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1.
Different kinds of chocolates produced in Serbia were analyzed regarding total polyphenol, flavonoid and proanthocyanidin content using spectrophotometric methods. Flavan-3ols and methylxanthines in all samples were determined with RP-HPLC. DPPH, FRAP, ABTS and ORAC assays were applied for measuring antioxidant capacity. The average of all four antioxidant tests for each cocoa product was used for calculating antioxidant potency composite index (ACI). Obtained results for all four assays have shown that antioxidant capacity of analyzed chocolate/cocoa extracts followed cocoa, polyphenol, flavonoid, and proanthocyanidin contents. Although the addition of raspberries to dark chocolates had no significant influence on their total polyphenol, flavonoid and proanthocyanidin contents, statistical analysis showed that there was significant increase in the antioxidant capacity of dark chocolates with raspberry compared to plain dark chocolates (p = 0.007). Overall range for theobromine content varied from 5.5 to 22.3 mg/g depending on the product type, while the content of caffeine was 13–30 times lower in all analyzed cocoa products. In addition, correlation between antioxidant potency composite index and declared percentage of cocoa was high (R2 = 0.798, p < 0.05) and indicated that declared cocoa content was a reliable indication for antioxidant capacity of chocolates produced in Serbia.  相似文献   
2.
目的:对青钱柳甜茶等几种别样茶中咖啡因、可可碱和茶碱进行检测,为别样茶的合理应用奠定基础。方法:采用超快速液相色谱法(RSLC),AcclaimPA2色谱柱(150mm×2.1mm,2.2μm),乙腈-水梯度洗脱;流速:0.5mL·min-1;检测波长:273nm,柱温:30℃。结果:除加入绿茶的商品中检测到适量的咖啡因外,青钱柳神茶、黄芩茶、多穗柯甜茶、悬钩子属甜茶,以及甜叶菊叶和湖北海棠叶中均未检测出上述3种生物碱。结论:相对于绿茶中含有较高含量的咖啡因、可可碱和茶碱,别样茶中未检出上述3种成分,为别样茶的科学应用提供指导。  相似文献   
3.
目的建立市售饮料中咖啡因、茶碱和可可碱的液相色谱-串联质谱法(LC-MS/MS)。方法将饮料用水稀释100倍后,采用三氯甲烷∶异丙醇(9∶1,V/V)进行提取,提取液经Allure PFP Propyl柱(100 mm×2.1 mm,5μm)分离,以5 mmol/L乙酸铵溶液(含5%甲醇、0.05%的甲酸)-甲醇为流动相进行梯度洗脱,采用电喷雾正离子化(ESI+)、多反应监测模式同时测定咖啡因、茶碱和可可碱。结果咖啡因、茶碱和可可碱在10 ng/ml^1000 ng/ml范围内方法的线性相关系数(r)均>0.9970,检出限为2 ng/ml^5 ng/ml,加标回收率均>60.68%,精密度均<14.41%。应用于实际市售饮料中,均检出咖啡因成分,部分饮品检出茶碱、可可碱成分。结论该方法简便、灵敏,可用于监测市售饮料中咖啡因、茶碱、可可碱的含量。  相似文献   
4.
