Alkaloids xanthine

Gilkey, R., Sheeley, R.M., Hurst, W.J., Martin, R.A. Dimerization of xanthine alkaloids as an explanation of extreme solublity differences, 16 MARM, 1984. 

Abstract Caffeine, a xanthine alkaloid, occurs in teaplants, coffee, mate leaves and cola nuts, ft is also commonly found beverages, such as cola drinks, tea and energy drinks. 

Several purine derivatives are found in nature, e.g. xanthine, hypoxanthine and uric acid. The pharmacologically important (CNS-stimulant) xanthine alkaloids, e.g. caffeine, theobromine and theophylline, are found in tea leaves, coffee beans and coco. The actual biosynthesis of purines involves construction of a pyrimidine ring onto a pre-formed imidazole system. 

HaitwickeJ al. (HIO) studied the use of high-ionic-strength solutions for the precipitation of serum proteins. In this technique a saturated solution of ammonium sulfate was added to serum and the supernatant was analyzed by RPLC after centrifugation. The recoveries for serum nucleosides and xanthine alkaloids were good, ranging from 93 to 100%. In addition, the serum profile showed no interference from this extraction technique. 

Indications Peripheral vascular disease, intermittent claudication Category Vasodilator, peripheral Xanthine alkaloid Half-life 0.4-0.8 hours... 

EXPERIMENTAL CONDITIONS USED FOR GAS CHROMATOGRAPHY OF XANTHINE ALKALOIDS... 

Q,xanthine alkaloids Various drugs Identification in serum... 

XANTHINE ALKALOIDS IN THE CONTEXT OF HPLC ANALYSIS OF DRUGS OF ABUSE (CHAPTER 7)... 

Xanthates. See Carbonodithioates 9/f-Xanthene, 9-chloro-9-phenyl- pixyl O-protection with, 341-324 Xanthine = 3,7-dihydro-ltf-purine-2,6-dione synthesis and methylation, 306 Xanthine alkaloids pr., 290 caffeine, 306... 

Bohinc, P. etal. 1977. Xanthine alkaloids in Ilex ambigua leaves Farmacevtski Vest-nikii-. 89-96. 

Caffeine is the most popular psychoactive stimulant. This xanthine alkaloid occurs in coffee, tea, and cola beverages. At a modest dose of 100-200 mg, it enhances wakefulness and reduces fatigue. However, intake of higher quantities (>500 mg/day) can cause addiction. Other psychostimulant substances include deanol, pemoline, and their derivatives. These substances have limited clinical apphcation. The structures of caffeine. 

The dominating active ingredients in the three plants are xanthine alkaloids caffeine, theobromine and theophylline (Fig. 2.36). Raw coffee contains 0.9-1.4% (Arabica) or 1.5-2.6% (Robusta) of caffeine. Tea leaves contain 3.2 % of caffeine, but the different preparation method results in about half as much caffeine in the drink compared to coffee. The main active ingredient of cocoa is theobromine, there is only 0.2% caffeine in it, but this small amount is still responsible for the stimulating effect. 

Many indigenous groups in the world have developed particular teas used as stimulant beverages. Among those are coffee, green tea, black tea, guarana, and mate. It is interesting to note that the xanthine alkaloid caffeine is a principal component of all these drinks. In this book, caffeine is described in Chapter 11.1. 

Their wide spectrum of biolc cal activities provides numerous classes of useful medicinal agents, and yet, at the same time, they provide a global paradox. In spite of many health beneficent effects, two alkaloids, cocaine and morphine (and its derivative heroin), are the ft)cus of a counter culture of illicit use of biological powerful alkaloids, and many alkaloids, because of their profound toxicity, are to be feared. On the other hand, the xanthine alkaloids, caffeine and threobromine, are an integral aspect of providing pleasure in the daily lives of most of the world in the consumption of tea, coffee, and chocolate. 

Other Sources of Imidazole Alkaloids Lythraceae alkaloids Maytansinoids Antitumor Activity Other Biological Activity Muscarine Alkaloids Naphthylisoquinoline Alkaloids Peptide Alkaloids Purine or Xanthine Alkaloids Biosynthesis... 

Fig. 37.10. Biogenesis of xanthine alkaloids (modified from Suzuki et al., 1992 modified and used with permission of the copyright owner, Elsevier Science Ltd., The Boulevard, Langford Lane, Kidlington 0X5 1GB, UK).

A Figure 7.2 Basic drugs and classes, the largest subgroup in the acid-base classification scheme. The alkaloids are (or at least once were) derived from plant matter, while nonalkaloids are generally synthetic or semisynthetic. Tropane alkaloids Include cocaine, while tryptamines include mescaline and psilocyn. Caffeine and theophylline are xanthine alkaloids. The selective serotonin reuptake inhibitors (SSRIs) include the second-generation SSRI antidepressants. Prozac (fluoxetine, shown) and Paxil belong to this class. 

Like the salicylates mentioned in the previous chapter, xanthine alkaloids (Figure 8.22) are of forensic interest not because they are controlled, but because... 

A Figure 8.22 Representative xanthine alkaloids. Theophylline is found in many teas, in chocolate, and, occasionally, as an adulterant, although caffeine is much more common. 

Caffeine A xanthine alkaloid sometimes encoxmtered as an adulterant of heroin or related drug samples. Cahn-Ingold-Prelog convention The most common method used to describe bonding around a chiral atom uses the R/S notation and assigned priorities. 

Xanthine alkaloids Alkaloids that include caffeine, theophylline and other compounds found in coffee, tea, and chocolate. 

The history of the xanthine alkaloids (Fig. 4.38) goes back to ancient times when their plant sources were discovered. Caffeine was extracted from tea, coffee and cocoa theophylline was mainly found in tea extract,... 

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