ビタミンA 化学特性,用途語,生産方法
定義
本品は、共役不飽和脂環式アルコールである。
解説
ビタミンA,ビタミンエー,アクセロフトール(axerophthol)，ビタミン A1，レチノール，A1 アルコールともいう．ビタミンAはretinolを意味し，ビタミン A2 発見以来，区別するためビタミン A1 とよぶ．淡黄色の柱状結晶．融点62～64 ℃．λmax 325 nm(2-プロパノール)で吸光係数E1cm1％1830．多くの有機溶媒，油脂に可溶，水に不溶．ビタミンAのクロロホルム溶液はSbCl3によって深青色を呈し，その吸収極大は620 nm にあり，E1cm1％5070である．そのほかの呈色試薬としては2,3-ジクロロ-1-プロパノール(GDH)がある．空気酸化を受けやすく，熱や紫外線に対しても不安定である．
化粧品の成分用途
皮膚コンディショニング剤
効能
ビタミンA補充薬, レチノイン酸受容体(RAR)作動薬
商品名
チョコラ (サンノーバ)
存在
魚肝油，ミルク，バター，卵黄，胚芽に存在し，肝油類の不けん化部分から得るか，または合成する．生体内では遊離アルコール型のほか，パルミチン酸，ステアリン酸，オレイン酸などのエステルとして存在することが認められている．ビタミンAの欠乏は夜盲症，皮膚の異常乾燥症，および角化亢進，骨変化，神経変性および成長発育の停止の病因となる．
説明
Human vitamin A is derived from the natural food. Natural vitamin A exists in dif ferent forms. In animal tissues, vitamin A is present in the form of retinoids.
However, in plants, the form of vitamin A called carotenoids is contained in the
green, orange, and yellow plant tissue. Vitamin A compounds such as retinol, reti nal, carotene, and so on from these foods can be converted to vitamin A in the
human body. Therefore, food is the main source of vitamin A.
As early as 1000 years ago, the Qian Jin Yao Fang written by Sun Simiao in Tang
Dynasty recorded that animal liver can cure night blindness. This is the early
recognition in vitamin A supplementation. The traditional Chinese medicine books
also recorded that nourishing the liver can improve eyesight. Researches on the
therapy of vitamin A deficient-diseases are mainly related to nourishing the liver
and kidney, supplementing essence and blood, and activating qi
化学的特性
Yellow-Orange Powder
物理的性質
Vitamin A1 (VA1), Molecular formula, C20H30O; MW, 286.45; CAS, 68-26-8.
Melting point: 62–64 °C. Boiling point: 137–138 °C
VA2, Molecular formula, C20H28O; MW, 284.44; Melting point: 17–19 °C.
来歴
The vitamin research is the great achievement in the development of life sciences,
while human beings only took half a century to discover and understand vitamins.
However, everything is still very difficult for scientists in the early stage of vitamin
discovery. From 1913 to 1915, Elmer McCollum and Marguerite Davis indicated
that the growth rate was maintained by at least two different kinds of growth factors:
one can be separated from eggs or butter, and the other one which multiple neuritis of chicks and pigeons can be extracted by water; thus they were
named fat-soluble vitamin A and water-soluble vitamin B.prevented
In 1919, the researchers demonstrated that fat-soluble vitamin A not only sup ported the rate of growth but also prevented eye dryness and night blindness in the
process of property study. In 1920, Dr. J.C. Drummond named this active lipid as
vitamin A. It exists in cod liver oil and prevents the occurrence of eye dryness and
night blindness.
使用
Occurs preformed only in animals; metabolized from carotenoids, such β-carotene, in the intestinal mucosa. Dietary sources include liver, milk, butter, cheese, eggs and fish liver oils or as carotenoi
s from fruits and vegetables. Stored primarily in the liver in esterified form; transported in the blood by retinol binding protein (RBP). Nutritional factor.
定義
ChEBI: A retinol in which all four exocyclic double bonds have E- (trans-) geometry.
適応症
Vitamin A, or retinol, is essential for the proper maintenance
of the functional and structural integrity of epithelial
cells, and it plays a major role in epithelial differentiation.
Bone development and growth in children
have also been linked to adequate vitamin A intake.
Vitamin A, when reduced to the aldehyde 11-cis-retinal,
combines with opsin to produce the visual pigment
rhodopsin. This pigment is present in the rods of the
retina and is partly responsible for the process of dark
adaptation.
世界保健機関（WHO）
Vitamin A, a fat-soluble vitamin, is used in the treatment and
prevention of vitamin A deficiency resulting from inadequate dietary intake. It has
been demonstrated to be teratogenic at high doses (more than 25,000 IU per day).
Daily dosages of less than 10000 IU seem to be free of this risk. Retinol (vitamin A)
is listed in the WHO Model List of Essential Drugs.
一般的な説明
Retinal, retinol and retinoic acid are the aldehyde, alcohol and acid forms of vitamin A. The retinoids exist as many geometric isomers due to the unsaturated bonds in the aliphatic chain. Retinol is biologically active in a wide range of processes.
臨床応用
Principal dietary sources of vitamin A are milk fat
(cheese and butter) and eggs. Since it is stored in the
liver, inclusion of liver in the diet also provides vitamin
A. A plant pigment, carotene, is a precursor for vitamin
A and is present in highly pigmented vegetables, such as
carrots, rutabaga, and red cabbage.
An early sign of hypovitaminosis A is night blindness.
This condition is related to the role of vitamin A as
the prosthetic group of the visual pigment rhodopsin.
The night blindness may progress to xerophthalmia
(dryness and ulceration of the cornea) and blindness.
Other symptoms of vitamin A deficiency include cessation
of growth and skin changes due to hyperkeratosis.
Since vitamin A is a fat-soluble vitamin, any disease
that results in fat malabsorption and impaired liver storage
brings with it the risk of vitamin A deficiency; these
conditions include biliary tract disease, pancreatic disease,
sprue, and hepatic cirrhosis. One group at great
risk are children from low-income families, who are
likely to lack fresh vegetables (carotene) and dairy
products (vitamin A) in the diet.
副作用
Acute hypervitaminosis A results in drowsiness,
headache, vomiting, papilledema, and a bulging fontanel
in infants. The symptoms of chronic toxicity include
scaly skin, hair loss, brittle nails, and hepatosplenomegaly.
Anorexia, irritability, and swelling of
the bones have been seen in children. Retardation of
growth also may occur. Liver toxicity has been associated
with excessive vitamin A intake. Vitamin A is teratogenic
in large amounts, and supplements should not
be given during a normal pregnancy. The IOM has reported
the UL of vitamin A to be 3,000 μg/day.
安全性プロファイル
Moderately toxic by
ingestion. Human teratogenic effects by
ingestion: developmental abnormalities of
the craniofacial area and urogenital system.
An experimental teratogen. Experimental
reproductive effects. Human mutation data
reported. When heated to decomposition it
emits acrid smoke and irritating fumes.
純化方法
Purify retinol by chromatography on columns of water-deactivated alumina and elute with 3-5% acetone in hexane. Separate the isomers by TLC plates on silica gel G, developed with pet ether (low boiling)/methyl heptanone (11:2). Store it in the dark, under N2, at 0o, or in Et2O, Me2CO or EtOAc. [See Gunghaly et al. Arch Biochem Biophys 38 75 1952, Beilstein 6 IV 4133.]
ビタミンA 上流と下流の製品情報
原材料
準備製品