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Showing 2 results for Dpph Assay
H. Ojha, K. Sharma, S. Kallepalli, S. Raina, P.k. Agrawala,
Volume 14, Issue 1 (1-2016)
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 EC50 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 (Ka = 8.257 x 104 M-1) compared to Ka = 1.834 x 104 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 g-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.
S. Ghorbanian Kelachayeh, Dr. M.h. Sangtarash, Prof H. Mozdarani,
Volume 18, Issue 1 (1-2020)
Abstract
Background: Melatonin is a natural antioxidant that is produced by the pineal gland. In this study was evaluated antioxidant and possible protective effects of melatonin on frequency of micronucleus (MN) formation in human cell lines exposed to γ-radiation. Materials and Methods: To achieve the best concentration for antioxidant activity of melatonin DPPH (1,1-diphenyl-2-picrylhydrazyl) assay was used. Hela and MRC5 cells were cultured and treated with optimum concentration of melatonin (1200μg/ml). After 2h, cells were exposed to 2Gy-gamma ray. For each cell group, one flask was considered as control. Immediately after irradiation, cells were exposed to cytochalasin B to arrest cells at cytokinesis. Then the frequency of MN induced by radiation alone or in the presence of melatonin was evaluated. Results: By DPPH assay, the optimum concentration of melatonin for its antioxidant activity was determined 1200μg/ml. Our results showed that the frequency of micronuclei increased in irradiated cells compared to the control groups (p<0.05). Conversely, pre-treatment of cells with melatonin significantly reduced the number of MN produced both in MRC5 and Hela cells (p<0.05). Conclusion: Results indicated that γ-radiation induced MN in the cells. The protective effect was achieved when melatonin was present in the cellular environment pre-irradiation. Indeed, melatonin with scavenging and antioxidant ability neutralizes toxic reactants and stimulates DNA repair pathways. Moreover, the results indicate that protective effect of melatonin is higher in MRC5 cells than in Hela cells. Therefore, it can be concluded that other mechanisms such as induction of cell cycle arrest by melatonin might be exist only in MRC5 cells. However, the radio-protective mechanism of melatonin is not clearly known.
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