title: A 3-hydroxy β-end group in xanthophylls is preferentially oxidized to a 3-oxo ε-end group in mammals.
abstract: We previously found that mice fed lutein accumulated its oxidative metabolites (3'-hydroxy-ε,ε-caroten-3-one and ε,ε-carotene-3,3'-dione) as major carotenoids, suggesting that mammals can convert xanthophylls to keto-carotenoids by the oxidation of hydroxyl groups. Here we elucidated the metabolic activities of mouse liver for several xanthophylls. When lutein was incubated with liver postmitochondrial fraction in the presence of NAD(+), (3'R,6'R)-3'-hydroxy-β,ε-caroten-3-one and (6RS,3'R,6'R)-3'-hydroxy-ε,ε-caroten-3-one were produced as major oxidation products. The former accumulated only at the early stage and was assumed to be an intermediate, followed by isomerization to the latter. The configuration at the C3' and C6' of the ε-end group in lutein was retained in the two oxidation products. These results indicate that the 3-hydroxy β-end group in lutein was preferentially oxidized to a 3-oxo ε-end group via a 3-oxo β-end group. Other xanthophylls such as β-cryptoxanthin and zeaxanthin, which have a 3-hydroxy β-end group, were also oxidized in the same manner as lutein. These keto-carotenoids, derived from dietary xanthophylls, were confirmed to be present in plasma of normal human subjects, and β,ε-caroten-3'-one was significantly increased by the ingestion of β-cryptoxanthin. Thus, humans as well as mice have oxidative activity to convert the 3-hydroxy β-end group of xanthophylls to a 3-oxo ε-end group.
authors.affiliation: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Nagao
authors.affiliation: Research Institute for Production and Development, Sakyo-ku, Kyoto 606-0805, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Maoka
authors.affiliation: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ono
authors.affiliation: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kotake-Nara
authors.affiliation: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Miyuki
authors.initials: M
authors.lastname: Kobayashi
authors.affiliation: National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan.
authors.forename: Mie
authors.initials: M
authors.lastname: Tomita
mesh_terms: D000818:Animals; D002338:Carotenoids / Q000737:chemistry / Q000378:metabolism; D065366:Cryptoxanthins / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D008099:Liver / Q000378:metabolism; D014975:Lutein / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D008297:Male; D008322:Mammals; D008813:Mice, Inbred ICR; D010084:Oxidation-Reduction; D024341:Xanthophylls / Q000737:chemistry / Q000378:metabolism*; D065146:Zeaxanthins / Q000737:chemistry / Q000378:metabolism
chemical_list: C552883:3'-hydroxy-epsilon,epsilon-caroten-3-one; D065366:Cryptoxanthins; D024341:Xanthophylls; D065146:Zeaxanthins; D002338:Carotenoids; D014975:Lutein
keywords: keto-carotenoid; liver; lutein; metabolism; mouse; oxidation; zeaxanthin; β-cryptoxanthin