A potent inhibitor of DNA topoisomerase I that induces cytoxicity and DNA damage in human HT-29 colon adenocarcinoma cells (IC50s = 33 nM and 0.28 μM, respectively; demonstrates a broad spectrum of antitumor activity against a variety of other tumors including ovarian cancer, cervical cancer, neuroblastoma, brainstem glioma, and Ewing’s sarcoma.