Isolation of three new carotenoids and proposed metabolic pathways of carotenoids in hen's egg yolk

Metabolism of lutein and zeaxanthin in rhesus monkeys: Identification of (3R,6′R)- and (3R,6′S)-3′-dehydro-lutein as common metabolites and comparison to humans

“…3′-Dehydro-lutein has been reported to be present in plasma and tissue of different species, including fish (Matsuno et al, 1986b), iguanas Costantini et al, 2005), birds (Matsuno et al, 1986a;McGraw and Schuetz, 2004), monkeys (Khachik et al, 1997) and humans (Khachik et al, 1992). Despite its possible importance for metabolomic investigations, it seems that the absolute stereochemistry of this metabolite has received thus far only little attention.…”

“…Only in few cases the stereochemistry was directly analysed, e.g., in egg yolk. Here, 3′-dehydro-lutein was shown to be either present as a scalemic mixture (Matsuno et al, 1986a) or as a single stereoisomer (Schiedt, 1998), depending on whether the feed of the animals contained both lutein and zeaxanthin or only zeaxanthin. Related investigations in human or monkey plasma seemingly have never been conducted.…”

A 3-hydroxy %-end group in xanthophylls is preferentially oxidized to a 3-oxo ε-end group in mammals

“…For example, goldfi nches oxidized hydroxyl groups of C3 and C3 ′ in lutein to 3-oxo carotenoids and cardinals oxidized C4 and C4 ′ of ␤ -carotene and zeaxanthin to canthaxanthin and astaxanthin ( 19 ). Several 3-oxo carotenoids were detected in hen egg yolk ( 20 ). Fish have the same oxidative activity as birds and the reductive metabolism of astaxanthin to tunaxanthins was also reported in yellowtail ( 21 ).…”

“…Under the HPLC conditions, the , -carotene-3,3 ′ -dione prepared from egg yolk was separated to three peaks ( Fig. 3I ), which represented all of the possible confi gurations: meso , 6 S ,6 ′ S , and 6 R ,6 ′ R isomers ( 20 ). Peak E1 showed no signal in CD (supplementary Fig.…”

Diet explains red flight feathers in Yellow-shafted Flickers in eastern North America

“…A clue as to what is happening in these feathers comes from the accumulation in both relative and absolute terms of 3 0 -dehydro-lutein, a yellow carotenoid normally present in the feathers of yellow color (Hudon et al 2015). 3 0 -dehydro-lutein is thought to be an intermediate in the interconversion of e-and b-end-rings and the production of lutein from zeaxanthin (Matsuno et al 1986, Katsuyama and Matsuno 1988, Nagao et al 2015. It is plausible that rhodoxanthin, or a metabolite, interferes with the reduction of 3 0 -dehydro-lutein to produce lutein, resulting in an accumulation of the former and a decrease in lutein.…”