In-vitro evaluation of rutin and rutin hydrate as potential radiation countermeasure agents

Background: DNA damage is one of the major consequences of radia on exposure onto the biological systems. A series of compounds including flavanoids were found to render DNA protec on against radia on damage. In this study we elucidated the poten al of ru n and ru n hydrate to protect plasmid DNA against damage induced by irradia on. Materials and Methods: DPPH and hydroxyl radical scavenging assays were performed to assess the an radical poten al of ru n and ru n hydrate. Absorp on measurements were performed to assess binding parameters of ru n and ru n hydrate with calf thymus (CT)-DNA. Plasmid relaxa on assay was performed to compare the radio protec ve poten al of ru n and ru n hydrate against gamma irradia on mediated oxida ve damage of pET28 plasmid DNA. Results: DPPH · assay indicated fast reac on kine cs for ru n and ru n hydrate. However an radical parameter in terms of EC50 suggested be/er scavenging capacity for ru n hydrate as compared to ru n. Hydroxyl radical scavenging assay further suggested that both the compounds displayed significant reduc on in hydroxyl radicals. Absorp on binding study with CT-DNA suggested that ru n hydrate has be/er binding constant value (Ka = 8.257 x 10 4 M -1 ) compared to Ka = 1.834 x 10 4 M -1 for ru n. Plasmid relaxa on study demonstrated that plasmid DNA remains predominantly in super-coiled form in the presence of both ru n and ru n hydrate a8er exposure to 100 Gy of g-radia on. Conclusion: The mechanis c studies suggested that binding and scavenging capacity of ru n hydrate and ru n contributes towards DNA radioprotec on. This study may be helpful in devising potent radioprotector molecules helpful for the radiotherapy treatment.