Bioactive components of the traditionally used mushroom Podaxis pistillaris

In the course of an ethnobotanical study on fungi used in Yemeni ethnomedicine the fungus Podaxis pistillaris (Podaxales, Podaxaceae, Basidiomycetes) was found to exhibit antibacterial activity against Staphylococcus aureus, Micrococcus flavus, Bacillus subtilis, Proteus mirabilis, Serratia marcescens and Escherichia coli. In the culture medium of P. pistillaris three epidithiodiketopiperazines were identified by activity-guided isolation. Based on spectral data (NMR, ESI-MS and DCI-MS) their identity was established as epicorazine A (1), epicorazine B (2) and epicorazine C (3, antibiotic F 3822), which have not been reported as constituents of P. pistillaris previously. It is assumed that the identified compounds contribute to the antibacterial activity of the extract.