ObjectiveThe aim was to investigate the effects of fluoride, strontium, theobromine and their combinations on caries lesion rehardening and fluoridation (EFU) under pH cycling conditions.DesignHuman enamel specimens were demineralized at 37 °C for 24 h using a pH 5.0 solution containing 50 mM lactic acid and 0.2% Carbopol 907 which was 50% saturated with respect to hydroxyapatite. Lesions were assigned to nine treatment groups (n = 16) based on Knoop surface microhardness indentation length.Treatmentaqueous solutions were: placebo, 11.9 mM sodium fluoride (F), 23.8 mM sodium fluoride (2 × F), 1.1 mM strontium chloride hexahydrate (Sr), 1.1 mM F theobromine, Sr + theobromine, F + Sr, F + theobromine, F + Sr + theobromine. Lesions were pH cycled for 5d (daily protocol: 3 × 1min-treatment; 2 × 60min-demineralization; 4 × 60 min & overnight-artificial saliva). Knoop indentation length was measured again and%surface microhardness recovery (%SMHr) calculated. EFU was determined using the acid-etch technique. Data were analysed using ANOVA.ResultsModel showed fluoride dose-response for both variables (2 × F > F > placebo). For%SMHr, F + Sr+/−theobromine resulted in more rehardening than F, however less than 2 × F. F + theobromine was similar to F. For EFU, F + Sr was inferior to F, F + theobromine and F + Sr + theobromine which were similar and inferior to 2 × F. In absence of fluoride, Sr, theobromine or Sr + theobromine were virtually indistinguishable from placebo and inferior to F.ConclusionsIt can be concluded that a) strontium aids rehardening but not EFU and only in presence of fluoride; b) theobromine does not appear to offer any anti-caries benefits in this model; c) there are no synergistic effects between strontium and theobromine in the presence or absence of fluoride.  相似文献   
5.
目的:研究咖啡因、茶碱、可可碱3种甲基黄嘌呤类生物碱与牛血清白蛋白(BSA)结合反应的荧光光谱行为,了解其与蛋白质结合的信息。方法:采用荧光光谱法研究25℃和37℃时3种生物碱不同浓度对BSA的荧光猝灭作用,通过Stern-Volmer曲线和Perrin曲线线性拟合计算得到动态猝灭常数和静态猝灭常数,判断猝灭机制;计算结合常数、结合位点数及热力学函数ΔH、ΔS、ΔG,判断其结合作用力模型。结果:随着3种生物碱浓度升高,BSA内源荧光强度有规律地降低;随温度的升高,静态猝灭常数和结合常数均降低,而3种生物碱与BSA的结合常数差别较大,但结合位点数均接近1;ΔG<0,ΔH<0,ΔS>0。结论:3种生物碱能较显著猝灭BSA的荧光,且机制均为静态猝灭,与白蛋白之间均存在以疏水相互作用为主的结合作用;3种结构相近的生物碱与BSA的相互作用存在差异。  相似文献   
6.
Theobromine versus placebo discrimination and caffeine versus placebo discrimination were studied in two consecutive experiments in seven volunteers who abstained from methylxanthines. Daily sessions involved PO double-blind ingestion of two sets of capsules sequentially, one of which contained drug and the other placebo. Subjects attempted to identify, and were later informed, which set of capsules contained the drug. In each experiment subjects were exposed to progressively lower doses. Five subjects acquired the theobromine discrimination; the lowest dose discriminated ranged from 100 to 560 mg. All seven subjects acquired the caffeine discrimination; the lowest dose discriminated ranged from 1.8 to 178 mg. A final experiment evaluated subjective effect ratings following 560 mg theobromine, 178 mg caffeine and placebo, which were administered double-blind in capsules once daily, five times each in mixed sequence. Caffeine produced changes in both group and individual ratings (e.g. increased well-being, energy, social disposition and alert). Theobromine did not produce changes in group ratings but changed ratings in some subjects. Across subjects, sensitivity to caffeine discriminative effects in the discrimination experiment correlated significantly with the number and magnitude of caffeine subjective effects in the final experiment. This study documents modest discriminative effects of theobromine in humans, but the basis of the discrimination is unclear. This study suggests that commonly consumed cocoa products contain behaviorally active doses of caffeine and possibly theobromine.  相似文献   
7.
以8-氯茶碱作为内标,利用高效液相色谱同时测定人血浆中咖啡及其3种去甲基代谢产物--副黄嘌呤、可可碱和茶碱的方法。这4种物质可以在一个固定相柱子上被同时分离;流动相为甲;0.1mol/L磷酸二氢钠(30:70)(V/V);流速:0.8ml/min;紫外检测器,波长274nm。实验表明这4种物质的最小检出量均在75ng/ml,并具有较好的线性、重复性及较高回收率。  相似文献   
8.
