1,3,6-linked galactose, 1,3,4-linked arabinose, 1,4-linked glucose and terminal- and 1,4-linked xylose residues. Sulfation was deduced from infrared spectroscopy and methylation analysis to occur on O-6 of galactose and O-3 of arabinose. The native polysaccharide could be fractionated by size exclusion chromatography into two overlapping fractions and the major fraction has a hydrodynamic volume similar to that of 70 kDa dextran. HWE was a selective inhibitor of reference strains and TK(-) acyclovir-resistant strains of herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) in Vero cells, with antiviral effective concentration 50% (EC(50)) values in the range of 2.2-4.2 microg/ml and lacking cytotoxic effects. Furthermore, HWE did not exhibit anticoagulant properties at concentrations near the EC(50).     

Stereoselective synthesis of [13C]methyl 2-[15N]amino-2-deoxy-beta-D-glucopyranoside derivatives

The chemical structure of carrageenans produced by the gametophytic and tetrasporophytic life cycle phases of Gigartina pistillata has been determined by permethylation analysis, IR and 13C NMR spectroscopies. The chemistry of the galactans varies according to the biological phases of the plant, the gametophytic alga produces heterogeneous kappa-iota type carrageenan containing minor amounts of nu-carrabiose. The tetrasporophytic alga synthesizes a complex sulfated galactan composed of lambda-, xi-, pi-carrabioses and sulfated carrabioses containing 3-linked galactopyranose 2,6-disulfate.     

Structural features and in vitro antiviral activities of sulfated polysaccharides from Sphacelaria indica

Many viruses display affinity for cell surface heparan sulfate proteoglycans with biological relevance to virus entry. This raises the possibility of the application of sulfated polysaccharides in antiviral therapy. In this study, we have analyzed xylogalactofucan- and alginic acid-containing fractions from Sphacelaria indica, a marine alga. The xylogalactofucan that has apparent molecular mass of 26±5 kDa and negative specific rotation [α](D)(32) -71° (c 0.2, H(2)O) contains, inter alia, (1→3)-linked L-fucopyranosyl and D-galactopyranosyl residues. The algin (molecular mass: 21±5kDa) contains 41% guluronic and 59% mannuronic acid residues. The 50% inhibitory concentration (IC(50)) values of these macromolecules and their chemically sulfated derivatives against herpes simplex virus type 1 (HSV-1) were in the range of 0.6-10 μg ml(-1) and they lacked cytotoxicity at concentrations up to 200 μg ml(-1). The antiviral activity was dependent on the sulfate contents of the polysaccharides. The results support the feasibility of inhibiting HSV infection by direct interaction of polysaccharides with viral particles.     

Structure and anti-dengue virus activity of sulfated polysaccharide from a marine alga

A sulfated polysaccharide, named fucoidan, from the marine alga Cladosiphon okamuranus is comprised of carbohydrate units containing glucuronic acid and sulfated fucose residues. Here we found this compound potently inhibits dengue virus type 2 (DEN2) infection. Viral infection was inhibited when DEN2, but not other serotypes, was pretreated with fucoidan. A carboxy-reduced fucoidan derivative in which glucuronic acid was converted to glucose did not inhibit viral infection. Elimination of the sulfated function group from fucoidan significantly attenuated the inhibitory activity on DEN2 infection with <1% fucoidan. DEN2 particles bound exclusively to fucoidan, indicating that fucoidan interacts directly with envelope glycoprotein (EGP) on DEN2. Structure-based analysis suggested that Arg323 of DEN2 EGP, which is conformationally proximal to one of the putative heparin binding residues, Lys310, is critical for the interaction with fucoidan. In conclusion, both the sulfated group and glucuronic acid of fucoidan account for the inhibition of DEN2 infection.     

