Natural products caffeine

Caffeine, a purine alkaloid, is one of the most widely known natural products. Caffeine is ingested as a natural component of coffee, tea, and cocoa, and the impact of caffeine on human health has been studied extensively. The biosynthetic pathway of caffeine has been elucidated recently on the genetic level. Caffeine biosynthesis has been studied most widely in the plant species Coffea (coffee) and Camellia (tea) (168, 169). 

Isolation and Characterization of a Natural Product Caffeine and Caffeine 5-Nitrosalicylate... 

Adsorption and Desorption Adsorbents may be used to recover solutes from supercritical fluid extracts for example, activated carbon and polymeric sorbents may be used to recover caffeine from CO9. This approach may be used to improve the selectivity of a supercritical fluid extraction process. SCF extraction may be used to regenerate adsorbents such as activated carbon and to remove contaminants from soil. In many cases the chemisorption is sufficiently strong that regeneration with CO9 is limited, even if the pure solute is quite soluble in CO9. In some cases a cosolvent can be added to the SCF to displace the sorbate from the sorbent. Another approach is to use water at elevated or even supercritical temperatures to facilitate desorption. Many of the principles for desorption are also relevant to extraction of substances from other substrates such as natural products and polymers. 

Class 4 Steam Distillation. Isolating tars, oils, and other liquid compounds insoluble, or slightly soluble, in water at all temperatures. Usually natural products are steam distilled. They do not have to be liquids at room temperatures (e.g., caffeine, a solid, can be isolated from green tea.). 

Caffeine (3,7-dihyro-l,3,7-trimethyl-lH-purine-2,6-dione) is a natural product from tea, coffee, and other plants, and is present in many beverages and food. It is primarily metabolized in the liver by cytochrome P450 enzymes to give M-demethylated xanthine and few other metabolites (Fig. 2) [2,48 - 50]. About 17 caffeine metabolites have been identified in humans [51]. 

After the nucleic acid purines adenine and guanine, the next most prominent purine in our everyday lives is probably caffeine. Caffeine, in the form of beverages such as tea, coffee, and cola, is one of the most widely consumed and socially accepted natural stimulants. Closely related structurally are theobromine and theophylline. Theobromine is a major constituent of cocoa, and related chocolate products. Caffeine is also used medicinally,... 

More than 50% of all known organic compounds are heterocyclic compounds. They play important roles in medicine and biological systems. A great majority of important drugs and natural products, e.g. caffeine, nicotine, morphine, penicillins and cephalosporins, are heterocyclic compounds. The purine and pyrimidine bases, two nitrogenous heterocyclic compounds, are structural units of RNA and DNA. Serotonin, a neurotransmitter found in our body, is responsible for various bodily functions. 

In 1979, a Swiss company developed a distillation method to remove the caffeine from coffee, creating decaffeinated coffee. The Swiss water process proved popular among young urban professionals as it was considered to make a more natural product in comparison to the earlier method of making decaffeinated coffee,... 

A variety of alkaloids bind to or intercalate with DNA or DNA/RNA processing enzymes and affect either transcription or replication (quinine, harmane alkaloids, melinone, berberine), act at the level of DNA and RNA polymerases (vinblastine, coralyne, avicine), inhibit protein synthesis (sparteine, tubulosine, vincrastine, lupanine), attack electron chains (pseudane, capsaicin, solenopsine), disrupt biomembranes and transport processes (berbamine, ellipticine, tetrandrine), and inhibit ion channels and pumps (nitidine, caffeine, saxitoxin). In addition, these natural products attack a variety of other systems that can result in serious biochemical destabilization... 

An important natural product for most of us is a fully methylated purine present in tea and coffee— caffeine. Theobromine, the partly methylated version, is present in chocolate, and both caffeine and theobromine act as stimulants. Caffeine is a crystalline substance easily extracted from coffee or tea with organic solvents. It is extracted industrially with liquid CO2 (or if you prefer Nature s natural effervescence ) to make decaffeinated tea and coffee. 

