Isocoumarin derivatives from endophytic fungus Phomopsis sp. RJ-21

Five isocoumarin derivatives 1–5, along with known compounds 6–10 were isolated from the fermentation of endophytic fungus Phomopsis sp. RJ-21. Among them, six compounds (2–7) were reported for the first time from the genus Phomopsis. The isolated compounds were screened in vitro for their antimicrobial activities. Amongst the tested compounds, vertixanthone (6) exhibited activities against three Methicillin resistant Staphylococcus aureus (MRSA) with inhibition zones of 13–15 mm (diameter). This work expanded the knowledge of the chemical diversity of the genus Phomopsis, and the chemotaxonomic significance of the isolates was also discussed.