• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.2
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• pp.224-232
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• 2008

The health benefits associated with tea consumption have resulted in the wide inclusion of green tea extracts in botanical dietary supplements, which are widely consumed as adjuvants for complementary and alternative medicines. Tea contains polyphenols such as catechins or flavan-3-ols including (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECG), and (-)-epigallocatechin gallate (EGCG), as well as the alkaloid, caffeine. The contents of catechins and caffeine in green tea are considered as a standard of quality evaluation of green tea. Therefor, the purpose of this study was to investigate the most suitable HPLC condition for simultaneous determination of catechins and caffeine in green tea extracts. The efficient HPLC analytical condition of catechins and caffeine contained green tea extracts was developed. The gradient elution employed a $250\;mm\;{\times}\;4.6\;mm$ i.d. YMC-pak ODS-AM 303 column. The gradient system was used two mobile phases. A gradient elution was performed with mobile phase A, consisting of 0.1% aqueous phosphoric acid, and mobile phase B, comprising 100% MeOH, and delivered at a flow rate of 1 mL/min as follows: $0{\sim}25\;min$, 80% A; $26{\sim}50\;min$, $80{\sim}70%$ A; 51 min, 80% A. $51{\sim}55\;min$, 80% A. The UV detection wavelength was set at 280 nm. The limit of detection (LOD) for catechins and caffeine standards were under 50 ng/mL.

• BMB Reports
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• v.29 no.1
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• pp.22-26
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• 1996

Agents that activate or inhibit the $Ca^{2+}$ release channel in cardiac sarcoplasmic reticulum (SR) were tested for their abilities to affect the activity of the SR $Ca^{2+}$-ATPase. Vesicles of junctional SR (heavy SR, HSR) from terminal cisternae were prepared from porcine cardiac muscle by density gradient centrifugation. The steady-state activity of $Ca^{2+}$-ATPases in intact HSR vesicles was/$347{\pm}5\;nmol/min{\cdot}mg$ protein (${\pm}$ SD). When the HSR vesicles were made leaky, the activity was increased to $415{\pm}5\;nmol/min{\cdot}mg$ protein. This increase is probably due to the uncoupling of HSR vesicles. Caffeine (10 mM), an agonist of the SR $Ca^{2+}$ release channel, increased $Ca^{2+}$-ATPase activity in the intact HSR vesicle preparation to $394{\pm}30\;nmol/min{\cdot}mg$ protein. However, caffeine had no significant effect in the leaky vesicle preparation and in the purified $Ca^{2+}$-ATPase preparation. The effect of caffeine on SR $Ca^{2+}$-ATPase was investigated at various concentrations of $Ca^{2+}$. Caffeine increased the pump activity over the whole range of $Ca^{2+}$ concentrations, from $1\;{\mu}M$ to $250\;{\mu}M$, in the intact HSR vesicles. When the SR $Ca^{2+}$-ATPase was inhibited by thapsigargin, no caffeine effect was observed. These results imply that the caffeine effect requires the intact vesicles and that the increase in $Ca^{2+}$-ATPase activity is not due to a direct interaction of caffeine with the enzyme. We propose that the activity of SR $Ca^{2+}$-ATPase is linked indirectly to the activity of the $Ca^{2+}$ release channel (ryanodine receptor) and may depend upon the amount of $Ca^{2+}$ released by the channels.

• Archives of Pharmacal Research
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• v.13 no.3
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• pp.215-220
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• 1990

Two different, derivative spectrophotometric and gas-liquid chromatographic, procedures for direct quantitation of caffeine and some commonly dispensed antihistaminics in bulk forms, in their laboratory prepared mmixtures and in dosage formulations, have been investigated. The limit, sensitivity reproducibility and accuracy of each method were studied for each individual drug substance and in some usual pharmaceutical formulations.

• Biomolecules & Therapeutics
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• v.19 no.2
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• pp.243-247
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• 2011

Rutaecarpine, an alkaloid originally isolated from the unripe fruit of Evodia rutaecarpa, has been shown to be anti-inflammatory. In the present study, a possible interaction between rutaecarpine and caffeine was investigated in male Sprague Dawley rats. Twenty four hr after the oral pretreatment with rutaecarpine at 80 mg/kg for three consecutive days, rats were treated intravenously with 10 mg/kg of caffeine. Compared with control rats, the pharmacokinetic parameters of caffeine in rutaecarpine-pretreated rats were significantly changed, possibly due to the rapid metabolism. The production of three metabolites of caffeine (i.e., paraxanthine, theobromine and theophylline) was also significantly changed in rats pretreated with rutaecarpine. The present results suggest that oral rutaecarpine would change the intravenous pharmacokinetic characteristics of caffeine.

