CHEMICAL COMPOUNDS caffeine

The accumulated scientific evidence of the relationships between coffee, caffeine, and serum cholesterol allows for several conclusions to be drawn, while some important issues remain either equivocal or unaddressed. The links involve a number of factors, including the chemical composition of coffee beans, its preparation method, the amount of daily consumption, and specific characteristics of coffee drinkers. Coffee contains hundreds of chemical compounds, caffeine being perhaps the best recognized and studied. Although caffeine has several well-established... 

How would you describe the differences between a cup of coffee and a cup of hot water What probably come to mind are the aroma, the dark color, and the taste of a good cup of coffee. Coffee s action as a stimulant is another obvious difference. These properties come from the chemical compounds that hot water dissolves from ground coffee beans. These compounds are molecules constructed from different atoms bound together in veiy specific arrangements. The molecule that makes coffee a stimulant is caffeine. Our background photo is a magnification of crystals of pure caffeine, and the inset is a ball-and-stick model of this molecule. 

Native to northeast South America, and cultivated worldwide, the seeds contain numerous chemical compounds, the most prominent being the alkaloids caffeine and theobromine. Serving as an antioxidant, there is the possibility of preventing or delaying such degenerative diseases as eaneer. 

Ouid. Whereas a neat compound may be soluble in SC-CO2. it may not be extractable from its matrix without the addition of an entrainer. This phenomenon is demonstrated in the decaffdnation of coffee (iO) neat caffeine is soluble in dry SC-C02. but moist SC-CO2 or moist coffee is necessary for the extraction of caffeine from coffee beans. This same phenomenon occurs with decuffeinaiion by traditional organic solvents. Investigators have hypoihesiwd that water frees the chemically bound" caffeine in the coffee matrix. 

The last part of the book, Chapters 10—17, reports on different applications of polymers in the field of analytical chemistry sorption of organic compounds, Hke phenols, pesticides or caffeine, the use of polymeric materials for size-exclusion chromatography, for HPLC packing materials or as solid phase extraction sorbents. The examples cover a broad variety of chemical compounds, fike pesticides, pharmaceuticals, organic acids in different matrices, such as food, biological fluids, non-aqueous media, air and the use of hemosorbents in blood purification. 

Seven chemical compounds (TEM, 2,3) TEPA, nitrogen mustard, MMS, 2) EMS, caffeine, and aflatoxins have been... 

Fig. 2.5.9 COSY spectra acquired at 600 MHz with an eight-coil probe along with the chemical structures of the compounds used. Each sample was a 10 mM solution in D20 loaded into the coil via the attached Teflon tubes, with the samples being (A) sucrose, (B) galactose, (C) arginine, (D) chloroquine, (E) cysteine, (F) caffeine, (G) fructose and (H)...

Alkaloids are compounds that contain nitrogen in a heterocyclic ring and are commonly found in about 15-20% of all vascular plants. Alkaloids are subclassified on the basis of the chemical type of their nitrogen-containing ring. They are formed as secondary metabolites from amino acids and usually present a bitter taste accompanied by toxicity that should help to repel insects and herbivores. Alkaloids are found in seeds, leaves, and roots of plants such as coffee beans, guarana seeds, cocoa beans, mate tea leaves, peppermint leaves, coca leaves, and many other plant sources. The most common alkaloids are caffeine, theophylline, nicotine, codeine, and indole... 

Not all agents can be readily metabolized. The toxic metals lead and mercury are elements that cannot be degraded but must still be removed from the body. Another important mechanism of detoxification is the attachment or binding of another compound to a toxic chemical to make it easier for the kidney to filter the compound out of the blood and excrete it in the urine. A primary purpose of the kidney is to screen the blood for waste products and concentrate them in the urine for excretion, as occurs, for example, with mercury. Caffeine is excreted in the urine at approximately the same concentration as the blood because the kidney cannot concentrate caffeine. Vitamins, however, are readily concentrated and excess quickly eliminated in the urine. 

In the CNS, glial cells aid in the communication between the densely packed neurons of the CNS. These cells also play a big part in forming the blood-brain barrier. The blood-brain barrier keeps some classes of chemicals from entering the brain, which can make it very difficult to treat diseases of the brain. However, some chemicals, such as caffeine, readily enter the brain, as do many other neuroactive compounds. Compounds essential for function are actively transported across this barrier. 

