2.4. Cell proliferation assay
Proliferation was measured using the crystal violet assay (Ishiyama et al., 1996;
Saotome et al., 1989). Cells were seeded at 1 _ 104 cells/well in 96-well plates and
incubated for 24 h. Cells were then treated with 100 ll media (used as untreated
control), 100 ll 1% ethanol in media (used as vehicle control) or 100 ll of varying
concentrations of individual compound for 48 h exposure duration. After treatment,
cells were stained with 0.5% crystal violet and destained with 33% acetic acid. The
absorbance was read on a microplate reader at 570 nm and the values were converted
to cells/well using a standard curve (based on 40,000 to 625 cells/well)
run with each experiment. The effect of compounds on cell proliferation was determined
via by converting cells/well to percent cell viability compared to the untreated
control