Showing papers on "Theobromine published in 1998"

Mate substitutes or adulterants: study of xanthine content

Abstract: The xanthine (caffeine, theobromine and theophylline) content of decoctions of seven Ilex spp. was studied by HPLC using UV and a photodiode-array detector. Ilex paraguariensis (‘Mate’ or ‘Yerba Mate’) is widely used in South America as a tealike beverage and the other six species are used as substitutes or adulterants of it. The results showed that I. paraguariensis has the highest amounts of caffeine and theobromine. Traces of caffeine were detected in I. theezans, I. dumosa, I. microdonta and I. pseudobuxus. Traces of theobromine were detected in I. argentina and I. microdonta. From the seven Ilex species investigated, theophylline was detected in I. theezans, I. dumosa and I. pseudobuxus, but only I. pseudobuxus has quantifiable amounts: 0.6 mg% (6 ppm). © 1998 John Wiley & Sons, Ltd.

Liquid chromatographic determination of methylxanthines and catechins in herbal preparations containing guaraná.

Abstract: Herbal preparations derived from the dried seeds of guarana (Paullinia cupana) have become a popular nutritional supplement used for stimulatory purposes. Once considered a drug substance in the United States, guarana currently is classified as a food additive and dietary supplement. The pharmacological activity of guarana-containing products is primarily due to methylxanthine alkaloids. For guarana preparations, methylxanthine levels and, more significantly, the presence of several polyphenol compounds (i.e., catechins) provide phytochemical markers of authenticity. Methylxanthines and polyphenols are extracted from sample matrix with a heated phosphate buffer-methanol solution, the cooled extract is filtered, and the extract is injected into the liquid chromatographic (LC) system. A Nova-Pak C18 column eluted with phosphate buffer-methanol mobile phase (pH = 3.50) and monitored at 272 nm gave satisfactory resolution for the methylxanthines theobromine, theophylline, caffeine and the polyphenols (+)-catechin and (-)-epicatechin. Twenty-four products including dried seeds, dried paste, seed powders, tablets, and capsule formulations were assayed and conclusions were drawn about their authenticity. The LC system responded linearly to methylxanthines over the 100-fold range in concentration from 0.043 to 4.30 micrograms/mL for theobromine and caffeine and from 0.041 to 4.10 micrograms/mL for theophylline. Precision data for the 3 methylxanthines obtained from 10 different products (n = 5) gave relative standard deviation (RSD) values of 1.18-15.52% within a concentration range of 0.01-52.28 mg/g. Recoveries of methylxanthines from fortified products varied from 87.5 to 120.0%. The response for catechins was linear over a 200-fold range in concentration of 0.05-10.0 micrograms/mL. Precision data from 5 products (n = 5) gave RSD values of 1.08-5.54% within a concentration range of 0.34-32.65 mg/g. Recoveries from these products ranged from 87.7 to 109.7%. Results and chromatographic profiles for 14 commercial products in solid dosage form indicate that a number of these products may not contain authentic guarana as an active ingredient or contain less than the declared quantity of guarana. The proposed procedure also was applied to 2 carbonated soft drinks and a sample of mate.

Biosynthesis and Metabolism of Purine Alkaloids in Leaves of Cocoa Tea (Camellia ptilophylla)

Abstract: The biosynthesis and metabolism of purine alkaloids in leaves ofCamellia ptilophylla (cocoa tea), a new tea resource in China, have been investigated. The major purine alkaloid was theobromine, with theophylline also being present as a minor component. Caffeine was not accumulated in detectable quantities. Theobromine was synthesized from [8-14C] adenine and the rate of its biosynthesis in the segments from young and mature leaves from flush shoots was approximately 10 times higher than that from aged leaves from 1-year old shoots. Neither cellfree extracts nor segments fromC. ptilophylla leaves could convert theobromine to caffeine. A large quantity of [2-14C] xanthine taken up by the leaf segments was degraded to14CO2 via the conventional purine catabolic pathway that includes allantoin as an intermediate. However, small amounts of [2-14C] xanthine were also converted to theobromine. Considerable amounts of [8-14C] caffeine exogenously supplied to the leaf segments ofC. ptilophylla was changed to theobromine. These results indicate that leaves ofC. ptilophylla exhibit unusual purine alkaloid metabolism as i) they have the capacity to synthesize theobromine from adenine nucleotides, but they lack adequate methyltransferase activity to convert of theobromine to caffeine in detectable quantities, ii) the leaves have a capacity to convert xanthine to theobromine, probably via 3-methylxanthine.

The influence of theobromine on angiogenic activity and proangiogenic cytokines production of human ovarian cancer cells.

