DNA damage induced by TH and OHT in MCF-7 cells. Comet assay was performed following treatment of cells with OHT (10 μM), TH (1%) and their combination for 24 hr. Cells were stained with SYBR Green and analyzed using Comet Image Analysis System software. Percentage of DNA in the tail (A), tail length (B) and Olive moment (C) were used as evaluation of DNA damage. The values are presented as means ± SD from three independent experiments. Cells were observed under fluorescence microscopy (D). Statistical analysis was determined using one-way ANOVA followed by post hoc Tukey multiple comparison test. Ψp < 0.05 for TH + OHT compared to TH; Ωp < 0.01 for TH + OHT compared to OHT; *p < 0.05, **p < 0.01 compared to untreated cells.