Cytotoxicity assay

HepG2 were seeded at a density of 5000 cells/well in a 96-well plate, and were allowed to attach overnight. Thereafter, cells were treated with various concentrations of the plants extracts for 24 h. To assess the cytotoxic effect of the three plants extracts, MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltratrazolium bromide) assay was carried out. Briefly, cells treated with the plant extracts were exposed to tetrazolium MTT at a concentration of 5 mg/mL. Viable active cells reduced yellow MTT salt to insoluble purple formazan, which was dissolved using DMSO. The absorbance of the coloured solution was measured at a wavelength of 570 nm using Epoch microplate spectrophotometer (BioTek). The obtained absorbance at 570 nm of both control and treated cells was used to calculate percentage of cell viability. Assuming 100% viability in control cells, percentage of treated cells viability will be calculated accordingly: