NEW ISOCHROMENES FROM THE FERMENTATION PRODUCTS OF ENTOPHYTIC FUNGUS ASPERGILLUS VERSICOLOR AND THEIR ANTI-TOBACCO MOSAIC VIRUS ACTIVITIES

摘要

Three new isochromenes, 6,7-dimethoxy-3-methyl-5-(3-methylbuten-2-yl)-1H-isochromene (1), 7-methoxy-3-methy1-5-(3-methylbuten-2-y1)-1H-isochromen-6-ol (2), 3-methyl-5-(3-methylbuten-2-y1)-1H-isochromen-6-ol (3), together with three known isocoumarins (4-6) 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) activities of compounds 1-3 and 6 were evaluated. The results revealed that compounds 1-3 and 6 showed anti-TMV activity with inhibition rates of 26.8 and 25.4, 24.2 and 18.6% at the concentration of 20 mu M, respectively.