Isolation, Structure, and HIV-1 Integrase Inhibitory Activity of Cytosporic Acid, a Fungal Metabolite Produced by a Cytospora sp.

HIV-1 integrase is a critical enzyme for replication of HIV, and its inhibition has the potential to lead to an anti-retroviral therapy that has advantages over existing therapies. Cytosporic acid (1) is a polyketide-derived novel natural product that was isolated from a fermentation broth of the filamentous fungus Cytospora sp. collected from Puerto Rico. It inhibited strand transfer reaction of HIV-1 integrase with an IC₅₀ of 20 μM. The isolation, structure elucidation, relative stereochemistry, and activity of 1 are described.