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Related to Xanthophylls: chlorophyll b, Phycobilins



oxygen-containing carotenoids, the principal components of the yellow pigments in the leaves, flowers, fruits, and buds of higher plants, as well as in many algae and microorganisms. Xanthophylls are found less frequently in the animal world, for example, in the yolk of chicken eggs and in the liver and fatty tissue of mammals. These carotenoids are contained in the chloroplasts of the green parts of plants, in the chromoplasts of flowers and fruits, and in the lipophil sections of bacterial cells. Together with flavonoids, xanthophylls are responsible for the autumnal coloration of leaves.

The biological importance of xanthophylls is related to their ability to absorb sunlight from the short-wave range of the visible spectrum (380-520 nanometers). All photosynthetizing organs of green plants and of photosynthetic microorganisms contain xanthophylls. In these organs the absorbed light energy is transformed into chlorophyll or similar complexes. In this way, xanthophylls participate as auxiliary pigments in the photosynthetic process. Apparently, they also play the role of filters, protecting sensitive enzymes from destruction by light.

There are more than 50 known xanthophylls; they fall into various functional groups, including alcohols, ketones, aldehydes, acids, and simple and complex ethers. They belong to acyclic, monocyclic, and bicyclic carotenoids, containing 40 atoms of carbon. A typical representative is zeaxanthin (C40H56O2), the yellow crystals (melting point, 207–215°C), and its isomer—xanthophyl (lutein)—whose crystals are violet (melting point, 190–193°C). The biosynthesis of xanthophylls from colorless carotenoid hydrocarbons is catalyzed by atmospheric oxygen in sunlight.


Kretovich, V. L. Osnovy biokhimii rastenii, 5th ed. Moscow, 1971.


References in periodicals archive ?
To cope with widely fluctuating light levels, many phytoplankton have certain red accessory pigments called xanthophylls that act like gatekeepers.
Eventually, xanthophylls and anthocyanins follow chlorophyll into oblivion, breaking down and leaving behind the hardy brown tannins.
The use of synthetic preservatives to stabilize xanthophylls (as some manufacturers of feed-grade marigold products do) was completely and demonstrably eliminated.
Resonance The rapid transfer of energy between pigments, possible through the close proximity of the electron orbitals of the pigments that are tightly packed in the thylakoid membrane Stroma The solution surrounding the thylakoid membranes Thylakoid The photosynthetic membranes inside the chloroplast Xanthophylls A class of carotenoids found in the antenna complex
There was also a strong correlation between water depth and content of carotenes and xanthophylls while the contrast in the concentrations in the shallower and deeper areas was generally greater in xantophylls.
Yellow carrots contain xanthophylls for eye health, red versions have lycopene to counter heart disease and some cancers, while the anti-oxidants in purple fight damaging free radicals.
In the reddest part of the phytonutrient rainbow, we find two different tribes of molecules: the orangish-red xanthophylls and the purplish-red anthocyanins.
Simultaneous determination of retinol, tocopherols, carotene, lycopene, and xanthophylls in plasma by means of reversed-phase high-performance liquid chromatography.
Sudden changes in levels of incident light--for example, sun flecks through an overstory--can induce excess light absorption that requires photoprotection via the xanthophylls cycle (Logan et al.
A long-term strategy to cope with the excess light is the development of extra pigments such as carotenoids and xanthophylls in the leaves.
These revealed pigments are known as xanthophylls (yellows), carotenes (oranges) and anthocyanins (deep reds).