Vitamin high functionality

The typical U.S. daily diet contains 1.1—3.6 mg of vitamin B, most coming from meats and vegetables. Poor diets may provide less than half of these amounts and less than the RDA. Some populations require higher amounts persons with high protein intakes, pregnant and lactating women, users of oral contraceptives, alcohoHcs, users of dmgs which interfere with vitamin B function, and those afflicted with some diseases. Several reviews have examined the relationship of vitamin B and specific diseases in more detail (4,23). 

Niacin (nicotinic acid, nicotinamide) has the active forms NAD and NADPH. It functions in electron transfer. A deficiency of niacin causes pellagra, which is characterized by der matitis, diarrhea, and dementia. There is no known toxicity for this vitamin. High doses of niacin are used to treat hyperlipidemia. 

The Takai-Utimoto reaction of alkyl halides 360 with aldehydes 361 is a convenient method for the synthesis of branched alcohols 363 with high functional group tolerance [455]. Vitamin B12 362 or cobalt phthalocyanine served as the catalyst and CrCl2 as the stoichiometric reducing agent (Fig. 99). The reactions proceeded well with aromatic and aliphatic aldehydes. 

The correct answer is B (excretion depends on the kidney). Most of the p-lactam antibiotics depend on the kidney for excretion. Ceftazidime is predominantly eliminated by glomerular filtration. Thus in this patient the dose of ceftazidime would have to be modified due to the patient s renal status. A (effective on oral administration) is incorrect. Ceftazidime is only given par-enterally. C (interferes in vitamin K function to cause an anticoagulant effect) is incorrect. This property is peculiar to cefoperazone and cefamandole. D (causes ototoxicity at high serum levels) is not correct. E. Ceftazidine is administered IV or intramuscularly (IM). 

It is interesting to note that canola oil is more than twice as high in alpha tocopherol (about 270 mg/kg) than soybean oil (about 116 mg/kg). Alpha tocopherol is now recognized as the main tocopherol with vitamin E function in humans (135). Canola oil is a very good source of vitamin E. 

All the water-soluble vitamins except vitamin C function as coenzymes. In spite of its name, vitamin C is not actually a vitamin because it is required in fairly high amounts and most mammals are able to synthesize it (Section 22.19). Humans and guinea pigs cannot synthesize it, however, so it must be included in their diets. We have seen that vitamin C and vitamin E are radical inhibitors and therefore are antioxidants. Vitamin C traps radicals formed in aqueous environments, whereas vitamin E traps radicals formed in nonpolar environments (Section 9.8). 

Recently a new strategy was developed whereby a nuld and highly selective enzymatic method was used to covalently couple the primary hydroxyl group of ascorbic acid with styrene and methyl acrylate monomers, followed by a second enzymatic reaction catalyzed by horseradish peroxidase to polymerize the styrene and acrylate monomers yielding vitamin C functionalized... 

Many carotenoids function in humans as vitamin A precursors however, not all carotenoids have provitamin A activity (Table 3). Of the biologically active carotenoids, -carotene has the greatest activity. Despite the fact that theoretically one molecule of -carotene is a biological source of two molecules of vitamin A, this relationship is not observed and 6 p.g -carotene is equivalent to 1 p. vitamin A. Although -carotene and vitamin A have complementary activities, they caimot totally replace each other. Because the conversion of -carotene to vitamin A is highly regulated, toxic quantities of vitamin A cannot accumulate and -carotene can be considered as a safe form of vitamin A (8). 

Vitamin C status is supposed to play a role in immune function and to influence the progression of some chronic degenerative diseases like atherosclerosis, cancer, cataracts, and osteoporosis. The role of vitamin C in immune function, especially during common cold and upper respiratory tract infection, is the subject of lively debate. The exact mechanisms of action have not yet been fully elucidated, but the results of several trials point to a reduced duration and intensity of infections in subjects consuming high amounts of vitamin C (200-1000 mg/d). However, the incidence of common cold was not influenced significantly (24). 

Vitamin K carboxylase is a transmembraneous protein in the lipid bilayer of the endoplasmatic reticulum (ER). It is highly glycosilated and its C-terminal is on the luminal side of the membrane. Besides its function as carboxylase it takes part as an epoxidase in the vitamin K cycle (Fig. 1). For the binding of the y-carboxylase the vitamin K-dependent proteins have highly conserved special recognition sites. Most vitamin K-dependent proteins are carboxy-lated in the liver and in osteoblasts, but also other tissues might be involved, e.g., muscles. 

Rats fed a purified nonlipid diet containing vitamins A and D exhibit a reduced growth rate and reproductive deficiency which may be cured by the addition of linoleic, a-linolenic, and arachidonic acids to the diet. These fatty acids are found in high concentrations in vegetable oils (Table 14-2) and in small amounts in animal carcasses. These essential fatty acids are required for prostaglandin, thromboxane, leukotriene, and lipoxin formation (see below), and they also have various other functions which are less well defined. Essential fatty acids are found in the stmctural lipids of the cell, often in the 2 position of phospholipids, and are concerned with the structural integrity of the mitochondrial membrane. 

SRB contains high-quality protein, oil, dietary fiber, polysaccharides, fat-soluble phytochemicals (plant derived bioactive compounds) and other bran nutrients. Rice bran and germ are the richest natural sources of B complex vitamins as well as E vitamins, polyphenols, several antioxidants and minerals. It is now available in the commercial food ingredient market as a safe and effective functional food and dietary supplement. 

Addition of such a-lithiosulfinyl carbanions to aldehydes could proceed with asymmetric induction at the newly formed carbinol functionality. One study of this process, including variation of solvent, reaction temperature, base used for deprotonation, structure of aldehyde, and various metal salts additives (e.g., MgBrj, AlMej, ZnClj, Cul), has shown only about 20-25% asymmetric induction (equation 22) . Another study, however, has been much more successful Solladie and Moine obtain the highly diastereocontrolled aldol-type condensation as shown in equation 23, in which dias-tereomer 24 is the only observed product, isolated in 75% yield This intermediate is then transformed stereospecifically via a sulfoxide-assisted intramolecular 8, 2 process into formylchromene 25, which is a valuable chiron precursor to enantiomerically pure a-Tocopherol (Vitamin E, 26). 

The consumption of dairy products plays a significant role in providing high-quality protein, vitamins, minerals, and other bioactive compounds to the American diet. Dairy products are consumed fresh in the United States in the form of fluid milk, cheese, yogurt, butter, and ice cream. Dried and condensed products such as nonfat dried milk, whey, whey protein concentrates, and isolates are also produced which are used as ingredients to boost the nutritional and functional properties of a host of other food... 

---