Isolation and structures of pipecolidepsins A and B, cytotoxic cyclic depsipeptides from the Madagascan sponge Homophymia lamellosa.

Two new cyclic depsipeptides, pipecolidepsins A and B (1 and 2), have been isolated from the sponge Homophymia lamellosa collected off the coast of Madagascar. Their structures were determined by a combination of NMR experiments and by LC-MS analysis of the amino acid fragments obtained by hydrolysis and derivatization using Marfey's reagent. In addition to… (More)