Identification, Quantification, and Relative Concentrations of Carotenoids and Their Metabolites in Human Milk and Serum

Abstract

Thirty-four carotenoids, including 13 geometrical isomers and eight metabolites, in breast milk and serum of three lactating mothers have been separated, identified, quantified, and compared by high-performance liquid chromatography (HPLC)−photodiode array (PDA) detection−mass spectrometry (MS). Among the metabolites were two oxidation products of lycopene and four of lutein/zeaxanthin. In addition, two metabolites of lutein, formed as a result of dehydration of this dihydroxycarotenoid under acidic conditions similar to those of the stomach, have also been identified in plasma and breast milk. The oxidative metabolites of lycopene with a novel five-membered-ring end group have been identified as epimeric 2,6-cyclolycopene-1,5-diols by comparison of their HPLC−UV/visible−MS profiles with those of fully characterized (¹H- and ¹³C-NMR spectroscopy) synthetic compounds. The HPLC procedures employed also detected vitamin A, two forms of vitamin E (γ- and α-tocopherol), and two non-carotenoid food components, i.e., piperine and caffeine, in serum and breast milk.