Three studies of natural xanthophylls

The purpose of this work was to isolate and study the oxidation of a carotenoid known as lactucaxanthin; to determine the dose vs. serum response of human subjects in a supplementation study of lutein, zeaxanthin, and meso-zeaxanthin; and to initiate an investigation of lutein in larval monarch butterflies. Our interest in lactucaxanthin arises because of its close structural homology to a keto carotenoid in human blood. The isolation of lactucaxanthin from Romaine Lettuce was accomplished by use of the reversed-phase HPLC. Preliminary results from the oxidation of lactucaxanthin using MnO2 show that two products are formed. Human subjects participated in supplementation studies of lutein and mesozeaxanthin. The effects of three daily dosages (5 mg, 10 mg, and 20 mg) of lutein on serum lutein concentrations were investigated to determine the magnitude of the serum response The concentration of lutein in larval monarch butterflies was investigated. These caterpillars have stripes of three distinct colors: black, white, and yellow. The striped sections of the skin were separated by color, extracted and analyzed using reversed-phase HPLC. The concentration of lutein was highest in the yellow stripes.