Isolation and Structure Elucidation of Two (Z)-Isomers of Lutein from the Petals of Rape (Brassica napus)

The yellow petals of rape ( Brassica napus ) were extracted with hexane/acetone/MeOH/toluene (10:7:6:7), EtOAc/hexane/acetone (6:1:1), and EtOAc/Et 2 O (1:1), and subsequently the saponified extract was submitted to a step gradient on an Al 2 O 3 column. From the most polar fraction, two ( Z )-isomers of lutein have been isolated by reversed-phase HPLC. On the basis of UV−vis, CD, 1D and 2D 400 MHz 1 H-NMR, and mass spectra they were identified as (9 Z,9‘ Z,3 R,3‘ R,6‘ R )-lutein and (13‘ Z, 3 R,3‘ R,6‘ R )-lutein.