**2.8 Cucurbitacin A (8′)**

 The antiproliferative effects of Cucurbitacin A (CuA) on A-549 cells were determined by using the MTT assay. This compound exhibited a potent cytotoxic effect on A-549 cells. The assay was carried out at different concentrations of CuA (0, 10, 20, 40, 100, 150, and 200 μM) with incubation for 24 and 48 h. CuA showed inhibitory effects on cell proliferation in a dose- and time-dependent manner. However, the effect of the incubation time was more pronounced at higher doses of the compound. CuA also induced morphological changes in these cells, featuring chromatin condensation, cell shrinkage, and apoptotic body formation. G2/M phase cell cycle collapse was also induced by CuA along with inhibition of the expression levels of m-TOR/PI3K/Akt proteins [26].
