Department of Chemical & Life Sciences, School of Science, Waterford Institute of Technology, Waterford, Ireland.
J Inorg Biochem. 2010 Oct;104(10):1091-8. doi: 10.1016/j.jinorgbio.2010.06.007. Epub 2010 Jun 27.
Isoflavone metal chelates are of interest as isoflavones act as oestrogen mimics. Metal interactions may enhance isoflavones biological properties so understanding isoflavone metal chelation is important for the commercial application of isoflavones. This work aimed to determine if isoflavones, daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone) could chelate with metals as isoflavone chelates. Biochanin A (4'-methoxy-5,7-dihydroxyisoflavone) was also examined for it's ability to chelate with Cu(II) and Fe(III). This study found daidzein does not chelate with Cu(II) and Fe(III) but genistein and biochanin A chelate with a 1:2 M/L stoichiometry. The copper and iron chelates were synthesised and characterised by elemental analysis, FTIR, thermogravimetric analysis (TGA) and electrospray ionisation mass spectrometry (ESI-MS). These studies indicated a 1:2 M/L stoichiometry and suggested the isoflavones bind with the metals at the 4-keto and the 5-OH site. 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibition assays showed that copper isoflavone chelates have higher antioxidant activity than free isoflavones while the iron isoflavone chelates showed pro-oxidant activity compared to the free isoflavone. Synergistic DPPH studies with 0.02 mM ascorbic acid revealed copper chelates exhibit reduced antioxidant activity versus free isoflavones whereas the iron chelates showed lower pro-oxidant activity except at 1.0 mM.
异黄酮金属配合物因其具有雌激素模拟作用而受到关注。金属相互作用可能会增强异黄酮的生物学特性，因此了解异黄酮的金属配合物对于异黄酮的商业应用非常重要。本研究旨在确定异黄酮（大豆苷元，4',7-二羟基异黄酮）和染料木黄酮（4',5,7-三羟基异黄酮）是否可以与金属形成配合物。还研究了大豆黄素（4'-甲氧基-5,7-二羟基异黄酮）与 Cu(II) 和 Fe(III) 的螯合能力。本研究发现，大豆苷元不与 Cu(II) 和 Fe(III) 形成配合物，但染料木黄酮和大豆黄素以 1:2 M/L 的化学计量比与金属形成配合物。通过元素分析、傅里叶变换红外光谱（FTIR）、热重分析（TGA）和电喷雾电离质谱（ESI-MS）对铜和铁配合物进行了合成和表征。这些研究表明，化学计量比为 1:2 M/L，并表明异黄酮在 4-酮和 5-OH 位与金属结合。2,2-二苯基-1-苦基肼（DPPH）抑制试验表明，铜异黄酮配合物的抗氧化活性高于游离异黄酮，而铁异黄酮配合物的抗氧化活性低于游离异黄酮。与 0.02 mM 抗坏血酸的协同 DPPH 研究表明，与游离异黄酮相比，铜配合物的抗氧化活性降低，而铁配合物的促氧化活性除在 1.0 mM 时外均降低。
