Alkaloids from the endophytic fungus Penicillium brefeldianum and their cytotoxic activities

Abstract One new indoloditerpene, 6,7-dehydropaxilline ( 1 ), one new indole-diketopiperazine, spirotryprostatin F ( 2 ), and one new 13-membered macrolide, N -demethylmelearoride A ( 3 ), as well as 8 known alkaloids ( 4 – 11 ), were isolated from the solid cultures of the endophytic fungus, Penicillium brefeldianum . The structures and absolute configurations of compounds 1 - 3 were elucidated by comprehensive spectroscopic analysis and the circular dichroism (CD) exciton chirality method. All the metablites were evaluated for their cytotoxic activites against three human tumor cell lines. Compound 2 exhibited cytotoxicities against HepG2 and MDA-MB-231 cells with IC 50 values of 14.1 μmol/L and 35.5 μmol/L, respectively. Compound 3 showed moderate activity against HepG2 cells with IC 50 values of 36.6 μmol/L.