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.

The gametic, carposporic and tetrasporic reproductive stages from the Mediterranean red alga Asparagopsis armata contain peculiar sulfated galactans with galactose:3,6-anhydrogalactose:sulfates molar ratio of 1:0.01:1.23, 1:0.04:0.47 and 1:0.01:1.13, respectively. These water-soluble polysaccharides were studied for their in vitro activity against the human immunodeficiency virus (HIV-1). Gametic and tetrasporic galactans inhibit HIV replication at 10 and 8 micrograms/ml, respectively, as measured by HIV-induced syncitium formation as well as reverse transcriptase activity in cell-free culture supernatant. The carposporic polysaccharide is ineffective, even at 100 micrograms/ml. The maximal antiviral effect involves the presence of the polysaccharides after or during infection but not before infection. This time of action suggests an inhibition of an early step of HIV infection.

Corresponding authorThe chemical composition and the structure of gametic, carposporic and tetrasporic water-soluble polysaccharides from Asparagopsis armata Harvey (Rhodophyta, Bonnemaisoniaceae), as well as two gametic samples harvested both in the Mediterranean Sea and Atlantic Ocean, have been compared. The structural analysis of the polysaccharides has been examined by infra-red spectroscopy and by methylation of native and desulphated samples. The different constitutive sugars have been separated and quantified by gas-phase chromatography after reductive hydrolysis. The sulphated galactans lacking anhydrogalactose have both carrageenan and agar features such as high proportions of 1,3-and 1,4-linked galactose units, the presence of D-and Lgalactose units, and negative or positive optical rotation values according to the stage considered. They are essentially sulphated on C-4 and ramified on C-3 and C-6. The carposporic polysaccharide differs primarily from the others by the presence of 15.9 % dry wt uronic acids and a threefold lower sulphation level.Brought to you by | Freie Universität Berlin Authenticated Download Date | 7/4/15 2:53 AM

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