2.2. MTT Assay

MTT assay is a common method used to measure the metabolic changes of tetrazolium salts in viable cells to determine cellular viability and proliferation [21]. At 24 h pretreatment, MCF-7 and MCF-10A cells were seeded in 96-well plates at 8 × 10³ and 9 × 10³ cells per well, respectively. The cells were incubated further in the presence of herbal compounds at various concentrations. Subsequently, 20 μL of 5 mg/mL MTT solution (Sigma-Aldrich, St. Louis, MO, USA) in phosphate buffered saline (PBS) was added to each well containing DMEM. Following 4 h incubation, the supernatant was removed, and formazan was dissolved with dimethyl sulfide (DMSO; Sigma-Aldrich). The colorimetric changes were determined by a microplate reader at a wavelength of 490 nm.