Rapid and Efficient Conversion of All-E-astaxanthin to 9Z- and 13Z-Isomers and Assessment of Their Stability and Antioxidant Activities

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• 作者：Cheng Yang ; Lianfu Zhang ; Hua Zhang ; Qingrui Sun ; Ronghua Liu ; Jing Li ; Leiyan Wu ; Rong Tsao
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2017
• 出版时间：February 1, 2017
• 年：2017
• 卷：65
• 期：4
• 页码：818-826
• 全文大小：501K
• ISSN：1520-5118

文摘

An optimized isomerization method was developed by heating all-E-astaxanthin in ethyl acetate (70 °C) with I-TiO₂ catalyst, yielding 22.7% and 16.9% of 9Z- and 13Z-astaxanthin, respectively, in 2 h, with 92–95% purity after semipreparative HPLC purification. 13Z-Astaxanthin had higher antioxidant activity than all-E- and 9Z-astaxanthins in oxygen radical absorbing capacity assay for lipophilic compounds, photochemiluminescence, and cellular antioxidant activity (CAA) assays, and 9Z-astaxanthin was higher in DPPH radical-scavenging activity assay and lower in CAA assay. All isomers were relatively stable between pH 2.0 and 11.6, except 13Z- and 9Z-astaxanthins at pH 2.0, suggesting they may be converted after passing the gastric phase in vivo. Metal ions did not significantly (p < 0.05) affect the stability. Results of the current study provides a means for further study into the mechanisms related to in vivo transformation and bioavailability of Z-astaxanthins, and their application in the development of functional foods and nutraceutical products.