Vitamin A
Introduce briefly
Vitamin A includes vitamins A1 and A2. Vitamins A1 and A2 are similar in structure) Retinol can be synthesised from plant-derived beta-carotene. Under the catalysis of β-carotene-15, 15'-peroxide (bioxygenase) in the body, β-carotene can be converted into two molecules of retinaldehyde (ratinal), and retinaldehyde in reductase It is reduced to retinol under the action of. Therefore, beta-carotene is also known as vitamin A.
Chemical properties
Vitamin A is a yellow flaky crystal or crystalline powder, insoluble in water and glycerine, and soluble in most organic solvents such as alcohols, ethers, hydrocarbons and halogenated hydrocarbons. The chemical name of the body of vitamin A - retinol is all-trance 3,7-dimethyl-9-(2,6,6-trimethyl-1-cyclohexene-1)-2,4,6,8-nontetraene-1-ol, with 4 conjugated double bonds on its side chain.
Physiological functions and effects
Vitamin A is a fat-soluble vitamin, and its physiological function is mostly in the form of retinoic acid. Carotene is an important source of vitamin A. The most bioactive vitamin A in carotene is beta-carotene. The absorption rate in the human intestine is about one-sixth of that of vitamin A. Vitamin A is mainly stored in the liver Chemicalbook in the body, accounting for about 90% to 95% of the total amount, and a small amount is stored in adipose tissue. Vitamin A plays a very important role in the metabolic function of the human body.
