Chemical structures and cell-death-inducing activities of metabolites produced by Penicillium maximae

Two previously undescribed compounds, maximeroterpenoid I (1) and maximazaphilone V (5), together with five known compounds (2-4, 6, and 7) were isolated from the airborne-derived fungus Penicillium maximae JKYM-AK2. The planar chemical structures and relative configurations of 1 and 5 were elucidated by high -resolution mass spectrometry and 1D and 2D NMR spectroscopy. The absolute configuration of 1 and 5 were established by comparing experimental and predicted electronic circular dichroism data. We isolated JBIR-113 (3), which has an interesting cyclic peptide structure, in relatively high yield (0.37 % from the EtOAc-soluble fraction); therefore, P. maximae JKYM-AK2 is a rich source of this unique peptide. The azaphilones [5, (+)-isochromophilone IX (6), and (+)-isochromophilone VI (7)] induce significant Adriamycin-treated HeLa-cell death.