Drimane Sesquiterpenoids and Isochromone Derivative from the Endophytic Fungus Pestalotiopsis sp. M-23.

Three new drimane sesquiterpenoids (1-3) together with the known 2α-hydroxyisodrimeninol (4), and a new isochromone derivative (5), were obtained from the solid cultures of fungal strain Pestalotiopsis sp. M-23, an endophytic fungus isolated from the leaves of Leucosceptrum canum (Labiatae). Their structures were determined by comprehensive 1D and 2D NMR, and MS analyses. The metabolites were evaluated for their antibacterial activities, and compound 3 showed weak inhibitory activity against Bacillus subtilis.