Abstract:

Background and Aims: Plant extracts are an important source of cytotoxic compounds and have consistently been an interesting field of research. The aim of this study is to investigate the cytotoxic and apoptotic effects of Thymus vulgaris (T. vulgaris) extracts on human breast cancer cell lines. Methods: This study was carried out using human breast cancer cell lines (MCF-7 and MDA-MB-231) as experimental groups and the healthy human fibroblast cell line (PCS-201-012) as the control group. Petroleum ether and ethanol extracts were obtained from T. vulgaris. The extracts were applied to MCF-7 and MDA-MB-231 human breast cancer cell lines and human breast cancer stem cells. Cytotoxicity studies were performed using the RTCA iCELLigence system (Agilent Technologies), and apoptosis studies were performed using terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling (TUNEL) and 4’,6-diamidino-2 phenylindole (DAPI) methods. Results: The T. vulgaris extracts were found to have concentration-dependent cytotoxic effects on human breast cancer cells. The growth of breast cancer stem cells was also determined to be inhibited when an effective concentration (45 μg/ mL) of the extracts was applied. Lastly, specific morphological changes related to apoptosis were detected in the cells that had been treated with the effective concentration. Conclusion: The T. vulgaris extracts were found to inhibit the proliferation of human breast cancer cells and human breast cancer stem cells selectively and concentration-dependently via an apoptosis-dependent pathway. The results suggest that the extracts may make promising sources for developing drugs for breast cancer therapy.

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