Novel Sesquiterpenoids from the Fermentation of <i>Xylaria </i><i>p</i><i>ersicaria</i> Are Selective Ligands for the NPY Y5 Receptor

Neuropeptide Y (NPY) is a polypeptide found in the peripheral and central nervous system and is involved in the regulation of feeding. Antagonists of NPY receptor activation could therefore have potential for development as antiobesity drugs. Fermentation of an isolate of <i>Xylaria persicaria</i> yielded two novel eremophilane sesquiterpenoids xylarenals A (<b>1</b>) and B (<b>2</b>). These compounds are selective for the NPY Y5 receptor but have only modest affinity. The isolation, structure elucidation, and biological activities of these compounds are described.