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

Two new butyrolactone derivatives, terrelactones A and B (1 and 2), together with four known butyrolactone derivatives (3-6), 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 and 2 were evaluated. The results showed that compounds 1 and 2 exhibited high anti-TMV activity with inhibition rates of 25.5% and 27.4%, respectively. The inhibition rate is close to that of positive control (28.9%).