Induction of apoptosis and cell cycle arrest by pericarp polyphenol-rich extract of Baneh in human colon carcinoma HT29 cells

Plants as important source of natural active components with anticancer effects commonly are different in structure and biological properties. The pericarp of Pistacia atlantica sub kurdica with local name of Baneh, a rich source of active phytochemicals, contains noticeable amounts of polyphenolic compounds, flavonoids and anthocyanins. Therefore, the antiproliferative, apoptosis induction and cell cycle alterations of Baneh were evaluated in human colon carcinoma HT29 cells. The Baneh extract (0.7 mg/ml) resulted in 50% growth inhibition similar to 500 nM of Doxorubicin (Dox) in HT29 cells after 72 h. The down-regulation of cyclin A protein by Baneh extract induced S phase delay in cell cycle progression of HT29 cells. Unlike the Baneh extract, Dox showed G2/M accumulation of HT29 cells which was associated with an increase in cyclin A and cyclin B1 protein expression. Furthermore, the induction of apoptosis following Baneh extract and Dox treatment in HT29 cells was confirmed by DNA fragmentation and translocation of phosphatidylserine. The morphological characteristics of apoptosis were also observed in HT29 cells exposed to the Baneh extract and Dox. These results suggest that due to the existence of bioactive components, methanolic extract of the Baneh has significant cytotoxic effects against human colon carcinoma HT29 cells.