The Pro-apoptotic Effect of Allicin on Human Colon Adenocarcinoma Cell Line HT29

The management of apoptotic cell death has been considered as a putative therapeutic strategy for cancer treatment. In the present study we investigated the putative pro-apoptotic effect of allicin, the main garlic organosulfur component with repeatedly claimed chemopreventive potency, on the human adenocarcinoma cell line HT29 as an apoptosis resistant cell line, in vitro. The HT29 cells were incubated with different concentrations of allicin (0-40μg/ml) and for different time periods (6-48h) to investigate its effect on cell proliferation and apoptotic cell death. Five and 10μg/ml allicin could induce a significant cell death only after 12h, whereas concentrations of 20 and 40μg/ml resulted in a significant cell loss as soon as 6h. The results of the TUNEL assay, presented as percentage of apoptotic cells to total cell loss, indicated that concentrations ≥5μg/ml significantly increased the apoptotic features in time periods 6-24h, but after 48h no significant changes could be detected. The ratio of the sum of the apoptotic features of the four studied time points to the total cell loss calculated after 48h was about 0.5. Allicin can induce apoptosis in a concentration- and time-dependent manner with most considerable effects achieved at 24h and by concentrations higher than 10μg/ml.