芦荟大黄素金属配合物的抗氧化活性研究

  目的  合成3种芦荟大黄素金属配合物，并比较配体和配合物的抗氧化活性。  方法  在无水乙醇溶剂中，通过溶解、搅拌合成芦荟大黄素-铁（Ⅱ）、芦荟大黄素-铜（Ⅱ）、芦荟大黄素-镁（Ⅱ）3种配合物，并对其结构进行表征，采用Fe2+-H₂O₂-亚甲蓝法、二苯代苦味肼基自由基法（DPPH法）等检测配体和配合物对超氧自由基（O₂－?）、羟基自由基（?OH）、二苯代苦味肼基自由基（DPPH?）的清除作用。  结果  成功合成芦荟大黄素-铁（Ⅱ）、芦荟大黄素-铜（Ⅱ）、芦荟大黄素-镁（Ⅱ）3种配合物，根据结构表征结果，推测芦荟大黄素金属配合物可能结构为两分子芦荟大黄素通过9位羰基和8位羟基与一分子金属离子（Fe2+、Mg2+、Cu2+）形成配合物。配合物和配体对3种自由基均有清除作用，但配合物的清除作用强于其配体（P<0.05）。  结论  芦荟大黄素与Fe2+、Cu2+、Mg2+ 3种金属离子配位后，增强了其配体本身的抗氧化活性。

Study on the Antioxidant Activity of Aloe-Emodin Metal Complex

  Objective   To synthesize three kinds of metal complexes of aloe-emodin and compare the antioxidant activities of the ligands and the complexes.  Methods  Three kinds of aloe emodin metal complex, the aloe-emodin-iron (Ⅱ), the aloe-emodin-copper (Ⅱ) and the aloe-emodin-magnesium (Ⅱ) complexes, were synthesized by dissolving and stirring in anhydrous ethanol solvent, and their structures were characterized. The Fe2+-H₂O₂-methylene blue method, the diphenyl bitter hydrazine radical method (DPPH method) and other assays were used to determine the clearance effect of ligands and complexes on superoxide radicals (O₂－?), hydroxyl radicals (?OH) and phenyl bitter hydrazine radical (DPPH?).  Results  Three kinds of aloe emodin metal complex, the aloe-emodin-iron (Ⅱ), the aloe-emodin-copper (Ⅱ) and the aloe-emodin-magnesium (Ⅱ) complexes, were successfully synthesized. According to the results of structural characterization, we speculated that the aloe-emodin metal complexes were formed at the site between the two molecules of aloe-emodin and one molecule of metal ions (Fe2+, Mg2+, Cu2+) via the 9th carbonyl and 8th hydroxyl groups of the aloe-emodin molecules. Both the complex and the ligand have clearance effects on three kinds of free radicals, and the complex showed stronger effects than its ligand (P<0.05).  Conclusion  Coordination of aloe-emodin with metal ions, such as Fe2+, Cu2+, and Mg2+, could enhance the antioxidant activity of the ligand itself.