Fig. 4 in Identification of seven undescribed cucurbitacins in Cucumis sativus (cucumber) and their cytotoxic activity

Fig. 4. Cucurbitacins induced caspase apoptosis pathway activation in HepG2 cells. (A) Apoptosis induction effects of four cucurbitacins on HepG2 cells. The cells were treated with each cucurbitacin for 24 h, and stained with Hoechst 33258 for cell apoptosis assay. Arrows, chromatin condensed HepG2 cells. (B) Quantitative data of panel A, percentage of apoptosis cells is shown. **P <0.01, ***P <0.001, student t-test. (C) Inhibition effects of four cucurbitacins in caspase apoptosis pathway on HepG2 cells. The cells were treated with each cucurtibitcin for 24 h, respectively, and the major apoptosis-related proteins (PARP, cleaved PARP, Caspase-9, Caspase-8 and Caspase-3) were detected by Western blot. β-actin was used as internal reference. (D) Quantitative data of panel C, expression levels of apoptosis-related proteins are shown. **P <0.01, ***P <0.001, student t-test.