Ellagic Acid: A potent Radio-sensitizer in Cancer Radiotherapy

The cytotoxic effect of radiotherapy of cancer is limited due to commonly observed radio-resistance in the clinic. It is, therefore, necessary to develop new strategies to enhance the radiosensitivity of tumor cells by combining therapeutic drugs with optimized radiation doses to improve the treatment outcome. Over the years, research has gained momentum in studying various herbal drugs that have the potential to sensitize tumor cells to ionizing radiation. Herbal drugs possess the property of non-toxic doses to higher concentrations and thereby minimize the undesirable side effects. Our lab recently reporte the combined effects of radiation and ellagic acid (EA) in generation of increasing ROS as a function of radiation dose in Hela thereby exhibiting the radiosensitizing effect. This article reviews the mechanism of action of EA involving ROS, cell cycle arrest, apoptosis and activation of signaling molecular cascade in the observed radiosensitization of some tumor cell lines and suggests its potential usefulness in clinic for improving cancer radiotherapy which uses the mechanism of increasing the oxidative stress through generation of ROS in cancer cells.