Monthly changes in the content and monosaccharide composition of fucoidan from <Emphasis Type="Italic">Undaria pinnatifida</Emphasis> (Laminariales,Phaeophyta)

Crude fucoidan was extracted from the brown alga Undaria pinnatifida collected monthly from April to last July in Peter the Great Bay (Japan Sea, Russia). The amount of crude fucoidan rose markedly from April to June–July (from 3.2 to 16.0% dry weight) as the plant matures. An analysis of the monosaccharide composition of the fucoidan extracted showed that the alga synthesized polysaccharides with various structures which were dependent on the algae age. In juvenile plants collected in April–May, this was represented by sulfated manno-galactofucan containing up to 19–28 mol% of mannose and about 20 mol% of galactose, whereas in matured plants collected in June–July, the polysaccharide was represented by a sulfated galactofucan containing more than 38 mol% galactose. It is postulated that the production of sori causes a subsequent effect on fucoidan synthesis and leads to an enhanced of crude fucoidan content and an increased molar concentration of galactose. Crude fucoidan content in sporophylls increased 5 times, and galactose content in this polysaccharide rose s1.6 times with sori formation. The structural characteristics of the fucoidan extracted from sporophylls of Undaria collected in July were also studied. The fractionation of crude fucoidan on DEAE-Sephadex A-25 gave two fractions, F1 and F2 in equal quantities. F1 was characterized as manno-galactofucan sulfate and F2 was galactofucan sulfate. The molecular weights of both fractions were in a range of 30–80 kDa. Analysis of fucoidan structure using ESI-FTICR mass spectrometry showed the presence of mixed oligosaccharides consisting of fucose and galactose. Presumably, the polysaccharide molecules contain blocks built up of successively linked residues of fucose and galactose. These blocks are built from two to five or more residues of monosaccharides. According to IR-spectroscopy data, the main portion of sulfates is located at C2; in addition, sulfate esters are also present at C4 on the fucose and C3 and C6 of the galactose units.     

Antioxidant activity of sulfated polysaccharide fractions extracted from Laminaria japonica

Fucoidan, a group of sulfated heteropolysaccharide, was extracted from Laminaria japonica, an important economic alga species in China. Three sulfated polysaccharide fractions (F1, F2, and F3) were successfully isolated through anion-exchange column chromatography and had their antioxidant activities investigated employing various established in vitro systems, including superoxide and hydroxyl radical scavenging activity, chelating ability, and reducing power. Chemical analysis suggested that F1 and F3 were heteropolysaccharide in which galactose was the major component, while F2 was a typical fucoidan. All fractions possessed considerable antioxidant activity, and F1, F2 and F3 had stronger antioxidant ability than fucoidan in certain tests. The correlation between the sulfate content and scavenging superoxide radical ability was positive. Available data obtained with in vitro models suggested that the ratio of sulfate content/fucose was an effective indicator to antioxidant activity of the samples.     

In Vitro Anti-influenza Virus Activities of Sulfated Polysaccharide Fractions from Gracilaria lemaneiformis

In this paper, in vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were investigated. Cytotoxicities and antiviral activities of Gracilaria lemaneiformis polysaccharides (PGL), Gracilaria lemaneiformis polysaccharide fraction-1 (GL-1), Gracilaria lemaneiformis polysaccharide fraction-2 (GL-2) and Gracilaria lemaneiformis polysaccharide fraction-3 (GL-3) were studied by the Methyl thiazolyl tetrazolium (MTT) method, and the inhibitory effect against Human influenza virus H1-364 induced cytopathic effect (CPE) on MDCK cells were observed by the CPE method. In addition, the antiviral mechanism of PGL was explored by Plaque forming unit (PFU), MTT and CPE methods. The results showed: i) Cytotoxicities were not significantly revealed, and H1-364 induced CPE was also reduced treated with sulfated polysaccharide fractions from Gracilaria lemaneiformis; ii) Antiviral activities were associated with the mass percentage content of sulfate groups in polysaccharide fractions, which was about 13%, in polysaccharides (PGL and GL-2) both of which exhibited higher antiviral activity; iii) A potential antiviral mechanism to explain these observations is that viral adsorption and replication on host cells were inhibited by sulfated polysaccharides from Gracilaria lemaneiformis. In conclusion, Anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were revealed, and the antiviral activities were associated with content of sulfate groups in polysaccharide fractions.     

