Vitamins from

Approximately 0.05 to 0.2% of vitamin > 2 stores are turned over daily, amounting to 0.5—8.0 )J.g, depending on the body pool size. The half-life of the body pool is estimated to be between 480 and 1360 days with a daily loss of vitamin > 2 of about 1 )J.g. Consequentiy, the daily minimum requirement for vitamin B22 is 1 fig. Three micrograms (3.0 J.g) vitamin B22 are excreted in the bile each day, but an efficient enterohepatic circulation salvages the vitamin from the bile and other intestinal secretions. This effective recycling of the vitamin contributes to the long half-life. Absence of the intrinsic factor intermpts the enterohepatic circulation. Vitamin > 2 is not catabolized by the body and is, therefore, excreted unchanged. About one-half of the vitamin is excreted in the urine and the other half in the bile. 

Total Synthesis. Poor yields encountered duriag the manufacture of vitamin D stimulated early attempts to synthesize vitamin D. In 1959 Inhoffen synthesized vitamin from 3-methyl-2-(2-carboxyethyl)-2-cyclohexenone (40), uskig the Wittig reaction extensively (103). 

Aside from chemical methods, several patents have appeared on the biochemical production of natural vitamin from callus tissue cultures (41). 

In addition, a patent has appeared which describes the concentration and purification of natural vitamin from deodorizer distillates (42). The... 

Dam, along with Karrar of Zurich, isolated the pure vitamin from alfalfa as a yellow oil. Another form, which was crystalline at room temperature, was soon isolated from fish meal. These two compounds were named vitamins Kj and K2. Vitamin K9 can actually occur as a family of structures with different chain lengths at the C-3 position. 

Gel permeation ehromatography (GPC)/normal-phase HPLC was used by Brown-Thomas et al. (35) to determine fat-soluble vitamins in standard referenee material (SRM) samples of a fortified eoeonut oil (SRM 1563) and a eod liver oil (SRM 1588). The on-line GPC/normal-phase proeedure eliminated the long and laborious extraetion proeedure of isolating vitamins from the oil matrix. In faet, the GPC step permits the elimination of the lipid materials prior to the HPLC analysis. The HPLC eolumns used for the vitamin determinations were a 10 p.m polystyrene/divinylbenzene gel eolumn and a semipreparative aminoeyano eolumn, with hexane, methylene ehloride and methyl tert-butyl ether being employed as solvent. 

The SP procedure of water-soluble vitamins from multivitamin tablets is particularly challenging due to the diverse analytes of varied hydrophobicities and pfC. Water-soluble vitamins (WSVs) include ascorbic acid (vitamin C), niacin, niacinamide, pyridoxine (vitamin B ), thiamine (vitamin Bj), folic acid, riboflavin (vitamin B2) and others. While most WSVs are highly water soluble, riboflavin is quite hydrophobic and insoluble in water. Folic acid is acidic while pyridoxine and thiamine are basic. In addition, ascorbic acid is light sensitive and easily oxidized. The extraction strategy employed was a two-step approach using mixed solvents of different polarity and acidity as follows ... 

There are several steps in the absorption of vitamin B. In the stomach and lumen of the small intestine it is hydrolysed from its (peptide) links with the proteins of which it is a component. It then attaches to gastric intrinsic factor, which is a glycoprotein of molecular mass about 50 000 kDa, to form a complex. This protects the vitamin from being damaged by acid in the stomach. The complex is carried into the ileum, where it binds to a receptor on the surface of the absorptive cells and is released from the intrinsic factor within the absorptive cell, hi the portal venous blood, it is transported to the liver bound to the vitamin B 12-binding protein, which also protects the vitamin. 

A healthy diet usually covers average daily vitamin requirements. By contrast, malnutrition, malnourishment (e.g., an unbalanced diet in older people, malnourishment in alcoholics, ready meals), or resorption disturbances lead to an inadequate supply of vitamins from which hypovitaminosis, or in extreme cases avitaminosis, can result. Medical treatments that kill the intestinal flora—e. g., antibiotics—can also lead to vitamin deficiencies (K, Bi2, H) due to the absence of bacterial vitamin synthesis. 

Reversed micelles can be used to concentrate water-soluble materials in the water pool of SCCO2. The extraction of water-soluble vitamins into reversed micelles has been examined. The efficiency of extraction was strongly affected by the extraction temperature and the concentration of reversed micelles, and the selectivity depended on the size of micelles. Water-soluble vitamins could be efficiently and rapidly extracted. The selective extraction of a model mixture of vitamins from pharmaceutical preparations was also demonstrated. Moreover, the usefulness of the proposed method for the determination of vitamins in various commercial tablets was also demonstrated. Using this method, the surfactant remains mixed with the extracted com-... 

