title: Partial synthesis of serum carotenoids and their metabolites.
abstract: Human serum and tissues contain in excess of 12 dietary carotenoids and several metabolites that originate from consumption of fruits and vegetables. Among these are hydroxycarotenoids: (3R,3'R,6'R)-lutein (1), (3R,3'R)-zeaxanthin (2), (3R,6'R)-α-cryptoxanthin (3), and (3R)-β-cryptoxanthin (4). In addition, several dehydration products of 1 have also been identified in human serum, these are: (3R,6'R)-3-hydroxy-3',4'-didehydro-β,γ-carotene (5), (3R,6'R)-3-hydroxy-2',3'-didehydro-β,ε-carotene (6), and (3R)-3-hydroxy-3',4'-didehydro-β,β-carotene (7). Several metabolites of 1 and/or 2, namely, (3R,3'S,6'R)-lutein (3'-epilutein, 8) and (3R,3'S;meso)-zeaxanthin (9) have also been characterized in human serum and ocular tissues. Semi-synthetic processes have been developed that separately transform commercially available 1 into 4 via 7 as well as 1 into 8. While 8 is converted into 2 by base-catalyzed isomerization, 7 is transformed into 2 and its (3R,3'S;meso)-stereoisomer (9) by regioselective hydroboration.
authors.affiliation: Department of Chemistry and Biochemistry, University of Maryland, College Park, USA. Khachik@umd.edu
authors.forename: Frederick
authors.initials: F
authors.lastname: Khachik
mesh_terms: D002338:Carotenoids / Q000097:blood* / Q000737:chemistry; D065366:Cryptoxanthins; D006801:Humans; D015394:Molecular Structure; D013237:Stereoisomerism; D024341:Xanthophylls / Q000097:blood / Q000737:chemistry
chemical_list: D065366:Cryptoxanthins; D024341:Xanthophylls; D002338:Carotenoids