Depsipeptides from a Guamanian marine cyanobacterium, Lyngbya bouillonii, with selective inhibition of serine proteases

Bouillomides A (1) and B (2) are two depsipeptide analogues of dolastatin 13. Isolated from a Guamanian sample of Lyngbya bouillonii, the planar structures were elucidated on the basis of HR-ESI-MS and NMR data, while the absolute configurations were determined by employing functional group conversions, modified Marfey's analysis, and detailed analyses of ROESY correlations. Compounds 1 and 2 selectively inhibited serine proteases elastase (IC50=1.9 mu M for both) and chymotrypsin (IC50 = 0.17 and 9.3 mu M, respectively) while showing no inhibition of trypsin (IC50 > 100 mu M). (C) 2010 Elsevier Ltd. All rights reserved.