Alkaloids from the endophytic fungus Penicillium brefeldianum and their cytotoxic activities

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 brefeidianum.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 35.5μmol/L,respectively.Compound 3 showed moderate activity against HepG2 cells with IC_(50) values of 36.6 μmol/L.