Wound Healing, Antioxidant, and Antiviral Properties of Bioactive Polysaccharides of Microalgae Strains Isolated from Greek Coastal Lagoons

Microalgae have gained significant attention as sustainable sources of high value compounds, such as bioactive polysaccharides that are usually rich in sulfated groups and exhibit antioxidant properties. Here, 14 new microalgae strains of the genera <i>Tetraselmis</i>, <i>Dunaliella,</i> and <i>Nannochloropsis</i>, isolated from Greek coastal lagoons were analyzed to quantify and characterize their polysaccharide content. Heterogeneity was observed regarding the content of their total sugars (5.5-40.9 g/100 g dry biomass). The strains with a total sugar content above 20% were analyzed concerning the content of total, <i>α</i>- and <i>β</i>-glucans. <i>Tetraselmis verrucosa</i> f. <i>rubens</i> PLA1-2 and <i>T</i>. <i>suecica</i> T3-1 were rich in <i>β</i>-glucans (11%, and 8.1%, respectively). The polysaccharides of the two <i>Tetraselmis</i> strains were isolated and they were mainly composed of glucose and galactose. The isolated polysaccharides were fractionated using ion-exchange-chromatography. The anionic fraction from <i>T</i>. <i>verrucosa</i> f. <i>rubens</i> PLA1-2 was rich in sulfated polysaccharides, had antioxidant capacity, and exhibited healing properties. The anionic polysaccharides from the two <i>Tetraselmis</i> strains did not negatively influence the viability of human cells, while exhibiting antiviral properties against the replication of Hepatitis C Virus (HCV), with median efficient concentrations (EC50) at a range of 210-258 μg/mL.