Further investigation of specific cyclins and cyclindependent kinases may help in understanding the mediation of this cell cycle arrest. Additionally, fraction 3 but not fraction 2 treatment suggested a significant accumulation of cells in the sub-G1 phase of the cell cycle, which indicated DNA fragmentation and apoptosis. The induction of apoptosis by fraction 3 treatment was further confirmed and quantified by caspase apoptotic and TUNEL assays. The positive results shown in SR-VAD-FMK staining in the caspase apoptotic assay also suggested that activation of the caspase
cascade was involved in the induction of apoptosis in Caco-2 cells treated with fraction 3. Further studies are required to determine the specific caspase involved. Similar cell death mechanism was reported in another colon carcinoma cell line with triterpenoid extract treatment [15].