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A new pyrone derivative 11-hydroxypyrophen (1), together with pyrophen (2) and six naphtho-γ-pyrones (3–8), were obtained from the culture extract of Aspergillus niger Pas67. All isolated compounds were evaluated for their antibacterial activities against methicillin-resistant Staphylococcus aureus (MRSA). Compounds 4 and 8 showed significant antibacterial activity against MRSA with minimum inhibitory concentration values (MICs) of 25 and 16 μg/mL, while compounds 1 and 2 did not display anti-MRSA activity. [ABSTRACT FROM AUTHOR]

Two new isochromenes, 5-methoxy-3-methyl-7-prenyl-1H-isochromene (1) and 7-(3-hydroxypropyl)-5-methoxy-3-methyl-1H-isochromene (2), along with four known ones (3–6) were isolated from the fermentation products of the Nicotiana tabacum-derived endophytic fungus Aspergillus versicolor. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were evaluated for their anti-tobacco mosaic virus (anti-TMV) and anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activities. The results showed that compounds 1 and 2 exhibited potential anti-TMV activities with inhibition rates of 36.5 and 42.2%, respectively, and also showed good anti-MRSA activities with IZD of 16.8 ± 2.2 and 20.6 ± 2.5 mm, respectively. [ABSTRACT FROM AUTHOR]