An alkaloid that inhibits the growth of mouse leukemia P388 cells (IC50 = 1.8 μg/ml); binds to and stabilizes the topoisomerase I-DNA binary complex, leading to DNA breakage and cell death (IC50 = 5.07-12.6 μM); selectively inhibits CYP1A1 and CYP1A2 (IC50 = ~6 μM for each) in human liver microsomes.