Echinacea Angustifolia DC Extract Induces Apoptosis and Cell Cycle Arrest and Synergizes with Paclitaxel in the MDA-MB-231 and MCF-7 Human Breast Cancer Cell Lines

Background Echinacea spp.displays different biological activities, such as antiviral, immunomodulatory, and anticancer activities. Currently, high sales of hydroalcoholic extracts ofEchinaceahave been reported; hence, the importance of studies onEchinacea. Aim To establish the effects ofEchinacea angustifoliaDC extract obtained with ethyl acetate (Ea-AcOEt) in breast cancer cell lines. Methods Cytotoxicity, cell cycle arrest, and cell death were evaluated. Besides, the safety of the extract, as well as its effect in combination with paclitaxel were investigated. Results The echinacoside and caffeic acid content in theEa-AcOEt extract were quantified by HPLC, and its antioxidant activity was assessed. TheEa-AcOEt extract showed cytotoxic activity on breast cancer MDA-MB-231 cells (IC(50)28.18 +/- 1.14 mu g/ml) and MCF-7 cells (19.97 +/- 2.31 mu g/ml). No effect was observed in normal breast MCF-10 cells. TheEa-AcOEt extract induced cell cycle arrest in the G1 phase and caspase-mediated apoptosis. No genotoxicity was foundin vitroorin vivo, and the extract showed no signs of toxicity or death at 2,000 mg/kg in rodents. In vitro, the combination ofEa-AcOEt extract and paclitaxel showed a synergistic effect on both cancer cell lines. Conclusion TheEa-AcOEt extract is a potential candidate for breast cancer treatment.