74 Carotenes, beta

Beta-carotene is one of the orange dyes found in most green leaves and in carrots. When leaves lose their chlorophyll in the fall, carotene is one of the colors left over in the leaf. 

Beta-carotene is used in foods to provide color (margarine would look as white as vegetable shortening without it). Another similar molecule, annatto, is used in cheeses. Another famous carotenoid dye, saffron, is used to color rice and other foods. 

The body turns beta-carotene into vitamin A, and it is sometimes added to foods or vitamin supplements as a nutrient. 

Another colorful carotene is lycopene. This is the red molecule that gives ripe tomatoes their color. 

Notice the alternating double and single bonds between the carbon atoms. These are called conjugated bonds, or resonance bonds. The electrons in those bonds are not locked on to one atom—instead they spend their time bouncing from atom to atom. This gives the effect of something in between a double bond and a single bond, more of a one-and-a-half bond. 

In plants, algae, and photosynthetic bacteria, beta-carotene plays an important role in photosynthesis, the process by which plants convert water and carbon dioxide into carbohydrates and oxygen. In nonphotosynthetic bacteria and fungi, beta-carotene protects the organism against the harmful effects of light and oxygen. 

Animals require beta-carotene for normal growth and development, but are unable to manufacture the compound 

Beta carotene. White atoms are hydrogen and black atoms are carbon, publishers 

Beta-carotene also acts as an antioxidant, a substance that attacks free radicals in the body that may cause cancer. It may also protect against heart disease and strengthen the body s immune system. 

Beta-carotene was first isolated by the German chemist Heinrich Wilhelm Ferdinand Wackenroder (1789-1854), who extracted the compound from carrot roots in 1831. The compound was first synthesized in 1950 by the Swiss chemist Paul Karrer (1889-1971). 

Sources are liver, salmon, and other cold-water fish, egg yolks, and fortified milk and dairy products. Beta Carotene 

Sources are orange and yellow fruits and vegetables, such as carrots, squash, and cantaloupes leafy green vegetables. 

FIGURE 66.1 Vitamins D3 and D2 are produced by ultraviolet irradiation of animal skin and plants, respectively. The precursor of vitamin D3 in skin is 7-dehydrocholesterol, or provitamin D. In humans, the storage, transport, metabolism, and potency of vitamins D2 and D3 are identical, and the net biologic activity of vitamin D in vivo results from the combined effects of the hydroxylated derivatives of vitamins D2 and D3. 

Cobalamin binding protein Intrinsic factor of Castle 

FIGURE 66.2 Both vitamin B12 and folic acid are essential for the synthesis of DNA, and this process is impaired in patients with megaloblastic anemia. 

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Hoskins L C 1984 Resonance Raman-spectroscopy of beta-carotene and lycopene—a physical-chemistry experiment J. Chem. Educ. 61 460-2... 

Mantini A R, Marzocchi M P and Smulevich G 1989 Raman excitation profiles and second-derivative absorption spectra of beta-carotene J. Chem. Phys. 91 85-91... 

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. 

Vitamins are classified by their solubiUty characteristics iato fat-soluble and water-soluble groups. The fat-soluble vitamins A, E, and K result from the isoprenoid biosynthetic pathway. Vitamin A is derived by enzymic cleavage of the symmetrical C q beta-carotene, also known as pro-vitamin A. Vitamins E and K result from condensations of phytyldiphosphate (C2q) with aromatic components derived from shikimic acid. Vitamin D results from photochemical ring opening of 7-dehydrocholesterol, itself derived from squalene (C q). 

Rj,=0.23 (red zone), R 3=0.31 (yellow zone), R =0.43 (light yellow zone), Rj =0.86 (red-brown zone). The last zone corresponds to zone of beta-carotene. Other pigments were not yet determined. 

Diels-Alder reaction of, 575 electrostatic potential map of, 576 evidence for, 575 structure of, 576 Bergman, Torbern, 2 Bergstrom, Sune K., 1068 Beta anomer, 984 Beta-carotene, structure of, 172 industrial synthesis of, 722 UV spectrum of, 504 Beta-diketone, 851... 

This means that in the strictest sense, PABA is not a vitamin, because the body can manufacture it. But in this sense, too, vitamin A is not technically a vitamin, as the body makes that from beta-carotene. 

Some colors are nutrients in their own right, and they have antioxidant properties that are beneficial to health. Beta-carotene, annatto, saffron, and turmeric all have these good properties in addition to their color. In fact, the same chemistry that makes them absorb light also helps them to absorb and neutralize dangerous oxygen free radicals in the body. 

Annatto is a colored pigment that is extracted from the Central and South American plant Bixa orellana. The color comes from the resinous outer covering of the seeds of the plant, which is composed of the carotenoid pigments bixin and norbixin and their esters. The central portion of those molecules is the same as that of the molecule beta-carotene, and the yellow-orange color of annatto comes from the same physical chemistry origins as the orange color of beta-carotene. 

As further described in the section on beta-carotene, organic dyes owe their colors to resonance structures in the molecule, where charges are free to move in the molecule at frequencies that fall in the range of visible light. 

The dye molecule in saffron is the carotenoid beta-gentiobiose crocetin. It is related to beta-carotene, and you can see the relationship in the center of the molecule. That center portion is the carotenoid pigment crocetin ... 

