Bioactive aromatic derivatives from endophytic fungus, Cytospora sp.

Two new benzyl gamma-butyrolactone analogues, (R)-5-((S)-hydroxy(phenyl)-methyl)dihydrofuran-2(3H)-one (1) and its 6-acetate (2), and a new naphthalenone derivative (8), together with eight additional known aromatic derivatives, (S)-5-((S)-hydroxy(phenyl)-methyl)dihydrofuran-2(3H)-one (3), (S)-5-benzyl-dihydrofuran-2(3H)-one (4), 5-phenyl-4-oxopentanoic acid (5), gamma-oxo-benzenepentanoic acid methyl ester (6), 3-(2,5-dihydro-4-hydroxy-5-oxo-3-phenyl-2-furyl)propionic acid (7), (3R)-5-methylmellein (9), integracins A (10) and B (11) were isolated from Cytospora sp., an endophytic fungus isolated from Ilex canariensis from Gomera. The structures of these compounds were elucidated by detailed spectroscopic analysis, comparison with reported data, and chemical interconversion. The absolute configurations of the new compounds (1, 2, 8) were established on the basis of optical rotation or CD spectra analysis. Preliminary studies showed antimicrobial activity of these compounds against the fungi Microbotryum violaceum, Botrytis cinerea and Septoria tritici, the alga Chlorella fusca, and the bacterium Bacillus megaterium.