P chloranil

All of the chemicals used in this study were of analytical grade. The saccharin stock solution (C₇H₄NNaO₃S·2H₂O, 10 mM) was prepared by dissolving 0.1206 g of sodium saccharin in 10 mL of absolute ethanol via a 15-min stirring that was followed by diluting to 50 mL with the same solvent. A 20-mM p-chloranil (Sigma Co., St. Louis, MO, USA) solution was prepared daily by dissolving 0.123 g of p-chloranil in 25 mL of acetone (Mallinckrodt Co., St. Louis, MO, USA). A H₂O₂ solution (7.10 M) was prepared from a 30% H₂O₂ concentrate (Merck Co., Darmstadt‎, Germany) via a convenient dilution in the ethanol (Mallinckrodt Co., St. Louis, MO, USA). A sodium phosphate-buffer solution (200 mM) was used as the carrier solution.

All reagents were obtained commercially and used with no further purification, unless otherwise stated. Reagent-grade SnCl₂∙2H₂O, p-chloranil, p-toluenesulfonyl hydrazide, 1,3-diphenylisobenzofuran (DPBF), anhydrous sodium sulfate, K₂CO₃ and 5,10,15,20-tetraphenyl-21H,23H-porphine zinc (ZnTPP), Rose Bengal, CDCl₃ and an MTT assay kit were purchased from Sigma Aldrich (St. Louis, MO, USA). CHCl₃, dimethylformamide (DMF) and methanol were procured from Merck. Type II water was prepared with an Elga Purelab Chorus 2 (RO/DI) system. MCF-7 cell cultures were purchased from Cellonex^®, while tissue-culture-grade penicillin-streptomycin-amphotericin B mix, 100 units·mL⁻¹ penicillin, 100 µg·mL⁻¹ streptomycin-amphotericin B and heat-inactivated fetal calf serum (FCS) were obtained from Biowest^®. Dulbecco’s modified Eagle’s medium (DMEM) and phosphate-buffered saline (DPBS) were supplied by Lonza^®.