Structures and antiviral activities of butyrolactone derivatives isolated from Aspergillus terreus MXH-23

A new butyrolactone derivative, namely butyrolactone VIII (1), and six known butyrolactones (2–7) were separated from the ethyl acetate (EtOAc) extract of the fermentation broth of a fungus, Aspergillus terreus MXH-23. The chemical structures of these metabolites were identified by analyzing their nuclear magnetic resonance (NMR) and mass spectrometry (MS). Known butyrolactone derivatives contain an α,β-unsaturated γ-lactone ring with α-hydroxyl and γ-benzyl, and butyrolactone VIII (1) was the first butyrolactones contains α-benzyl and γ-hydroxyl on α,β-unsaturated lactone ring. All of the butyrolactone derivatives were tested for their anti-influenza (H1N1) effects. Derivatives 4 and 7 showed moderate antiviral activities while the newly-identified, derivative 1, did not.