Botanical Extracts as Medical Countermeasures for Radiation Induced DNA Damage

Abstract : This study provides information for testing of readily available, low toxicity, long shelf life, easily administered botanicals which can be prophylactic radioprotectants. A selection of assays to test antioxidant capacity, metabolic and drug interactions, and DNA damage were performed to assess commercially available grape seed extract supplements and Labrador tea whole leaf extracts as potential radioprotectants. Three different commercial grape seed extracts were shown to have differing antioxidant capacities when compared to a known antioxidant (vitamin C) and radioprotectant (amifostine). Grape seed extract and Labrador tea did not interact with a well-studied drug metabolism pathway (CYP3A4), indicating that they may have potential for use as radioprotectants due to minimal drug and metabolism interactions. Using a cellular system as a model for identifying the DNA damage while allowing for minimal repair, no protection was provided by any extract. Under acellular conditions, assessing DNA damage with no repair potential resulted in increased DNA damage following radiation exposure. Overall, this study has been useful in identifying and validating a set of procedures to use in screening potential antioxidant radioprotectants. Further work explores the optimal concentrations of these and other botanical extracts as potential radioprotectants.