A brief introduction to caffeine, the active ingredient in coffee beans

Caffeine (Caffeine) is an alkaloid extracted from tea and coffee fruit. Moderate use of caffeine can dispel fatigue and excitatory nerves. Caffeine is used in clinical treatment of neurasthenia and coma resuscitation. However, large doses or long-term use will also cause damage to the human body, especially it is addictive, once discontinued, there will be mental fatigue, fatigue and other withdrawal symptoms, although its addiction is weak, abstinence symptoms are not very serious. However, when the drug dosage is increasing due to drug tolerance, caffeine can not only act on the cerebral cortex, but also directly stimulate the medulla oblongata, cause paroxysmal convulsions and bone tremors, and damage important internal organs such as liver, stomach and kidney. cause respiratory tract inflammation, women's breast adenoma and other diseases, and even lead to mental retardation and limb deformities of the next generation of users. Therefore, it is also included in the scope of psychotropic drugs controlled by the state.

Caffeine abuse usually has two forms of smoking and injection, and its excitatory stimulation, side effects, symptoms and drug dependence are similar to those of amphetamine.

China has cracked a number of cases in which drug traffickers at home and abroad colluded to smuggle caffeine out of the "Golden Triangle" area. At present, the legal production of caffeine in China is greater than the legal demand, and the situation of illegal channels is more serious.

chemical property

Caffeine is an alkaloid of methylxanthine. Pure caffeine is a white, strongly bitter powder. Its chemical formula is C8H10N4O2. Its chemical name is 1meme3re7-trimethylxanthine or 3meme7-dihydro-1meme3pr 7 trimethyl-1H-purine-2je 6-Dione. Molecular weight, 194.19

physical property

White powder or hexagonal prism crystal, melting point 238 °, 178 °, sublimation. 1g soluble in 46ml water, 5.5ml 80 °water, 1.5ml boiling water, 66ml ethanol, 22ml 60 °ethanol, 50ml acetone and 5.5ml chloroform. IR v max cm-1: 3100, 2970, 1700, 1660, 1550, 1480, 1360, 1240, 1020, 980,750,610; UV λ MeOHmax nm (ε): 272 (8510); NMR (CDCl3) δ: 3.4,3.6,4.0,7.6; MSm/e: 3100 (100,67 (66), 1660 (66), 55 (44), 82 (39), 42 (28), 40 (18), 41 (16) [1].

History.

As early as the Stone Age, humans began to use caffeine. Early people found that chewing the seeds, bark or leaves of certain plants can relieve fatigue and refresh. It was not until many years later that people found that the use of hot water in these plants could increase the effectiveness of caffeine. Many cultures have myths about the discovery of these plants by people in ancient times.

According to an ancient Mongolian myth, Shennong, the Chinese emperor around 3000 BC, discovered by chance that some leaves floated into boiling water to produce a fragrant and refreshing drink. The name of Shennong is also mentioned in Lu Yu's Classic of Tea, an ancient book about tea.

The early history of coffee is hazy, but a widespread myth takes us back to Ethiopia, the birthplace of Arabica coffee. According to this myth, a shepherd named Kadi found that goats become excited when they eat berries on coffee bushes and lose sleep at night, and goats constantly eat the berries again to experience the same vitality. The earliest written record of coffee is probably Bunchum, written by Persian physician al-Razi in the 9th century. In 1587, Malaye Jaziri compiled a book that traces the history and legality of coffee, called Umdat al safwa fi hill al-qahwa. In this book, Jaziri records that Jamal-al-Din al-Dhabhani, an Islamic imam of Aden, was the first person to drink coffee in 1454, and after the 15th century, Sufi Muslims in Yemen began to drink coffee regularly to keep awake during prayer. Towards the end of the 16th century, European residents in Egypt recorded the use of coffee, around which time coffee began to be widely used in the near East. Coffee was the most popular drink in Europe in the 17th century and was originally called Arabian wine. During this period, coffee shops began to increase, and the first coffee houses were in Constantinople and Venice. In England, the first coffee shop opened in 1652 on St. Michael Lane on Cornhill Street in London. Coffee soon became popular in Western Europe and played an important role in social communication in the 17th and 18th centuries.

