Bovistols E and F, New bis-Sesquiterpenes Isolated From Psathyrella microrhiza CF-117891

Bioactivity-based purification of the acetone extract of a culture of the fungus Psathyrella microrhiza CF-117891 led to the isolation of the new bis-sesquiterpenes bovistols E and F (1 and 2) together with the anti-plasmodial coriolic acid (3). The structures of the new compounds isolated were determined by a combination of positive electrospray ionization time-of-flight mass spectrometry and nuclear magnetic resonance spectroscopy. Of the three compounds isolated, coriolic acid displayed previously unreported moderate anti-Plasmodium falciparum 3D7 activity, with a half-maximal effective concentration value of 17.8 µM, whereas the new bovistols did not show any biological activity in their pure forms against this parasite nor against Trypanosoma cruzi Tulahuen parasites.