Vitamin isolation

Garrod. Inborn Errors of Metabolism. Concept of pH introduced by Sorensen. Tsvett used chromatography to separate chlorophylls. Vitamins isolated. B vitamins shown to be parts of co-... 

The symptoms of pantothenic acid deficiency have not been clinically described. Since pantothenic acid is a ubiquitous vitamin, isolated deficiency is unlikely. However, marginal deficiency may exist in persons with general malnutrition. 

Although the early studies established the relationships and properties of the classic families of aldoses and ketoses, and their simple derivatives, some unusual monosaccharide structures were later encountered that were of importance in the biomedical area. The antiscorbutic vitamin isolated from paprika in 1928 by Szent-Gyorgi (40) and initially termed hexuronic acid was subsequently shown to be a six-carbon furanose lactone containing an enediol structure (Scheme 10)... 

In the meantime Kogl and co-workers continued the study of biotin isolated from egg yolk and came to the conclusion that it was not identical with the vitamin isolated from liver concentrates but was an isomer of the structure (2), (ref. 14). 

Vitamin B,2 is produced by the growth of certain micro-organisms, and occurs also in liver, being the extrinsic anti-pernicious anaemia factor the isolation of which was sought for many years. 

Several substances having vitamin K. activity have been isolated from natural sources. Vitamin Ki from alfalfa oil, is 2-methyl-3-phytyl-1,4-naphthoquinone. 

The term vitamin K2 was applied to 2-methyl-3-difarnesyl-l,4-naphthoquinone, m.p. 54 C, isolated from putrefied fish meal. It now includes a group of related natural compounds ( menaquinones ), differing in the number of isoprene units in the side chain and in their degree of unsaturation. These quinones also appear to be involved in the electron transport chain and oxidative phosphorylation. 

The use of an indicator or marking substance, which is adsorbed on the column in a position in known relation to that of the colourless substance (e.g., Sudan III for isolation of Vitamin D upon alumina). 

As noted by Robinson and Strachan (1), after considerable activity in the period 1885 to 1895 thiazolecarboxylic acids received little attention until 1935. Isolation of 4-methyl-5-thiazolecarboxylic acid after degradation of vitamin Bj gave new interest to the chemistry of these compounds. 

The vitamin B12 content of a multivitamin tablet is determined by dissolving ten tablets in water. The dissolved tablets are transferred to a 100-mL volumetric flask and diluted to volume. A 50.00-mL portion is removed and treated with 0.500 mg of radioactive vitamin B12 having an activity of 572 cpm. After homogenization, the vitamin B12 in the sample is isolated and purified, producing 18.6 mg with an activity of 361 cpm. Calculate the average concentration of vitamin B12 in the tablet (in milligrams per tablet). 

The isoprene unit exists extensively in nature. It is found in terpenes, camphors, diterpenes (eg, abietic acid), vitamins A and K, chlorophyll, and other compounds isolated from animal and plant materials. The correct stmctural formula for isoprene was first proposed in 1884 (7). 

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. 

During this 70 year period, all 13 of the substances now recognized as vitamins were discovered and isolated ia pure form. Stmcture elucidation for each vitamin was completed, as was its total synthesis (Table 1). 

Vitamin Discovery Isolation Chemical stmcture Synthesis... 

Preparation of the vitamins in commercial quantities can involve isolation, chemical synthesis, fermentation, and mixed processes, including chemical and fermentation steps. The choice of process is economic, dictated by the need to obtain materials meeting specifications at the lowest cost. Current process technologies (ca 1997) employed for each vitamin are indicated in Table 9. 

