Phomopsidone A, a Novel Depsidone Metabolite from the Mangrove Endophytic Fungus Phomopsis Sp. A123.

One novel pentacyclic depsidone containing an oxetane unit, phomopsidone A (1), together with the reported excelsione (also named as phomopsidone) (2), and four known isobenzofuranones (3–6) were isolated from the mangrove endophytic fungus Phomopsis sp. A123. Their structures were elucidated by 1D and 2D NMR spectroscopic analysis and high resolution mass spectrometry. The bioactivity assays showed that these compounds possess cytotoxic, antioxidant, and antifungal activities.