Study of the virucidal effect on Human Adenovirus type 5 of polysaccharides extracted from Arthrospira platensis and Dunaliella salina

The current epidemiological scenario has so far focused on the environmental circulation of human viral pathogens. In this context, there is an increasing need for knowledge on the use of virucidal compounds, especially of natural origin. Polysaccharides secreted from Arthrospira platensis and Dunaliella salina exhibits antimicrobial activity, suggesting an effect on viral infectivity. To deep evaluate this possible effect, a series of experimental tests were carried out using Human Adenovirus serotype 5 (HAdV5), which is representative of waterborne viruses. Firstly, polysaccharides were extracted from microalgae coltures by standardized method. Arthrospira platensis polysaccharides were extracted by Lye method, deproteinized with papain and purified by trichloracetic acid (TCA). Dunaliella salina exopolysaccharides were concentrated with heat and cold methanol, dialyzed for 48 hours, purified by TCA and lyophilized. The concentration of 0.2 mg/ml, resulted no toxic for A549 cell cultures, was choosen for tests with HAdV. Two different viral concentrations were used with extracted molecules and the viral abatement was calculated by the estimation of HAdV infectious titer (TCID50/ml) after a specific contact time (15 mins). HAdV5 was shown to be sensitive to polysaccharides basing on the initial titer of the virus. These results could be an important starting point for further research aimed at improving the characterization and the quantification of these microalgae polysaccharides activity under different experimental conditions and against other viruses.