Showing papers on "Theobromine published in 2003"

Producing decaffeinated coffee plants

Abstract: The demand for decaffeinated coffee is increasing because the stimulatory effects of caffeine can adversely affect sensitive individuals by triggering palpitations, increased blood pressure and insomnia1. Three N-methyltransferase enzymes are involved in caffeine biosynthesis in coffee plants — CaXMT1, CaMXMT1 (theobromine synthase) and CaDXMT1 (caffeine synthase), which successively add methyl groups to xanthosine in converting it into caffeine2,3,4. Here we describe the construction of transgenic coffee plants in which expression of the gene encoding theobromine synthase (CaMXMT1) is repressed by RNA interference (RNAi). The caffeine content of these plants is reduced by up to 70%, indicating that it should be feasible to produce coffee beans that are intrinsically deficient in caffeine.

Antioxidant and prooxidant properties of caffeine, theobromine and xanthine.

Abstract: Background Caffeine, along with its catabolic products theobromine and xanthine, is a key component of tea and coffee. These compounds are structurally similar to uric acid, a known antioxidant which is present in blood at relatively high concentrations, but also shows prooxidant activity. In view of the structural similarity between uric acid and caffeine and its metabolites, we studied the antioxidant and prooxidant properties of these compounds. Material/methods Antioxidant activity was determined by measuring the quenching effect of the compounds on oxidative DNA degradation by a hydroxyl radical generating system. Prooxidant activity was studied by measuring the ability of the compounds to oxidatively degrade DNA in the presence of copper ions. Results Caffeine, theobromine and xanthine have a quenching effect on the production of hydroxyl radicals, as well as on oxidative DNA breakage by hydroxyl radicals. Consistent with previous observations that many known antioxidants of plant origin are also capable of prooxidant action, the purine alkaloids also show oxidative DNA breakage in the presence of transition metal ions. Conclusions The alkaloid caffeine and its catabolic products theobromine and xanthine exhibit both antioxidant and prooxidant properties. The results lead to the observation that caffeine and its metabolites may also contribute to the overall antioxidant and chemopreventive properties of caffeine-bearing beverages, such as tea.

Molecular Cloning and Functional Characterization of Three Distinct N-Methyltransferases Involved in the Caffeine Biosynthetic Pathway in Coffee Plants

Abstract: Caffeine is synthesized from xanthosine through N -methylation and ribose removal steps. In the present study, three types of cDNAs encoding N -methyltransferases were isolated from immature fruits of coffee ( Coffea arabica ) plants, and designated as CaXMT1 , CaMXMT2 , and CaDXMT1 , respectively. The bacterially expressed encoded proteins were characterized for their catalytic properties. CaXMT1 catalyzed formation of 7-methylxanthosine from xanthosine with a K m value of 78 μm, CaMXMT2 catalyzed formation of 3,7-dimethylxanthine (theobromine) from 7-methylxanthine with a K m of 251 μm, and CaDXMT1 catalyzed formation of 1,3,7-trimethylxanthine (caffeine) from 3,7-dimethylxanthine with a K m of 1,222 μm. The crude extract of Escherichia coli was found to catalyze removal of the ribose moiety from 7-methylxanthosine, leading to the production of 7-methylxanthine. As a consequence, when all three recombinant proteins and E. coli extract were combined, xanthosine was successfully converted into caffeine in vitro. Transcripts for CaDXMT1 were predominantly found to accumulate in immature fruits, whereas those for CaXMT1 and CaMXMT2 were more broadly detected in sites encompassing the leaves, floral buds, and immature fruits. These results suggest that the presently identified three N -methyltransferases participate in caffeine biosynthesis in coffee plants and substantiate the proposed caffeine biosynthetic pathway: xanthosine → 7-methylxanthosine → 7-methylxanthine → theobromine → caffeine.

Chocolate feeding of pregnant mice influences length of limbs of their progeny.

Abstract: UNLABELLED We previously reported the inhibitory effect of various methyloxantines and phenolic compounds on tumor-induced angiogenesis and the production of angiogenic growth factors The aim of the present work was to evaluate the effect of chocolate (CH), food containing substantial amounts of methyloxantine theobromine and polyphenols (mainly catechins), given to mice during pregnancy and the lactation period, on weight of organs, length of limbs, and bone vascular endothelial growth factor (VEGF) concentration (tested by ELISA), in 4-week old offspring The study was performed on 2-month old Balb/c mice fed during pregnancy and lactation 400 mg of CH daily Content of polyphenols (catechines) and theobromine in the chocolate was estimated by high liquid perforance chromatography (HPLC) Concentration of VEGF was tested by ELISA Feeding pregnant mice chocolate produced the following effects: decrease of relative length of limbs and thigh bones in 4-week old progeny and decrease in VEGF content of offspring femoral bones CONCLUSION attention should be paid to possible unwanted effects of catechine- and methyloxantine-rich food and beverages during pregnancy and lactation 200 mg of chocolate per mouse corresponds to 100 g per person

RNA binding efficacy of theophylline, theobromine and caffeine.