Most current industrial vitamin C production is based on the efficient second synthesis developed by Reichstein and Grbssner in 1934 (15). Various attempts to develop a superior, more economical L-ascorbic acid process have been reported since 1934. These approaches, which have met with htde success, ate summarized in Crawford s comprehensive review (46). Currently, all chemical syntheses of vitamin C involve modifications of the Reichstein and Grbssner approach (Fig. 5). In the first step, D-glucose (4) is catalytically (Ni-catalyst) hydrogenated to D-sorbitol (20). Oxidation to L-sotbose (21) occurs microhiologicaRy with The isolated L-sotbose is reacted with acetone and sulfuric acid to yield 2,3 4,6 diacetone-L-sorbose,... 

Pyridine carboxamide [98-92-0] (nicotinamide) (1) and 3-pyridine carboxylic acid [59-67-6] (nicotinic acid) (2) have a rich history and their early significance stems not from their importance as a vitamin but rather as products derived from the oxidation of nicotine. In 1867, Huber prepared nicotinic acid from the potassium dichromate oxidation of nicotine. Many years later, Engler prepared nicotinamide. Workers at the turn of the twentieth century isolated nicotinic acid from several natural sources. In 1894, Su2uki isolated nicotinic acid from rice bran, and in 1912 Funk isolated the same substance from yeast (1). 

As vitamin Bg is mainly located in the germ and aleurone layer in cereal grains polishing for the production of flour removes a substantial portion. White bread is therefore a poor source unless fortified. Some nonedible yeasts contain up to 38 mg/100 g dry weight vitamin B, the highest level of the natural sources (4,27). As a rule, these amounts are too low for cost-effective isolation. 

In 1933, R. Kuhn and his co-workers first isolated riboflavin from eggs in a pure, crystalline state (1), named it ovoflavin, and deterrnined its function as a vitamin (2). At the same time, impure crystalline preparations of riboflavin were isolated from whey and named lyochrome and, later, lactoflavin. Soon thereafter, P. Karrer and his co-workers isolated riboflavin from a wide variety of animal organs and vegetable sources and named it hepatoflavin (3). Ovoflavin from egg, lactoflavin from milk, and hepatoflavin from Hver were aU. subsequently identified as riboflavin. The discovery of the yeUow en2yme by Warburg and Christian in 1932 and their description of lumiflavin (4), a photochemical degradation product of riboflavin, were of great use for the elucidation of the chemical stmcture of riboflavin by Kuhn and his co-workers (5). The stmcture was confirmed in 1935 by the synthesis by Karrer and his co-workers (6), and Kuhn and his co-workers (7). 

The stmcture of vitamin A [11103-57-4] and some of the important derivatives are shown in Figure 1. The parent stmcture is aH-Zra/ j -retinol [68-26-8] and its lUPAC name is (all-E)-3,7-dimethyl-9-(2,6,6-trimethyl-l-cyclohexen-l-yl)-2,4,6,8-nonatetraen-l-ol (1). The numbering system for vitamin A derivatives parallels the system used for the carotenoids. In older Hterature, vitamin A compounds are named as derivatives of trimethyl cyclohexene and the side chain is named as a substituent. For retinoic acid derivatives, the carboxyl group is denoted as C-1 and the trimethyl cyclohexane ring as a substituent on C-9. The stmctures of vitamin A and -carotene were elucidated by Karrer in 1930 and several derivatives of the vitamin were prepared by this group (5,6). In 1935, Wald isolated a substance found in the visual pigments of the eye and was able to show that this material was identical with Karrer s retinaldehyde [116-31-4] (5) (7). 

Parallel to the activities in the treatment of pernicious anemia were observations in the 1930s that most farm animals had a requirement for an unknown factor beyond the vitamins then known. The lack of this factor became apparent, eg, when chicks or pigs fed a diet with only vegetable protein evidenced slow growth rate and high mortahty. It became apparent that the requited factor, termed animal protein factor, was present in animal sources such as meat and tissue extracts, milk whey, and cow manure. Subsequent to its isolation, it was rapidly shown that vitamin B 2 is the same as animal protein factor. 

After its separation from Hver extracts, vitamin B 2 was also isolated from cultures of Streptomjces aureofaciens (12). AH vitamin sold commercially is produced by microbial fermentation. 

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