Vitamin A and Carotenoids

Vitamin A 1909/1931 Fish liver oil 11 -(Z)-Retinal Visual process 

Vitamin B, 1897/1911 Rice Thiamine diphosphate Thiamine triphosphate Decarboxylation of a-oxo-acids, aldehyde group transfer, PO -donor 

Vitamin B2 1920/1933 Eggs Flavin mononucleotide Flavin adenine dinucleotide Hydride/electron transfer 

Vitamin Bg 1934/1938 Rice Pyridoxal-5-phosphate Amino-group transfer 

Vitamin C 1912/1928 Citrus fruits Hydroxy lation, subcellular antioxidant 

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Petrochemical-based methods of citral manufacture are very important for the large-scale manufacture of Vitamin A and carotenoids. Dehydrolinalool and its acetate are both made from the important intermediate, P-methyUieptenone. 

Lindqvist, A. and Andersson, S., Biochemical properties of purified recombinant human beta-carotene 15,15-monooxygenase, J. Biol. Chem., 277, 23942, 2002. Krinsky, N.I., Cornwell, D.G., and Oncley, J.I., The transport of vitamin A and carotenoids in human plasma. Arch. Biochem. Biophys., 73, 233, 1958. 

Palace VP, Khaper N, Qin Q and Singal PK. 1999. Antioxidant potentials of vitamin A and carotenoids and their relevance to heart disease. Free Rad Biol Med 26 746—761. 

The transformations of compounds which are precursors for vitamin A and carotenoids have a special position among the rearrangements of the conjugated polyenes. Numerous isomerizations such as cw-fraws-isomerization, the dehydration of polyunsaturated acetylenic carbinols etc. were utilized to prepare the various carotenoides (e.g. /1-carotene, lycopene, cryptoxanthin, zeaxanthin) (for reviews, see References 146 and 147). However, one of these rearrangements turned out to be a considerable hindrance for the synthesis of target products. 

The concentration of vitamin A and carotenoids in milk is strongly influenced by the carotenoid content of the feed. Milk from animals fed on pasture contains higher levels of carotenes than that from animals fed on concentrate feeds. There is also a large seasonal variation in vitamin A concentration summer milk contains an average of 62 fig retinol and 31 fig carotene per 100 g while the values for winter milk are 41 and 11 fig per... 

Facts About Vitamin A and Carotenoids hitp //www.cc.nih.gov/ccc/supplenients/viia.htnil... 

Park, C.K., Ishimi, Y., Ohmura, M., Yamaguchi, M., andlkegami, S. 1997. Vitamin A and carotenoids stimulate differentiation of mouse osteoblastic cells. J. Nutr. Sci. Vitaminol. 43, 281-296. 

Yamamura, Y. and Muto, S. (1961). Change of vitamin A and carotenoids during the development of salmon eggs. Bulletin of the Tokai Regional Fisheries Research Laboratory 19,171-179. 

Carotenoids are used to an increasing extent for the coloration of foodstuffs and animal feedstuffs, since, as natural constituents of many foodstuffs, they have been part of the human diet for thousands of years and are thus toxicologically acceptable8. The precursors from the vitamin A and carotenoid syntheses also include some of the important fragrances which are used in the perfume industry. In addition, this chemistry led to the synthesis of a number of other interesting flavors and fragrances. 

The vitamin A content of foods is often given in terms of the international unit (IU). One IU of vitamin A is defined as 0.3 tg of all-trans-retinol. The term retinol equivalent (RE) is used to convert all sources of vitamin A and carotenoids in the diet to a single unit. One RE is by definition 1 pg of all-trans retinol, 12 pg of P-carotene, or 24 pg of other (mixed) provitamin A carotenoids. The recommended dietary allowance for vitamin A ranges from 375 pg RE/day for infants to 1,000 RE/day for adults. 

Vitamin A and Carotenoids, in Blood and tissue. Microdetermination of (McLaren,... 

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