Figure 1.

The IC₅₀ for (−)-P, (+)-P and (R)-P in CRC and fibroblast cell lines. CRC cell lines and human foreskin fibroblasts (HFF) were treated with different concentrations of (−)-P, (+)-P and (R)-P and their viability was determined by crystal violet assay. Data are the mean ± standard deviation (SD) of five technical replicates from a representative experiment normalised to the vehicle control. Non-linear regression analysis for (−)-P, (+)-P and (R)-P was used to calculate IC₅₀ values for each form of drug. Data are representative of three independent experiments.