Antiviral Activities of Sulfated Polysaccharides Isolated from Sphaerococcus coronopifolius (Rhodophytha, Gigartinales) and Boergeseniella thuyoides (Rhodophyta, Ceramiales)

Water-soluble sulfated polysaccharides isolated from two red algae Sphaerococcus coronopifolius (Gigartinales, Sphaerococcaceae) and Boergeseniella thuyoides (Ceramiales, Rhodomelaceae) collected on the coast of Morocco inhibited in vitro replication of the Human Immunodeficiency Virus (HIV) at 12.5 μg/mL. In addition, polysaccharides were capable of inhibiting the in vitro replication of Herpes simplex virus type 1 (HSV-1) on Vero cells values of EC50 of 4.1 and 17.2 μg/mL, respectively. The adsorption step of HSV-1 to the host cell seems to be the specific target for polysaccharide action. While for HIV-1, these results suggest a direct inhibitory effect on HIV-1 replication by controlling the appearance of the new generations of virus and potential virucidal effect. The polysaccharides from S. coronopifolius (PSC) and B. thuyoides (PBT) were composed of galactose, 3,6-anhydrogalactose, uronics acids, sulfate in ratios of 33.1, 11.0, 7.7 and 24.0% (w/w) and 25.4, 16.0, 3.2, 7.6% (w/w), respectively

Galactans: an overview of their most important sourcing and applications as natural polysaccharides

Since last decades, lot of biological and rheological properties of polysaccharides and oligosaccharides were described. Among them, galactans and more especially sulfated galactans from seaweeds have shown interesting and specific properties not only as texturing agents but also as biological active compounds on several organisms. This class of polysaccharides includes classical sulfated galactans extracted from seaweeds and classified as agar and carrageenans. However, some galactans are more complex and their specific structural features have been characterized after their extraction from terrestrial plants, seaweeds but also animals and microoragnisms. This review catalogues the origins, structural characteristics and potentialities of these polysaccharides and their oligosaccharides derivatives

Highly sulphated galactan from Halymenia durvillei (Halymeniales, Rhodophyta), a red seaweed of Madagascar marine coasts

International audienceHalymenia durvillei is a red seaweed with a great potential as sulphated galactan producer collected in the coastal waters of small island of Madagascar (Nosy-be in Indian Ocean). To elucidate the structure of its polysaccharide, NMR (1H and 13C), FTIR, HPAEC and different colorimetric methods were carried out. It has been shown that this polysaccharide, consisted mainly of galactose, was branched by xylose and galactose in minor amounts. Arabinose and fucose were also detected. This galactan was found highly sulphated (42%, w/w) and pyruvylated (1.8%, w/w). Analysis of glycosidic linkages by CPG-MS and 13C NMR indicated that the polysaccharide has the defining linear backbone of alternating 3-β-d-galactopyranosyl units and 4-linked α-l/d-galactopyranosyl residues. 3,6-Anhydrogalactose units have been also detected in minor quantity. This λ-carrageenan like polysaccharide has shown original sulphatation patterns with 2-O (26%) or 2/6-O (58%) sulphated 3-linked β-d-galactopyranosyl units and 6-O (19%) or 2/6-O (47%) 4-linked α-l/d-galactopyranosyl residues

Oligosaccharides biologiquement actifs obtenus par dégradation enzymatique d’un arabinogalactane extrait de cladodes de Cereus triangularis

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Rheological Behavior and Non-enzymatic Degradation of a Sulfated Galactan from Halymenia durvillei (Halymeniales, Rhodophyta)

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Characterization of arabinogalactan-rich mucilage from Cereus triangularis cladodes

International audienceCereus triangularis (Cactaceae) is a cactus used in food decoction as a traditional medicine in the North region of Madagascar to reduce stomach ache and intestinal diseases. Hydrocolloids were sequentially extracted from its cladodes with a yield of 24% (240 mg/g based on dried cladodes powder). Structural analyses has revealed that this polysaccharide with a molecular mass of 8430,000 g/mol was mainly composed of a galactan backbone of a (1 → 4) linked β-d-Galp residues probably substituted at position 3 by l-arabinofuranosyl residues. In vitro antioxidant activity of this arabinogalactan-rich fraction was detected and quantified by radical DPPH scavenging, hydroxyl radical scavenging, radical anion superoxide scavenging and reducing power method