Bioactive γ-lactones from the fermented broth of Neosartorya sp.

Two γ-lactone derivatives, namely neosartolactone (1) and its 7-methyl ester analogue (2), have been isolated from the ethyl acetate extract of the fermented broth of Neosartorya sp. isolated in Taiwan. Structural elucidations of compounds 1 and 2 were achieved on the basis of spectroscopic analysis. Although they had been obtained via the chemical modification of avenaciolide isolated from Aspergillus avenaceus several decades ago, this is the first report to describe them from a natural resource with detailed spectroscopic interpretations. The effects of 1 and 2 on the inhibition of NO production in lipopolysaccharide (LPS)-activated murine macrophages were further evaluated. Compounds 1 and 2 significantly inhibited NO production with the IC(50) values of 12.2 ± 1.5 and 11.4 ± 1.0 µM, respectively; but displayed cytotoxicity at considerably higher concentrations than 50 µM. © Georg Thieme Verlag KG Stuttgart · New York.