Abstract: Angiogenesis plays an important role in ovarian cancer growth and metastasis formation. Adenosine is one of the most potent stimulator of neovascularisation. The aim of present study was to determine if theobromine, adenosine receptor antagonist, influences angiogenic activity and proangiogenic cytokines production. Theobromine caused significant inhibition of angiogenic activity of ovarian cancer cells. In in vivo and in vitro cultures theobromine diminished vascular endothelial growth factor (VEGF) production. Production of basic fibroblast growth factor (bFGF) and interleukin-8 (IL-8) was not altered by the examined drug. These findings suggest that theobromine might be a potent inhibitor of angiogenesis induced by ovarian cancer cells and its mechanism of action is related to inhibition of VEGF production.

Inhibitory effect of theobromine on induction of angiogenesis and VEGF mRNA expression in v-raf transfectants of human urothelial cells HCV-29.

Abstract: Neovascularisation plays a crucial role in solid tumor growth and metastasis formation. Our previous studies showed that theophylline and theobromine suppressed cutaneous neovascular reaction induced in mice by human blood leukocytes, and lung as well as ovarian cancer cells. Here, we investigated the in vivo effect of theobromine on angiogenic activity of human urothelial cell line HCV-29, v-raf transfected (mouse cutaneous assay), and the in vitro effect of this drug on VEGF, tPA, uPA and PAI mRNA expression in these cells (RT-PCR method). Theobromine suppressed angiogenesis induced in mice by HCV-29-v-raf cells, inhibited VEGF mRNA expression, and had no effect on transcription of uPA and tPA in these cells. HCV-29-v-raf transfectants do not display transcripts of PAI, in the presence or the absence of theobromine.

Detection and determination of theobromine and caffeine in urine after administration of chocolate-coated peanuts to horses.

Abstract: The objective of this study was to determine the urinary excretion of methylxanthines in horses following ingestion of chocolate over eight days. The study was performed in response to gas chromatography-mass spectrometry (GC-MS) confirmation of the presence of caffeine in a positive urine test in a racehorse. The trainer of the horse alleged that he often administered chocolate-coated peanuts as treats to his horses, and he believed that the ingestion of chocolate was responsible for the positive urine test. The urinary excretion of theobromine and caffeine after the ingestion of chocolate-coated peanuts was investigated in three horses. Enzyme-linked immunoassay (ELISA), high-performance liquid chromatography (HPLC), and GC-MS assays were performed on all urine specimens. Theobromine (HPLC) was detected for 72 h and caffeine (GC-MS) for 48 h after chronic ingestion of chocolate-coated peanuts. Methylxanthines were detected by ELISA for 120 h after administration of chocolate.

A sensitive method for the simultaneous determination of caffeine and its dimethylxanthine metabolites in human plasma : Application to CYP1A2 phenotyping

Abstract: A sensitive high performance liquid chromatographic assay was developed for the determination of caffeine and its dimethylxanthine metabolites in human plasma. Caffeine, paraxanthine, theophylline, and theobromine were extracted from 0.5 mL of matrix with methylene chloride. Separation of the analytes was achieved using a mobile phase consisting of 0.1 M sodium acetate pH 4.5, methanol, tetrahydrofuran, and distilled water (10:6.5:1.4:82.1, v/v) and a Microsorb MV C18 analytical column with UV detection at 274 nm. Excellent linearity was observed for each analyte over the concentration range of 20 – 8000 ng/mL. The within- and between-day coefficients of variation were less than 4.1% at all concentrations examined. This method is suitable for pharmacokinetic or pharmacogenetic studies utilizing caffeine as a probe for CYP1A2 activity whether given alone or in combination with other CYP probe drugs.

Sensitization of Burkholderia cepacia to antibiotics by cationic drugs.

Abstract: Chlorpromazine and prochlorperazine have previously been shown to enhance the susceptibility of Burkholderia cepacia to aminoglycosides. To screen other non-antibiotic drugs containing similar amine (-N-CH 3 ) groups, we examined a range of such agents that are in current clinical use for the treatment of non-infectious diseases, in combination with antibiotics that are ineffective against B. cepacia. At a concentration of 0.2 mM, theobromine, theophylline, trifluoperazine, fluophenazine and coumarin-152 significantly reduced (by fourfold) the MICs of gentamicin and ceftazidime. Theobromine and theophylline also reduced the MICs of amikacin and azithromycin.

