Figure 2.

Carotenoid composition of higher plants. (A) HPLC separation of pigments from dark-adapted samples from S. oleracea (dark) and C. reflexa (dark), C. reflexa exposed to light at 1,200 μmol photons m⁻² s⁻¹ for 2–4 h [C. reflexa (light)]. The identification of the lutein-5,6-epoxide in C. reflexa was achieved by comparing its elution times and absorption spectrum (inset) with a pure sample of lutein-5,6-epoxide (standard); they were identical. N, neoxanthin; V, violaxanthin; Lx, lutein-5,6-epoxide; A, antheraxanthin; L, lutein; Z, zeaxanthin; a, chlorophyll a; b, chlorophyll b; C, β-carotene. (B) Biosynthetic pathway of carotenoids showing that neoxanthin is synthesized later than β-carotene-derived xanthophyll cycle carotenoids and distinct from α-carotene-derived lutein.