The toxicity of OL and HT at the defined amounts was examined using RPMIm for Caco-2 viability, and MTS assay with phenazine methosulfate (PMS) method. This colorimetric technique allows quantitative determination of cell viability based on the capability of viable cells to transform the MTS salt into aqueous soluble formazan, in the presence of PMS that acts as electron-coupling agent.
The procedure was performed as per manufacturer's instructions. The cell toxicity was expressed as percent of cell viability relative to control (i.e. plain cells).(Han et al., 2009 and Lavermicoca et al., 2005) – and were the same for all assays.