Secondary metabolites of Pyrenochaeta sp. B36, an endophytic fungus from Annona squamosa L.

Four new metabolites, named pyrenochaetamide A, pyrenochaetolide A, pyrenochaetoxy A and pyrenochaetolide B, together with five known compounds, were isolated from strain Pyrenochaeta sp. B36, an endophytic fungus of Annona squamosa L. Their structures were elucidated by spectroscopic analyses including 1D- and 2D-NMR (HMQC, HMBC, ¹H-¹H COSY and NOESY) and HRFT-MS. The cytotoxic activities of these compounds were evaluated and some of them showed substantial effect.