Bioactive metabolites from the desert plant-associated endophytic fungus Chaetomium globosum (Chaetomiaceae)

Globosumin, an undescribed chromene-4,7(4aH)-dione-tetramic acid PKS-PKS-NRPS hybrid, and globosumone, an undescribed azaphilone, together with ten known metabolites, were isolated from the desert plant-associated endophytic fungus Chaetomium globosum (Chaetomiaceae). The planar structures and relative configurations of globosumin and globosumone were determined by high-resolution ESI-MS and NMR data, and the absolute configurations of these two metabolites were determined by electronic circular dichroism (ECD) and circular dichroism (CD) combined with time-dependent density functional theory (TDDFT)-based quantum-chemical calculations. Chaetoglobosin A displayed biological effects against the seedling growth of Arabidopsis thaliana (Brassicaceae) in a dose-dependent manner, and this compound also exhibited biological activity against two cancer cell lines, A549 and HepG2, with IC50 values of 6.82 +/- 2.34 and 38.62 +/- 7.44 mu M, respectively.

Automated summary

New metabolites globosumin and globosumone were isolated from the endophytic fungus Chaetomium globosum, showing inhibitory effects on Arabidopsis thaliana seedling growth and cancer cell lines A549 and HepG2, with Chaetoglobosin A demonstrating dose-dependent biological activity.