In vitro activity: Triptolide is a diterpene triepoxide with potent immunosuppressive and antiinflammatory properties. Triptolide is shown to inhibit the expression of IL-2 in activated T cells at the level of purine-box/nuclear factor and NF-κB mediated transcription activation. Triptolide inhibits the proliferation and colony formation of tumor cells at extremely low concentrations (2–10 ng/mL). Triptolide has an inhibitory activity on breast, stomach and leukemia cell line HL-60 cells. Triptolide induces apoptosis in tumor cells by blocking NF-κB activation and sensitizing tumor cells for TNF-&alpha induced programmed cell death.

Cell Assay: The viability of differentiated PC12 cells treated with different concentrations of Triptolide. After differentiated PC12 cells are cultured on 96-well plates with RPMI 1640 medium for stabilization, differentiated PC12 cells are incubated with different concentrations of Triptolide (0.01, 0.1, and 1 nM) for 24 hours. The concentrations in this study are chosen. Then cell viability is determined by the MTT assay. Each condition and experiment is repeated three times.

J Biol Chem. 1999 May 7;274(19):13443-50; Mol Cancer Ther. 2003 Jan;2(1):65-72.