INHIBITION OF HIV-1 REPLICATION BY AN AQUEOUS EXTRACT OF SPIRULINA-PLATENSIS (ARTHROSPIRA-PLATENSIS)

An aqueous extract of the blue-green filamentous algae Arthrospira pla tensis (previously called Spirulina platensis) inhibited HIV-1 replica tion in human T-cell lines, peripheral blood mononuclear cells (PBMC), and Langerhans cells (LC). Extract concentrations ranging between 0.3 and 1.2 mu g/ml reduced viral production by approximately 50% (50% ef fective concentration [EC50]) in PBMCs. The 50% inhibitory concentrati on (IC50) of extract for PBMC growth ranged between 0.8 and 3.1 mg/ml. Depending on the cell type used, therapeutic indices ranged between 2 00 and 6000. The extract inactivated HIV-1 infectivity directly when p reincubated with virus before addition to human T-cell lines. Fraction ation of the extract revealed antiviral activity in the polysaccharide fraction and also in a fraction depleted of polysaccharides and tanni ns. We conclude that aqueous A platensis extracts contain antiretrovir al activity that may be of potential clinical interest.