Introduction: Breast cancer is the second most common cancer worldwide among women. Chemotherapy is one of the prevalent treatments for breast cancer which is associated with various challenges including relapse, multidrug resistance, and undesired side effects. Hence, new anticancer agents should be considered. In this way, the cytotoxic activity of the synthesized tert-butyl p-nitroperbenzoate compound was evaluated against MDA-MB-231 and MCF-7 human breast cancer cell lines. In addition to the anti-cancer effect, the antioxidant properties of this compound were also investigated. Methods: 2 mg of the compound was dissolved in 1 mL dimethyl sulfoxide (DMSO) to prepare 2mg/mL concentration and diluted in the culture medium. The final concentration of DMSO in the treated cells was 1%. To measure the cytotoxicity of the compound, the cells were seeded in a 96-well plate and incubated for 48 hours with different concentrations (8.36, 20.90, 41.80, and 83.60 μM) of the compound and doxorubicin as a positive control. The viability of the cells was measured by the standard protocol of the MTT assay. The half maximal inhibitory concentration (IC50) values were estimated by fitting the data in a sigmoidal dose-response curve based on non-linear regression analysis using Microsoft Excel for each cell line. Antioxidant activity of the compound was determined using DPPH and ABTS tests. Results: Results showed that tert-butyl p-nitroperbenzoate has significant cytotoxicity activity with IC50 values of 42±0.02 and 107±0.04 µM on MDA-MB-231 and MCF-7 cancer cells, respectively. Also, tert-butyl p-nitroperbenzoate exhibited no DPPH and ABTS radical scavenging activities. Conclusion: The results of this study show that tert-butyl p-nitroperbenzoate may be suitable for investigating the applicability of this compound for cancer therapy.
