Potentials of Bismuth-Based Nanoparticles and Baicalein Natural Compounds as Radiosensitizers in Cancer Radiotherapy: a Review

Radiotherapy treatment on cancer patients has the limitation of the possible side effects to the unrelated healthy tissues. Hence, radiosensitizers have been utilized to enhance the radiation dose onto the cancer sites and reduce the radiation effects on the surrounding areas. Recent findings have found the potentials of nanomaterials such as gold, platinum, and bismuth as radiosensitizers that would induce more radiation absorption due to their high atomic numbers (Z) profile. Among the types of high-Z nanomaterials that have been applied clinically as radiosensitizers are iron oxide, hafnium oxide, and gadolinium-based nanoparticles. Another potential radiosensitizer that has gained interest due to its safe utilization and anticancer properties is derived from natural compounds. Both radiosensitizers from nanomaterials and natural compound have shown intriguing outcome that might improve cancer treatment. This article reviews the effects of bismuth-based nanoparticles and natural compounds from the Oroxylum indicum plant as prospective radiosensitizers for radiotherapy. The individual effects of the bismuth nanoparticles and natural compounds, as well as their potential synergies in cancer radiotherapy, are discussed based on their physical, chemical, and biological interactions. This review summarizes the applicability and mechanisms of bismuth-based nanoparticles and baicalein natural compounds as radiosensitizers, which are valuable for future research and approaches in cancer radiotherapy.