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Vitamin A
- Mar 23, 2018 -

Unsaturated one-yuan alcohol, a fat-soluble vitamin. Because the human body or mammals lack of vitamin A is prone to dry eye disease, it is also known as anti-dry eye alcohol. Known as vitamin A has A1 and A2 two species, A1 in the liver, blood and eye of the retina, also known as retinol, natural vitamin A mainly in this form. A2 mainly exists in the liver of freshwater fishes. Vitamin A1 is a kind of fat-soluble yellowish flake crystal, melting point 64 ℃, vitamin A2 melting point 17~19℃, usually gold-like oil. Vitamin A is a polyol containing a beta-angelica ring. The difference between the chemical structure of vitamin A2 and A1 is only a double bond on the 3.4-digit beta-ketone ring. Vitamin A molecule has unsaturated key, the chemical nature is lively, in the air is easy to be oxidized, or is exposed to the ultraviolet light to destroy, loses the physiology function, therefore the vitamin A preparation should install in the brown bottle to avoid the light to save. Both A1 and A2 can be used with antimony trichloride to present a dark blue color, which can be a basis for quantitative determination of vitamin A. Many plants such as carrots, tomatoes, green leafy vegetables, corn containing carotenoids, such as α, beta, γ-carotene, occult yellow, lutein and so on. Some carotenoids have the same ring structure as vitamin A1, can be converted into vitamin A in vivo, so called Vitamin A, beta-carotene contains two vitamin A1 ring structure, the highest conversion rate.