γ-Butenolide and furanone derivatives from the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178.

Chromatographic separation of the broth extract of the soil-derived fungus Aspergillus sclerotiorum PSU-RSPG178 resulted in isolation of four γ-butenolide-furanone dimers, aspersclerotiorones A-D, a furanone derivative, aspersclerotiorone E, and two γ-butenolide derivatives, aspersclerotiorones F and G, together with six known compounds, penicillic acid, dihydropenicillic acid, 5,6-dihydro-6-hydroxypenicillic acid, 6-methoxy-5,6-dihydropenicillic acid, coculnol and (4R,5R)-4,5-dihydroxy-3-methoxy-5-methylcyclohex-2-en-1-one. Their structures were determined by spectroscopic evidence. For aspersclerotiorones A and B, the structures were confirmed by single-crystal X-ray diffraction crystallography. Penicillic acid displayed weak antibacterial activity against Staphylococcus aureus and Escherichia coli with equal MIC values of 128 μg/mL, and it was noncytotoxic towards African green monkey kidney fibroblast cells.