IM J Arnaud, Nestle S.A., Vevey, Switzerland
© 2005 Elsevier Ltd. All rights reserved.
During the period 1820-1827, three white crystalline substances called 'caffein' or 'coffein,' 'guar-anin,' and 'thein' were isolated from green coffee beans, guarana, and tea, respectively. These substances were shown in 1838-1840 to be identical. Later, caffeine was also discovered in mate; prepared from Ilex paraguariensis and kola nuts. Since then, caffeine has been shown to be a natural constituent of more than 60 plant species.
Two other related compounds, theophylline and theobromine, have also been isolated from tea and cocoa beans, respectively while a third, paraxanthine, was isolated from human urine (Figure 1). By the end of the nineteenth century, all of these methylated xanthines had been synthesized. Caffeine, both natural and synthetic, has been used as a flavoring agent in food and beverages and as an active component of a variety of over-the-counter pharmaceutical products and drugs. A regulation adopted by the European Commission requires the compulsory labeling 'high caffeine content' when soft drinks contain more than 150 mg caffeine per liter.
In addition to natural caffeine obtained by the industrial decaffeination process, caffeine can also be obtained by the methylation of theobromine and also by total chemical synthesis using dimethyl-carbamide and malonic acid.
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