The medicinal properties of compounds extracted from seaweed have been used for medicinal purposes. These compounds, as a class called sulphated polysaccharides, have been shown to have anti-inflammatory and antiviral properties. Of interest here is their anti-retroviral activity which makes them potential drugs against HIV.
A team from Chennai has extracted one such sulphated polysaccharide known as fucoidan from two seaweed species collected from the Mandapam, Thondi and Rameswaram regions along the coast of Tamil Nadu. The team further shows that, in vitro, this compound inhibits the functioning of the HIV-1 strain of the human immunodeficiency virus to a degree that is comparable to the drug tenofovir that is presently in vogue for antiretroviral action. The research was published in Scientific Reports.
Two species of marine brown algae, also known as macroalgae (seaweed), Dictiyota bartaysiana and Turbinaria decurrence were chosen by the team for extraction of the bioactive compound. “We studied many algae species along with these macroalgae and found that these two have more sulphated polysaccharide (fucoidan) than others,” says Sanniyasi Elumalai Professor and Head, Department of Biotechnology, University of Madras.
The idea that sulphated polysaccharides can inhibit the activity of viral strains and arrest their growth has been known for some time now. The Chennai group’s effort has been in identifying and extracting such a compound in two species of algae mentioned here that are common and available at low cost.
HIV comes in two strains, HIV-1 and HIV-2, and of these the former strain is more widespread and this is the strain that the group studied. The proliferation of HIV in cells is related to the expression of a protein called gagP24. The bioactive compound extracted from the seaweed and purified was used to treat cell lines (in vitro) and these were compared with two types of control cells. One set of controls were not treated with any chemical, and the second set was treated with tenofovir. The HIV cell lines treated with fucoidan did show a high percentage of inhibition (close to 90%) of the expression of the protein as compared with untreated controls. The drug tenofovir had a high degree of inhibition effect also.
“We are planning to test this macroalgal sulphated polyacrylamide in animal models,” says Prof. Elumalai.