Cytotoxic and antimalarial azaphilones from Chaetomium longirostre.

Four new azaphilones named longirostrerones A-D (1-4) and three known sterols, ergosteryl palmitate, ergosterol, and ergosterol peroxide, have been isolated from ethyl acetate extract of the fungus Chaetomium longirostre. These structures were determined by 1D and 2D NMR, IR, UV, MS, and CD spectroscopy. Compounds 1-4 exhibited strong cytotoxicity against KB cancer cell lines (IC(50) 0.23-6.38 μM), while only 1 showed potent cytotoxicity against MCF7 and NCI-H187 cell lines (IC50 0.24 and 3.08 μM, respectively). In addition, 1-3 showed antimalarial activity against Plasmodium falciparum (IC50 0.62-3.73 μM).