Coibamide A, a potent antiproliferative cyclic depsipeptide from the panamanian marine cyanobacterium Leptolyngbya sp.

Coibamide A (1) is a new, potent antiproliferative depsipeptide which was isolated from a marine Leptolyngbya cyanobacterium collected from the Coiba National Park, Panama. The planar structure of I was elucidated by a combination of NMR spectroscopy and mass spectrometry. Exhaustive 1 D and 2D NMR spectroscopy included natural abundance (15)N and variable temperature experiments; mass spectrometry included TOF-ESI-MS(n) and FT-MS(n) experiments, Chemical degradation followed by chiral HPLC- and GC-MS analyses was used to assign the absolute configuration of 1. This highly methylated cyclized depsipeptide exhibited an unprecedented selectivity profile in the NCl 60 cancer cell line panel and appears to act via a novel mechanism.