Two New Antibacterial Anthraquinones from Cultures of an Endophytic Fungus Phomopsis sp.

Two new anthraquinones, 3-hydroxy-6-hydroxymethyl-2,5-dimethylanthraquinone (1) and 6-hydroxymethyl-3-methoxy-2,5-dimethylanthraquinone (2), were isolated from the fermentation products of the endophytic fungus Phomopsis sp. Their structures were elucidated by spectroscopic methods, including extensive 1D and 2D NMR techniques. Compounds 1 and 2 were evaluated for their antimethicillin-resistant Staphylococcus aureus activity. The results showed that compounds 1 and 2 showed good inhibition with IZD of 14.2 ± 2.0 and 14.8 ± 2.2 mm, respectively. Compounds 1 and 2 were also tested for antioxidant activity; they show good activity with IC50 values of 4.18 and 4.36 μg/mL, respectively.