Alkaloids caffeine

The major pharmacological constituents of tea are the purine alkaloids caffeine (2.9-4.2%), theobromine (0.15-0.2%), and theophylline (0.02-0.04%). Also present are triterpene saponins (including barringtogenol C and Rl-barringenol), catechins (theaflavine, theaflavin acid, thearubigine), and caffeic acid derivatives (chlorogenic acid and theogallin). A cup of brewed tea contains approximately 20-100 mg of caffeine... 

As these examples show, different defenses among plant parts and seasonal differences have to be considered together. Coffee Coffea arabica) is a well-investigated example of increased chemical defenses when the plant is most vulnerable to herb ivory. The concentration of the alkaloid caffeine (Fig. 11.18) varies between plant parts and with the growth cycle. In the germinating seed, the... 

During imbibition of whole tea seeds (6 days) two purine alkaloids, caffeine and theobromine, did not decrease in the seed coats and there was no increase in the seeds. In parallel with and after the breaking seed coats there was a gradual release of caffeine from coats of germinating seeds. By contrast, when the seed was freed from the outer seed coat and soaked, imbibition of the seed required only two days and simultaneously caffeine was released from the inner seed coat. 

Purine alkaloids Caffeine synthase Camellia sinensis, Coffea arabica... 

All alkaloids are bases that react with acids to form salts. An example is the alkaloid caffeine, shown here reacting with phosphoric acid. 

The purine alkaloids caffeine, theobromine, and theophylline (Figure 6.135) are all methyl derivatives of xanthine and they commonly co-occur in a particular plant. The major sources of these compounds are the beverage materials such as tea, coffee, cocoa, and cola, which owe their stimulant properties to these water-soluble alkaloids. They competitively inhibit phosphodiesterase, resulting in an increase in cyclic AMP and subsequent release of adrenaline. This leads to a stimulation of the CNS, a relaxation of bronchial smooth muscle, and induction of diuresis, as major effects. These effects vary in the three compounds. Caffeine is the best CNS stimulant, and has weak diuretic action. Theobromine has little stimulant action, but has more diuretic activity and also muscle relaxant properties. Theophylline also has low stimulant action and is an effective diuretic, but it relaxes smooth muscle better than caffeine or theobromine. 

As can be seen from Table I a substantial number of alkaloids display significant insect toxicity, including nicotine, pipeline, lupine alkaloids, caffeine, gramine, strychnine, berberine, ephedrine, and steroidal alkaloids. Only the specialists can tolerate the respective alkaloids. The tobacco homworm (Manduca sexto), for example, can grow on a diet with more than 1% nicotine without any adverse effects. Most of the nicotine is either degraded or directly eliminated via the Malpighian tubules and in feces 182). Because nicotine binds to the acetylcholine (ACH) receptor, it is likely that in Manduca this receptor has been modified in such a way that ACH can still bind, but not nicotine (so-called target site modification). 

The purine group of alkaloids includes the vegetable alkaloids caffeine, theobromine, theophylline and the animal alkaloids xanthine, hypoxanthine, guanine and adenine. The most common substance which is a purine compound is uric acid, but, though directly related to the alkaloids given above, it is not itself usually considered as an alkaloid. The constitution of uric acid has been fully considered (Part I, p. 442). It is the tri-hydroxy derivative of a substance known as purine which is the mother substance of the purine alkaloids also. 

The alkaloid caffeine is found in coffeef tea, and kola. It is also known less commonly by the name of theine, especially as found in tea. The amount present in coffee and tea is from 1-4.8 per cent in tea and 1-1.5 per cent in coffee. Caffeine crystallizes from water or alcohol, m.p. 234°. It is slightly soluble in water, less so in alcohol and ether and more in chloroform. It acts as a weak base. It may be prepared from either theobromine or from theophylline by further methylation, which confirms the constitution as the 1-3-7-tri-methyl product. 

Coc,various opium alkaloids,caffeine,strychnine, quinine,ephedrine Procaine.ligno-caine, barbiturate, paracetamol Analysis illicit heroin preparations(Fig.7.2)... 

Ergta.Ergtaine, butalbital.pheno- Separation with ion-pair diHErgta.tropane barbital. barbit- chromatography alkaloids,caffeine al.pizotifene... 

Even some or most of the common garden vegetables and fruits contain trace amounts of alkaloids as well as other potentially beneficial types of compounds. Our daily cups of coffee contain the alkaloid caffeine. Tobacco and some other plants contain the alkaloid nicotine, and there is ongoing research to determine beneficial medicinal properties for nicotine and related compounds, possibly even against cancer. The alkaloid colchicine is sometimes used as a treatment for gout, although it is a drug also used in horticulture to induce mutations in plant species. 

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. 

Saldana M.D.A., Mazzafera P. and Mohamed R.S. (1997) Extraction of the alkaloids caffeine and trigonelline from coffee beans using supercritical CO2 (Portuguese) Cienc. Tecnol.Aliment. 17(4), 371-6 Chem Abstr., 129, 215926). 

Caffeine enters the bloodstream about ten minutes after its ingestion and stays in the body for up to twelve hours. Like other alkaloids, caffeine has powerful physiological effects on humans and animals. It stimulates heart muscle and relaxes certain structures that contain smooth muscle, including the coronary arteries and the bronchi. It is a diuretic. Theophylline and theobromine, two other plant alkaloid derivatives of xanthine, have physiological effects similar to those of caffeine. 

There is less information in the literature about binding of alkaloids to ribonucleic acid than there is for deoxyribonucleic acid but such binding does occur. However, since ribonucleic acid is single-stranded, the intercalation mechanism does not apply. Binding of the purine alkaloids caffeine and theophylline follows the reverse order from their binding to DNA — theopylline binds with 10,000 times the affinity of caffeine [345], Elliptinium acetate, best-known for its intercalation into DNA, is easily oxidized to an A-ring quinone amine that binds to the 2 -oxygen atom of ribose units in RNA. The first product then cyclizes to a spiro derivative [346]. 

Keywords Alkaloid, caffeine, energy drinks, spectrophotometry. 

Which N-P-K rating would you expect for coffee grounds, which contain significant quantities of the alkaloid caffeine 2-0-3-o.2,o.3-2-o.2,or 0.3-0.2-2 ... 

Scheme 4. Biosynthesis of the purine alkaloids caffeine and theobromine. Molecular clones have been isolated for all enzymes shown. Abbreviations CS, caffeine synthase MXN, 7-methyIxanthosine nucleosidase MXS, 7-methyIxanthosine synthase.

The popularity of coffee is certainly attributable to its caffeine content. The alkaloid caffeine acts mildly euphorigenic, stimulating or relaxing, devoid of leading to any physical dependency, not even to a compensatory depressive phase or state of exhaustion. [487]... 

The dominating active ingredients in the three plants are xanthine alkaloids caffeine, theobromine and theophylline (Fig. 2.36). Raw coffee contains 0.9-1.4% (Arabica) or 1.5-2.6% (Robusta) of caffeine. Tea leaves contain 3.2 % of caffeine, but the different preparation method results in about half as much caffeine in the drink compared to coffee. The main active ingredient of cocoa is theobromine, there is only 0.2% caffeine in it, but this small amount is still responsible for the stimulating effect. 

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