ISOLATION AND IDENTIFICATION OF CAROTENOIDS FROM THE PETALS OF RAPE (BRASSICA-NAPUS)

From the yellow petals of rape flowers (Brassica napus), the carotenoids have been extracted and some compounds were identified. A HPLC analysis of the whole extract showed at least 80 different carotenoids, ranging from hydrocarbons to highly oxygenated species, including naturally occurring E/Z-isomers. The most polar part of the extract was further investigated by HPLC and UV-vis photodiodearray detection. The major carotenoids were isolated and identified, from UV-vis, CD, 400 MHz H-1-NMR, and mass spectra, as (8'R)- and (8'S)-luteoxanthin, (13Z,8'R)-luteoxanthin, flavoxantkin/chrysanthemaxanthin, taraxanthin, and (all-E)-, (9Z)-, and (13Z)-violaxanthin. This shows the existence of different E/Z-isomers in nature. It was shown that luteoxanthin is found as an 8'-epimeric mixture, whereas there were no epimers found for violaxanthin.