Khaizil Emylia Zazali, Hasmah Abdullah and Noor Izani Noor Jamil (2013). Methanol extract of Oroxylum indicum leaves induces G1/S cell cycle arrest in HeLa cells via p53-mediated pathway. International Journal of Medicinal Plant Research 2(7): 225-237
Oroxylum indicum is a Malaysian edible plant with traditional claims for some medicinal properties. This research was done to investigate the methanol extract of O. indicum leaves (MEOIL) for antiproliferative activity against human cervical cancer cell line, HeLa and its mode of cell death. Results from methylene blue assay showed that MEOIL exhibited antiproliferative activity on HeLa cells with IC50 of 3.87 µg/ml without affecting normal cells. Phase contrast microscopy indicated the confluency reduction in HeLa cells and changes on the cell shape. Nuclear staining with Hoechst 33258 displayed the formation of apoptotic bodies and fragmented nuclei. MEOIL was shown to induce early apoptosis event in HeLa cells as confirmed by FITC-Annexin V/propidium iodide staining by flow cytometry analysis. Protein study by flow cytometry indicated the increment of p53, slight increase of Bax and unchanged level of Bcl-2. Cell cycle analysis indicated the growth arrest of HeLa cells at G1/S phase. In conclusion, MEOIL demonstrated an antiproliferative activity in HeLa cell by inducing G1/S cell cycle arrest via p53-mediated pathway.