The fungal natural product (1S,3S)-austrocortirubin induces DNA damage in HCT116 cells via a mechanism unique from other DNA damaging agents.

Screening a series of natural product-based tetrahydroanthraquinones led to the identification of a novel molecule, (1S,3S)-austrocortirubin (2), which acts via inducing DNA damage. Compound 2 has a GI50 of 3μM against HCT116 and induces apoptosis. Mechanism of action studies indicate that it causes significant DNA damage during G0/G1, S, and G2 cell cycle phases. Cells are stopped at the G2/M phase checkpoint, and do not reach mitosis due to large amounts of DNA damage. Thus, compound 2 exhibits a unique mechanism of action, one that is distinct from doxorubicin, despite the high degree of structural homology between these two quinone-based structures.