Cryptoxanthin
Encyclopedia
Cryptoxanthin is a natural carotenoid
Carotenoid
Carotenoids are tetraterpenoid organic pigments that are naturally occurring in the chloroplasts and chromoplasts of plants and some other photosynthetic organisms like algae, some bacteria, and some types of fungus. Carotenoids can be synthesized fats and other basic organic metabolic building...

 pigment. It has been isolated from a variety of sources including the petals and flowers of plants in the genus Physalis
Physalis
Physalis is a genus of plants in the nightshade family , native to warm temperate and subtropical regions throughout the world. The genus is characterised by the small orange fruit similar in size, shape and structure to a small tomato, but partly or fully enclosed in a large papery husk derived...

, orange rind, papaya, egg yolk, butter, apples, and bovine blood serum.

Chemistry

In terms of structure, cryptoxanthin is closely related to β-carotene
Beta-carotene
β-Carotene is a strongly-coloured red-orange pigment abundant in plants and fruits. It is an organic compound and chemically is classified as a hydrocarbon and specifically as a terpenoid , reflecting its derivation from isoprene units...

, with only the addition of a hydroxyl
Hydroxyl
A hydroxyl is a chemical group containing an oxygen atom covalently bonded with a hydrogen atom. In inorganic chemistry, the hydroxyl group is known as the hydroxide ion, and scientists and reference works generally use these different terms though they refer to the same chemical structure in...

 group. It is a member of the class of carotenoids known as xanthophyll
Xanthophyll
Xanthophylls are yellow pigments that form one of two major divisions of the carotenoid group. The name is from Greek xanthos + phyllon , due to their formation of the yellow band seen in early chromatography of leaf pigments...

s.

In a pure form, cryptoxanthin is a red crystalline solid with a metallic luster. It is freely soluble in chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...

, benzene
Benzene
Benzene is an organic chemical compound. It is composed of 6 carbon atoms in a ring, with 1 hydrogen atom attached to each carbon atom, with the molecular formula C6H6....

, pyridine
Pyridine
Pyridine is a basic heterocyclic organic compound with the chemical formula C5H5N. It is structurally related to benzene, with one C-H group replaced by a nitrogen atom...

, and carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...

.

Biology and medicine

In the human body, cryptoxanthin is converted to vitamin A
Vitamin A
Vitamin A is a vitamin that is needed by the retina of the eye in the form of a specific metabolite, the light-absorbing molecule retinal, that is necessary for both low-light and color vision...

 (retinol
Retinol
Retinol is one of the animal forms of vitamin A. It is a diterpenoid and an alcohol. It is convertible to other forms of vitamin A, and the retinyl ester derivative of the alcohol serves as the storage form of the vitamin in animals....

) and is, therefore, considered a provitamin A
Provitamin
A provitamin is a substance that may be converted within the body to a vitamin.The term "previtamin" is a synonym.For example, Provitamin B5 is a name for Panthenol, which may be converted in the body to Pantothenic Acid ....

. As with other carotenoids, cryptoxanthin is an antioxidant and may help prevent free radical damage to cells and DNA, as well as stimulate the repair of oxidative damage to DNA.

Recent findings of an inverse association between β-cryptoxanthin and lung cancer risk in several observational epidemiological studies suggest that β-cryptoxanthin could potentially act as a chemopreventive agent against lung cancer. On the other hand, in the Grade IV histology group of adult patients diagnosed with malignant glioma, moderate to high intake of cryptoxanthin (for second tertile and for highest tertile compared to lowest tertile, in all cases)) was associated with poorer survival.

Other uses

Cryptoxanthin is also used as a substance to colour food products (INS number 161c); it is not approved for use in the EU or USA however it is approved for use in Australia and New Zealand.
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