o-Quinone involvement in the prooxidant tendency of a mixture of quercetin and caffeic acid
o-Quinone involvement in the prooxidant tendency of a mixture of quercetin and caffeic acid
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DOI：
10.1016/j.foodchem.2012.06.094
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发表时间：
2012-12-01
期刊：
影响因子：
8.8
通讯作者：
Kefalas, Panagiotis
中科院分区：
文献类型：
--
作者：
Chedea, Veronica Sanda;Choueiri, Lamis;Kefalas, Panagiotis
通过 LC-MS 分析了之前测试的槲皮素 (Q) 和咖啡酸 (CA) 1:2 促氧化剂混合物的氧化产物。进一步研究了在 t(R) = 9.11 min、t(R) = 14.36 min 和 t(R) = 30.30 min 处洗脱的三个色谱峰的 UV-Vis 和 MS 光谱。初步鉴定的化合物的结构表明聚合物分子。由 3 单位槲皮素和 2 单位咖啡酸形成的五聚体归因于峰 t(R) = 9.11 分钟和 t(R) = 14.36 分钟。槲皮素醌 (QQ) - 一种聚合中间体 - 是在 MS 谱中鉴定的化合物的片段，m/z = 323 来自 Q 邻醌 m/z = 300 加上来自 Na+ 的 23。根据紫外-可见光谱，我们建议采用不同的分子间排列，从而提供更广泛的电子离域。在 t(R) = 30.30 分钟时，光谱帮助我们初步确定该氧化产物是由 4 个 CA 单元和 1 个 QQ 组成的聚合物。 (C) 2012 Elsevier Ltd. 保留所有权利。
The oxidation products of a previously tested prooxidant mixture of quercetin (Q) and caffeic acid (CA) at 1:2 ratio were analysed by LC-MS. The UV-Vis and MS spectra of three chromatographic peaks eluting at t(R) = 9.11 min, t(R) = 14.36 min and t(R) = 30.30 min were studied further. The structures of the tentatively identified compounds indicate polymeric molecules. A pentamer formed by 3 units of quercetin and 2 units of caffeic acid was attributed in the case of peaks t(R) = 9.11 min and t(R) = 14.36 min. The quercetin quinone (QQ) - a polymerization intermediate - is a fragment of the compound identified in the MS spectrum with the m/z = 323 coming from Q o-quinone m/z = 300 plus 23 from Na+. According to the UV-Vis spectrum, we suggest a different intermolecular arrangement which gives a more extended e-delocalisation. At t(R) = 30.30 min, the spectra helped us to tentatively identify this oxidation product as being a polymer of 4 CA units and 1 QQ. (C) 2012 Elsevier Ltd. All rights reserved.