Photochemical and Optical Properties of Water-Soluble Xanthophyll Antioxidants: Aggregation vs Complexation
Photochemical and Optical Properties of Water-Soluble Xanthophyll Antioxidants: Aggregation vs Complexation
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DOI：
10.1021/jp4062708
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发表时间：
2013-09-05
影响因子：
3.3
通讯作者：
Kispert, Lowell D.
中科院分区：
文献类型：
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作者：
Polyakov, Nikolay E.;Magyar, Adam;Kispert, Lowell D.
叶黄素类胡萝卜素在水溶液中可以自组装形成J型和H型聚集体。这一特征显著改变了这些类胡萝卜素的光物理和光学性质，并对太阳能转化和光诱导的氧化损伤产生影响。在这项研究中，我们已经应用EPR和光学吸收光谱研究络合作用如何影响叶黄素类胡萝卜素玉米黄质，叶黄素和虾青素的聚集能力，它们的光稳定性和抗氧化活性。结果表明，与多糖阿拉伯半乳聚糖（AG）聚合物基质和三萜糖苷类胡萝卜素（GA）二聚体的复合降低了聚集速率，但没有完全抑制聚集。此外，这些络合剂与类胡萝卜素的单体和H-聚集体形成包合络合物。类胡萝卜素的H-聚集体在水溶液中表现出比单体更高的光稳定性，但抗氧化活性低得多。结果发现，络合增加的单体和叶黄素类胡萝卜素的聚集体的光稳定性。此外，它们捕获过氧化氢自由基的能力在GA的存在下增加，因为GA形成甜甜圈状二聚体，其中叶黄素的疏水多烯链及其H-聚集体位于甜甜圈孔内受到保护，允许亲水末端暴露于周围环境。
Xanthophyll carotenoids can self-assemble in aqueous solution to form J- and H-type aggregates. This feature significantly changes the photophysical and optical properties of these carotenoids, and has an impact on solar energy conversion and light induced oxidative damage. In this study we have applied EPR and optical absorption spectroscopy to investigate how complexation can affect the aggregation ability of the xanthophyll carotenoids zeaxanthin, lutein, and astaxanthin, their photostability, and antioxidant activity. It was shown that complexation with the poly-saccharide arabinogalactan (AG) polymer matrix and the triterpene glycoside glycyrrhizin (GA) dimer reduced the aggregation rate but did not inhibit aggregation completely. Moreover, these complexants form inclusion complexes with both monomer and H-aggregates for carotenoids. H-aggregates of carotenoids exhibit higher photostability in aqueous solutions as compared with monomers, but much lower antioxidant activity. It was found that complexation increases the photostability of both monomers and the aggregates of xanthophyll carotenoids. Also their ability to trap hydroperoxyl radicals increases in the presence of GA as the GA forms a donutlike dimer in which the hydrophobic polyene chain of the xanthophylls and their H-aggregates lies protected within the donut hole, permitting the hydrophilic ends to be exposed to the surroundings.