Theobromine, theophylline, and caffeine in 42 samples and products of guaraná (Paullinia cupana, Sapindaceae)

Abstract: Guaranas, the carbonated beverages (sodas) of choice throughout much of Brazil, are mandated by Brazilian law to contain at least 300 mg guara’a (Paullinia cupana, Sapindaceae) seed per 100 ml soda. Were all the soda manufacturers adhering to the law, they would be consuming almost three times the annual production of seed. Guarana seeds contain unusually high levels of caffeine, along with smaller amounts of the related purine alkaloids theobromine and theophylline. We investigated the purine alkaloid content of three ethnobotanical guarana collections and 39 commercial products using HPLC/UV. Many of the products did contain caffeine as the major alkaloid, with traces of theobromine and theophylline. Numerous sodas and syrups contained up to ten times more theobromine than caffeine, and we suspect that these products were adulterated with cacao (Theobroma cacao, Sterculiaceae), the major source of theobromine.

Simultaneous Determination of Theobromine and Caffeine in Cocoa by Partial Least-Squares Multivariate Spectrophotometric Calibration

Abstract: The use of partial least - squares multivariate spectrophotometric calibration for the simultaneous determination of theobromine and caffeine in cocoa is presented. The results show that these components in a molar ratio of about 6 : 1 in cocoa have been determined simultaneously with standard deviations of about 0.05 and 0.02 for theobromine and caffeine, respectively.

Pharmacology of Caffeine

Abstract: The widespread societal use of caffeine-containing beverages has engendered extensive interest in the pharmacological mechanisms underlying the in vivo effects of caffeine, and to a lesser extent the other naturally occurring methylxanthines, namely, theophylline and theobromine. Caffeine is ingested primarily because of mild central stimulant properties, whereby it tends to increase vigilance and defer sleep. Research, therefore, has focused primarily on the pharmacological effects of caffeine relevant to the central nervous system. The pharmacology of methylxanthines, in particular caffeine, has been reviewed in detail (Daly, 1993; Fredholm, Arslan, Johansson, Kull, & Svenningsson, 1997; Nehlig, 1994) and the present chapter will attempt only a succinct overview without extensive citations of the literature covered in those reviews.

Inducing neurotransmitter and neuropeptide activity

Abstract: A method and compositions for promoting the neural synthesis and release in an animal subject of the neurotransmitters acetylcholine, GABA, glutamate, norepinephrene, dopamine, aspartate, histamine and serotonin. To enhance release of the neurotransmitter in the subject precursors for each of these neurotransmitters may be administered concomitantly with a xanthine and with one or more precursors for another neurotransmitter selected from precursors for the neurotransmitters histamine, glutamine and aspartate. The xanthines include caffeine, theophylline and theobromine. This procedure for the promotion of synthesis and release of the neurotransmitters may be employed in the treatment of subjects having a neurotransmitter deficiency, including reduced neural tone and excessive neural activity.

Effects of methylxanthine derivatives on antitumor activity and toxic side effect of adriamycin induced by inhibition of DNA biosynthesis

Abstract: The antitumor activity of adriamycin (ADR) was enhanced by combination with theobromine or pentoxifylline. Theobromine increased the concentration of ADR in the tumor without any effects on that in the heart and the liver. The influence of the combination of theobromine or pentoxifylline with ADR on the lipid peroxide level (indicating the ADR-induced side effect) and on DNA biosynthesis (indicating the side effect and antitumor activity) were examined. When ADR was administered into mice, the lipid peroxide level in the liver and the heart increased. However, the combination of theobromine or pentoxifylline did not enhance the ADR-induced increment of the lipid peroxide level in the liver, and moreover, it inhibited that in the heart. The decrease of DNA biosynthesis in the liver and the heart, induced by ADR, were not enhanced by combination with theobromine or pentoxifylline. On the other hand, the combination of theobromine with ADR significantly increased the inhibition of DNA biosynthesis in the tumor. These findings indicate that the combination of theobromine or pentoxifylline with ADR have no effect on the side effects of ADR in the liver and the heart, with the increase of antitumor activity of ADR in the tumor, and it is suggested that these drugs will be of value as a biochemical modulator of ADR.

Caffeine Demethylation Monitoring Using a Transdermal Sweat Patch

Abstract: Caffeine and two metabolites (paraxanthine and theobromine) were quantitated by high-performance liquid chromatography (HPLC) using extracts from transdermal sweat patches that

Aminotransferase activity in serum, liver and heart tissue of rats exposed to theobromine

