Design、Synthesis And Radioprotective Activity Of Mitochondria Targeted Micromolecular Antioxidants

Objective:Design and synthesis mitochondria-targeted antioxidants,evaluating their ROS scavenging activity to screen effective radioprotectors.Methods:The research work contained two parts of experiments.The one is chemical part which mainly synthesized some mitochondria-targeted antioxidants and confirmed structures using NMR and mass spectrometry.We designed and synthesized two series compounds.First,we synthesized a novel rosmarinic acid(RA)derivative that included a positively charged triphenylphosphonium(TPP)group.Second,the synthesis started from ethyl acetoacetate and nicotinamide,which also combined with a positively charged TPP group,respectively.The other is biological part which evaluated mitochondria-targeted compounds through some radioprotective experiments,such as cell survival rate,clonogenic assay,ROS detection,y-H2AX detection,chromosomal aberration assay,micronucleus assay and comet assay.Results:We synthesized and confirmed five new mitochondria-targeted antioxidants which are not reported.These structures have low toxicities to CHO-Kland effective radio protective abilities.Results of cell survival indicated that mitochondria-targeted antioxidants could improve cell survival rate radiated after 24h;DCFH-DA assay suggested these compounds are excellent scavengers of radiation-induced intracellular ROS;Chromosomal aberration assay indicated that these structures could protect DNA of human peripheral blood cells from radiation-induced damage;Single cell gel(SCG)electrophoresis assay indicated mitochondria-targeted antioxidants protected integrity of nuclear DNA after y-ray radiation;y-H2AX detection indicated nuclear DNA strands breaks would greatly decrease by treating mitochondria-targeted antioxidants before radiation.At the same time,cellular distributions of mitochondria-targeted compounds showed that they are successfully accumulated in mitochondria to prevent radiation-induced mitochondrial dysfunction.Conclusion:Compared radio protective ability of rosmarinic acid and mitochondria-targeted roamarinic acid(Mito-RA),results of ROS scavenging and comet assay indicated that Mito-RA is a more effective radiation mitigator than RA.In addition,we designed and synthesized Mito-DH1、Mito-DH2、Mito-DH3 and Mito-N,due to the similar structure with NAD(P)H,an important endogenous antioxidant.The structures of four compounds have been confirmed by NMR and mass spectrum.These compounds not only have an acceptable toxicity in vitro,but also have effective radio protective activity.Results of experiments indicated that this series compounds could scavenge ROS and prevent CHO-K1 or Hela cells from radiation-induced damage.In conclusion,mitochondria-targeted antioxidants are promising compounds which have effective ROS scavenging abilities and protect integrity of functional bio-macromolecules.These research work may provide a new method to develop radiation mitigators for the future work.