Why is caffeine an alkaloid

Caffeine is an alkaloid , which means that it contains mostly nitrogen atoms. Morphine and nicotine are also common alkaloids. Pure caffeine is also known as trimethylxanthine and is highly water-soluble. Caffeine is metabolized by the liver and broken down into theophylline, theobromine, and paraxanthine. A mg dose of caffeine would take about 40 hours to be completely metabolized based on the average caffeine half-life of hours. However, the greatest perceived effects from the caffeine are experienced during the first hours after consumption.

While being metabolized by the body caffeine has several well-documented positive effects on the body and its processes. Here are some of the major effects. People who are experiencing the negative side-effects of caffeine are advised to quit or cut back on their consumption. Originally caffeine was only ingested through the consumption of plant parts that naturally contain caffeine, but food scientists began synthesizing caffeine as an additive for all kinds of beverages and foods.

According to our databases , there are over products that contain some level of caffeine and there are many more yet to be added from all around the world. Generally, caffeine is found in coffee and tea-based beverages and products, chocolate-based beverages and products, sodas, energy drinks, energy shots, and a wide range of supplements including pain relievers as well as workout supplements.

Many companies have begun voluntarily disclosing how much caffeine their products contain on labels and we expect this trend to continue. See our extensive database for the caffeine content of beverages here and the amount in foods here. Because caffeine is a stimulant, it should be respected and kept within safe levels for daily consumption. For a more in-depth look at daily caffeine safety amounts as well as visual representations of each amount see this article.

Recently both caffeine overdose and caffeine withdrawal were both added to the latest edition of the Diagnostic and Statistical Manual of Mental Disorders DSM-5 , but caffeine addiction has not been added as a diagnosable condition. However, those that use caffeine and have tried to quit can attest that caffeine causes some degree of both psychological and physiological addiction. Caffeine addiction can range from mild to severe and most of the time it is an addiction most people can live a healthy life with.

This is not the case when dangerous amounts of caffeine are being consumed daily or if caffeine is consumed through sugary beverages, which are linked to obesity and type 2 diabetes. Use our Caffeine Addiction Diagnosis Tool to assess your level of addiction to caffeine. Cutting back on caffeine would be recommended for anyone who begins to consume amounts exceeding what is recommended as safe or if getting enough caffeine interferes with work or daily functioning. Since caffeine is a toxic substance it can cause severe overdose reactions and even death if too much is consumed at one time or over a short period of time.

Coffea canephora robusta is known to contain more caffeine than Coffea Arabica arabica However, as a basic guideline an average sized cup of soluble coffee contains approximately 65mg caffeine, whilst a cup of roast and ground coffee contains around 85mg.

A 30ml espresso cup contains around mg caffeine. Although the presence of the other gene that encodes 7-methyl-XMP synthase cannot be excluded, current evidence supports the hypothesis that caffeine biosynthesis is begins with xanthosine.

However, isolation of the native enzyme as well as RNA encoding this enzyme has not yet been reported in coffee plants. Theobromine synthase and caffeine synthase: Bifunctional caffeine synthase, which catalyses both the conversion of 7-methylxanthine to theobromine and theobromine to caffeine, was first purified from tea leaves up to apparent homogeneity Kato et al.

This enzyme is monomeric, with an apparent molecular mass of 41 kDa, and displays a sharp pH optimum of pH 8. In coffee, bifunctional caffeine synthase has been partially purified from fruits and leaves by Mazzafera et al.

This enzyme preparation possessed second and third N -methyltransferase activity. In coffee, genes encoding two types of N -methyltransferase for the last two steps of caffeine biosynthesis have recently been reported Mizuno et al. As shown in Table 1, substrate specificity of the recombinant theobromine synthase is specific for theobromine synthesis step 2 , but the recombinant caffeine synthase utilises paraxanthine, theobromine and 7-methylxanthine, as in the native tea caffeine synthase Kato et al.

Although paraxanthine is the most suitable substrate, formation of paraxanthine in coffee plant tissues in vivo seems to be very restricted. Therefore, this enzyme seems to contribute to the conversion of 7-methylxanthine to caffeine via theobromine in planta. Caffeine biosynthesis in coffee leaves: Caffeine is synthesised in young leaves of Coffea arabica , but its biosynthetic activity from adenine is absent in fully developed leaves Fujimori and Ashihara, It has been proposed that the synthesis of caffeine in buds and leaves of coffee plants is to prevent predation by animals Frischknecht et al.