Summary The aim of this study was to test the effects of the three classical methylxanthines, theophylline, caffeine and theobromine, on local cerebral blood flow and glucose utilization. Equimolar doses (1.6 mol/kg/min i.v.) of theophylline and caffeine produced increases in local cerebral glucose utilization and decreases in local cerebral blood flow. These compounds, therefore, re-set the ratio of cerebral blood flow per unit of glucose utilization at a lower level. These results are interpreted with respect to the known adenosine antagonist properties of caffeine and theophylline. Theobromine, a substance with less significant adenosine antagonist properties, had minimal effects on local cerebral blood flow and glucose utilization at a dose of 1.6 mol/kg/min i.v. These data may provide supportive evidence for the hypothesis that adenosine plays an important role in cerebral blood flow-metabolism coupling.Part of this work has previously been presented at the Deutsche Pharmakologische Gesellschaft March 13–16, 1984 on Mainz  相似文献   
9.
Objective: To compare caffeine and theobromine absorption after oral administration of capsules, cola beverage and chocolate candy. Methods: Three males and four females who abstained from methylxanthines received five methylxanthine-containing treatments: caffeine in capsules (72 mg), administered twice; theobromine in capsules (370 mg); cola beverage (72 mg caffeine) and chocolate candy (72 mg caffeine and 370 mg theobromine). Plasma methylxanthine levels were assayed from samples collected before and 0.25, 0.50, 0.75, 1.0, 1.5, 2.0, and 3.0 h after caffeine capsule and cola treatments and, additionally, at 4.0 and 6.0 h after theobromine capsule and chocolate treatments. Results: Caffeine plasma concentrations increased rapidly and peaked at approximately 30 min following both capsule treatments 1 (Cmax: 1.93 μg ⋅ ml−1); and 2 (Cmax: 2.05 μg ⋅ ml−1). Relative to capsules, caffeine absorption from cola and chocolate was delayed and produced lower maximum caffeine plasma concentrations which peaked 1.5–2.0 h after treatment (For cola, Cmax: 1.57 μg ⋅ ml−1); and for chocolate, Cmax: 1.50 μg ⋅ ml−1. Theobromine plasma concentrations peaked approximately 3 h after capsule administration (Cmax: 6.72 μg ⋅ ml−1). Relative to capsules, theobromine absorption from chocolate was more rapid and produced higher maximum theobromine plasma concentrations which peaked approximately 2 h after treatment (Cmax: 8.05 μg ⋅ ml−1). Conclusions: The results suggest that a usual dietary portion of the cola or chocolate used in this study would produce behaviorally discriminable plasma levels of caffeine in most subjects and of theobromine in at least one subject. Received: 6 December 1995/Accepted in revised form: 6 July 1996  相似文献   
10.
On the basis of general pharmacological information (blood cells/plasma partition, plasma protein binding) and using HPLC as the principal analytical method, we investigated the kinetics and metabolism of theobromine (a caffeine metabolite) in male rats after a single dose and after a 2 week chronic application. Doses in both conditions varied between 1 and 100 mg/kg. In in vitro and in vivo the fraction of theobromine unbound to plasma proteins averaged 0.90 over a wide range of concentrations. No significant difference was found in the pharmacokinetic profile of the drug after acute or chronic treatment at different doses except for a reduction in the absorption rate constant as the dose increased. AUC values increased in proportion to the dose. The 2 treatment schedules were also similar as regards metabolism, at least 50% of the administered dose of theobromine being excreted unchanged, and 25% as 6-amino-5-[N-methyl-formylamino]1-methyluracil. Only at the highest doses was there a tendency for theobromine to accumulate at the expense of its major metabolite (a uracil compound).  相似文献   
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