Isocoumarins from the fermentation products of a plant entophytic fungus Penicillium oxalicum.

ABSTRACT

Three new isocoumarins, terrecoumarins A-C (1-3), together with six known isocoumarins (4-9) were isolated from the fermentation products of the fungus Penicillium oxalicum 0403. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. The anti-tobacco mosaic virus (anti-TMV) activities of 1-9 were evaluated. The results revealed that compound 1 showed high anti-TMV activity with inhibition rate 25.4 ± 3.5%. Other compounds also showed weak activity with inhibition rate in the range of 11.3-18.9%.