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.