Caffeine physiological effects

Chlorogenic acid forms a 1 1 complex with caffeine, which can be crystallized from aqueous alcohol and yields very little free caffeine on extraction with chloroform. Other compounds with which caffeine will complex in this way include isoeugenol, coumarin, indole-acetic acid, and anthocyanidin. The basis for this selection was the requirement for a substituted aromatic ring and a conjugated double bond in forming such a complex. This kind of complex does modify the physiological effects of caffeine.14 Complex formation will also increase the apparent aqueous solubility of caffeine in the presence of alkali benzoates, cinnamates, citrates, and salicylates.9... 

The physiological effects of tea that are caused by caffeine alone will not be discussed further in this chapter. 

This chapter is intended as a brief overview of the basic metabolism and physiological effects of caffeine and other methylxanthines. It is designed in a form to make possible easy access to key points on each topic, rather than as an in-depth discussion and review. In the spirit of a book... 

Another category of potential confounding variables includes dosing issues. Caffeine researchers have administered a wide variety of experimental dosages, an issue related obviously to physiological effects but also of interest to those concerned with caffeine doping. The timing of the... 

The increasing scientific attention devoted to caffeine in recent years9 reflects not only its popularity and widespread use, but also concern that it may have detrimental physiological effects and interest in its impact on psychological functioning and behavior. Health concerns have focused primarily on cardiovascular function.4-10 Early studies suggested that caffeine consumption may increase the risk of some cardiovascular problems.11-12 However, more recent studies provide little support for this concern, with the possible exception of blood pressure.13 Lipid profiles appear to be unaffected by habitual caffeine consumption.1417 Moreover,... 

Hasenfratz, M., and Battig, K., Action profiles of smoking and caffeine Stroop effect, EEG, and peripheral physiology. Pharmacology, -Biochemistry-and-Behavior 42(1), 155-161, 1992. 

Rush, C., Sullivan, J. and Griffiths, R., Intravenous caffeine in stimulant drug abusers Subjective reports and physiological effects. Journal of Pharmacology and Experimental Therapeutics 273(1), 351-358, 1995. 

Caffeine is the most widely consumed stimulant drug in the world. It occurs naturally in coffee, tea, and the cola nut and is added to many soft drinks. Many of us consume coffee and soft drinks because of the desirable stimulatory effects produced by caffeine many of us have consumed too much caffeine and felt the consequences. The undesirable effects of caffeine, the agitation, the inability to concentrate, the mild tremors, and the general unpleasantness, are a form of neurotoxicity. Literally your brain, and more specifically, the adenosine receptors in your brain, has too much caffeine. These effects are a reversible form of neurotoxicity. Fortunately, we metabolize caffeine quickly and the undesirable effects end. By experience we have learned how to moderate our caffeine consumption to avoid the unpleasant side effects. A great deal of money is made from the neuroactive and physiological effects of caffeine. You can learn more about this fascinating drug in the chapter on caffeine. 

Alkaloid. A large, varied group of complex nitrogen-containing compounds, usually alkaline, that reacts with acids to form soluble salts, many of which have physiological effect on humans, e.g., nicotine and, caffeine, etc. 

There are other small biomolecules, specific to certain types of cells or organisms. For example, vascular plants contain, in addition to the universal set, small molecules called secondary metabolites, which play a role specific to plant life. These metabolites include compounds that give plants their characteristic scents, and compounds such as morphine, quinine, nicotine, and caffeine that are valued for their physiological effects on humans but used for other purposes by plants. The entire collection of small molecules in a given cell has been called that cell s metabolome, in parallel with the term genome (defined earlier and expanded on in... 

As indicated in Fig. 25-18, free adenine released from catabolism of nucleic acids can be deaminated hydrolytically to hypoxanthine, and guanine can be deaminated to xanthine.328 The molybdenum-containing xanthine oxidase (Chapter 16) oxidizes hypoxanthine to xanthine and the latter on to uric acid. Some Clostridia convert purine or hypoxanthine to xanthine by the action of a selenium-containing purine hydroxylase.3283 Another reaction of xanthine occurring in some plants is conversion to the trimethylated derivative caffeine. 328b One of the physiological effects of caffeine in animals is inhibition of pyrimidine synthesis.329 However, the effect most sought by coffee drinkers may be an increase in blood pressure caused by occupancy of adenosine receptors by caffeine.330... 

The contradictions that abound in the experimental findings about tolerance to caffeine are probably a result of poor research methods, such as not specifying caffeine-use patterns in subjects (Curatolo Robertson, 1983). In general, tolerance probably does develop to caffeine s effects on renal function, sleep, and other physiological functions, such as blood pressure and heart rate. On the other hand, little tolerance seems to develop to caffeine s stimulant effects (Hogan, Hornick, Bouchoux, 2002). 