Like coffee berries and tea, cola tree nuts have ancient origins. Many West African civilizations restore energy and reduce hunger by chewing cola tree nuts individually or in groups. In 1911, when the US government confiscated 40 large barrels and 20 small barrels of Coca-Cola, Coke became the first recorded focus of health panic. On March 13 of that year, the US government began its response to 40 and 20 small barrels of Coca-Cola, hoping to force Coca-Cola to remove caffeine from its formula through exaggerated publicity, such as at a girls' school. Excessive consumption of Coca-Cola leads to "night absurdity, violation of college rules and female etiquette, and even immorality." Although the judge finally supported Coca-Cola, two bills aimed at amending the Pure Food and Drug Act were submitted to the House of Representatives in 1912, adding caffeine to the list of "addictive" and "harmful" substances that must be listed on the product label.

The earliest evidence of the use of cocoa is the residue found in pots of the ancient Mayan civilization in the 8th century BC. In the new world, chocolate is mixed with a bitter drink called Xocoatl, often accompanied by vanilla, chili and rouge. Xocoatl is widely thought to be anti-fatigue, probably due to theobromine and caffeine. Chocolate was a luxury in Central America before Columbus discovered America, and cocoa beans were also used as currency.

Chocolate was introduced to Europe by the Spaniards in 1700, and they also introduced cocoa trees to the West Indies and the Philippines. They are used in alchemy, called black beans.

In 1819, German chemist Friedrich Ferdinand Runge isolated pure caffeine for the first time. According to a legend, he did so at Goethe's command.

Now, international sales of caffeine have reached 120000 tons a year, which is equivalent to one serving of coffee drink per person per day, which makes it the most popular mental substance in the world. In North America, 90% of adults consume a certain amount of caffeine every day.

Pharmacology

Caffeine begins to excite the central nervous system, so it can increase alertness, alert people, think quickly and clearly, increase attention and maintain good physical condition. [20] finally enter the spinal cord and maintain a high dose. In the body, the chemical reaction about caffeine is very complex [20], and the general mechanisms are as follows:

Metabolism

Caffeine is broken down in the liver to produce three primary metabolites parxanthine (84%), theobromine (12%) and and theophylline (4%). Caffeine is completely absorbed by the stomach and small intestine within 45 minutes after intake. After absorption, it will be distributed in all organs of the body, and the transformation process conforms to the chemical kinetic first-order reaction.

The half-life of caffeine, the time it takes for the body to convert half of the caffeine consumed, varies dramatically from individual to individual, mainly depending on age, liver function, pregnancy or not. at the same time, the intake of other drugs and the number of enzymes in the liver related to caffeine metabolism. The half-life of caffeine in a healthy adult is about 3-4 hours, extended to 5-10 hours in women who take contraceptives and 9-11 hours in pregnant women. When some individuals suffer from severe liver disease, caffeine accumulates and the half-life is extended to 96 hours. Caffeine in babies or children may have a longer half-life than adults and can last up to 30 hours in a newborn baby. Some other factors also shorten the half-life of caffeine, such as smoking.

The metabolism of caffeine occurs in the liver and is oxidized by the cytochrome P450 (especially 1A2 isozyme) enzyme system to form three different dimethylxanthines, which have different effects on the body.

Paraxanthine (1, 7-dimethylxanthine, 84%)-can accelerate lipolysis, resulting in an increase in the content of glycerol and free fatty acids in plasma.

Theobromine (12%)-can dilate blood vessels and increase urine volume. Theobromine is also the main alkaloid in cocoa beans and is also found in chocolate.

Theophylline (4%)-soothes bronchial smooth muscle and is used to treat asthma. The dose used in the treatment is much larger than that produced by caffeine metabolism.

These compounds are further metabolized and eventually excreted through the urine.

The effect of moderate intake

Caffeine is a central nervous system stimulant and a metabolic stimulant. Caffeine is used as both a drink and a medicine. its function is to refresh and relieve fatigue. The exact dose of caffeine that everyone needs to produce an effect varies, depending on body size and caffeine tolerance. Caffeine can begin to work in the body in less than an hour, and the effect disappears in three to four hours for a mild dose of caffeine intake. Caffeine consumption does not reduce the amount of sleep required, it can only temporarily reduce the feeling of sleepiness.

