Novel Chromone Derivatives from the Fungus <i>Aspergillus </i><i>v</i><i>ersicolor</i> Isolated from the Marine Sponge <i>Xestospongia </i><i>e</i><i>xigua</i>

Abstract

From the marine sponge Xestospongia exigua collected in Indonesia the fungus Aspergillus versicolor was isolated. Following cultivation in a seawater-based medium seven new angular tricyclic chromone derivatives (1-7) were obtained from the mycelia and culture filtrate. Compounds 2-7 contain an additional dihydropyran ring system which is replaced by a pyridine ring in 1. The structures of the new natural products were established on the basis of extensive one- and two-dimensional NMR spectroscopic studies (1H, 13C, COSY, HMQC, HMBC, NOE difference spectra) as well as on mass spectral analysis.