Isolation and Total Synthesis of Ukabamide, an Antitrypanosomal Lipopeptide from a Marine Moorena sp. Cyanobacterium.

Human African trypanosomiasis (HAT) is one of the most lethal of the neglected tropical diseases. While the discovery of a novel antitrypanosomal drug is highly desired, the creation of a superior lead compound is challenging. Herein we report ukabamide (1), which was isolated from a marine Moorena sp. cyanobacterium, as a selective and potent antitrypanosomal lipopeptide (IC50 = 34 ± 18 nM against Trypanosoma brucei rhodesiense). Its structure was elucidated by spectroscopic analyses and degradation reactions and confirmed by total synthesis. In addition, we prepared two modified analogs and revealed the importance of the fatty acid chain length for biological activity. These findings may provide design guidelines for an antitrypanosomal drug.