Hahk-Soo Kang, Aleksej Krunic, and Jimmy Orjala*
Stigonemapeptin (1), a depsipeptide containing an Ahp (3-amino-6-hydroxy-2-piperidone) residue, was isolated from a bloom sample of the freshwater cyanobacterium Stigonema sp. collected from North Nokomis Lake in the Highland Lake District of northern Wisconsin. The planar structure was determined by 1D and 2D NMR experiments as well as HRESIMS analysis. The absolute configurations of the amino acids were determined using the advanced Marfey’s method after acid hydrolysis. Stigonemapeptin (1), characterized by the presence of the Ahp residue, also contained the modified amino acids Abu (2-amino-2-butenoic acid) and N-formylated Pro. Stigonemapeptin (1) showed in vitro elastase and chymotrypsin inhibitory activity, with IC50 values of 0.26 and 2.93 μM, respectively.
Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 S. Wood Street, Chicago, Illinois 60612, United States
J. Nat. Prod., Article ASAP
DOI: 10.1021/np300150h
Publication Date (Web): April 6, 2012
Copyright © 2012 The American Chemical Society and American Society of Pharmacognosy
