Polar xanthophylls comprise at least two hydroxyl groups (lutein, zeaxanthin, capsanthin) bound to ɛ-, β-, or κ-ionone rings, or possess one aldehyde (β-apo-8′carotenal) or two keto groups (canthaxanthin), rather nonpolar xanthophylls comprise a terminal ester group (β-apo-8′...
Major carotenoids that have been found in human plasma can be divided into two groups, carotenes (nonpolar molecules, such as 尾-carotene, 伪-carotene or lycopene) and xanthophylls (polar carotenoids that include an oxygen atom in their structure, such as lutein, zeaxanthin and 尾-cryptoxanthin)...