Vitamin C Is the Synthetic Vitamin as Good as the Natural One A claim put forth by some purveyors of health foods is that vitamins obtained from natural sources are more healthful than those obtained by chemical synthesis. For example, pure L-ascorbic acid (vitamin C) extracted from rose hips is better than pure L-ascorbic acid manufactured in a chemical plant. Are the vitamins from the two sources different Can the body distinguish a vitamin s source ... 

The bright orange-yellow color and brilliant greenish fluorescence of riboflavin first attracted the attention of chemists. Blyth isolated the vitamin from whey in 1879 and others later obtained the same fluorescent, yellow compound from eggs, muscle, and urine. All of these substances, referred to as flavins because of their yellow color, were eventually recognized as identical. The structure of riboflavin was established in 1933 by R. Kuhn and associates, who had isolated 30 mg of the pure material from 30 kg of dried albumin from 10,000 eggs. The intense fluorescence assisted in the final stages of purification. The vitamin was synthesized in 1935 by R Karrer.3... 

Apparendy all forms of life, both plant and animal, with the possible exception of simple forms, such as bacteria that have not been studied dioroughly. either synthesize the vitamin from other nutrients or require it as a nutrient Dormant seeds contain no measurable quantity of the vitamin, but after a few hours of soaking in water, die vitamin is formed. 

Nearly all vitamins are associated in some way with the normal growth function as well as with the maintenance and efficiency of living things. Various species are capable of synthesizing some of the vitamins from precursors llial are present in tlie body. Synthesis is frequently by way of intestinal bacteria. In the case of vitamin D, substances in the skin combine with ultraviolet radiation from sunlight to yield the essential substance. Some vitamins, such as vitamin C. are specific, singular substances—in this case ascorbic acid. With other vitamins, there is a range of related compounds, as exemplified by the D, F., and K vitamins. 

TABLE 1. COMPARATIVE LOSSES OF VITAMINS FROM VEGETABLES (CANNING AND FREEZE PROCESSING)... 

Methods of extracting the fat-soluble vitamin from food matrices include alkaline hydrolysis, enzymatic hydrolysis, alcoholysis, direct solvent extraction, and supercritical fluid extraction of the total lipid component. 

In general, it is very difficult reliably to extract and quantitate multiple vitamins from complex food systems, due to their diverse physical and chemical properties. Consequently, the extraction of the vitamins from the food matrix is usually the greatest challenge of vitamin analysis. This is especially true for the naturally occurring vitamins, which are often bound to other food constituents, such as carbohydrates or proteins. To prevent vitamin degradation or loss, the extraction conditions should complement the labile nature of the vitamins. Indiscriminate mixing and matching of extraction and quantitation methods is not recommended, since the extraction conditions can affect subsequent separation and quantitation steps. 

Ihara, T., N. Suzuki, T. Maeda, K. Sagara, and T. Hobo. 1995. Extraction of water-soluble vitamins from pharmaceutical preparations using AOT (sodium di-2-ethylhexylsulfosuccinate)/pentane reversed micelles. Chem. Pharm. Bull. 43 626-630. 

A better method is to first add an equal volume of dimethylsulfoxide (DMSO) or dimethylformamide (DMF) to the aqueous sample. This breaks both biological and encapsulation membranes and pulls polar and nonpolar material into solution. The second step is to dilute the sample with 10 volumes of water. At this point, nonpolars can be removed by solvent extraction or with a Cig SFE. Charged molecules can be recovered with pH-controlled extraction or with ion pairing reagents. The DMSO or DMF stays with the water layer. Customers have told me they can achieve almost complete recovery of both fat-soluble and water-soluble vitamins from polymer-encapsulated mixtures. Vitamins are encapsulated to protect potency from air-oxidation. Water-soluble vitamins have nonpolar encapsulation fat-soluble vitamins have polar encapsulation. Either vitamin can be extracted by themselves, but they are difficult to extract under the same condition unless DMSO or DMF are used to break both capsules. 

Vitamins are organic (carbon-containing) compounds required for normal growth and the maintenance of animal life. The absence of a given vitamin from the diet, or its impaired absorption or utilization, results in a specific deficiency disease or syndrome. 

Scheme III Mass spectral fragmentation pattern of vitamin (from reference 22. Copyright 1972. Reprinted by permission of John Wiley Sons, Inc.)...

Despite increasing acceptance by scientists, some people viewed the synthesis of natural compounds as unnatural. Indeed proponents of the vital force theory can still be found on a quick scan of the Internet more than 100 years after it was discredited as a scientific theory. For example, vestiges of the vital force theory linger in the belief that vitamins from natural sources are somehow healthier than vitamins that are synthesized. 

The biomedical information for vitamins and hormones can be obtained from the Merck manual online at http //www.merck.com/pubs/mmanual/. For example, entering vitamin returns a list of vitamins from which an entry describing deficiency, dependence, and/or toxicity of the vitamin can be selected, viewed, and saved. 

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