Vitamins importance

Thiamine. A water-soluble B vitamin important as a cofactor for enzymes involved in energy production and nucleic acid synthesis in the cell. 

Vitamin A (retinol) is a fat-soluble vitamin important for the maintenance of skin, bone, and blood vessels, as well as for the promotion of vision (Theodosiou et al. 2010). It is obtained from the diet either as all-trans-retinol, retinyl esters, or P-carotene (Blomhoff and Blomhoff 2006) and is stored in the liver (Moise et al. 2007). Vitamin A is converted to retinoic acid (RA), which is formed mainly through intracellular oxidative metabolism by retinal dehydrogenases (RALDHs) (Lampen et al. 2000). RA plays important roles in embryonic development, organogenesis, tissue homeostasis, cell proliferation, differentiation, and apoptosis (Theodosiou et al. 2010). In adult mammals, RALDH is found in intestinal epithelial cells (lECs) and gut associated-dendritic cells (DCs) from Peyer s patches and mesenteric lymph nodes (Iwata 2004, Coombes et al. 2007). Gut-associated DCs and lECs can metabolize vitamin A to RA in vitro (Lampen 2000), which indicates they may be a source of RA in gut mucosa. RA binds to two families of nuclear receptors, RA receptor (RAR) isotypes (a, p, and y) and retinoic X receptor (RXR) isotypes (a, p, and y). RAR and RXR form heterodimers and interact with retinoic acid response elements (RAREs) within the promoters of retinoic acid responsive genes (Blomhoff and Blomhoff 2006). RAR is ubiquitously expressed and up-regulated by RA. RXR also... 

Nicotinamide is a water-soluble vitamin important in metabolism. A deficiency in this vitamin results in the debilitating condition known as pellagra. Nicotinamide is 59.0% C, 5.0% H, 22.9% N, 13.1% O, by mass. Addition of 3.88 g of nicotinamide to 30.0 mL nitrobenzene, C6H5NO2 d = 1.204 g/mL), lowers the freezing point from 5.7 to -1.4 °C. What is the molecular formula of this compound ... 

It is important in the body as, except for methionine, it is the only substance known to take part in methylating reactions. Sometimes regarded as a member of the vitamin B group. 

It may be regarded as the parent of a number of important classes of compounds derived from the y-pyrone skeleton (e.g. flavone, xan-thone) and the important chroman derivatives called the tocopherols (vitamin E). 

Manganese is widely distributed throughout the animal kingdom. It is an important trace element and may be essential for utilization of vitamin Bl. 

Thiazolium salts with alkyl (103, 722), arylalkyl (116), aryl (305), or heteroaryl (96) substituents on the nitrogen have been also prepared by this procedure. As in the thiazole series, N-substituted thioamides can be formed directly in the reaction mixture from phosphorus pentasulfide and N-substituted amides (127). These methods are important in the synthesis of thiamine 102 (vitamin Bj) (Scheme 45). 

An example of a biologically important aide hyde is pyridoxal phosphate which is the active form of vitamin Bg and a coenzyme for many of the reac tions of a ammo acids In these reactions the ammo acid binds to the coenzyme by reacting with it to form an imine of the kind shown in the equation Re actions then take place at the ammo acid portion of the imine modifying the ammo acid In the last step enzyme catalyzed hydrolysis cleaves the imme to pyridoxal and the modified ammo acid... 

Another physiologically important quinone is vitamin K Here K stands for koag ulation (Danish) because this substance was first identified as essential for the normal clotting of blood... 

Deficiency Diseases. Not only did cereals make an important contribution to improving the general status of humankind, but they also were important dietary components of some groups of people who showed certain nutritional deficiencies. This observation led to the discovery of some of the vitamins. These deficiency diseases have been most prominently associated with use of rice, com, and wheat. 

Beriberi, Thiamine Deficiency. The recognition of vitamins and their importance to the health of human beings came about when Eijkman, a Dutch pathologist, was sent to Java in an attempt to cure an epidemic of beriberi that had appeared in one of the hospitals. Eijkman kept a flock of chickens on the hospital grounds to assist in discovering the disease agent he assumed was involved in the etiology of beriberi. These chickens were fed the scraps from the plates of the hospital patients—primarily poHshed rice, the common food in that part of the world (11). 

Vitamins A, D, and E are required by mminants and, therefore, their supplementation is sometimes necessary. Vitamin A [68-26-8] is important in maintaining proper vision, maintenance and growth of squamous epitheHal ceUs, and bone growth (23). Vitamin D [1406-16-2] is most important for maintaining proper calcium absorption from the small intestine. It also aids in mobilizing calcium from bones and in optimizing absorption of phosphoms from the small intestine (23). Supplementation of vitamins A and D at their minimum daily requirement is recommended because feedstuffs are highly variable in their content of these vitamins. 

Certain factors and product precursors are occasionally added to various fermentation media to iacrease product formation rates, the amount of product formed, or the type of product formed. Examples iaclude the addition of cobalt salts ia the vitamin fermentation, and phenylacetic acid and phenoxyacetic acid for the penicillin G (hen ylpenicillin) and penicillin V (phenoxymethylpenicillin) fermentations, respectively. Biotin is often added to the citric acid fermentation to enhance productivity and the addition of P-ionone vastly iacreases beta-carotene fermentation yields. Also, iaducers play an important role ia some enzyme production fermentations, and specific metaboHc inhibitors often block certain enzymatic steps that result in product accumulation. 

