Fig. 7

Tryptanthrin affected cell cycle profile resembled that of ISAE. A Jurkat cells were exposed to indicated concentrations of ISAE (146 µg/mL), indigo (10 µM), indirubin (10 µM), tryptanthrin (10 µM), or doxorubicin (0.06 µM) for 24 h, then fixed for propidium iodide (PI) staining. Cell cycle profiles were recorded by flow cytometry. Control solvent was distilled water for ISAE and Dimethyl sulfoxide (DMSO) at final concentration of 0.1% for pure compounds. B Jurkat cells were pre-exposed for 1 h to Caffeine, and then treated with tryptanthrin (20 µM) for 24 h. Cells were then harvested for cell cycle analysis. C Jurkat cells were treated with indicated concentrations (2.5, 5, 10, 20 µM) of indigo, indirubin, or tryptanthrin for 72 h. The resazurin reagent was used to determine cell viability. DMSO at 0.1% was used as solvent control (“0” concentration) for 100% viability. Data are presented as mean ± SD from three independent experiments. * indicates significant difference from control group (*p < 0.05, **p < 0.01, one-way ANOVA). Tryptanthrin, but not indigo nor indirubin, can induce G2/M arrest to a similar extent as ISAE did in Jurkat cells. Co-treatment with caffeine blocked tryptanthrin-induced G2/M arrest in Jurkat cells