ABSTRACT
Seven new guanacastane-type diterpenoids, namely dahlianes E-K (1-7), and three known ones (8-10) were isolated from the cultures of the fungus Verticillium dahliae. Their structures were established by extensive spectroscopic data analysis along with Rh2(OCOCF3)4- and Mo2(OAc)4-induced electronic circular dichroism (ECD) experiment. Dahliane G showed an 80-fold potentiation effect on the sensitization of doxorubicin at the concentration of 15⯵M when screening the reversal activity on doxorubicin-resistant human breast cancer cells (MCF-7/DOX).
Subject(s)
Diterpenes/pharmacology , Verticillium/chemistry , Animals , China , Diterpenes/isolation & purification , Doxorubicin , Drug Resistance, Neoplasm/drug effects , Heteroptera/microbiology , Humans , MCF-7 Cells , Molecular StructureABSTRACT
Seven undescribed phenylspirodrimane derivatives, stachybochartins A-G (1-7), and four known analogues (8-11) were isolated from the endophytic fungus Stachybotrys chartarum obtained from Pinellia ternata. Stachybochartins A-D are four rare C-C-coupled dimeric derivatives and stachybochartin G features a seco-bisabosqual skeleton. Their structures and configurations were elucidated via spectroscopic analysis, electronic circular dichroism (ECD) calculations, the ECD exciton chirality method and the modified Mosher's method. Stachybochartins A-D and G displayed cytotoxic activities against MDA-MB-231 breast cancer cells and U-2OS osteosarcoma cells, with IC50 values ranging from 4.5 to 21.7 µM. Stachybochartins C and G exerted strong anti-proliferative activities against U-2OS cells in concentration- and time-dependent manners and induced apoptosis.
