Cytotoxic apoptotic enhancing activities of the crude juice of an ornamental plant [Euphorbia tirucalli] on human cancer cells

ABSTRACT

Currently used Cancer chemotherapy has numerous side effects. This motivates researchers towards finding safer and clinically effective anti-cancer drugs of plant origin. We tested the milky juice of Euphorbia tirucalli [called sap or latex] after an observation of a fast irritant action on the skin and mucous membranes exposed to the sap coming out from its cut parts. Cell cultures, prepared from the fresh surgically removed human primary tumors [glioma, myelo-genous leukemia and breast cancer] were used in this study in the following number of patients 18, 26 and 20 respectively. Cell suspensions of 0.5 lamda10[5] cells/ml were maintained in RPMI-1640 culture media, and then the plant juice was added in serial dilutions to reach a final concentration of 5,10, 20, micro l per ml tissue culture. All cells were incubated for 72 hours in humidified CO2 incubator. Cells were examined at 24 hours interval for 3 days using viability test, staining with FITC [Fluorescene Iso Thio-Cynate]-conjugated anti-Caspase 9 antibodies and flow cytometry Normal white blood cells [n=20 volunteers] were used as controls to test selectivity and cytotoxicity. A significant direct selective cytotoxic action of the sap of Euphorbia tirucalli on human cancer cells compared to the controls [P < 0.001] for glioma cells, myelogenous leukemia cells and breast cancer cells. Also, similar significant effects of antimetabolite drug [methotrexate sodium] but with a more significant toxicity on normal WBCs, compared to / tirucalli sap Malignant cells responded to the sap treatments in a dose and duration dependent manner and the IC[50] [Inhibition Concentration 50] of the crude juice was found to be 10 microl of crude juice per ml tissue culture medium. Cell cycle analysis showed that the crude juice of Euphorbia tirucalli is capable of arresting the majority of cells in G[1] phase of the cell progression cycle. At the IC[50], the control cells did not show microscopically detectable change of morphology or viability. This study may introduce a new candidate plant for further studies to isolate and characterize the active, selectively cytotoxic and potentially anti-proliferative biological components in the sap of Euphorbia tirucalli