Ethyl acetate fraction of Calotropis gigantea roots induce apoptosis through increased G2/M and increased expression of caspase-8 in colon cancer WiDr cell line

Cell apoptosis is one of important mechanisms and used as target for anticancer drugs. This study aimed at determining the mechanism of apoptosis induced by the most active fraction of Calotropis gigantea root extract in colon cancer cells WiDr. Calotropis gigantea root extract (CGRE) was fractionated using solvents including water, dichloromethane, ethyl acetate and butanol. All four fractions were tested for cytotoxicity using MTT method and the absorbant was measured at wavelength of 595 nm. Further, the mechanisms of cell cycle and apoptosis induced by the most active fraction were analyzed using Fluorescence-Activated Cell Sorting with marker (probe) propidium iodine (PI) and annexin V. The results showed that the cytotoxicity of CGRE on WiDr cell line was 44.2 μg/ml, F1 (IC₅₀ 0,367μg/ml), F2 (IC₅₀ 0.063 μg/ml), F3 (IC₅₀ 0.18 μg/ml), and F4 (IC₅₀ 2.24 μg/ml). WiDr cells treated with F2 caused changes in the cell cycle profile through an increased G2/M phase ( 38.18%), increased cell apoptosis (20.05%) and increased expression of caspase-8 (27.4%). In conclusion, F2 of CGRE exhibited anticancer activity against WiDR cell through Cell cycle arrest G2/M phase enhancement and increased expression of caspase-8, that resulted in an increased cell apoptosis.