• Journal of Nutrition and Health
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• v.41 no.3
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• pp.216-223
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• 2008

The purpose of this study was to examine the effects of dietary caffeine supplementation on bone mineral density and bone mineral content in ovariectomized rats. Twenty eight female Sprague-Dawley rats (body weight $210\;{\pm}\;5\;g$) were divided into two groups, ovariectomy (OVX) and Sham groups, which were each randomly divided into two subgroups that were fed control and control supplemented with caffeine diets (caffeine 0.03% diets). All rats were fed on experimental diet and deionized water ad libitum for 6 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin) in spine and femur. Serum alkaline phosphatase activity (ALP) and osteocalcin and urinary DPD crosslinks value were measured as markers of bone formation and resorption. The results of this study indicate that body weight gain and food intake were higher in OVX groups than in Sham groups regardless of diets. There were no differences weight gain between the control and caffeine groups in both OVX and Sham groups. Within the OVX groups, serum Ca concentration was lower in rats fed caffeine than in rats fed the control diet. Serum ALP, osteocalcin, urinary Ca, and phosphate were not different in each group. Spine BMD, spine BMD/weight, and spine BMC/weight, femur BMD/weight and femur BMC/weight of ovariectomy groups were significantly lower than Sham groups. Within the OVX group, there were no differences in spine BMD and BMC and femur BMD and BMC. These results indicate that no significant differences in spine and femur BMD were found due to 0.03% caffeine intakes in diet in OVX rats for 6 weeks. No negative effect of caffeine in 0.03% diet on bone mineral density were found in the present study. Further investigation of the relation between caffeine and bone mineral density are warranted. (KoreanJNutr2008; 41(3): 2l6~223)

• The Korean Journal of Food And Nutrition
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• v.32 no.2
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• pp.122-132
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• 2019

The purpose of this study was to conduct a survey on coffee intake habits, preference of coffee and other beverages, and awareness of caffeine in coffee by college students in some areas of Jeonbuk province. According to the survey result, 83.9% of subjects drank coffee usually, and males (46.4%) and the females (54.2%) drank coffee at school stores and coffee shops, respectively. Companions to drink coffee with were mainly friends, and frequency of coffee intake was one to two cups daily for males and females. Males and females drank coffee at any time (60.0%) and after lunch (38.7%), respectively. Most males and females drank only coffee without snacks. Males preferred more soft drinks and sports drinks than females, but females preferred more milk and dairy products, tea, and coffee than males. Coffee was consumed most frequently, among several beverages. Reasons for drinking coffee was to prevent sleepiness (64.6%), and to enjoy its taste and aroma (38.0%) for males and females, respectively. Male (47.2%) and female (73.5%) subjects could detect caffeine, and most of them could detect caffeine in coffee. Additionally, all subjects agreed that less intake of caffeine was better for their health. Based on the survey of intake habits of coffee, the university students need nutrition education relative to labeling caffeine contents in coffee and intake of caffeine, and need to make an effort to overcome the potential damage of caffeine intake.

• Korean Journal of Veterinary Research
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• v.31 no.1
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• pp.123-130
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• 1991

The present study was performed to investigate the effect of Ca ion concentration on sperm viability and acrosome reaction rate and to evaluate the effect of treatments using caffeine and Ca-ionophore A23187 on acrosome reaction rate in frozen-thawed bull spermatozoa. Viabilities of in vitro capacitated bull spermatozoa at 0, 2.25 and 4.5 mM Ca ion concenrations were 21.00, 26.00 and 22.59%, respectively and significantly higher in Ca ion 2.25mM added group than Ca ion free group (p<0.05) and acrosome reaction rates of in vitro capacitated bull spermatozoa were 17.09, 52.15 and 47.92%, respectively and significantly high in Ca ion added groups(p<0.05). Viabilities in vitro capacitation by caffeine and Ca-ionophore A23187 in control, caffeine treated group, Ca-ionophore A23187 treated group and caffeine+Ca-ionophore A23187 treated group were 37.91, 27.67, 22.33 and 25.59%, respectively and significantly higher in control than treated groups(p<0.05), there were no significant differences among the treated groups, and acrosome reaction rates were 10.33, 37.92, 48.09 and 57.17%, respectively and there were significant differences among the groups(p<0.05), especially higher in caffeine+Ca-ionophore A23187 treated group than others.