Anti-herpes simplex virus activity of sulfated galactans from the red seaweeds Gymnogongrus griffithsiae and Cryptonemia crenulata

This study presents the chemical composition and antiviral activity against herpes simplex virus type 1 (HSV-1) and 2 (HSV-2) of sulfated galactan crude extracts and main fractions obtained from two red seaweeds collected in Brazil, Gymnogongrus griffithsiae and Cryptonemia crenulata. Most of the eighteen tested products, including homogeneous kappa/iota/nu carrageenan and DL-galactan hybrid, exhibited antiherpetic activity with inhibitory concentration 50% (IC50) values in the range 0.5-5.6 microg/ml, as determined in a virus plaque reduction assay in Vero cells. The galactans lacked cytotoxic effects and showed a broad spectrum of antiviral activity against HSV-1 and HSV-2. No direct virus inactivation was observed after virion treatment with the galactans. The mode of action of these compounds could be mainly ascribed to an inhibitory effect on virus adsorption. Most importantly, a significant protection against a murine vaginal infection with HSV-2 was afforded by topical treatment with the sulfated galactans.     

Physicochemical properties and antitumor activities of water-soluble native and sulfated hyperbranched mushroom polysaccharides

A water-soluble hyperbranched beta-glucan, coded as TM3b, extracted from sclerotia of an edible fungus (Pleurotus tuber-regium) was fractioned into eight fractions coded as F1-F8 by a nonsolvent addition method. Five fractions were treated with chlorosulfonic acid at 35 degrees C to synthesize successfully sulfated derivatives coded as S-F2, S-F3, S-F4, S-F5, and S-F8 with degree of substitution of 0.28-0.54. The 13C NMR results of these sulfated beta-glucans indicated that while the C-6 position was fully substituted, C-2, C-3, and C-4 were only partially substituted by the sulfate groups. The weight-average molecular weights (Mw) and intrinsic viscosities ([eta]) of the native and sulfated TM3b fractions were determined using multi-angle laser light scattering and viscometry in 0.15M aq NaCl at 25 degrees C, respectively. The dependences of [eta] on Mw for TM3b and sulfated TM3b were found to be [eta]=0.18Mw(0.28+/-0.03) (Mw range from 3.30 x 10(4) to 3.90 x 10(7)) and [eta]=2.24 x 10(-2)Mw(0.52+/-0.06) (Mw range from 3.24 x 10(4) to 3.15 x 10(5)) in 0.15M aq NaCl at 25 degrees C, respectively. It revealed that both the native TM3b and its sulfated derivatives exist in a spherical chain conformation in 0.15M aq NaCl. Furthermore, the native and sulfated TM3b fractions showed potent antitumor activities in vivo and in vitro. The sulfated derivatives exhibited relatively higher in vitro antitumor activity against human hepatic cancer cell line HepG2 than the native TM3b. Water solubility and introduction of sulfate groups were the main factors in enhancing the antitumor activities.     

In vitro anti-influenza virus activities of sulfated polysaccharide fractions from <Emphasis Type="Italic">Gracilaria lemaneiformis</Emphasis>

In this paper, in vitro anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were investigated. Cytotoxicities and antiviral activities of Gracilaria lemaneiformis polysaccharides (PGL), Gracilaria lemaneiformis polysaccharide fraction-1 (GL-1), Gracilaria lemaneiformis polysaccharide fraction-2 (GL-2) and Gracilaria lemaneiformis polysaccharide fraction-3 (GL-3) were studied by the Methyl thiazolyl tetrazolium (MTT) method, and the inhibitory effect against Human influenza virus H1-364 induced cytopathic effect (CPE) on MDCK cells were observed by the CPE method. In addition, the antiviral mechanism of PGL was explored by Plaque forming unit (PFU), MTT and CPE methods. The results showed: i) Cytotoxicities were not significantly revealed, and H1-364 induced CPE was also reduced treated with sulfated polysaccharide fractions from Gracilaria lemaneiformis; ii) Antiviral activities were associated with the mass percentage content of sulfate groups in polysaccharide fractions, which was about 13%, in polysaccharides (PGL and GL-2) both of which exhibited higher antiviral activity; iii) A potential antiviral mechanism to explain these observations is that viral adsorption and replication on host cells were inhibited by sulfated polysaccharides from Gracilaria lemaneiformis. In conclusion, Anti-influenza virus activities of sulfated polysaccharide fractions from Gracilaria lemaneiformis were revealed, and the antiviral activities were associated with content of sulfate groups in polysaccharide fractions.     

