Atranones from Stachybotrys chartarum and their antitumor activities in MG-63 human osteosarcoma cells.

Abstract Two new atranones T and U (1 and 2), and three known analogues atranone B (3), atranone Q (4), and stachatranone C (5) were isolated from the toxigenic fungus Stachybotrys chartarum. Their structures and absolute configurations were elucidated by spectroscopic data and calculated ECD analyses. The cytotoxicities of all the atranones (1–5) were evaluated against MG-63 human osteosarcoma cell lines. Compound 4 exhibited significant cytotoxic effect against MG-63 with IC50 value of 8.6 μM, being more active than the positive control, 5-FU (IC50 10.4 μM). Morphological features of apoptosis activities were evaluated in 4-treated MG-63 cells. Compound 4 effectively induced apoptosis of MG-63, which was associated with G0/G1-phase cell cycle arrest. Flow cytometric analysis showed that the treatment by 4 significantly induced MG-63 cell apoptosis in a dose-dependent manner.