Two New Diphenyl Ether Derivatives from the Fermentation Products of an Endophytic Fungus Phomopsis fukushii

Two new diphenyl ethers, 1-[2-methoxy-4-(3-methoxy-5-methylphenoxy)-6-methylphenyl]-ethanone ( 1 ) and 1-[4-(3-(hydroxymethyl)-5-methoxyphenoxy)-2-methoxy-6-methylphenyl]-ethanone ( 2 ), together five known diphenyl ether derivatives ( 3–7 ), were isolated from the fermentation products of an endophytic fungus Phomopsis fukushii . Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were evaluated for their anti-methicillin-resistant Staphylococcus aureus (anti-MRSA) activity. Compounds 1 and 2 showed good inhibition with IZD of 13.8 ± 1.5 mm and 14.6 ± 1.6 mm, respectively.