In this chapter, we will focus on three groups of NHC that are either generated from natural products like caffeine or thiamine or use starting materials that are the active centre of enzymes like thiazole in thiamine or are important building blocks in biopolymers like amino acids. 

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. 

A drug product that contains the same active constituent as a botanical product would be regulated according to different paths, as long as they are marketed with different intent. The combination of caffeine with any other stimulant, such as ephedrine alkaloids2, may not be sold as an OTC drag product (20). However, dietary supplement products that contain ma huang (a source of ephedrine) and natural product stimulants such as kola nut (50% caffeine) are permitted on the market under DSHEA. 

The largest class of small-molecule PDE5 inhibitors incorporates a modified purine core which is found in cGMP and other natural products such as caffeine, theophylline, and theobromine (Fig. 5). 

A large body of experimental data has been accumulated on the solubility and extractability of natural products, such as steroids, alkaloids, anticancer agents, oils from seeds, and caffeine from coffee beans, in various SCF solvents such as CO2, ethane, ethylene, and N2O. Carbon dioxide is probably the most widely investigated SCF solvent since its critical temperature T = 31.1°C) makes it an ideal solvent for extracting materials that are thermally labile. Also, CO2 is nontoxic, nonflammable, environmentally acceptable, and inexpensive. 

A natural product is a compound synthesized by a plant or an animal. Alkaloids are natural products that contain one or more nitrogen heteroatoms and are found in the leaves, bark, roots, or seeds of plants. Examples include caffeine (found in tea leaves, coffee beans, and cola nuts) and nicotine (found in tobacco leaves). Morphine is an alkaloid obtained from opium, the juice derived from a species of poppy. Morphine is 50 times stronger than aspirin as an analgesic, but it is addictive and suppresses respiration. Heroin is a synthetic compound that is made by acetylating morphine (Section 30.3). 

In the first of the three extraction methods, the natural product (coffee beans, tea leaves, or kola beans) are treated with an organic solvent that dissolves the caffeine from the plant material. The solvent is then evaporated leaving behind the pure caffeine. A second method follows essentially the same procedure, except that hot water is used as the solvent for the caffeine. A more recent procedure involves the use of supercritical carbon dioxide for the extraction process. Supercritical carbon dioxide is a form of the familiar gas that exists at high temperature and high pressure. It behaves as both a liquid and a gas. Not only is the supercritical carbon dioxide procedure an efficient method of extracting caffeine, hut it has virtually none of the harmful environmental and health problems associated with each of the other two methods of extraction. 

The natural products theophylline 34 (1,3-dimethylxanthine), theobromine 35 (3,7-dimethylxanthine) and caffeine 36 (1,3,7-trimethylxanthine) are derived from the lactam form of xanthine. Theophylline occurs in tea leaves and is a diuretic and a coronary vasodilator. Cocoa beans contain ca. 5% theobromine, which is a stronger diuretic than theophylline or caffeine. 

There are many literature reports on industrial uses of supercritical fluids, and many patents have been issued for various uses of supercritical fluids as solvents in extraction processes. Randall (1) prepared an excellent review on the uses and patents issued up to 1982 in the area of supercritical fluid extraction and chromatography. Many of these applications deal with natural products such as flavors, fragrances, oils and fats, or the removal of unwanted components from natural materials such as caffeine from coffee or tea and nicotine from tobacco. 

One of the best known and most influential developments in the use of SCCO2 was based on the work of Kurt Zosel in the early 1960s, where SCCO2 played a key role in the extraction of caffeine from coffee, which has obvious benefits to the consumer over alternative, solvent-based processes." This is now carried out industrially on a huge scale, producing many thousands of tons of decaffeinated coffee per year. Liquid and supercritical CO2 are routinely used for the extraction of natural products, particularly hops and essential oils, and this is now considered to be a relatively mature area of CO2 technology. 

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