[11]-Chaetoglobosins from <i>Pseudeurotium bakeri</i> Induce G2/M Cell Cycle Arrest and Apoptosis in Human Cancer Cells

Twelve new [11]-chaetoglobosins, chaetopseudeurins A–L (1–12), were identified from the fermentation of the endophytic fungus Pseudeurotium bakeri P1-1-1. Their structures with absolute configurations were elucidated by detailed interpretation of NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. Compounds 2 and 5–7 exhibited significant cytotoxicities against seven human cancer cell lines, with IC50 values ranging from 4.7 ± 1.0 to 12.2 ± 0.7 μM, and induced G2/M cell cycle arrest and apoptosis in MCF-7 and A427 cells dose dependently. Western blot analysis showed that compound 2 induced apoptosis of MCF-7 cells via the Bcl-2/caspase-3/PARP pathway.