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Most modern people start daily life with drinking a cup of coffee. Many people would also finish their daily work with coffee. As such, coffee drinking is an important part of daily life these days. It has been told that coffee is a driving force for human to develop science, because it has an alerting effect on human brain. However, some people with experience of feeling irregular heartbeat or headache are reluctant to drink coffee, which suggests individual variation to coffee intolerance. This review is to briefly summarize the effect of coffee on human health.
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integr med res 3 (2014) 189–191
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Integrative Medicine Research
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Mini Review
Coffee and health
Jae-Hoon Bae, Jae-Hyung Park, Seung-Soon Im, Dae-Kyu Song
Department of Physiology, Keimyung University School of Medicine, Daegu, Korea
article info
Article history:
Received 31 July 2014
Received in revised form
21 August 2014
Accepted 22 August 2014
Available online 30 August 2014
chlorogenic acid
coffee drinking
type 2 diabetes
Most people start their day with a cup of coffee. Many people would also finish their daily
work with coffee. As such, coffee drinking is an important part of modern daily life. It has
been told that coffee is a driving force for humans to develop science, because it has an
alerting effect on the human brain. However, some people report experiencing irregular
heartbeat or headaches and are thus reluctant to drink coffee, which suggests individual
variation to coffee intolerance. The aim of this review is to briefly summarize the effects of
coffee on human health.
© 2014 Korea Institute of Oriental Medicine. Published by Elsevier. This is an open access
article under the CC BY-NC-ND license
Coffee has taken an important place in human society for at
least 1200 years. Its consumption, which probably originated
in northeast Africa, spread out to the Middle East in the 15th
century and thence to Europe. After oil, coffee has become the
second most valuable commodity around the world. Today,
coffee is among the most widely consumed pharmacologically
active beverages, and its consumption has become a regular
part of daily life worldwide. It is estimated that more than half
of Americans drink coffee every day. The average consumption
for a person in the European Community is 5.1 kg/year, which
is similar to that in the United States.1
In fact, coffee is a complex mixture of chemicals, and is the
main source of caffeine in many populations. However, it also
contains thousands of different chemicals, including carbo-
hydrates, lipids, nitrogenous compounds, vitamins, minerals,
alkaloids, and phenolic compounds (Fig. 1).2
Corresponding author. Department of Physiology, Keimyung University School of Medicine, 1095 Dalgubeol-daero, Dalseo-gu, Daegu
704-701, Korea.
E-mail address: (J.-H. Bae).
Although caffeine is a major component of coffee, the con-
tent is highly variable—ranging between 30mg and 175 mg in
a cup (150 mL) of home-prepared coffee. Caffeine is the most
widely consumed psychoactive drug worldwide and appears
to exert most of its biological effects through the antago-
nism of the adenosine receptor. Adenosine is an endogenous
inhibitory neuromodulator that prompts feelings of drowsi-
ness, and thus caffeine induces generally stimulatory effects
in the central nervous system. In addition, the physiologi-
cal effects of caffeine intake include acute elevation of blood
pressure, increasing metabolic rate, and diuresis.3Based on
the data reviewed, it can be concluded that moderate caf-
feine intake (2–3 cups or 300 mg/day) is not associated with
adverse effects, such as cardiovascular stimulatory effects and
behavioral changes, at least in healthy adults.4However, caf-
feine is not completely harmless. In fact, caffeine crosses
2213-4220/© 2014 Korea Institute of Oriental Medicine. Published by Elsevier. This is an open access article under the CC BY-NC-ND license
190 Integr Med Res (2014) 189–191
Fig. 1 Chemical structures of major biologically active compounds in coffee.
the human placenta, rapidly reaching a similar concentra-
tion in the fetus and mother. The excessive intake of caffeine
has been implicated as a cause of spontaneous abortion or
impaired fetal growth.3Caffeine intake for women who plan to
become pregnant and for women during gestation should not
exceed 300 mg/day. In a variety of studies for caffeine inges-
tion, children can be defined as another risk group because
altered behavior including nervousness or anxiety is found.3
It is judged that an intake of 2.5 mg/kg body weight/day is
an upper limit of caffeine consumption in children (Federal
Department of Health, Ottawa, Ontario, Canada).
Is there an antioxidant in coffee? Yes, indeed. Coffee is the
number one diet source of antioxidants in many countries
including the United States, Italy, Spain, and Norway. Coffee
beans contain phenolic antioxidant compounds. The major
polyphenol in coffee is chlorogenic acid. Chlorogenic acid is
one of the major strong antioxidant compounds in coffee.5The
antioxidant activity of coffee depends on the chemical compo-
sition. In addition, it was observed that the antioxidant activity
of coffee varies according to the degree of roasting. Maximum
antioxidant activity was measured for the medium-roasted
Coffee consumption has been associated with higher
concentrations of serum total cholesterol and low den-
sity lipoprotein cholesterol. Cafestol and kahwoel are two
diterpenes found in coffee oil. Diterpenes are the main
cholesterol-raising compounds in coffee, but they are mostly
removed by paper filters. Therefore, unfiltered coffee is a
significant source of diterpenes, whereas the consumption
of filtered coffee results in very little increase in serum
The relationship of coffee with health has been featured in
more than 8000 professional medical studies during the past
40 years. However, in many cases, conflicting findings and con-
cerns have arisen, making it difficult for health professionals
and the public to interpret the data. Coffee consumption tends
to attract tobacco smoking, but many studies did not account
for this potential confounding the data analysis.8Some mea-
surement errors seem to be inevitable in the assessment of
coffee consumption, because people consume a wide variety
of coffee from day to day. Coffee intake is determined by the
size of the coffee cup and the strength of the brew as well
as frequency of consumption. Despite 20 years of reassuring
research, many people still avoid caffeinated coffee because
they worry about the biological effects of caffeine. What is the
conclusion of so much attention? We have thought that cof-
fee is good for your health when consumed in moderation.