Following the development of the test, an in-house validation was conducted to evaluate the performance of FETAX compared to the results in the rat and/or rabbit. Thirteen reference chemicals were tested including eight compounds known to be teratogenic in rats and/or rabbits (caffeine, retinoic acid, hydroxyurea, ethanol, cyclophosphamide, nicotine, acetylsalicylic acid, dexametha-sone) and five non-teratogens (isoniazid, saccharin, paracetamol, penicillin G, sildenafil). The estimation of teratogenicity in rats and rabbits was based on published data (9). 

Rx Butalbital/aspirin/caffeine Butalgen, Fiorinal, Fiorgen, Fiormor, Fortabs, Iso-butal. Isobutyl, Isolin, Isollyl, Laniroif, Lanorinal, Marnal, Tecnal, Virbutal Rx Butalbital/aspirin/caffeine wifh codeine Ascomp with Codeine No3, Butalbital Compound with Codeine, Butinal with Codeine NoB, Fiorinal with Codeine NoB, Idenal with Codeine, Isollyl with Codeine Chemical Class Barbituric acid derivative... 

Sweetness Production by the Combination of Bitter and Sweet Tastes. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylfiiiourea, caffeine and bitter peptides were performed. Sensory tests using typically bitter compounds such as brucine, strychnine, phenylthiourea, caffeine and bitter peptides were performed. Sensory taste impression were also measured for combinations of acetic acid (sour) and typical bitter compounds (5). The data from these studies indicated that the tastes of ese bitter/sour mixtures changed to a sweet taste regardless of their chemical structure of the bitter component (Table II). 

Xanthine derivatives are a group of chemically similar compounds that exert a variety of pharmacologic effects. Common xanthine derivatives include theophylline, caffeine, and theobromine (Fig. 26-2) these compounds are frequently found in various foods and beverages (tea, coffee, soft drinks). Theophylline and several theophylline derivatives are also administered therapeutically to produce bronchodilation in asthma and other forms of reversible airway obstruction (bronchitis, emphysema).65,79 Theophylline and caffeine are also potent CNS stimulants, and some of the more common side effects of these drugs are related to this CNS excitation (see Adverse Side Effects, later in this chapter). 

The methylxanthine molecule is built on a foundation common to many biologic compounds, the xanthine double ring of carbons. The three methylxanthines, caffeine, theophylline, and theobromine, all block the action of the body s adenosine molecule, sending a signal that helps slow the chemical buildup inside cells. Because the methylxanthines closely resemble adenosine at the molecular level, they can occupy the molecular sites on cells that normally recognize, and react to, adenosine. Caffeine prevents the normal slowing action of adenosine at the cellular level, in both nerves and muscle. 

The major bases found in nucleic acids are adenine and guanine (purines) and uracil, cytosine, and thymine (pyrimidines). Thymine is found primarily in DNA, uracil in RNA, and the others in both DNA and RNA. Their structures, along with their chemical parent compounds, purine and pyrimidine, are shown in Figure 10.1, which also indicates other biologically important purines that are not components of nucleic acids. Hypoxanthine, orotic acid, and xanthine are biosynthetic and/or degradation intermediates of purine and pyrimidine bases, whereas xanthine derivatives—caffeine, theophylline, and theobromine—are alkaloids from plant sources. Caffeine is a component of coffee beans and tea, and its effects on metabolism are mentioned in Chapter 16. Theophylline is found in tea and is used therapeutically in asthma, because it is a smooth muscle relaxant. Theobromine is found in chocolate. It is a diuretic, heart stimulant, and vasodilator. 

All the methods of extracting caffeine take place before the beans are roasted. Caffeine and the other organic compounds that give coffee its taste are mainly non-polar. (Caffeine does contain some polar bonds, however, which allows it to dissolve in hot water.) Non-polar solvents, such as benzene and trichloroethene, were once used to dissolve and remove caffeine from the beans. These chemicals are now considered to be too hazardous. Today most coffee manufacturers use water or carbon dioxide as solvents. 

Organic synthesis is the construction of complex organic compounds from simple starting compounds by a series of chemical reactions. The compounds synthesized in nature are called natural products. Nature provides a plethora of organic compounds and many of these possess interesting chemical and pharmaceutical properties. Examples of natural products include cholesterol (1.1), a steroid found in most body tissues limonene (1.2), a terpene found in lemon and orange oils caffeine (1.3), a purine found in tea leaves and coffee beans and morphine (1.4), an alkaloid found in opium. 

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