ABSTRACT
Background: DNA damage is one of the major consequences of radiation exposure onto the biological systems. A series of compounds including flavanoids were found to render DNA protection against radiation damage. In this study we elucidated the potential of rutin and rutin hydrate to protect plasmid DNA against damage induced by irradiation. Materials and Methods: DPPH and hydroxyl radical scavenging assays were performed to assess the antiradical potential of rutin and rutin hydrate. Absorption measurements were performed to assess binding parameters of rutin and rutin hydrate with calf thymus [CT]-DNA. Plasmid relaxation assay was performed to compare the radio protective potential of rutin and rutin hydrate against gamma irradiation mediated oxidative damage of pET28 plasmid DNA. Results: DPPH· assay indicated fast reaction kinetics for rutin and rutin hydrate. However antiradical parameter in terms of EC[50] suggested better scavenging capacity for rutin hydrate as compared to rutin. Hydroxyl radical scavenging assay further suggested that both the compounds displayed significant reduction in hydroxyl radicals. Absorption binding study with CT-DNA suggested that rutin hydrate has better binding constant value [K[a] = 8.257 x 10[4] M[-1]] compared to K[a] = 1.834 x 10[4] M[-1] for rutin. Plasmid relaxation study demonstrated that plasmid DNA remains predominantly in super-coiled form in the presence of both rutin and rutin hydrate after exposure to 100 Gy of gamma-radiation. Conclusion: The mechanistic studies suggested that binding and scavenging capacity of rutin hydrate and rutin contributes towards DNA radioprotection. This study may be helpful in devising potent radioprotector molecules helpful for the radiotherapy treatment
ABSTRACT
Ionizing radiation causes deleterious effects on living system mainly due to oxidative damages of macromolecules and protein is the major target due to its abundance. The aim of this study was to investigate the effects of ionizing radiation induced changes in the molecular properties of bovine serum albumin [BSA]; its secondary and tertiary structures, degradation, cross linking and radioprotective role of ferulic acid, a natural antioxidant on these radiation induced changes. This study was carried out to investigate the gamma radiation induced oxidative, structural damage of BSA and radioprotective efficacy of ferulic acid through SDS-PAGE, DTNB assay, DNPH assay, FOX assay methods. Hydroxyl radical scavenging capacity of ferulic acid was estimated using 2-deoxy ribose assay. Further, radiation induced changes in the anisotropy and excitation state lifetimes of BSA were examined. SDS -PAGE data suggested that the loss of protein was linearly dependent on the radiation dose. Gamma-irradiation of BSA caused the formation of protein carbonyls, hydroperoxides and loss of thiols. Ferulic acid protected the radiation induced loss of protein as well as reduced various oxidative damages. Ferulic acid protected the protein from radiation induced damages in a concentration dependent manner. The results provide insight into radiation induced molecular changes in the protein. Ferulic acid protected the BSA from oxidative modification caused by radiation suggesting that ferulic acid possesses strong antiradical properties. Ferulic acid is known to protect DNA, the prime target of radiation and further its ability to protect protein suggesting its ability to protect different biomolecules and therefore can be a good candidate for development radioprotector