Isolation of carotenoids from plant materials and dietary supplements by high-speed counter-current chromatography

Methods for the isolation of lipophilic pigments from crude extracts of plant materials (spinach and sweet corn) by high-speed counter-current chromatography (HSCCC) were developed. Particular attention was given to (all-E)-lutein and (all-E)-zeaxanthin. However, the concomitant pigments neoxanthin, violaxanthin and β-carotene as well as chlorophylls a and b were also considered. Furthermore, for the first time dietary supplements containing lutein and zeaxanthin were also used as a source for the recovery of carotenoids. Due to their simple matrix (oily excipient in soft gelatine capsules), sample preparation was facilitated and consumption of solvents was minimized. The carotenoids were characterized by 1H NMR spectroscopy, by LC/APcI-MS in the positive ionization mode, and by UV–vis spectroscopy. Data showed that the target compounds were of high purity (90–93%). Lutein and zeaxanthin may be used as reference substances for analytical purposes.