Pestalotiopisorin B, a new isocoumarin derivative from the mangrove endophytic fungus sp. HHL101.

A new isocoumarin derivative pestalotiopisorin B (), along with six known compounds, ()-(-)- mellein methyl ether (), pestalotiopyrone G (), ()-mevalonolactone (), pestalotiollides A-B () and pestalotiopsol A() were isolated from sp., an endophytic fungus obtained from Chinese mangrove plant Their structures were elucidated unambiguously by the comprehensive analysis of extensive spectroscopic data. Compound exhibited modest antibacterial activity against and with 12.5 μg/ml, 50 μg/ml, respectively. Compound showed moderate calcineurin inhibitory activity towards -nitrophenyl phosphate (IC =134.29 ± 5.377 μM).