College of Life Sciences, Agricultural University of Hebei, Baoding, 071001, China.
J Agric Food Chem. 2010 Nov 24;58(22):11548-52. doi: 10.1021/jf102372t. Epub 2010 Oct 25.
Free radical-scavenging activity of isoflavones and some isoflavone metabolites have been described previously, but the results are inconsistent. The objective of the present study was to find out the pivotal factors that influence an accurate detection of both superoxide anion and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity. We here showed for the first time that organic solvents, including methanol, ethanol and acetone, were of strong superoxide radical-scavenging activity at concentrations down to 0.1% (v/v), however, no such activity was observed with acetonitrile at concentrations up to 2.0% (v/v). In DPPH assay, we found that the DPPH radical-scavenging ratio increased together with the extended reaction time. Based on our findings, improved in vitro assays for the detection of radical-scavenging activity of both isoflavones (daidzein and genistein) and isoflavone metabolites, including dihydrodaidzein (DHD), dihydrogenistein (DHG), and O-desmethylangolensin (O-Dma), were established.
先前已经描述了异黄酮和一些异黄酮代谢物的清除自由基活性，但结果不一致。本研究的目的是找出影响超氧阴离子和 1,1-二苯基-2-苦基肼（DPPH）自由基清除活性准确检测的关键因素。我们首次表明，甲醇、乙醇和丙酮等有机溶剂在低至 0.1%（v/v）的浓度下具有很强的超氧自由基清除活性，但在高达 2.0%（v/v）的浓度下，乙腈没有这种活性。在 DPPH 测定中，我们发现 DPPH 自由基清除率随着反应时间的延长而增加。基于我们的发现，建立了改进的体外检测异黄酮（大豆苷元和染料木黄酮）和异黄酮代谢物（二氢大豆苷元（DHD）、二氢染料木黄酮（DHG）和 O-去甲安哥拉定（O-Dma））清除自由基活性的方法。