Abstract: The binding of naturally occurring methylxanthines such as theophylline, theobromine and caffeine to nucleic acids are reckoned to be pivotal as they are able to modulate the cellular activities. We explore the interaction of yeast RNA binding efficacy of the above xanthine derivatives by using UV absorption differential spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy. Both the analyses show discrimination in their binding affinity to RNA. The differential UV-spectrum at P/D 3.3 reveals the greater RNA binding activity for theophylline (85 +/- 5%), whereas moderate and comparatively less binding activity for theobromine (45 +/- 5%) and caffeine (30 +/- 5%) and the binding activity was found to depend on concentration of the drugs. In FTIR analysis we observed changes in the amino group (NH) of RNA complexed by drugs, where the NH band is found to become very broad, indicating hydrogen bonding (H-bonding) with theophylline (3343.4 cm(-1)), theobromine (3379.8 cm(-1)) and caffeine (3343 cm(-1)) as compared to the free RNA (3341.6 cm(-1)). Furthermore in RNA-theophylline complex, it is observed that the carbonyl (C=O) vibration frequency (nu(C=O)) of both drug (nu(C=O)=1718, 1666 cm(-1)) as well as RNA (nu(C=O)=1699, 1658 cm(-1)) disappeared and a new vibration band appeared around 1703 cm(-1), indicating that the C=O and NH groups of drug and RNA are effectively involved in H-bonding. Whereas in RNA-theobromine and RNA-caffeine complexes, we found very little changes in C=O frequency and only broadening of the NH band of RNA due to complexation is observed in these groups. The changes in the vibrations of G-C/A-U bands and other bending frequencies are discussed. Thus the discrimination in the binding affinity of methylxanthines with RNA molecule shows that strong RNA binding drugs like theophylline can selectively be delivered to RNA targets of microbial pathogens having the mechanism of RNA catalysis.

Antagonism of adenosine receptors by caffeine and caffeine metabolites in equine forebrain tissues.

Abstract: Objective—To determine the presence of adenosine receptor subtypes A1 and A2a in equine forebrain tissues and to characterize the interactions of caffeine and its metabolites with adenosine receptors in the CNS of horses. Sample Population—Brain tissue specimens obtained during necropsy from 5 adult male research horses. Procedure—Membrane-enriched homogenates from cerebral cortex and striatum were evaluated by radioligand binding assays with the A1-selective ligand [ 3 H]DPCPX and the A2a-selective ligand [ 3 H]ZM241385. Functional responses to adenosine receptor agonists and antagonists were determined by a nucleotide exchange assay using [ 35 S]-guanosine 5'-(γ-thio) triphosphate ([ 35 S]GTPγS). Results—Saturable high affinity [ 3 H]DPCPX binding (A1) sites were detected in cerebral cortex and striatum, whereas high-affinity [ 3 H]ZM241385 binding (A2a) sites were detected only in striatum. Caffeine and related methylxanthines had similar binding affinities at A1 and A2a sites with rank orders of drug binding affinities (theophylline > paraxanthine ≥ caffeine >> theobromine) similar to other species. [ 35 S]GTPγS exchange revealed that caffeine and its metabolites act as pure adenosine receptor antagonists at concentrations that correspond to A1 and A2a receptor binding affinities. Conclusions and Clinical Relevance—Results of our study affirm the presence of guanine nucleotide binding protein linked adenosine receptors (ie, high-affinity A1 and A2a adenosine receptors) in equine forebrain tissues and reveal the antagonistic actions by caffeine and several biologically active caffeine metabolites. Antagonism of adenosine actions in the equine CNS by these stimulants may be responsible for some central actions of methylxanthine drugs, including motor stimulation and enhanced racing performance. (Am J Vet Res 2003;64:216–224)

Caffeine and Theobromine Composition of Mate (Ilex paraguariensis) Leaves in Five Plantations of Misiones, Argentina

Abstract: Marked differences regarding both caffeine and theobromine contents of mate leaves (Ilex paraguariensis) were found among 230 mass selected candidate trees distributed across 5 plantations in the region of Misiones, Argentina. In the vast majority of the analyzed samples, the caffeine concentrations ranged within the established limits for mate leaves, however theobromine contents (average content 0.96%) generally surpassed literature figures so far published [4,10]. By means of a simple cluster analysis using “group average” as the clustering algorithm, the samples were divided into eight different groups according to the contents of both purine alkaloids. Based upon this division it will be possible to pick appropriate genotypes for breeding ideotypes which meet more precisely the different specific consumer expectations.

