Isomerization of trans-Astaxanthin Induced by Copper(II) Ion in Ethanol

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• 作者：Liyan Zhao ; Fang Chen ; Guanghua Zhao ; Zhengfu Wang ; Xiaojun Liao ; and Xiaosong Hu
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2005
• 出版时间：November 30, 2005
• 年：2005
• 卷：53
• 期：24
• 页码：9620 - 9623
• 全文大小：81K
• 年卷期：v.53,no.24(November 30, 2005)
• ISSN：1520-5118

文摘

Carotenoids are unstable and susceptible to disruption by environmental factors such as heat, light,and solvents. However, there is little information on the effect of metal ions on stability of carotenoids,especially those essential elements in human nutrition. Astaxanthin is one of the few carotenoidscontaining four oxygen donors. Usually, these oxygen donors can coordinate with heavy metal ionssuch as Cu(II) and Fe(III). In the present study, the interaction of trans-astaxanthin with Cu(II) wasexamined. It was found that Cu(II) markedly induces the conversion of trans-astaxanthin to its cisforms, which mainly consist of 9-cis-astaxanthin and 13-cis-astaxanthin as suggested by UV-visiblespectra and HPLC measurements. Increasing either incubation time of Cu(II) and trans-astaxanthinin ethanol or the Cu(II)/astaxanthin ratio results in an increased percentage of cis isomers derivedfrom trans-astaxanthin. All these results provide important information on the effects of dietary factorson the bioavailability and bioactivity of trans-astaxanthin.Keywords: Cu(II); astaxanthin; isomerization; carotenoids