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 Fe 2+-H 2O 2-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 (O 2 －•), 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 (Fe 2+, Mg 2+, Cu 2+) via the 9 th carbonyl and 8 th 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 Fe 2+, Cu 2+, and Mg 2+, could enhance the antioxidant activity of the ligand itself.
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。
Keywords: Aloe-emodin; Antioxidant; Metal complex; Synthesis.
Copyright© by Editorial Board of Journal of Sichuan University (Medical Sciences).