G2/M arrest and apoptosis of human colorectal cancer cells induced by water extract from residues of jelly fig achene

Jelly fig (Ficus awkeotsang) achenes have been utilized to prepare a traditional drink in Taiwan. Herein, we evaluated the effect of water extract from jelly fig seed residues (WERJFA) on cancer cells. WERJFA could inhibit the growth of human colorectal cancer cells, COLO205 and HT29 in both dose- and time-dependent manners. The flow cytometric analysis with propidium iodide (PI) showed that WERJFA primarily arrested COLO205 and HT29 cells at the G2/M phase of cell cycle as the concentration reached to at least 0.5 mg/ml. WERJFA induced apoptosis of these two cell lines, as evidenced by annexin V-FITC/PI and 4', 6-diamidino-2-phenylindole (DAPI) staining using flow cytometry and confocal microscopy, respectively. Reactive oxygen species (ROS) production and the loss of mitochondrial membrane potential in WERJFA-treated cells were detected by flow cytometry with H₂DCF-DA and 5,5', 6,6'-Tetrachloro-1, 1', 3,3'-tetraethylbenzimidazolocarbocyanine iodide (JC-1). Our results showed that WERJFA exerted anti-proliferative and apoptotic effects on colorectal cancer cells. WERJFA arrested cell cycle, and caused apoptotic death in these cancer cells possibly via mitochondrial pathway involved with exceeding ROS level.