• Clinical and Experimental Reproductive Medicine
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• v.51 no.1
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• pp.28-41
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• 2024

Objective: Chronic scrotal hyperthermia (SHT) can lead to serious disorders of the male reproductive system, with oxidative stress playing a key role in the onset of these dysfunctions. Thus, we evaluated the impact of caffeine, a potent antioxidant, on cellular and tissue disorders in mice with chronic SHT. Methods: In this experimental study, 56 adult male NMRI mice were allocated into seven equal groups. Apart from the non-treated control group, all were exposed to heat stress. Two groups, termed "preventive" and "curative," were orally administered caffeine. The preventive mice began receiving caffeine immediately prior to heat exposure, while for the curative group, a caffeine regimen was initiated 15 consecutive days following cessation of heat exposure. Each treated group was subdivided based on pairing with a positive control (Pre/ curative [Cur]+PC) or a vehicle (Pre/Cur+vehicle). Upon conclusion of the study, we assessed sperm characteristics, testosterone levels, stereological parameters, apoptosis, antioxidant and oxidant levels, and molecular markers. Results: Sperm parameters, testosterone levels, stereological parameters, biochemical factors (excluding malondialdehyde [MDA]), and c-kit gene expression were significantly elevated in the preventive and curative groups, especially the former, relative to the other groups. Conversely, expression levels of the heat shock protein 72 (HSP72) and nuclear factor kappa beta (NF-κβ) genes, MDA levels, and apoptotic cell density were markedly lower in both caffeine-treated groups relative to the other groups, with more pronounced differences observed in the preventive group. Conclusion: Overall, caffeine attenuated cellular and molecular abnormalities induced by heat stress in the testis, particularly in the mice treated under the preventive condition.

• The Korean Journal of Pharmacology
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• v.8 no.2
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• pp.27-34
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• 1972

The present study is concerned with the demonstration of the influence of long term treatment with caffeine and phenobarbital on pentobarbital sleeping time, gastric secretion, increase rate of body weight and brain and liver weight in rats. The experimental subjects were rats weighing about 140 to 150 g, each of them was isolated in a separate cage. Each group was given 1 ml normal saline solution as control, caffeine 10 mg/kg and phenobarbital 30 mg/kg as experimental groups. All drugs were injected intraperitoneally, daily for 4 weeks. The results obtained are summarized as follows; 1. There was significant difference between before and after injection of drugs (caffeine citrate 10 mg/kg and phenobarbital 30 mg/kg) on pentobarbital sleeping time. The sleeping time of caffeine treated group was delayed (22.4%, p<0.01) significantly compared with that of before injection. The sleeping time of phenobarbital treated group was markedly shortened (93.6%, p<0.001) compared with that of before injection of drugs. 2. The volume, free and total acidity and pH of gastric juice determined five hours after pyloric ligation in fasting rats were not significantly changed in experimental groups compared with control group. However the volume of gastric juice was increased 25% in both caffeine and phenobardital treated group. 3. The increased ratio of body weight revealed no remarkable difference compared with intial body weight. However, caffeine treated group showed markedly increased body weight after first and second week of injection. 4. The brain and liver weight in experimental group showed no significant difference compared with control group (as percentage of body weight).

• Journal of Food Hygiene and Safety
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• v.22 no.3
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• pp.173-178
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• 2007

Children may respond differently to the caffeine from adults because they have different physiologic makeup and are functionally immature in terms of hepatic and renal function; this leads to the slower clearance of caffeine in early life. Therefore, children are often assumed to be more susceptible to caffeine effects. Alarge number of food supplements may interfere with these processes, and therefore caffeine exposure may have more serious consequences for children than for adults, irrespective of sensitivity. However, there has never been a national dietary survey on caffeine intakes in children. The purpose of our study was to identify caffeine intakes and beverage sources of caffeine in a representative sample of children in Busan, Korea. Caffeine intakes were based only on beverages included in the Continuing Surveys of Food Intakes by individuals. The caffeine content of the beverages ranged from 2.8 to 65.2mg/100ml for cola, soft drinks, and teas. Caffeine was not completely absent from caffeine-free colas, juice, and milk. In this study, cola-type beverages were an important dietary source of caffeine in the children. Daily caffeine intake for children was estimated to range from 12.5 to 250 mg/day. In general, the acceptable daily intake (ADI) of caffeine should cover the entire population including children. Therefore, special considerations should be needed regarding the consumption of soft drinks containing caffeine to children below the 12 years of age.