Antibacterial Naphthalene Derivatives from the Fermentation Products of the Endophytic Fungus Phomopsis fukushii

Two new naphthalene derivatives, 1-(3-hydroxy-1-(hydroxymethyl)-2-methoxy-6-methylnaphthalen-7-yl) propan-2-one (1) and 1-(3-hydroxy-1-(hydroxymethyl)-6-methylnaphthalen-7-yl)propan-2-one (2), together three known naphthalene derivatives (3–5) were isolated from the fermentation products of the 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. The results showed that compounds 1 and 2 showed weak inhibition with IZD of 10.2 ± 1.8 and 11.3 ± 2.0 mm, respectively.