Because of these effects, caffeine is a functional enhancer: improving the brain and body. A 1979 study showed that athletes who consumed caffeine had a 7% increase in performance in long-distance cycling compared with the control group. Other studies have yielded more significant results: an experiment on trained runners showed that after consuming a dose of 9 mg of caffeine per kilogram of body weight, the athletes' straight-line running durability increased by 44%. Ring running endurance increased by 55%. Such a significant improvement is not an isolated accident, and some subsequent studies have yielded similar results. Another study showed that the duration of cycling programs increased by 29% after consuming 5.5 milligrams of caffeine per kilogram of body weight.

Caffeine is sometimes mixed with other drugs to improve their efficacy. Caffeine can increase the efficacy of headache-relieving drugs by 40% and make the body absorb these drugs faster and shorten the time it takes to work. As a result, many over-the-counter headaches contain caffeine. Caffeine is also used in conjunction with ergot to treat migraines and cluster headaches, as well as to overcome the drowsiness caused by antihistamines.

Respiratory problems in premature babies are sometimes treated with citric acid caffeine. After using citric acid caffeine therapy, the bronchial dysplasia of premature infants was significantly reduced. The only drawback of this treatment is that temporary weight gain slows down during treatment. Citrate caffeine is available only by prescription in many countries.

Caffeine is safe for humans, but caffeine is toxic to some animals, such as dogs, horses and parrots, because these animals are much less able to break down caffeine than humans. Caffeine has a significant effect on spiders, much more than other drugs.

overuse

Too much caffeine in a short period of time can lead to addiction and a series of physical and psychological adverse reactions. in the case of long-term intake, high doses of caffeine is a drug that can lead to "caffeine poisoning". Caffeine poisoning includes addiction and a range of physical and psychological adverse reactions, such as nervousness, irritability, anxiety, tremors, muscle convulsions (hyperreflexia), insomnia and palpitations (under the strict definition of addiction, only gradually increasing dosage is addictive, it is more appropriate to describe caffeine dependence, but under a widely accepted definition, all chronic behaviors that are difficult to get rid of are called addiction. So it can also be described as caffeine addiction.) In addition, because caffeine can increase stomach acid, sustained high doses can lead to peptic ulcers, erosive esophagitis and gastroesophageal reflux disease. However, because both normal coffee and decaffeinated coffee stimulate the gastric mucosa and increase gastric acid secretion, caffeine may not be the only ingredient in coffee.

Four caffeine-induced disorders verified by the Diagnostic and Statistical Manual of Mental Disorders (fourth Edition) include caffeine overexertion, caffeine anxiety, caffeine sleep disorders and other caffeine-related disorders.

Caffeine is overexcited

A sharp overdose of caffeine, usually more than 250 milligrams (equivalent to 2-3 cups of brewed coffee), can cause overexcitement in the central nervous system. Symptoms of caffeine overexcitement include irritability, nervousness, excitement, insomnia, blushing, increased urine, gastrointestinal disorders, muscle convulsions, distraction, irregular or rapid heartbeat, and restlessness.

Consuming extremely large doses of caffeine can lead to death. For experimental mice, the half lethal dose of caffeine was 192 mg per kilogram of body weight. The half-lethal dose of caffeine depends on weight and personal sensitivity, about 150 to 200 milligrams per kilogram of body weight, about 140 to 180 cups of coffee consumed by the average adult in a limited period of time, depending on the biological half-life. Although it is almost impossible to die from drinking regular coffee, there are reports of deaths due to excessive use of caffeine pills.

The treatment of caffeine overexertion is usually auxiliary, that is, individual symptoms are treated accordingly. However, if the patient's serum caffeine concentration is too high, it is possible to take peritoneal dialysis, hemodialysis and hemofiltration and other methods.

Caffeine anxiety disorder and sleep disorder

Long-term excessive caffeine intake can cause a series of mental disorders. Two of those identified by the American Psychiatric Association are caffeine anxiety disorder and caffeine sleep disorder.

