BASIC SCIENCE: PDF OnlyInhibition of HIV-1 Replication by an Aqueous Extract ofSpirulina platensis(Arthrospira platensis)Ayehunie, Seyoum*; Belay, Amha†; Baba, Timothy W.*‡; Ruprecht, Ruth M.*Author Information *Laboratory of Viral Pathogenesis, Dana-Farber Cancer Institute, and Harvard Medical School, Boston, Massachusetts; †Earthrise Farms, Calipatria, California; ‡Division of Newborn Medicine, Department of Pediatrics, Tufts University School of Medicine, Boston, Massachusetts, U.S.A. Address correspondence and reprint requests to Ruth M. Ruprecht, Dana-Farber Cancer Institute and Harvard Medical School, Laboratory of Viral Pathogenesis, 44 Binney Street, Boston, MA 02115, U.S.A.; email: [email protected]. Manuscript received August 18, 1997; accepted December 10, 1997. Journal of Acquired Immune Deficiency Syndromes & Human Retrovirology: May 1, 1998 - Volume 18 - Issue 1 - p 7-12 Free Abstract An aqueous extract of the blue-green filamentous algae Arthrospira platensis (previously called Spirulina platensis) inhibited HIV-1 replication in human T-cell lines, peripheral blood mononuclear cells (PBMC), and Langerhans cells (LC). Extract concentrations ranging between 0.3 and 1.2 μg/ml reduced viral production by approximately 50% (50% effective concentration [EC50]) in PBMCs. The 50% inhibitory concentration (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 200 and 6000. The extract inactivated HIV-1 infectivity directly when preincubated with virus before addition to human T-cell lines. Fractionation of the extract revealed antiviral activity in the polysaccharide fraction and also in a fraction depleted of polysaccharides and tannins. We conclude that aqueous A platensis extracts contain antiretroviral activity that may be of potential clinical interest. © Lippincott-Raven Publishers.