Partition of Indicaxanthin in Membrane Biomimetic Systems. A Kinetic and Modeling Approach

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• 作者：Maria Liria Turco Liveri ; Luciana Sciascia ; Mario Allegra ; Luisa Tesoriere ; Maria A. Livrea
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2009
• 出版时间：November 25, 2009
• 年：2009
• 卷：57
• 期：22
• 页码：10959-10963
• 全文大小：750K
• 年卷期：v.57,no.22(November 25, 2009)
• ISSN：1520-5118

文摘

The solubilization site of indicaxanthin (Ind) in lipid bilayers was investigated by the kinetics of Ind oxidation by peroxyl radicals in water and in aqueous/l-α-dipalmitoyl-phosphatidylcholine (DPPC) vesicles, pH 7.4, and 37.0 and 48.0 °C, that is, in a gel-like and a crystal liquidlike bilayer state, respectively. The time-dependent Ind absorbance decay, matched with a successful simulation of the reaction kinetic mechanism by Gepasi software, supported a multistep pathway. Computer-assisted analysis allowed calculation of the rate constants associated with the reactions involved, the values of which decreased with increasing DPPC concentration. The binding constant calculated according to a pseudo two-phase distribution model did not vary with the physicochemical state of the vesicle, indicating location of Ind in a region whose state is not affected by temperature changes, at the interface between hydrophobic core and hydrophilic head groups. Other measurements carried out in the presence of dimyristoyl-phosphatidylcholine vesicles, indicated that the phytochemical was confined to the aqueous phase.