Natural products with anti-HIV activity from marine organisms.

In order to combat the human immunodeficiency virus (HIV), diverse strategies have been developed to research on compounds which can be developed as therapeutic agents. Screening of natural products derived from numerous species has afforded metabolites with significant antiviral activity against the HIV. The marine environment representing approximately half of the global biodiversity offers an enormous resource for novel compounds. Currently more than 150 natural products with promising levels of anti-HIV activity have been isolated following bioassay guided protocols from aqueous or organic extracts of marine organisms. Some of the most characteristic marinemetabolites that have exhibited significant anti-HIV activity on different biochemical assays designed for chemotherapeutic strategies are: Cyanovirin-N, a protein from a blue green alga; various sulfated polysaccharides extracted from seaweeds (i.e. Nothogenia fastigiata, Aghardhiella tenera); the peptides tachyplesin and polyphemusin, which are highly abundant in hemocyte debris of the horseshoe crabs Tachypleus tridentatus and Limulus polyphemus; sponge metabolites such as avarol, avarone, ilimaquinone and several phloroglucinols; and a number of metabolites from marine fungi such as equisetin, phomasetin and integric acid. Considering that number of unique metabolites that have been isolated from a small extent of the ocean's biological and chemical diversity, the oceans represent a virtually untapped resource for the discovery of novel bioactive compounds.