Eleven New Triterpenoid Glycosides from the Roots of Ilex asprella

Asprellosides A‐K, nine new ursane‐type triterpenoid glycosides ( 1 – 9 ), and two new oleanane‐type triterpenoid glycosides ( 10 and 11 ), including six rare sulfated triterpenoid glycosides, were isolated from the roots of Ilex asprella. Their structures were determined on the basis of comprehensive spectroscopic analysis and chemical methods. Among these compounds, asprelloside B ( 2 ) and asprelloside C ( 3 ) are the first examples of triterpenoid glycosides bearing a rare 3,4‐O‐disulfo‐xylopyranosyl residue. All the saponins isolated showed no significant effects against respiratory syncytial virus (RSV) and lipopolysaccharide‐induced nitric oxide production in Raw264.7 macrophages.     

Sulfated mannans from the red seaweed Nemalion helminthoides of the South Atlantic

Nemalion helminthoides, collected in the Argentine South Atlantic coast, was extracted with hot water and the crude product fractionated using cetrimide. The complexed material was subjected to fractional solubilization in solutions of increasing sodium chloride concentration and seven fractions were separated and analyzed. Structural analysis of the main fractions, those soluble in 3.0 and 4.0 M NaCl (yields 21.0% and 13.8%, respectively) and those insoluble in 4.0 M NaCl (yield 20.0%), indicated that this seaweed biosynthesizes (1 → 3)-linked α-d-mannans that are sulfated at positions 4 and 6. Three mannan fractions comprising considerable amounts of xylose were also isolated in very low total yield (2.0%). The fractions that were soluble in 3.0 and 4.0 M NaCl showed low antiherpetic activity whereas this activity was considerable for the fraction solubilized in 2.0 M NaCl (yield 0.5%) which contained single stubs of β-d-xylose. A xylan, soluble in cetrimide solution, containing (1 → 3, 1 → 4)-linked β-d-xylose residues, was also isolated in minor amount.     

Evaluation of sulfated fungal beta-glucans from the sclerotium of Pleurotus tuber-regium as a potential water-soluble anti-viral agent

Six water-insoluble fractions of fungal beta-glucans extracted by hot alkali (TM8-1 to TM8-6) from the sclerotia of Pleurotus tuber-regium (PTR) having different molecular weights (M(w)) were sulfated to give their corresponding water-soluble derivatives (S-TM8-1 to S-TM8-6) with the degree of sulfation (DS) ranging from 1.14 to 1.74. The in vitro anti-viral activities of the native beta-glucans (TM8s) and their sulfated derivatives (S-TM8s) were evaluated by the cytopathic effect assay (CPE) and the plaque reduction assay (PRA) against four kinds of viruses, including herpes simplex virus type 1 (HSV-1), herpes simplex virus type 2 (HSV-2), respiratory syncytial virus (RSV), and influenza A virus (Flu A). Although TM8s were inactive in inhibiting the viral replication in cell cultures, the S-TM8 fractions with the defined M(w) range had potent anti-viral activity against HSV-1 and HSV-2 as shown by the CPE assay. The PRA results suggested that S-TM8 fractions seemed to exert their anti-viral effect by binding to the viral particles, preventing the latter from infecting the host cells. It was plausible that the negative charges on the polymer chain of S-TM8 could interact with the positively charged glycoproteins on the surface of HSV, minimizing the interaction between the HSV and the negatively charged host cells. The anti-viral activity of the S-TM8s might also be explained by their more extended chain conformation in solution due to an increase in one of their molecular parameter, persistence length (q), as compared to the native TM8s. The potential use of S-TM8s as a water-soluble anti-HSV agent is discussed.     

