the effects of pre-treatment and post-treatment of thymol against tert-butyl hydroperoxide (t-bhp) cytotoxicity in mcf-7 cell line and fibroblast derived foreskin

Background: some recent studies have reported anti-tumor activity for thymol, but the findings are inconsistent. this study aimed to investigate and compare thymol’s effects on mcf-7 cancer cells and fibroblasts while treated with tert-butyl hydroperoxide (t-bhp).methods: in the pre-treatment, mcf-7 and fibroblast cells were treated with various thymol concentrations and incubated for 24 h. then, t-bhp was added to a final concentration of 50 μm, and the cells were incubated for one h. in the post-treatment, cells were incubated first with 50 μm t-bhp for one h and then treated with thymol. cell viability was tested by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (mtt) assay. thymol’s antioxidant capacity was measured by dpph and frap assays, and lipid peroxidation levels were determined by the tbars method.results: the thymol effects were dose-dependent, and despite their antioxidant properties, at concentrations of 100 µg/ml or more, increased t-bhp toxicity and reduced cancer cell viability. mtt assay result showed that pre-treatment and post-treatment with thymol for 24 hours effectively reduced mcf-7 and fibroblast cell viability compared with the untreated control group. both pre- and post-treatment of thymol, normal fibroblast cell viability was significantly greater than that of the mcf-7 cells.conclusions: our finding showed that thymol appears to be toxic to mcf-7 cells at lower concentrations than fibroblasts after 24 hours of incubation. pre-treatment with thymol neutralized the oxidative effect of t-bhp in fibroblasts but was toxic for mcf-7 cells.