Cochlioquinone derivatives with apoptosis-inducing effects on HCT116 colon cancer cells from the phytopathogenic fungus Bipolaris luttrellii L439.

A new cochlioquinone derivative, cochlioquinone F (1), as well as three known compounds, anhydrocochlioquinone A (2), isocochlioquinone A (3), and isocochlioquinone C (4), were isolated from the PDB (potato dextrose broth) culture of the phytopathogenic fungus Bipolaris luttrellii. The structure of 1 was elucidated on the basis of NMR techniques. The apoptosis-inducing effects of compounds 1-4 were evaluated against HCT116 cancer cells. Compound 2 exhibited the strongest activity in inducing apoptosis on HCT116 cells within the range of 10-30 μM. In addition, the caspase activation, the release of cytochrome c from mitochondria, and the downregulation of Bcl-2 protein in HCT116 cells treated with compound 2 were detected.