Segall, S. 2000. Comparing coffee and tea. In Caffeinated beverages, health benefits, physiological effects and chemistry, ed. T. H. Parliament, C.-T. Ho, and P. Schieberle, 20-28. ACS Symposium Series 754. Washington, DC American Chemical Society. 

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. 

Discuss the potential toxic physiologic effects of caffeine consumption. 

Lin JK, Liang YC, Lin YL, Ho CT. Cancer prevention of tea Biochemical mechanisms. In Parliament TH Ho CT, Schieherle P, Eds. Caffeinated Beverages, Health Benefits, Physiological Effects and Chemistry. Washington. DC American Chemical Society, 2000 78-86. 

Caffeine is an alkaloid classified as a methylxanthine, a group of closely related compounds including caffeine, theophylline, and theobromine, that have similar physiological effects. Caffeine is the most widely consumed... 

Four neurotransmitters are acetylcholine, norepinephrine, dopamine, and serotonin. Epinephrine is also known as the flght-or-flight hormone. The amphetamines have structures similar to that of epinephrine. Alkaloids are nitrogen-containing compounds isolated from plants. They exhibit a variety of physiological effects on the body. Examples of alkaloids include nicotine, caffeine, quinine, atropine, morphine, and codeine. 

Theobromine and theophylline have milder effects on the central nervous system, their physiological effect is to relax smooth mirscle in the Irmgs and act as a diuretic. These effects are trsed in asthma treatment Horses are more susceptible to the effects of caffeine and theobromine than humans, so eating chocolate before a race is a sort of doping for them. Theobromine is toxic for cats, dogs and birds, so pets should not be treated to chocolate. But humans have no problem, and they can also enjoy the beneficial effects of a daily dose of caffeine. 

These three alkaloids are well-known compounds, as they are present in everyday foods and beverages, such as cocoa, drinking chocolate, tea, and cola, as well as in pharmaceutical products. In cocoa products, theobromine is the major alkaloid, followed by caffeine, which is found in small quantities. Slight traces of theophylline have been identified therefore, it is not considered relevant and is not reviewed in the cocoa products [22,23], The range of methylxanthines also depends on variables such as the origin of the cocoa beans, the fermentation process, and the cocoa production process. Thus, for instance, defatted cocoa beans may contain about 4% and 0.2% of theobromine and caffeine, respectively [24], Regarding their physiological effects in humans, methylxanthines have been related to various body systems, mainly the central nervous system, but also the cardiovascular, renal, and respiratory systems [25,26],... 

The best known N-compound is caffeine (1,3,7-trimethylxanthine) because of its physiological effects (stimulation of the central nervous system, increased blood circulation and respiration). It is mildly bitter in taste (threshold value in water is 0.8-1.2 mmole/1), crystallizes with one molecule of water into silky, white needles, which melt at 236.5 °C and subhme without decomposition at 178 °C. The caffeine content of raw Arabica coffee is 0.9-1.4%, while in the Robusta variety, it is 1.5-2.6%. In contrast there are caffeine-free Coffea varieties. Santos, an Arabica coffee, is on the low side, while Robusta from Angola is at the top of the range given for caffeine content. Other purine alkaloids are theobromine (Arabica 36-40 mg/kg, Robusta 26-82 mg/kg)... 

The physiological effects of caffeine are not beneficial nor are they tolerated by everyone. Hence, many processes have been developed to remove caffeine (<0.1%) from coffee. The following process steps are normally used ... 

Apart from the possible prevention of unwanted physiological effects, hydrotropes can have a direct action on efficacy. Theobromine is soluble in water to the extent of 1 in 2000 an equimolar mixture with sodium acetate has a solubility of 1 in 1.5, and a mixture with sodium salicylate, 1 in 1. Clinical evaluation of various theophylline and theobromine preparations in the treatment of angina pectoris [288] showed a theobromine-sodium acetate mixture to be the most effective. Ergotamine levels have been shown to be enhanced when the drug is administered in combination with caffeine, which increases the solubility and rate of solution of the ergotamine [289]. 

Because the physiological and pharmacological properties of caffeine represent the cumulative effects of not only the parent compound but also its metabolites, it is quite possible that effects attributed to caffeine per se are in fact mediated by one or more of its metabolites. It must also be noted that most of the knowledge about caffeine s effects has been derived from acute administration to fasted subjects submitted to a period of caffeine abstinence in order to ensure low plasma caffeine concentrations. It is thus difficult to extrapolate the results to the usual pattern of caffeine consumption in which... 

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