Theobromine with anticancer activity

Abstract: Disclosed is theobromine with an anti-carcinogenic activity which inhibits the suppression of GJIC (gap junctional intercellular communication), a pathological phenomenon occurring during development of various kinds of cancers including liver cancer, as well as DNA synthesis of cancer cells thereby inhibiting proliferation of liver, gastric and colon cancer cells.

The Use of Catechins and Purine Alkaloids as Descriptors for the Differentiation of Tea Beverages

Abstract: A high performance liquid chromatography method using a C-18 reversed-phase column, a gradient elution system of acetonitrile-water-formic acid and a photodiode array detector was used to determine catechins and purine alkaloids in tea beverages (−)-epicatechin, (+)-catechin, (−)-epigallocatechin, (−)-epigallocatechin gallate, (−)-epicatechin gallate, gallic acid, caffeine, theophylline and theobromine were analysed in different tea beverages made of black, green and instant tea Other products containing tea were also considered Principal component, cluster, linear discriminant analysis and soft independent modelling class analogy were applied to the data in order to differentiate tea beverages according to the catechin and purine alkaloid profiles of the different samples considered

Agent for enhancing and promoting production of adiponectin

Abstract: PROBLEM TO BE SOLVED: To provide a safe medicament having activities for promoting and enhancing the production of adiponectin in the body, and hardly providing side effects. SOLUTION: The medicament for promoting or enhancing the production of the adiponectin in the body is obtained by using an extract extracted from a rhizome of turmeric with an organic solvent, or curcumin contained therein, or by using theophylline, caffeine or theobromine in combination therewith. COPYRIGHT: (C)2005,JPO&NCIPI

Determination of cocoa purine content by near infrared spectroscopy

Abstract: Caffeine and theobromine are involved in cocoa flavour development. Measurement of their contents is still used to determine the cocoa content of chocolate. It also seems to be accepted that the contents of these two compounds are linked to genetic and geographical origin. This study, which was conducted on cocoa varieties of different geographical origins, showed that near infrared spectroscopy can be a rapid and non-destructive alternative for determining these compounds. (Resume d'auteur)

Theobromine and Caffeine Recovery with Solvent Extraction

Abstract: A chloroform extraction process was developed for recovery of theobromine and caffeine from the effluent of a theobromine synthesis plant. The product distributions in the extraction process were studied experimentally. In a chloroform–water system, the caffeine distribution ratio was about 15 and was not affected by pH in the 2 to 12 range, while the distribution ratio of theobromine was about 0.45 for pH 10. Therefore, theobromine and caffeine can be recovered separately by adjusting the pH in the aqueous phase. The crude products of theobromine and caffeine can been obtained in the recovery process by evaporation. The thermal stability of theobromine in aqueous solution was also studied. A reciprocating plate column (RPC) is suitable for this extraction process. Pilot tests were conducted with two columns having 38-mm I.D. Scale-up of the RPCs for an industrial system of 23 t/d capacit...

Composite utilization of a group of genes in biosynthetic pathway of caffeine

Abstract: In the biosynthetic reaction system of caffeine, enzymes which catalyze these reactions respectively, and a method of composite utilization of genes encoding these enzymes, respectively are provided. A process for producing 7-methylxanthine, theobromine or caffeine which comprises methylation of xanthosine, ribose removal of 7-methylxanthosine, methylation of 7-methylxanthine, and/or methylation of theobromine ex vivo, in the presence of a combination of two or more of the enzymes a, c and d, and the cellular extract b. a: an enzyme which catalyzes methylation of xanthosine at the 7-position of the purine ring and has the amino acid sequence set out in SEQ ID NO: 1, b: a crude cellular extract obtained from Escherichia coli which catalyzes ribose removal of 7-methylxanthosine at the 9-position of the purine ring, c: an enzyme which catalyzes methylation of 7-methylxanthine at the 3-position of the purine ring and has the amino acid sequence set out in SEQ ID NO: 4, d: an enzyme which catalyzes methylation of theobromine at the 1-position of the purine ring and has the amino acid sequence set out in SEQ ID NO: 7.