Effect of lycopene and beta-carotene on the number of viable cells in culture. All cell lines showed normal growth characteristics expected under standard in vitro conditions. Previous studies reported that lycopene formulated as 10% WS granules was not toxic (23). Hereafter, all the results refer to lycopene with this vehicle, already used in our previous studies in vitro (24-26). Lycopene showed distinct effects when added to different types of cells, but reduction in cell viability was observed in all cancer cells.