Antigenic relationship between Candida parapsilosis and Candida albicans serotype B

We examined the antigenic relationship between Candida parapsilosis and C. albicans serotype B with respect to antigenic factors 13 and 13b, specific for the former species and common to both species, respectively. Acetolysis of C. albicans serotype B cell-wall mannan gave six oligosaccharides. Their chemical structure was determined by 1H-nuclear magnetic resonance (NMR) spectroscopy, methylation analysis, and partial acid hydrolysis. The structure of the hexasaccharide derived from C. albicans serotype B mannan was alpha-D-Manp-(1-2)-alpha-D-Manp-(1-3)-alpha-D-Manp-(1- 2)-alpha-D-Manp-(1-2)- alpha-D-Manp-(1-2)-D-Man (M6) which is identical to that from C. parapsilosis mannan. Inhibition of two precipitin reaction systems (anti-C. albicans serotype B serum and anti-C. parapsilosis serum to the respective homologous mannan), by oligosaccharides from homologous and heterologous mannans indicated that M6 from either C. albicans serotype B or C. parapsilosis was the most effective inhibitor. Moreover inhibition of the agglutination reaction between factor serum containing anti-factors 13 and 13b and C. albicans serotype B or C. parapsilosis cells by oligosaccharides from both mannans also indicated that the M6s were the most effective inhibitors. These results suggest that the M6s derived from the two species are identical in their chemical structure, although the structures of the whole mannans of the two species are not identical as demonstrated by gel diffusion precipitation patterns, and that M6s may be involved in the specificities of antigenic factors 13 and 13b. The amount of M6 is larger in C. parapsilosis cell-wall mannan, suggesting that high repeating frequency of M6 fragment may induce the antibody specific for C. parapsilosis.     

Isolation of Polysaccharides Sulfated during Early Embryogenesis in Fucus

Beginning 10 hours after fertilization, zygotes of Fucus distichus L. Powell incorporate (35)S into polysaccharides as a sulfate ester of fucose. These sulfated polysaccharides are sequestered in only the rhizoid cell of the two-celled embryo and can serve as a marker of cellular differentiation. Zygotes were pulsed at different times after fertilization with Na(2) (35)SO(4) to identify and isolate the fucans localized within the region of cytoplasm destined to become the rhizoid cell. Low molecular weight pools of (35)S were saturated within 60 minutes, with the greatest incorporation into ethanol-soluble and insoluble fractions occurring with 0.1 mm Na(2)SO(4) in the artificial sea water medium. At the time of rhizoid formation, four fucose-containing polysaccharide fractions incorporated (35)S. When each fraction was subjected to diethylaminoethyl chromatography, two components were eluted with KCl that contained over 84% of the fucose and 93% of the (35)S of the particular fraction. Highvoltage paper electrophoresis of each fraction also resulted in the separation of these two major components. Both components from each of the four fractions behaved identically when separated by diethylaminoethyl chromatography and paper electrophoresis. By comparing the incorporation of (35)S into the polysaccharide fractions at 4 and 16 hours after fertilization, the fucan-sulfate components that are localized in the cytoplasm at the time of rhizoid formation were isolated. Although sulfated polysaccharides in brown algae are reported to be very heterogeneous in terms of their sugar composition and complexes with other heteropolymers, we propose that there are two major components that are sulfated during early embryogenesis in Fucus. The location of these two sulfated polysaccharides in different chemical fractions may reflect their subcellular localization (e.g., cytoplasmic vesicles or cell walls), or their association with other heteropolymers.     

Isolation and characterization of soluble sulfated polysaccharide from the red seaweed Gracilaria cornea

The composition, structure and rheological properties of a soluble sulfated polysaccharide from Gracilaria cornea (Brazilian red marine alga) were investigated. Agarocolloid yield, intrinsic viscosity, monosaccharide composition, sulfate and cation content as well as molecular weight were determined. The main polysaccharide components were 3,6-anhydrogalactose (24.7%) and galactose (64.6%). In addition, minor components such as 6-O-methyl-galactose (8.5%), glucose (1.5%), xylose (0.7%) and sulfated groups (4.8%) were detected. Comparison between sulfate contents determined by Fourier transform IR (FT-IR) spectroscopy and microelemental analysis was made. Data from ¹³C NMR and FT-IR provided evidence of sulfation in C-4 and C-6 of galactose. Sodium, calcium, magnesium and potassium cations were detected in the agarocolloid. The intrinsic viscosities were lower than typical values for agar in the same experimental conditions. No gelation in 1.5, 2.0 and 3.0% (w/v) aqueous solution was observed, even by cooling up to 4 °C. Gel permeation chromatography indicated two major polysaccharide fractions of M_pk 7.4×10⁴ and 1.8×10⁴ g/mol and a minor fraction of M_pk 2.1×10⁶ g/mol, probably a protein–polysaccharide complex.