Isocoumarins from the fermentation products of an endophytic fungus of Aspergillus versicolor

Abstract Three new Isocoumarins, versicoumarins A–C ( 1 – 3 ), along with four known isocoumarins ( 4 – 7 ) were isolated from the fermentation products of an endophytic fungus Aspergillus versicolor . Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. The anti-tobacco mosaic virus (anti-TMV) activity of 1 – 7 were evaluated. Compound 1 showed high anti-TMV activity with inhibition rate of 28.6%, which is close to that of positive control ningnanmycin (31.5%). Compounds 1 – 7 were also tested for their cytotoxicities against five human tumor cell lines (NB4, A549, SHSY5Y, PC3, and MCF7), and 1 showed high cytotoxicities against A549 and MCF7 cell with IC 50 values of 3.8 and 4.0 μM, respectively.