Definition of vitamin a Vitamin a is the collective name for a group of fat-soluble vitamins. the most useful form of the vitamin is retinol often called vitamin a as it is the active form in the body Retinol (an alcohol) can only be found in animal sources and can be converted by the body into tinal an aldehyde and retinoic acid ( a carboxylic acid), other active forms of vitamin a
Definition of Vitamin A • Vitamin A is the collective name for a group of fat-soluble vitamins. The most useful form of the vitamin is retinol, often called vitamin A1 as it is the active form in the body. • Retinol (an alcohol) can only be found in animal sources and can be converted by the body into retinal (an aldehyde) and retinoic acid (a carboxylic acid), other active forms of vitamin A
Structure of vitamin A1 H3C CH3 CH3 CH3 CH3 Vitamin a, has four double bounds all trans)at positions 2, 4, 6, 8 on unsaturated side chain containing 9 carbon atoms There are three methyl groups at positions 2 6,6 of Cyclohexenyl ring attached to position 9 on the side chain
Structure of Vitamin A1 • Vitamin A1 has four double bounds (all trans ) at positions 2,4,6,8 on unsaturated side chain containing 9 carbon atoms. • There are three methyl groups at positions 2´ , 6´ , 6´ of Cyclohexenyl ring attached to position 9 on the side chain. H3C CH3 CH3 OH CH3 CH3
Vitamin a deficiency(VAD) Vad is the leading cause of preventable blindness in children and raises the risk of disease and death from severe infections. In pregnant women Vad may increase the risk of maternal mortality VAD is a public health problem in 118 countries especially in africa and south -east asia Vitamin a is used for treatment of vad
Vitamin A deficiency (VAD) • VAD is the leading cause of preventable blindness in children and raises the risk of disease and death from severe infections. In pregnant women VAD may increase the risk of maternal mortality. • VAD is a public health problem in 118 countries, especially in Africa and South-east Asia. • Vitamin A is used for treatment of VAD
History In 1913, vitamin a was found in fish liver oil or yolk In 1931, retinol was isolated in mammal and salt water fish which was called vitamin A1 Afterward, 3-dehydroretinol was isolated in fresh water fish, which was called vitamin A 2 H3C CH3 CH CH3 H3C CH3 CH3 Vitamin a2 Vitamin al
History • In 1913, vitamin A was found in fish liver oil or yolk. • In 1931, retinol was isolated in mammal and salt water fish, which was called vitamin A1 . • Afterward, 3-dehydroretinol was isolated in fresh water fish, which was called vitamin A2 . H3C CH3 CH3 OH CH3 CH3 Vitamin A1 H3C CH3 CH3 OH CH3 CH3 Vitamin A2
Beta carotene is called provitamin a, which can be converted to retinol by the body In the liver. one molecule of beta carotene can be cleaved by an intestinal enzyme into two molecules of retinol so beta carotene can also be good sources of retinol 6 15
• Beta carotene is called provitamin A, which can be converted to retinol by the body. • In the liver, one molecule of beta carotene can be cleaved by an intestinal enzyme into two molecules of retinol, so beta carotene can also be good sources of retinol