Catechol amide derivatized polyhydroxylated fullerene as potential chelating agents of radionuclides: Synthesis, reactive oxygen species scavenging, and cytotoxic studies

Radionuclide internal contamination can induce chemical and radioactive intoxication and produce harmful free radicals in vivo. At present, administration of Chelating Agents is the most effective treatment against nuclide contamination. However, traditional studies on Chelating Agents have ignored the damage caused by free radicals to the body. The present study aimed to develop a type of a bifunctional sequestering agent that can chelates nuclides and scavenges free radicals simultaneously. Therefore, a novel catechol amide-derivatized polyhydroxylated fullerene was designed and prepared. The poor water solubility of fullerene was ameliorated by chemically modifying hydrophilic catechol amide and multiple hydroxyl groups, and obtaining high water-soluble fullerene derivatives. The affinities of chelators were investigated via sulfochlorophenol competitive complexing method and antioxidant capacities were examined by electron paramagnetic resonance. The results revealed the good complexation of the designed and synthesized chelating agent with uranyl ions; and its efficiency in scavenging hydroxyl radicals. This chelating agent showed extremely low toxicity and notable protective effect against oxidative stress on A549 cells. Besides, in U(VI)-exposed A549 cells, immediate treatment with catechol amide-derivatized polyhydroxylated fullerene significantly decreased the Lactate Dehydrogenase (LDH) release by inhibiting the cellular U(VI) intake, promoting the intracellular U(VI) release and inhibiting the production of intracellular Reactive Oxygen Species (ROS). These results suggest that this fullerene derivative may be a valuable in vivo antioxidant and radionuclide decorporation agent.