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Oryzaeins A–D (1-4), four new isocoumarin derivatives, along with five known ones (5-9) were isolated from solid cultures of an endophytic fungus Aspergillus oryzae. Their structures were elucidated by detailed spectroscopic analysis and by comparison with reported data of related derivatives. Among them, compounds 1 and 2 represent the first examples of isocoumarins possessing an unusual 2-oxopropyl group and a rare 3-hydroxypropyl group. Compounds 1 and 2 displayedmoderate anti-tobacco mosaic virus activities with inhibition rates of 28.4% and 30.6%, respectively, at the concentration of 20 μM. The new compounds showed moderate inhibitory activities against several human tumor cell lines with IC50 values in the range of 2.8-8.8 μM. [ABSTRACT FROM AUTHOR]

Versicolactones A-D (1-4), four new butyrolactones, along with four known butyrolactones (5-8) were isolated from the fermentation products of the endophytic fungus Aspergillus versicolor. The structures of compounds 1-4, including absolute configuration, were elucidated by interpretation of the NMR and CD data. Compound 2 was further confirmed by single-crystal X-ray diffraction analysis. In particular, compound 1 is the first naturally occurring butyrolactone possessing an unusual 2-oxopropyl group. More importantly, compounds 1 and 8 displayed significant antitobacco mosaic virus activities with inhibition rates of 46.4% and 35.4%, even more potent than the positive control ningnanmycin (30.8%). Compound 1 also showed moderate cytotoxicity against A549 and MCF7 cells with IC50 values of 3.2 and 2.5 μM, respectively. [ABSTRACT FROM AUTHOR]