Joined in 2023 
82 
63 About this deal
In 1895, German chemist Hermann Emil Fischer (1852–1919) first synthesized caffeine from its chemical components (i.e. a " total synthesis"), and two years later, he also derived the structural formula of the compound. [267] This was part of the work for which Fischer was awarded the Nobel Prize in 1902. [268] Historic regulations Caffeine is metabolized in the liver by the cytochrome P450 oxidase enzyme system, in particular, by the CYP1A2 isozyme, into three dimethyl xanthines, [188] each of which has its own effects on the body: The command line is now interpreted and shows in the tooltip. This means you can see what Caffine has recognised. In 1827, M. Oudry isolated "théine" from tea, [264] but in 1838 it was proved by Mulder [265] and by Carl Jobst [266] that theine was actually the same as caffeine. In addition to its activity at adenosine receptors, caffeine is an inositol trisphosphate receptor 1 antagonist and a voltage-independent activator of the ryanodine receptors ( RYR1, RYR2, and RYR3). [167] It is also a competitive antagonist of the ionotropic glycine receptor. [168] Effects on striatal dopamine
Regular consumption of caffeine may protect people from liver cirrhosis. [129] It was also found to slow the progression of liver disease in people who already have the condition, reduce the risk of liver fibrosis, and offer a protective effect against liver cancer among moderate coffee drinkers. A study conducted in 2017 found that the effects of caffeine from coffee consumption on the liver were observed regardless of how the drink was prepared. [130]
The power of caffeine to keep us awake and alert, to stem the natural tide of exhaustion, freed us from the circadian rhythms of our biology and so, along with the advent of artificial light, opened the frontier of night to the possibilities of work. This is an edited extract from This Is Your Mind on Plants: Opium-Caffeine-Mescaline by Michael Pollan, published by Allen Lane on 8 July and available at guardianbookshop.co.uk Extraction of caffeine from coffee, to produce caffeine and decaffeinated coffee, can be performed using a number of solvents. Following are main methods:
Caffeine is also a common ingredient of soft drinks, such as cola, originally prepared from kola nuts. Soft drinks typically contain 0 to 55 milligrams of caffeine per 12 ounce (350mL) serving. [232] By contrast, energy drinks, such as Red Bull, can start at 80 milligrams of caffeine per serving. The caffeine in these drinks either originates from the ingredients used or is an additive derived from the product of decaffeination or from chemical synthesis. Guarana, a prime ingredient of energy drinks, contains large amounts of caffeine with small amounts of theobromine and theophylline in a naturally occurring slow-release excipient. [233] Other beverages Awwad S, Issa R, Alnsour L, Albals D, Al-Momani I (December 2021). "Quantification of Caffeine and Chlorogenic Acid in Green and Roasted Coffee Samples Using HPLC-DAD and Evaluation of the Effect of Degree of Roasting on Their Levels". Molecules. 26 (24): 7502. doi: 10.3390/molecules26247502. PMC 8705492. PMID 34946584. For the general population of healthy adults, Health Canada advises a daily intake of no more than 400mg. [72] This limit was found to be safe by a 2017 systematic review on caffeine toxicology. [73] Children Chocolate derived from cocoa beans contains a small amount of caffeine. The weak stimulant effect of chocolate may be due to a combination of theobromine and theophylline, as well as caffeine. [237] A typical 28-gram serving of a milk chocolate bar has about as much caffeine as a cup of decaffeinated coffee. By weight, dark chocolate has one to two times the amount of caffeine as coffee: 80–160mg per 100g. Higher percentages of cocoa such as 90% amount to 200mg per 100g approximately and thus, a 100-gram 85% cocoa chocolate bar contains about 195mg caffeine. [221] Tablets No-Doz 100mg caffeine tabletsIn 1819, Runge was invited to show Goethe how belladonna caused dilation of the pupil, which Runge did, using a cat as an experimental subject. Goethe was so impressed with the demonstration that: Funk GD (November 2009). "Losing sleep over the caffeination of prematurity". The Journal of Physiology. 587 (Pt 22): 5299–300. doi: 10.1113/jphysiol.2009.182303. PMC 2793860. PMID 19915211. High caffeine consumption in energy drinks (at least 1 liter or 320mg of caffeine) was associated with short-term cardiovascular side effects including hypertension, prolonged QT interval, and heart palpitations. These cardiovascular side effects were not seen with smaller amounts of caffeine consumption in energy drinks (less than 200mg). [79] Severe intoxication Death from caffeine ingestion appears to be rare, and most commonly caused by an intentional overdose of medications. [144] In 2016, 3702 caffeine-related exposures were reported to Poison Control Centers in the United States, of which 846 required treatment at a medical facility, and 16 had a major outcome; and several caffeine-related deaths are reported in case studies. [144] The LD 50 of caffeine in rats is 192 milligrams per kilogram, the fatal dose in humans is estimated to be 150–200 milligrams per kilogram (2.2lb) of body mass (75–100 cups of coffee for a 70kg (150lb) adult). [145] [146] There are cases where doses as low as 57 milligrams per kilogram have been fatal. [147] A number of fatalities have been caused by overdoses of readily available powdered caffeine supplements, for which the estimated lethal amount is less than a tablespoon. [148] The lethal dose is lower in individuals whose ability to metabolize caffeine is impaired due to genetics or chronic liver disease. [149] A death was reported in 2013 of a man with liver cirrhosis who overdosed on caffeinated mints. [150] [151] Interactions My special was unbelievably good, a ringing reminder of what a poor counterfeit decaf is; here were whole dimensions and depths of flavour that I had completely forgotten about. Everything in my visual field seemed pleasantly italicised, filmic, and I wondered if all these people with their cardboard-sleeve-swaddled cups had any idea what a powerful drug they were sipping. But how could they?