Fine chemical companies are generally either small and privately held or divisions of larger companies, such as Eastman Fine Chemicals (United States) and Lonza (Switzerland). Examples of large public fife science companies, which market fine chemicals as a subsidiary activity to their production for captive use, are Hoffmann-La Roche, Sandoz, and Boehringer Ingelheim, which produce and market bulk vitamins and liquid crystal intermediates, dyestuff intermediates, and bulk active ingredients, respectively. Table 3 fists some representative companies having an important fine chemical business. 

Spices and herbs can play an important indirect role in good nutrition. They are not high in nutrient values, but they help to increase the appeal and satisfaction of foods that are highly nutritious. Spices do contain fat, protein and carbohydrates, electrolytic minerals, iron and B vitamins, and others, but even the highest calorie spice, poppy seeds, contains only two to three calories per serving in normal use (12). 

Sulfur Dioxide and Sulfites. Sulfur dioxide [7446-09-5], SO2, sodium bisulfite [15181-46-1], NaHSO, and sodium metabisulfite [23134-05-6] ate effective against molds, bacteria, and certain strains of yeast. The wine industry represents the largest user of sulfites, because the compounds do not affect the yeast needed for fermentation. Other appHcations include dehydrated fmits and vegetables, fmit juices, symps and concentrates, and fresh shrimp (79). Sulfites ate destmctive to thiamin, and cannot be used in foods, such as certain baked goods, that ate important sources of this vitamin. 

X5lenol is an important starting material for insecticides, xylenol—formaldehyde resins, disinfectants, wood preservatives, and for synthesis of a-tocopherol (vitamin E) (258) and i7/-a-tocopherol acetate (USP 34-50/kg, October 1994). The Bayer insecticide Methiocarb is manufactured by reaction of 3,5-x5lenol with methylsulfenyl chloride to yield 4-methylmercapto-3,5-xylenol, followed by reaction with methyl isocyanate (257). Disinfectants and preservatives are produced by chlorination to 4-chloro- and 2,4-dich1oro-3,5-dimethylpheno1 (251). 

Oxa2oles react with dienophiles to give pyridines after dehydration or other aromatization reactions (69,70). A commercially important example is the reaction of a 5-aLkoxy-4-methyloxa2ole with 1,4-butenediol to yield pyridoxine (55), which is vitamin... 

Biochemical Reactions. The quinones in biological systems play varied and important roles (21,22). In insects they are used for defense purposes, and the vitamin K family members, eg, vitamin [11104-38-4] (32) and vitamin [11032-49-8] (33), which are based on 2-meth5l-l,4-naphthoquiaone, are blood-clotting agents (see Vitamins, vitamin k). 

The quaHty, ie, level of impurities, of the fats and oils used in the manufacture of soap is important in the production of commercial products. Fats and oils are isolated from various animal and vegetable sources and contain different intrinsic impurities. These impurities may include hydrolysis products of the triglyceride, eg, fatty acid and mono/diglycerides proteinaceous materials and particulate dirt, eg, bone meal and various vitamins, pigments, phosphatides, and sterols, ie, cholesterol and tocopherol as weU as less descript odor and color bodies. These impurities affect the physical properties such as odor and color of the fats and oils and can cause additional degradation of the fats and oils upon storage. For commercial soaps, it is desirable to keep these impurities at the absolute minimum for both storage stabiHty and finished product quaHty considerations. 

Rearrangement of dehydrolinalool (4) using vanadate catalysts produces citral (5), an intermediate for Vitamin A synthesis as well as an important flavor and fragrance material (37). Isomerization of the dehydrolinalyl acetate (6) in the presence of copper salts in acetic acid followed by saponification of the acetate also gives citral (38,39). Further improvement in the catalyst system has greatly improved the yield to 85—90% (40,41). 

Geranyl acetone is an important intermediate in the synthesis of isophytol [505-32-8], famesol [106-28-5], and neroHdol [40716-66-3]. Isophytol is used in the manufacture of Vitamin E. 

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. 

Dlterpenes. Diterpenes contain 20 carbon atoms. The resin acids and Vitamin A are the most commercially important group of diterpenes. GibbereUic acid [77-06-5] (110), produced commercially by fermentation processes, is used as a growth promoter for plants, especially seedlings. 

Phytol [505-06-5] (111) and isophytol [150-86-7] (112) are important intermediates used in commercial synthesis of Vitamins E and K. There is a variety of synthetic methods for their manufacture. Chlorophyll [479-61-8] is a phytyl ester. 

An important function of certain carotenoids is their provitamin A activity. Vitamin A may be considered as having the stmcture of half of the P-carotene molecule with a molecule of water added at the end position. In general, all carotenoids containing a single unsubstituted P carotene half have provitamin A activity, but only about half the activity of P carotene. Provitamin A compounds are converted to Vitamin A by an oxidative enzyme system present in the intestinal mucosa of animals and humans. This conversion apparendy does not occur in plants (see Vitamins, VITAMIN a). 

The reversible oxidation of L-ascorbic acid to dehydro-L-ascorbic acid is the basis for its known physiological activities, stabiUties, and technical apphcations (2). The importance of vitamin C in nutrition and the maintenance of good health is well documented. Over 22,000 references relating only to L-ascorbic acid have appeared since 1966. 

Fermentation. Much time and effort has been spent in undertaking to find fermentation processes for vitamin C (47). One such approach is now practiced on an industrial scale, primarily in China. It is not certain, however, whether these processes will ultimately supplant the optimized Reichstein synthesis. One important problem is the instabiUty of ascorbic acid in water in the presence of oxygen it is thus highly unlikely that direct fermentation to ascorbic acid will be economically viable. The successful approaches to date involve fermentative preparation of an intermediate, which is then converted chemically to ascorbic acid. 

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