In vitro cytotoxicity of P128. Cytotoxicity of P128 was evaluated on mammalian cell lines (A) Vero cells and (B) HEp2 cells. Mitomycin C was used as a control cytotoxic agent and absorbance at 590 nm was interpreted as a function of cell viability. Calculation of viable cells in case of the Mitomycin C or P128-treated groups was based on the cell-control and taking viability in the control group to be 100%. Each group was evaluated in quadruplicates and the whole experiment repeated twice. Results are expressed as means±standard deviation.