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 alpha,beta-unsaturated gamma-lactone ring with alpha-hydroxyl and gamma-benzyl, and butyrolactone VIII (1) was the first butyrolactones contains alpha-benzyl and gamma-hydroxyl on alpha,beta-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.