Caffeine sleep disorder refers to a sleep disorder caused by an individual's regular intake of high doses of caffeine, which can be detected by clinical diagnosis.

For some individuals, the anxiety caused by large doses of coffee is enough to be detected by clinical diagnosis. Caffeine anxiety disorders can take different forms, including general anxiety disorders, panic attacks, obsessive-compulsive disorder and even phobia. Because these symptoms are easily confused with basic neurological disorders, such as panic disorder, general anxiety disorder, bipolar disorder or even schizophrenia, some medical workers believe that some people who eat too much caffeine are misdiagnosed and given unnecessary treatment. they believe that caffeine-induced mental illness can be easily controlled by cutting off the source of caffeine. Although rarely diagnosed, chronic caffeine poisoning affects at least 1/10 of the population, according to a survey by the British Journal of Addiction (British Journal of Addiction).

Source

The main source of caffeine in the food industry is coffee beans. But the caffeine content of coffee beans varies from variety to variety. Some trees found in Ethiopia in 2004 had 15 times higher caffeine than the average. The amount of caffeine in a cup of coffee ranges from 75 to 250 milligrams. Tea and cola contain less caffeine than coffee, while Madai tea is much higher. Here are the caffeine levels of some foods:

Chocolate

Sweet and bitter chocolate-875 mg / kg

Cream chocolate-100 to 210 mg / kg

Cocoa-17 mg / L

Coffee

Freshly brewed coffee-130 to 680 mg / L

Decaffeinated coffee-13 to 20 mg / L

Instant coffee-130 to 400 mg / L

Italian espresso-3400 mg / L

Tea

(related to the method and time of making tea)

Black tea-100 to 470 mg / L

Oolong tea-120 mg / L

Green tea-85 mg / L

White tea-68 mg / L

Caffeinated tea-17 mg / L

The caffeine in tea is sometimes called tea caffeine or tea pigment. People may think the two are different, but there are other xanthines in tea, including theophylline, Madine and other compounds.

Red Bull drink

Red Bull Beverage (made in China)-50 mg / can

Coke drinks

Coke drinks-about 45 mg / can

Metabolism, toxicity and effects on health

Caffeine blocks adenosine receptors in the brain. Adenine nucleoside binds to its receptor to slow down the activity of nerve cells. It is common to combine the two during sleep. Caffeine molecules are similar to adenine nucleosides and can bind to the same receptor. But it does not reduce cell activity. On the contrary, it prevents adenine nucleoside from binding to its receptor. The result is increased activity of nerve cells, which secrete the hormone epinephrine. Adrenaline causes the heart to beat faster, blood pressure to increase, blood flow to the muscles to increase, blood flow to the skin and viscera to decrease, and the liver to release glucose into the blood. In addition, caffeine, like aminopropylbenzene, increases the neurotransmitter dopamine in the brain.

Unlike other substances and alcohol that stimulate the central nervous system, caffeine has a short effect. For most people, caffeine does not affect their attention and other advanced intellectual functions, so caffeinated drinks are often consumed in the workplace.

Drinking caffeine for a long time can lead to a habit of caffeine in the body. If caffeine is interrupted at this time, the body will be overly sensitive to adenosine and blood pressure will drop too much, leading to headaches and other symptoms. Some recent studies seem to suggest that caffeine consumption reduces the risk of Parkinson's disease, but the findings of this study have yet to be confirmed.

Too much caffeine can lead to caffeine poisoning. The symptoms are irritability, nervousness, irritation, insomnia, blushing, polyuria and gastrointestinal discomfort. Some people have these symptoms when they take less than 250 milligrams a day. More than 1 gram a day can lead to spasms, sudden changes in thought and language, unstable heartbeat, tachycardia and psychomotor agitation. The symptoms of caffeine poisoning are somewhat similar to panic attacks and generalized anxiety disorders. 192 mg / kg of body weight [source request] or 72 cups of coffee for the average adult can kill half of people.

Caffeine is safe for humans, but caffeine and other similar substances such as theophylline and caffeine can be highly toxic to other animals, such as dogs and horses, because their liver metabolism is different from that of humans. At present, the medical profession believes that caffeine is associated with bone loss and osteoporosis, so it is recommended to eat coffee, tea and other drinks.