Introduction: There are problems such as treatment failure, drug resistance, heavy costs and other problems related to cancer treatment, which cause the plants to attract the interest of many researchers, because they have fewer side effects than chemical drugs. Studies have shown that Nigella Sativa has anticancer effects but the molecular mechanism of cell death of cancer cells is not clear.  So the present study aimed to explore the  effect of Nigella Sativa on the viability of MCF7 breast cancer cell line.

Methods: In this study, MCF7 cells were treated with different concentrations of hydro alcoholic extracts of Nigella sativa (0, 200, 400 µg/mL) for 24, 48 and 72 h. Effect of extract on cell viability and caspase-3 gene expression were analyzed by trypan blue staining and Real time PCR, respectively.

Results: The results revealed that cell viability significantly decreased in a dose and time dependent manner compare to the control (p < 0.05). Real time PCR results showed that the expression of Caspase-3 under different concentrations of extract (200 and 400 µg/ml) significantly increased compare to the
control (p < 0.05).

Conclusion: It seems that Nigella sativa caused cell death by increasing of caspase-3 gene expression