Ashihara et al. Caffeine synthase activity therefore seems to be present in coffee leaves even after maturation. This is different from tea leaves, in which caffeine synthase activity disappeared after full development of the leaves Fujimori et al.

Caffeine biosynthesis in coffee fruits: Biosynthesis of caffeine can be estimated from the incorporation of [methyl- 14 C]methionine. It occurs mainly during the immature green stage of coffee fruit development Suzuki and Waller, More detailed studies have recently been made by Koshiro et al. Their data indicate that caffeine biosynthetic activity, as estimated from the incorporation of [8- 14 C]adenine into theobromine and caffeine, is higher in pericarps and seeds of fruits in the early stages of development than in the later stages.

However, expression of the caffeine synthase gene, estimated by RT-PCR, was found in all stages of coffee fruit development up to the pre-maturation stage Koshiro et al.

Degradation of caffeine: As stated above, caffeine is produced in young leaves and immature fruits, and continues to accumulate gradually during the maturation of these organs. However, it is very slowly degraded with the removal of the three methyl groups, resulting in the formation of xanthine figure 3.

Xanthine is further degraded by the conventional purine catabolism pathway to CO 2 and NH 3 via uric acid, allantoin and allantoate. A detailed review of catabolism of caffeine in plants and microorganisms has been published by Mazzafera Since exogenously supplied [8- 14 C]theophylline is degraded to CO 2 far more rapidly than [8- 14 C]caffeine, the initial step, namely the conversion of caffeine to theophylline, seems to be the major rate-limiting step of caffeine catabolism Ashihara et al.

In leaves of Coffea eugenioides , a low caffeine-containing species, [8- 14 C]caffeine was degraded rapidly, and much of the radioactivity was recovered as 14 CO 2 Ashihara and Crozier, Coffea eugenioides therefore possessed far higher levels of caffeine demethylase activity, and is able to convert endogenous caffeine efficiently to theophylline, which is rapidly degraded further. However, attempts to detect caffeine demethylase activity in the extracts in vitro are have still been unsuccessful Ashihara and Crozier, unpublished result.

Biotechnology of caffeine: In economic terms, coffee is one of the most valuable agricultural products exported by developing countries in Central and South America, Southeast Asia and Africa. Beans of Arabica and Robusta coffee respectively contain ca. Since the early s, the demand for decaffeinated coffee has increased rapidly.

This is because of a growing belief that ingestion of large amounts of caffeine has adverse effects on health. This has led to extensive debate in the medical literature, although no clear conclusions have been drawn Ashihara and Crozier, The use of genetic engineering to produce transgenic caffeine-deficient coffee has been investigated.

Genes encoding N -methyltransferases have been cloned. This development makes it possible by genetic engineering to produce transgenic coffee plants that are naturally deficient in caffeine. The use of such products to make full flavoured caffeine-free beverages will be of interest to the increasing number of consumers who are concerned about the adverse effects of caffeine consumption, such as insomnia.

The cloning of genes related to caffeine biosynthesis N -methyltransferase genes is an important advance towards the production of transgenic caffeine-deficient coffee through gene silencing with RNA interference technology. Recently, using nucleotide sequences of genes encoding N -methyltransferases for caffeine biosynthesis, transgenic caffeine-deficient Coffea canephora plants have been created Ogita et al.

The preparation of a low caffeine good quality tea using gene silencing of other genes has been attempted. Keya et al. It is currently believed that the tea-specific amino acid, theanine, makes a major contribution to umami taste, which is quite distinct from four basic tastes Koshiishi et al.

IMP may also be involved, since nucleotide seasonings are known to interact synergistically with amino acid-based tastes. Purine nucleotides in fresh tea leaves may be converted to IMP during commercial processing. Metabolic engineering to accumulate IMP and related nucleotides would therefore be of value. Kaya et al. Besides interfering on adenosine receptors, caffeine interacts with acetylcholinesterase, monoamine oxidase, phosphodiesterase, ryanodine receptors and others.

Current research is devoted to the role of caffeine in neurodegenerative diseases and immunity alteration. New chemical compounds based on caffeine moiety are prepared Tab. Abstract Caffeine 1,3,7-trimethylxanthine is a plant secondary metabolite with a significant impact on multiple processes and regulatory pathways in the body.