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Information about Xanthophyll

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The chemical structure of cryptoxanthin
Xanthophylls (originally phylloxanthins) are yellow pigments from the carotenoid group. Their molecular structure is based on carotenes; contrary to the carotenes, some hydrogen atoms are substituted by hydroxyl groups and/or some pairs of hydrogen atoms are substituted by oxygen atoms. They are found in the leaves of most plants and are synthesized within the plastids. They are involved in photosynthesis along with green chlorophyll, which typically covers up the yellow except in autumn, when the chlorophyll is denatured by the cold.

In plants, xanthophylls are considered accessory pigments, along with anthocyanins, carotenes, and sometimes phycobiliproteins. Xanthophylls, along with carotenic pigments are seen when leaves turn orange in the autumn season.

Animals cannot produce xanthophylls, and thus xanthophylls found in animals (e.g. in the eye) come from their food intake. The yellow color of chicken egg yolks also comes from ingested xanthophylls.

Xanthophylls are oxidized derivatives of carotenes. They contain hydroxyl groups and are more polar; therefore, they are the pigments that will travel the furthest in paper chromatography.

The group of xanthophylls is composed of lutein, zeaxanthin, and α- and β-cryptoxanthin.

Xanthophyll cycle

The xanthophyll cycle involves conversions of pigments from a non-energy-quenching form to energy-quenching forms. This is a way to reduce the absorption cross-section of the light harvesting antenna, and thus to reduce the amount of energy that reaches the photosynthetic reaction centers. Reducing the light harvesting antenna is one of the main ways of protecting against photoinhibition and changes in the xanthophyll cycling takes place on a time scale of minutes to hours [1]. In higher plants there are three carotenoid pigments that are active in the xanthophyll cycle: violoxanthin, antheraxanthin and zeaxanthin. During light stress violoxanthin is converted to antheraxanthin and zeaxanthin, which functions as photoprotective pigments.

In diatoms and dinoflagellates the xanthophyll cycle consists of the pigment diadinoxanthin, which is transformed into diatoxanthin (diatoms) or dinoxanthin (dinoflagellates), at high light [2].

References

1. ^ Falkowski, P. G. & J. A. Raven, 1997, Aquatic photosynthesis. Blackwell Science, 375 pp
2. ^ Jeffrey, S. W. & M. Vesk, 1997. Introduction to marine phytoplankton and their pigment signatures. In Jeffrey, S. W., R. F. C. Mantoura & S. W. Wright (eds.), Phytoplankton pigments in oceanography, pp 37-84. – UNESCO Publishing, Paris.
  • Demmig-Adams, B & W. W. Adams, 2006. Photoprotection in an ecological context: the remarkable complexity of thermal energy dissipation, New Phytologist, 172: 11–21.

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Major families of biochemicals
Peptides | Amino acids | Nucleic acids | Carbohydrates | Lipids | Terpenes | Carotenoids | Tetrapyrroles | Enzyme cofactors | Steroids | Flavonoids | Alkaloids | Polyketides | Glycosides
Analogues of nucleic acids:Types of CarotenoidsAnalogues of nucleic acids:
General:
Xanthophylls: Astaxanthin | Canthaxanthin | Fucoxanthin | Lutein | Zeaxanthin
Carotenes: Lycopene | Carotene
pigment is a material that changes the color of light it reflects as the result of selective color absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which the material itself emits light.
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Carotenoids are organic pigments that are naturally occurring in plants and some other photosynthetic organisms like algae, some types of fungus and some bacteria. There are over 600 known carotenoids; they are split into two classes, xanthophylls and carotenes.
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Carotene is responsible for the orange colour of the carrots and many other fruits and vegetables.]] The term carotene is used for several related substances having the formula C40H56.
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Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. The neutral form is a hydroxyl radical and the hydroxyl anion is called a hydroxide.
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leaf is an above-ground plant organ specialized for photosynthesis. For this purpose, a leaf is typically flat (laminar) and thin, to expose the cells containing chloroplast (chlorenchyma tissue, a type of parenchyma) to light over a broad area, and to allow light to penetrate
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Plantae
Haeckel, 1866[1]

Divisions

Green algae
  • Chlorophyta
  • Charophyta
Land plants (embryophytes)
  • Non-vascular land plants (bryophytes)

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Plastids are major organelles found in plants and algae.

