Determination of cytotoxic effect of Curcuma longa extract on MDA-MB-231 and MCF-10A cell lines

Abstract: Background: Breast cancer therapy is limited by drug resistance and systemic toxicity. Curcuma longa contains hydrophobic curcuminoids with reported anticancer activity. Objectives: The study evaluated the cytotoxic and apoptosis-inducing effect of dichloromethane extract of Curcuma longa on MDA-MB-231 breast cancer cells and MCF-10A non-tumourigenic mammary epithelial cells. Methods: Curcuma longa rhizomes were extracted with dichloromethane. Chemical profiling was performed by high-performance liquid chromatography, liquid chromatography-mass spectrometry and Fourier-transform infrared spectroscopy. MDA-MB-231 and MCF-10A cells were treated with Curcuma longa extract or doxorubicin. Cell viability was assessed by MTT assay. Trypan blue, phase-contrast microscopy, Annexin V/propidium iodide staining, Hoechst/propidium iodide staining, reactive oxygen species assay, wound-healing assay, lactate dehydrogenase assay, JC-1 assay, caspase-3/7 and caspase-9 assays and reverse transcription quantitative polymerase chain reaction were used to assess cytotoxicity, apoptosis, oxidative stress, mitochondrial damage and gene-expression changes. Results: Curcuma longa extract reduced MDA-MB-231 viability in a dose-dependent manner and showed limited toxicity toward MCF-10A cells. The IC₅₀ was 18.50 µg mL^-¹ in MDA-MB-231 cells and remained above 256 µg mL^-¹ in MCF-10A cells. The extract increased reactive oxygen species levels, lactate dehydrogenase release, mitochondrial depolarisation and caspase activity in cancer cells. It also increased BAX and CASP9 expression and reduced BCL2 and TOP2A expression. Chemical analysis confirmed curcumin, demethoxycurcumin and bisdemethoxycurcumin. Conclusion: Dichloromethane extract of Curcuma longa showed selective anticancer activity against MDA-MB-231 cells through oxidative stress and mitochondria-mediated apoptosis.