Abstract: 0bjectives:To find out the effect of theobromine or aminotransferase enzyme activities in serum, heart and liver in rats. Methods: Theobromine in two doses was administered by oral gavage to albino Wistar rats (n=8 for each group) for a four day period and both alanine aminotransferase (AST) and aspartate aminotransferase (ALT) enzyme activities were measured in serum, heart and liver tissues Control group (n=8) was administered only vehicle and enzyme activities were measured. Serum AST:ALT ratios were also computed for all the groups. Results: Theobromine administration in moderate (600 mglkg body weight) to high (700 mglkg body weight) doses induced a highly significant (p<0.001) time and dose dependent increase in aspartate aminotransferase (AST) activities of the serum and heart tissue, but not of the liver. Similarly, the alanine aminotransferase activities of theobromine treated animals were significantly higher (p<0.001) for the heart, and (p<0.05) for the serum compared with their respective controls at 700 mglkg body weight. There were no changes in the ALT activities in the liver tissue. The computed AST:ALT ratio for the theobromine treatment group showed an increase with values of 1.93 and 2.01 for the 600mg/kg and 700 mg/kg theobromine dose regimens respectively, compared with the control value of 1.37. Conclusion: Theobromine toxicity appears to be heart directed.

Effect of Theophylline, Caffeine and Dimethylxanthines on Endogenous Glucocorticoid Levels in Mice. A Possible Mechanism of Anti‐inflammatory Activity of Theophylline

Abstract: We studied the effect of theophylline and other dimethylxanthines on endogenous glucocorticoid levels in mice. Intraperitoneal administration of theophylline increased serum glucocorticoid levels in a dose-dependent manner. Caffeine, 1, 7-dimethylxanthine and aminophylline also increased serum glucocorticoid levels, but pentoxifylline, theobromine and xanthine had no effect. Theophylline-induced glucocorticoidogenesis was completely suppressed by pretreatment with dexamethasone. The results suggest that dimethylxanthines, particularly those with a methyl group at the N-1 nitrogen position, increase endogenous glucocorticoid levels through the activation of the hypothalamopituitary adrenocortical axis. This increase in endogenous glucocorticoid levels might be one component of theophylline anti-inflammatory activity.

Methylation of the cyclic homolog of xanthine

Abstract: Alkylation of the cyclic homolog of xanthine in the methyl iodide-sodium hydride system as a function of the reagent-alkylating system ratio yields different products: for a 1∶3 ratio of reagents, a homolog of caffeine is formed, while for a 1∶2 ratio, a homolog of theobromine is formed. In contrast to xanthine, methylation of its cyclic homolog initially takes place at the imidazole ring and occurs in the sequence N(1), N(4), N(7).

The regulation of caffeine production in Camellia sinensis L. cv. Iranian and Darjeeling tea

Abstract: In the first part of this project, the distribution of caffeine and associated purine alkaloids in tea seedlings (C. sinensis cv. Iranian tea No. 100, and C. sinensis cv. Darjeeling tea) were investigated. Analysis was carried out by high performance liquid chromatography. The major purine alkaloid in tea seedling is caffeine. More than 90% of the caffeine was detected in the leaves. The highest amounts of caffeine were found in apical bud of Iranian and Darjeeling tea both of which contained ca. 38 mg caffeine per gram fresh weight. The lowest levels of caffeine were found in roots and cotyledons. Theobromine, a precursor of caffeine biosynthesis, was found in leaves, but in amounts far lower than those of caffeine. Trace amounts of paraxanthine were detected occasionally in leaves of Iranian tea. The second part of this project investigated the biosynthesis of caffeine in tea leaves using 14C-labelled adenine and guanine. Both substrates were converted to caffeine but adenine was a more effective precursor than guanine. Time-course and pulse-chase studies showed a transient incorporation of label into theobromine, the immediate precursor of caffeine, prior to a more substantial rise in [14C]caffeine. Biosynthesis of caffeine occurred more extensively in young leaves, declining substantially in mature and aged leaves. Although the exact pathway was not elucidated in this study, the available data supports the operation of an AMP → IMP → xanthosine → theobromine → caffeine pathway. [8-14C]Caffeine was degraded only slowly to 14CO2, via the purine catabolism pathway, which explains the accumulation of endogenous caffeine in tea leaves. Caffeine catabolism was, however, more extensive in leaves incubated in light than in darkness. In the third section of this project, the effects of the phytohormones, abscisic acid, indole-3-acetic acid, gibberellic acid and zeatin, on the metabolism of [8- 14C]adenine and caffeine by the first leaves of Iranian and Darjeeling tea in light and darkness, were investigated. Overall the phytohormones had little effect on the conversion of adenine to caffeine. However, incubations with [8-14C] caffeine showed that in darkness the phytohormones, most notably abscisic acid and indole-3-acetic acid, increased the rate of catabolism of caffeine after 12 h. In light the effect was less marked with caffeine degradation being enhanced by zeatin, and to a lesser degree abscisic acid and gibberellic acid, but only after in incubation period of 24 h.