MTT assay

Anti-proliferative activities of hypericin on the MCF-7 breast cancer cell line and Fibroblasts, was determined by MTT colorimetric assay [31]. Briefly, cells (8000 and 6000/well) in 200 ml DMEM containing 10 % FBS were seeded on 96-well plates and incubated overnight. These cells subsequently treated with various concentrations of hypericin, and Cisplatin as a positive control for 24 and 48 h. Afterwards, 20 μl of MTT solution (5 mg/ml in PBS) was added to each well and incubated for an additional 4 h followed by adding 200 μl of dimethyl sulfoxide. Cell viability was measured at 570 nm by an ELISA reader (Biotek ELX800 microplate reader). Lethal dose 50 (LD50) or IC50, the concentration reducing the absorbance of treated cells by 50 % with respect to untreated cells, determined by the standard curve method.