Preparation of (3R, 3′R)-astaxanthin monoester and (3R, 3′R)-astaxanthin from Antarctic krill (Euphausia superba Dana)

Abstract

A special method is described for the preparation of (3R, 3′R)-astaxanthin monoester (AM) and (3R, 3′R)-astaxanthin from Antarctic krill (Euphausia superba Dana). Purified AM was obtained on a large scale from crude extract extracted from Antarctic krill in 38.14 % yield by silica gel column chromatography. After the AM was saponified with methanolic KOH (0.10 mol L−1) and separated by high-performance thin-layer chromatography, pure astaxanthin was obtained. There was only one optical (3R, 3′R)-isomer of the esterification of astaxanthin with (-)-camphanic acid chloride detected by high-performance liquid chromatography compared with astaxanthin standard. It was further proved that the AM consists of only one optical (3R, 3′R)-isomer. Twelve types of fatty acids in the AM from Antarctic krill were found by gas chromatography–mass spectrometer. Eicosapentaenoic and docosahexaenoic acids are the major fatty acids. It is the first time to prepare (3R, 3′R)-AM and (3R, 3′R)-astaxanthin from Antarctic krill. The purified (3R, 3′R)-AM and (3R, 3′R)-astaxanthin can be used as a standard for further related study.