Astaxanthin Isomers: A Comprehensive Review of Isomerization Methods and Analytic Techniques

Abstract

The presence of multiple conjugated double bonds and chiral carbon atoms endows astaxanthin with geometric and optical isomers, and these isomers widely exist in biological sources, food processing, and in vivo absorption. However, there remains no systematic summary of astaxanthin isomers regarding isomerization methods and analytic techniques. To address this need, this Review focuses on a comprehensive analysis of Z-isomerization methods of astaxanthin, including solvent system, catalyst, and heat treatment. Comparatively, high-efficiency and health-friendly methods are more conducive to put into practical use, such as food-grade solvents and food-component catalysts. In addition, we outline the recent advances in analysis techniques of astaxanthin isomers, as well as the structural characteristics reflected by various methods (e.g., HPLC, NMR, FTIR, and RS). Furthermore, we summarized the related research on the safety evaluation of astaxanthin isomers. Finally, future trends and barriers in Z-transformation and analysis of astaxanthin isomers are also discussed.

Cluster of Differentiation 36 (CD36) Preferentially Mediates Intestinal Absorption of Dietary Z-Astaxanthin and Especially 9-Z-Isomer via Higher Binding Affinity

“…Astaxanthin, a carotenoid mainly found in shrimp, crab, fish, and microalgae with potent antioxidant properties and numerous health benefits, has garnered significant interest. , Similar to other carotenoids, its Z -configuration, particularly 9- Z -astaxanthin, displays superior biological functions to the all- E -isomer. For example, studies have shown that Z -astaxanthin has enhanced anti-inflammatory properties. − Our prior experiments have solidified the role of CD36 as the principal transporter protein facilitating astaxanthin absorption at dietary concentrations .…”