Organic extracts of Larrea divaricata Cav. induced apoptosis on tumoral MCF7 cells with an higher cytotoxicity than nordihydroguaiaretic acid or paclitaxel.

The methanolic and methane dichloride extracts of aerial parts of Larrea divaricata Cay. (Jarilla) plants exhibited a pronounced cytotoxic effect by arresting cell viability at a level of 35% against the MCF-7 cell line, a human breast adenocarcinoma, while only a weak cytotoxic effect was observed for the aqueous extract. Apoptosis was detected by flow cytometry, using annexin V and by cytological detection with fluorescein diacetate / propidium iodide staining. The annexin V, as well as the uptake of fluorescein diacetate/propidium iodide staining, revealed that methanolic and methane dichloride extracts of L. divaricata treatment of cells resulted in a rapid plasma membrane perturbation and triggered cellular death (>70%). Methanolic extracts were submitted to further treatment by bioassay-guided purification, involving fractionation and chromatography. 0.1% (w/w) nordihydroguaiaretic acid (NDGA) was found, which displayed weak citotoxic activity.