Colored substances contain molecules with chromophores, areas of the molecule that have double bonds between carbon atoms or oxygen atoms. A good example is beta-carotene, and that section goes into more detail on how molecules become colored. Bleaches attack these chromophores in one of two ways. 

ALBANES D, HEINONEN O P, HUTTUNEN J K, TAYLOR P R, VIRTAMA J, EDWARDS B K, HAAPAKDSKI J, RAUTALATHI M, HARTMAN A M and PALMGREN J (1995) Effects of alpha-tocopherol and beta carotene supplements on cancer incidence in the alpha-tocopherol beta-carotene cancer prevention study , Am J Clin Nutr, 62, 1427S-30S. 

ALPHA-TOCOPHEROL BETA-CAROTENE (ATBC) CANCER PREVENTION STUDY GROUP (1994) The effect of vitamin E and beta carotene on the incidence of lung cancer and other cancers in male smokers , New Engl J Med, 330, 1029. 

HENNEKENS c H, BURNING J E, MANSON J E and STAMPFER M (1996) Lack of effect of long-term supplementation with beta-carotene on the incidence of malignant neoplasms and cardiovascular disease . New Engl J Med, 334, 1145. 

WANG X D (1994) Review absorption and metabolism of beta-carotene , JAm Coll Nutr, 13, 314-25. 

It is well known that excessive intake of P-carotene may lead to carotenodermia (yellow skin), and it is undoubtedly the case that some carotenoid is directly lost via the skin or through photo-oxidation in the skin. As far as is known the carotenoids are not cytotoxic or genotoxic even at concentrations up to 10 times the normal plasma concentration which may cause carotenodermia. However, they are associated with amenorrhoea in girls who may be consuming bizarre diets and, in long-term supplementation studies, with an increase in lung cancer (The Alpha-tocopherol, Beta-carotene Cancer Prevention Study Group, 1994). 

BARTH T J, ZOLER J, KUBELER A, BORN A I and OSSWALD H (1997) Redifferentiation of oral dysplasic mucosa by the application of the anti-oxidants beta-carotene, a-tocopherol and vitamin C. Int J Vitam Nutr Res 67(5) 368-76. 

PILLION L, COLLINS A and SOUTHON s (1998) Beta-carotene enhances the recovery of lymphocytes from oxidative DNA damage. Acta Biochim Pol. 45(1) 183-90. 

Carotenoid and tocopherol concentrations in plasma, peripheral blood mononuclear cells and red blood cells after long-term beta-carotene supplementation in men. Am J Clin Nutr 63(4) 553-8. 

GAMBOA-PINTO A J, ROCK C L, FERRUZZI M G, SCHOWINSKY A B and SCHWARTZ S J (1998) Cervical tissue and plasma concentrations of alpha-carotene and beta-carotene in women are correlated. /iVMtr. 128(11) 1933-6. 

HININGER I A, MEYER-WENGER A, MOSER U, WRIGHT A, SOUTHON S, THURNHAN D, CHOPRA M, VAN CEN BERG H, OLMEDILLA B, FAVIER A E and ROUSSEL A M (2001) No significant effects of lutein, lycopene or beta-carotene supplementation on biological markers of oxidative stress and LDL oxidisability in healthy adult subjects. J Am Coll Nutr. 20(3) 232-238. 

HUGHES D A, WRIGHT A J, FINGLAS P M, PEERLESS A C, BAILEY A L, ASTLEY S B, FINDER A C and SOUTHON s (1996) Beta-carotene supplementation enhances the expression of functionally associated molecules on human monocytes. Biochem Soc Trans. 24(3) 3888S. 

Micozzi M s, BROWN E D, TAYLOR and WOLFE E (1988) Carotenodermia in men with elevated carotenoid intake from foods and beta-carotene supplements. Am J Clin Nutr. 49(6) 1330-31. 

OMENN G S, GOODMAN G E, THORNQUIST M D, BALMES J, CULLEN M R, GLASS A, KEOGH J P, MEYSKENS F L, VALANIS B, WILLIAMS J H, BARNHART S and HAMMAR S (1996) Effects of a combination of beta-carotene and vitamin A on lung cancer and cardiovascular disease. N EnglJ Med 1150-1155. 

CANFIELD w K (1993). Study of beta-carotene metabolism in humans using 13C-beta-carotene and high precision isotope ratio mass spectrometry. Annals of the New York Academy of Sciences 691 86-95. 

RiBAYA-MERCADO J D, GARMYN M, GiLCHREST B A and RUSSELL R M (1995) Skin lycopene is destroyed preferentially over beta-carotene during ultraviolet irradiation in humans. J Nutr 125(7) 1854-9. 

STAHL w, SCHWARZ w, SUNDQUIST A R and SIES H (1992) Cis-trans isomers of lycopene and beta-carotene in human serum and tissues. Arch Biochem Biophys 294(1) 173-7. 

VAN VLIET T, SCHREURS w H and VAN DEN BERG H (1995) Intestinal beta-carotene absorption and cleavage in men response to beta-carotene and retinyl esters in the triglyceride-rich lipoprotein fi action after a single oral dose of beta-carotene. Am J Clin Nutr 62(1) 110-16. 

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