Aurasperone F -: a new member of the naphtho-gamma-pyrone class isolated from a cultured microfungus, Aspergillus niger C-433

A novel dimeric naphtho-gamma-pyrone, named aurasperone F ( 1), was isolated from the fermentation broth of the culture extracts of Aspergillus niger C-433, isolated from grapes, along with the known compounds fonsecin ( 2), aurasperone B ( 3), aurasperone C ( 4), aurasperone D ( 5) and aurasperone E ( 6). The chemical structure of the new natural product was established by extensive one- and two-dimensional NMR spectroscopic studies (H-1, C-13, COSY, HMQC, 1D NOE spectra), as well as on the UV, MS and IR spectral analysis.