Plastids in plants

Plastids are responsible for photosynthesis, storage of products like starch and for the synthesis of many classes of molecules such as fatty acids and terpenes which are needed as cellular
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Green is a color, the perception of which is evoked by light having a spectrum dominated by energy with a wavelength of roughly 520–570 nm. It is considered one of the additive primary colors.
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Chlorophyll is a green pigment found in most plants, algae, and cyanobacteria. Its name is derived from ancient Greek: chloros = green and phyllon = leaf.
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Autumn (also known as Fall in North American English) is one of the four temperate seasons. Autumn marks the transition from summer into winter. In the northern hemisphere, the start of autumn is generally considered to be around September and in the southern hemisphere, its
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Accessory pigments are light-absorbing compounds, found in photosynthetic organisms, that work in conjuction with chlorophyll a. They include other forms of this pigment, such as chlorophyll b
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Anthocyanins (from Greek: ἀνθός (anthos) = flower + κυανός (kyanos)
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Carotene is responsible for the orange colour of the carrots and many other fruits and vegetables.]] The term carotene is used for several related substances having the formula C40H56.
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Phycobiliproteins are water-soluble proteins present in cyanobacteria and certain algae (rhodophytes, cryptomonads, glaucocystophytes) that capture light energy which is then passed on to chlorophylls during photosynthesis.
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In most birds and reptiles, an egg (Latin ovum) is the zygote, resulting from fertilization of the ovum. To enable incubation the egg is usually kept within a favourable temperature range as it nourishes and protects the growing embryo.
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egg yolk is the part of an egg which serves as the food source for the developing embryo inside. Prior to fertilization the yolk together with the germinal disc is a single cell. Mammalian embryos live off their yolk until they implant on the wall of the uterus.
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Carotene is responsible for the orange colour of the carrots and many other fruits and vegetables.]] The term carotene is used for several related substances having the formula C40H56.
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Hydroxyl in chemistry stands for a molecule consisting of an oxygen atom and a hydrogen atom connected by a covalent bond. The neutral form is a hydroxyl radical and the hydroxyl anion is called a hydroxide.
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Chemical polarity, also known as bond polarity or simply polarity, is a concept in chemistry which describes how equally bonding electrons are shared between atoms.
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Paper chromatography is an analytical technique for separating and identifying mixtures that are or can be colored, especially pigments. This can also be used in secondary or primary schools in ink experiments.
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Lutein (LOO-teen) (from Latin lutea meaning "yellow") is one of over 600 known naturally occurring carotenoids. Found in green leafy vegetables such as spinach and kale, lutein is employed by organisms as an antioxidant and for blue light absorption.
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Zeaxanthin is one of the two carotenoids contained within the retina of the eye.

Within the central macula, zeaxanthin is the dominant component, whereas in the peripheral retina, lutein predominates.
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Cryptoxanthin[1]

IUPAC name
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Bacillariophyceae

Orders
  • Centrales
  • Pennales
Diatoms (Greek: διά (dia) = "through" + τέμνειν
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Dinoflagellata
Bütschli 1885

Classes

Dinophyceae
Noctiluciphyceae
Syndiniophyceae

The dinoflagella are a large group of flagellate protists. Most are marine plankton, but they are common in fresh water habitats as well.
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Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. Created and updated by the United States National Library of Medicine (NLM), it is used by the MEDLINE/PubMed
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Biochemistry is the study of the chemical processes in living organisms.[1] The word "biochemistry" comes from the Greek word βιοχημεία biochēmeia, which means "the chemistry of life.
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Peptides (from the Greek πεπτίδια, "small digestibles") are short polymers formed from the linking, in a defined order, of α-amino acids.
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