Radiosensitizing effects of Oroxylum indicum extract in combination with megavoltage radiotherapy beams

Abstract Radiotherapy is an important treatment modality for cancer treatment, particularly for locally advanced tumours and it is known to induce cell death in tumours. Radiotherapy is limited by the total dose that can be prescribed without damaging normal tissueThe main aims of radiotherapy to optimally eradicate tumours while sparing the normal tissue could be achieved with the combination treatment using natural products based medicinal plants. Oroxylum indicum (OI) is a Malaysian consumable plant with a variety of health attributes that contains useful active biocompound that serves as anticancer agent. In this study, the potentials of OI extracts to increase cells radiosensitivity towards radiotherapy were investigated. Initially, the cytotoxic effects of OI extracts were determined in-vitro using HeLa cells. The cells with non-toxic concentration of OI extracts were irradiated with 6 MV and 10 MV photon beams. The cell survivals after irradiation were then evaluated using PrestoBlue assay. The OI extracts with maximum concentration of 0.01 mg/ml are found nontoxic to HeLa cells. The combination of OI extracts and irradiation are found to reduce the cells survival which indicates radiosensitization effects. The sensitization enhancement ratio (SER) calculated indicate higher radiosensization observed for 6 MV photon beams compare to 10 MV photon beams. SER also increased at higher OI concentration. In conclusion, the OI extracts are found to induce radiosensitization in HeLa cancer cells when irradiated with megavoltage photon beams. This study indicates the potential of plant based natural product to be applied as radiosensitizer to increase the therapeutic efficiency in radiation therapy of cancer.