Remember that caffeine is found in quite a few sources including: tea, green tea, coffee, energy drinks, cola and chocolate Should I avoid energy drinks because of their caffeine content?Supercritical carbon dioxide extraction: Supercritical carbon dioxide is an excellent nonpolar solvent for caffeine, and is safer than the organic solvents that are otherwise used. The extraction process is simple: CO 2 is forced through the green coffee beans at temperatures above 31.1°C and pressures above 73 atm. Under these conditions, CO 2 is in a " supercritical" state: It has gaslike properties that allow it to penetrate deep into the beans but also liquid-like properties that dissolve 97–99% of the caffeine. The caffeine-laden CO 2 is then sprayed with high-pressure water to remove the caffeine. The caffeine can then be isolated by charcoal adsorption (as above) or by distillation, recrystallization, or reverse osmosis. [207] Caffeine can be quantified in blood, plasma, or serum to monitor therapy in neonates, confirm a diagnosis of poisoning, or facilitate a medicolegal death investigation. Plasma caffeine levels are usually in the range of 2–10mg/L in coffee drinkers, 12–36mg/L in neonates receiving treatment for apnea, and 40–400mg/L in victims of acute overdosage. Urinary caffeine concentration is frequently measured in competitive sports programs, for which a level in excess of 15mg/L is usually considered to represent abuse. [209] Analogs Caffeine may be synthesized in the lab starting with dimethylurea and malonic acid. [ clarification needed] [200] [201] [205]
Caffeine is a bitter, white crystalline purine, a methylxanthine alkaloid, and is chemically related to the adenine and guanine bases of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). It is found in the seeds, fruits, nuts, or leaves of a number of plants native to Africa, East Asia and South America, [18] and helps to protect them against herbivores and from competition by preventing the germination of nearby seeds, [19] as well as encouraging consumption by select animals such as honey bees. [20] The best-known source of caffeine is the coffee bean, the seed of the Coffea plant. People may drink beverages containing caffeine to relieve or prevent drowsiness and to improve cognitive performance. To make these drinks, caffeine is extracted by steeping the plant product in water, a process called infusion. Caffeine-containing drinks, such as coffee, tea, and cola, are consumed globally in high volumes. In 2020, almost 10 million tonnes of coffee beans were consumed globally. [21] Caffeine is the world's most widely consumed psychoactive drug. [22] [23] Unlike most other psychoactive substances, caffeine remains largely unregulated and legal in nearly all parts of the world. Caffeine is also an outlier as its use is seen as socially acceptable in most cultures and even encouraged in others. a b c d Poleszak E, Szopa A, Wyska E, Kukuła-Koch W, Serefko A, Wośko S, Bogatko K, Wróbel A, Wlaź P (February 2016). "Caffeine augments the antidepressant-like activity of mianserin and agomelatine in forced swim and tail suspension tests in mice". Pharmacological Reports. 68 (1): 56–61. doi: 10.1016/j.pharep.2015.06.138. PMID 26721352. S2CID 19471083. These HUGE bottles, 1 litre each, will last you a very, very long time (great value for money. I find the shampoo to be really nourishing on its own, so I tend to only the conditioner 1 – 2 times a week, and that seems to be working wonders for my hair. Pure anhydrous caffeine is a bitter-tasting, white, odorless powder with a melting point of 235–238°C. [10] [11] Caffeine is moderately soluble in water at room temperature (2g/100 mL), but very soluble in boiling water (66g/100 mL). [193] It is also moderately soluble in ethanol (1.5g/100 mL). [193] It is weakly basic (pK a of conjugate acid = ~0.6) requiring strong acid to protonate it. [194] Caffeine does not contain any stereogenic centers [195] and hence is classified as an achiral molecule. [196]
On this page
Caballero B, Finglas P, Toldra F (2015). Encyclopedia of Food and Health. Elsevier Science. p.561. ISBN 978-0-12-384953-3 . Retrieved 17 June 2018. A systematic review and meta-analysis from 2014 found that concurrent caffeine and L-theanine use has synergistic psychoactive effects that promote alertness, attention, and task switching; [57] these effects are most pronounced during the first hour post-dose. [57] Physical performance This section needs expansionwith: practical management of overdose, see PMID 30893206. You can help by adding to it. ( November 2019)
Related:
Great Deal 
New Comment