Xanthine base

This chapter has compiled and evaluated information on the methylxanthine composition of cocoa and various chocolate foods and beverages, as well as the consumption pattern for these commodities. Cacao is the major natural source of the xanthine base theobromine. Small amounts of caffeine are present in the bean along with trace amounts of theophylline. Numerous factors, including varietal type and fermentation process, influence the methylxanthine content of beans. 

Hlavay J., Haemmerli S.D., Guilbault G.G., Fibre-optic biosensor for hypoxanthine and xanthine based on a chemiluminescence reaction, Biosens. Bioelectron 1994 9 189-195. 

Pierce Chemical Co. (14) supplies the reagent under the name Methelute. Their literature describes applications for various sedatives, barbiturates, xanthine bases, phenolic alkaloids and Dilantin. Supelco Inc. also supplies the reagent for barbiturate determinations (30). Care should be taken to insure the column is stable to traces of methanol. Also, chromatographic temperatures must be high enough to insure adequate rates of reaction. 

The total nitrogen of extracts varies from 8-5 to 9-5% at least 10% of the total nitrogen should be in the form of creatine and creatinine, which are the most characteristic chemical constituents of meat ext racts. Albumoses also are normal components and vary between 5 and 10%, while the proportion of the total nitrogen in the form of xanthine bases should be 6-9%. The ammonia should not exceed o-6% (mean of numerous analyses). 

E. Brochmann-Hanssen and T. O. Oke, Gas chromatography of barbiturates, phenolic alkaloids, and xanthine bases Flash-heater methylation by means of trimethylanilinium hydroxide, J. Pharm. Sci., 55 370(1969). 

The firm of C. F. Boehringer Sohne (Waldhof-Mannheim) has patented 2 Tafel s process for reducing xanthine bases. 

The imidazo[l,5-a]pyrimidines 68 and benzo[4,5]imidazo[l,2-a]pyrimidines 69 were prepared. Cyclization of imidazolones with thiourea or cyanoguanidine gave the cis and trans isomers of 70. Xanthine bases, caffeine, theophyline gave the 6-thio and 2,6-dithio derivatives by using Lawesson s reagent. ... 

Phosphoproteins.—Proteins of this class when subjected to the action of pepsin and hydrochloric acid, undergo hydrolysis, and yield proteoses and an acid containing phosphorus, which is called paranucleic acid. This acid is sharply distinguished from the nucleic acids, as neither xanthine bases, pyrimidine derivatives, nor pentoses occur among its dissociation-products. Paranucleic acid has not been obtained in the pure condition, and its decomposition-products are not definitely known. The phosphoproteins are distinctly acid, are insoluble in water, and form soluble salts which contain the alkali metals and ammonium. 

Fig. 9. A model of the interactions between a substrate ribonucleotide (ADP), an effector deoxy-ribonucleotide (dGTP), and ribonucleotide reductase. An underlying network of ionic forces and hydrogen bonds is proposed, as known from nucleotide - amino acid interactions in general. This model could explain the inactivity of ribonucleotides having N-methylated, syn-oriented, or anionic (xanthine) bases, the action of effector nucleotides through induced-fit positioning of the substrate base, and greater structural freedom observed for the effector sites - (H)B- indicates a...

The nudeo-proteins under the influence of enzymes are successively transformed into nucleins, into nudeic adds, then into xanthin bases, into phosphoric acid, etc. But only the first phase of the transformation, that which corresponds to the formation of protein and nudein, can be realized by p>epsin and trypsin. The nudeins resist the action of the digestive juices, botii gastric arid pancreatic. The transformation of the nucleins first into nucldc adds, then into phosphoric add and into purin bas, is induced in living cells, on the contrary, by the endo-cellular enzymes, which bear the name of nucleases. 

The nudease of pancreas in dry form is prepared in the following manner i kilogram of pancreas is reduced to paste with sand, then submitted to the action of a Budmer press. The juice which immediately flows out is saturated with ammonium sulphate. The precipitate obtained is washed with alcohol and with ether, and then dried. In this form it preserves very well. This product rapidly liquefies the Jelly of nudeic add to give xanthin bases and phosphoric acid. 

Levene, who made remarkable investigations on the chemistry of the nucleins, believes that to the three phases of the decomposition of nucleins correspond three dasses of different enzymes nttdeimses, nucleotidases, nucleosidases. The first transform nuddc molecules into nudeotids without liberation of phosphoric acid the second split nudeotids into nudeosids and phosphoric add finally, the third decompose nudeosids into carbohydrate and xanthin bases. 

A number of miscellaneous types of alkaloids not easily assignable to other alkaloid classes, but that are of interest because of their medical, drug, systematic, biosynthetic, or other properties, are surveyed in this chapter. Many of these are of limited distribution, whereas others, such as caffeine (a xanthine base), are widely and sporadically distributed. 

Fonolla Moreno, A. Plot, B. Cosmetic composition with slimming action comprising a xanthine base. U.S. Pat. Appl. Publ. US 2006134234, 2006 Chem. Abstr. 2006,145, 69851. 

Alkaloids are classified into two main groups heterocyclic and non-heterocyclic. In this work, authors will only deal with the heterocyclic alkaloids that have a quinoUne nucleus (tryptophan derivatives), which include the alkaloids of quina, and the group of diverse alkaloids, specifically the xanthine bases or purine alkaloids. 

Xanthine bases or purine alkaloids are secondary metabolites, derivatives of xanthine caffeine, theophylline and theobromine are three very well-known examples. These compounds occur naturally in the seeds of coffee, cola, guarana and cacao, as well as in the leaves of tea and mate (Council of Europe, 1989 Zheng et al 2004). These compounds improve and stimulate blood circulation, an action that justifies the use of these vegetable compounds in anti-cellulite cosmetic formulations (Bertin et al 2001). Such an effect is the consequence of their adenosine-antagonist action, which influences the )S-adrenergic system by stimulating the vasodilator response. Additionally, xanthine bases specifically... 

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