Xanthophylls are found in young as well as in etiolated leaves.
They are also found in papaya, peaches, prunes, etc.
Examples of xanthophylls are lutein, zeaxanthin, neoxanthin, violaxanthin, flavoxanthin, and α- and β-cryptoxanthin.Jun 17, 2022.
In flowers, the main role of these pigments is to attract insects that help pollination.
Carotenoid components in petals vary widely among plant species, but the majority are xanthophylls (oxygenated carotenoids)1,2..
As previously mentioned, plastids are doubled membraned 'sac-like' organelles, generally involved in either the manufacture or storage of food.
They include chloroplasts, chromoplasts, and leucoplasts.
Leucoplasts are colorless plastids.
Xanthophylls are yellow pigments that impart a yellow colour to the plant..
Carotenoids are plant pigments commonly found in fruits and vegetables.
They are made up of 2 classes, xanthophylls and carotenes.
Whereas carotenes are composed of only carbon and hydrogen, xanthophylls include hydroxyl groups, making them slightly more hydrophilic than carotenes..
Xanthophylls are carotenoids that occur widely in nature.
They are yellow pigments; thus, this accounts for their name, 'xanthophyll', which is derived from Greek xanthos– (yellow) and ”phyllon (leaf).Jun 17, 2022.
The Xanthophyll Cycle
Under conditions of excess light, violaxanthin is de-epoxidized to zeaxanthin via the monoepoxide antheraxanthin due to the activation of violaxanthin de-epoxidase, a thylakoid lumen enzyme.
Another enzyme, zeaxanthin epoxidase reverses the reaction in low light..
The products of the light-dependent phase of xanthophyll cycles play an important role in the protection against oxidative stress generated not only by an excess of light but also by other ROS-generating factors such as drought, chilling, heat, senescence, or salinity stress..
Dietary sources of xanthophylls include lutein and zeaxanthin in green leafy vegetables and corn, and β-cryptoxanthin in pumpkins, papayas, and peppers.
The minor xanthophylls astaxanthin and canthaxanthin are found in certain fish and seashells, and in certain mushrooms (2)..
A very important aspect of the operation of the xanthophyll cycle in the thylakoids as a mechanism protecting plants against oxidative stress is the direct presence of carotenoid pigments in the lipid phase of the thylakoid membrane and not assembled into pigment–protein complexes..
Dietary sources of xanthophylls include lutein and zeaxanthin in green leafy vegetables and corn, and β-cryptoxanthin in pumpkins, papayas, and peppers.
The minor xanthophylls astaxanthin and canthaxanthin are found in certain fish and seashells, and in certain mushrooms (2)..
Xanthophylls Xanthophylls represent oxygenized carotenoids and tetraterpenoid pigments that occur in the leaves of all plants.
Xanthophylls comprise the oxygenated derivatives of carotenoids (C 40 tetraterpenoids; see “ Carotenoids in Plants ”) and occur in the leaves of all plants.
Plant xanthophylls form the bright yellow band next to the green As both are carotenoids, xanthophylls and carotenes are similar in structure, but xanthophylls contain oxygen atoms while carotenes are purely hydrocarbons, which do not contain oxygen.
Definition of xanthophyll :
Unlike chlorophyll, however, xanthophylls do not need light for production.
Therefore, leaves will only show the yellow pigments if the leaf does not get enough light ( etiolation ). The name comes from the Greek words for "yellow" ( xanthos, ξανθός ), and "leaf" ( phyllon, φύλλον ).
