Setosol, a biologically active heptaketide-like metabolite from the Pleiochaeta setosa phytopathogen

Setosol, a biologically active natural product, was extracted from Pleiochaeta setosa, an organism isolated from volcanic rock in the Canaries. With molecular formula C15H16O5 and a melting point of 139 degrees C, this pale yellow and amorphous compound inhibited the growth of Pyricularia oryzae, Drechslera oryzae, and Gerlachia oryzae. Isolation of the new compound was performed by repeated centrifugal TLC on silica gel, and its structure was established as 2,8-dimethyl-4-methoxy-6,10,11-trihydroxy-benzooxaonin by detailed spectral studies, including COSY, 2D 1H-13C direct chemical shift correlation (XHCORR), 2D 1H-13C correlation via long-range coupling (COLOC), heteronuclear-gated decoupling (GATEDEC), and single-frequency heteronuclear-gated decoupling (SFDEC) NMR techniques, as well as UV, IR, and MS