Harvard Women’s Health Watch (2004) reported that current
research reveals that in moderation coffee is a safe bever-
age that may even offer some health benefits.9However, it is
also emphasized that difficulties and challenges in designing
a solid experiment or clinical trials to elucidate the effects of
coffee on human health are present.
Many studies show that coffee consumption may help pre-
vent several chronic diseases. In particular, long-term coffee
consumption is associated with significant dose-dependent
reductions in the risk of developing type 2 diabetes.4Fur-
thermore, coffee intake reduces the risk of liver damage in
people at high risk for liver disease including hepatic injury,
cirrhosis, and hepatocellular carcinoma.10 Its consumption is
also inversely associated with the risk of Parkinson’s disease
in men and women who have never used postmenopausal
estrogen.11 The risk of Alzheimer’s disease is lower in those
who regularly consume caffeine-containing coffee than in
those who do not drink it.12 Coffee has also been shown to
improve endurance performance in long-duration physical
J.-H. Bae et al/Coffee and health 191
activities. It is very interesting that the relative risk of suicide
was decreased by 13% for every cup of coffee consumed daily.13
In general, coffee consumption has been inversely associated
with the risk of cancer at various sites including liver and
colorectum, but there is no clear explanation of how coffee
protects against cancer.14
It should be considered that coffee does have modest car-
diovascular effects such as tachycardia, high blood pressure,
and occasional arrhythmia.1The acute effects of coffee on
the cardiovascular system might arise in the time immedi-
ate to coffee intake or in more susceptible individuals. Recent
analyses have concluded that a weak inverse association may
exist between coffee consumption and the risk of stroke, but
further research is needed to clarify this.14 Although there
is no definite clinical relationship between coffee intake and
the risk of cardiac arrhythmia, many doctors would not rec-
ommend coffee for the patients. Any contribution of coffee
ingestion to the development of hypertension is likely to be
small, but it is considerable particularly in infrequent coffee
drinkers.4Caffeine leads to a slight decrease in the efficiency
of calcium absorption in gastrointestinal tract. Thus, an ade-
quate intake of calcium and vitamin D and a limitation of
coffee intake to 2–3 cups/day may help reduce the risk of
osteoporosis and its related fracture particularly in elderly
Coffee consumption is used for social activity, leisure,
improvement of work performance, and well-being. Coffee
is not only a medicinal alternative but also a beverage con-
taining numerous potential health benefits. The results from
many types of research suggest the positive effects of cof-
fee consumption on various aspects of health, as mentioned
above briefly. Despite the general good outcomes, it should
be emphasized that individual sensitivity to coffee and the
biological effects of coffee among humans may vary because
of personal single nucleotide polymorphic variants, as shown
in an investigation on genetic polymorphisms in apolipopro-
tein E (APOE).15 And some negative effects of coffee tend to
emerge in excessive drinking, so it is the best to avoid heavy
coffee intake. This minireview covers just a few of the health
benefits and adverse effects associated with drinking coffee.
Further studies on the functionally significant polymorphisms
are needed for a better understanding of the effects of coffee
on personal health.
Conflicts of interest
All contributing authors declare no conflicts of interest.
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... Next to petroleum-related commodities, coffee marks the second most-traded and consumed product globally. Owed to its high consumption and trade, coffee industry generates a considerable amount of byproducts and waste which eventually leads to environmental pollution [10][11][12]. Recent studies have shown that used-coffee grounds (UCG) can be converted into hierarchical nanostructured activated carbon (HNAC) material, which exhibits excellent electrochemical properties and can be incorporated as an electrode material in supercapacitors [13][14][15]. ...
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Hierarchical nanostructured activated carbon electrode material was prepared from the used-coffee grounds to fabricate a cost-effective, scalable and high-performance symmetric supercapacitor. The interconnected, disordered and microporous material was synthesized in a simple two-stage method of chemical activation with zinc chloride followed by direct pyrolysis of the coffee grounds at 900 ºC in nitrogen atmosphere. The N2 adsorption and desorption analysis showed that the prepared material had an extraordinary surface area of ~1178 m2 g-1. The fabricated symmetric supercapacitor device in non-aqueous tetraethylammonium tetrafluoroborate (TEABF4) electrolyte exhibited 2.7 V cell voltage with superior specific capacitance, energy and power density of 129 F g–1, 56.4 Wh kg–1 and 797.9 W kg–1, respectively. Besides, it also had a high specific capacitance retention of 99% even after 10,000 cycles. This work demonstrated an effective approach to transform coffee grounds into high performance electrode material for renewable energy devices. The observed electrochemical performance evidently showed that the materials derived from waste coffee grounds could be recycled into potential electrode material for supercapacitors. The cost-effectiveness and abundance of waste coffee grounds combined with the simple activation process and high performance of the synthesized material increased its feasibility for commercial applications in energy storage devices.
Coffee is rich in phenolic compounds, which can be evaluated by the total phenolic or specific individual phenolics. The composition and concentration of phenolics in coffee are affected by various factors, including postharvest and roasting. This study aimed to compare the ratio of phenolic acid (measured as chlorogenic acid) to total phenolic in Bogor arabica coffee, considering different postharvest treatments and roasting levels. The coffee samples were treated with different postharvest (dry, wet, and honey) and roasting processes (light and dark). Green coffee bean was used as a control. The roasting process involved heating the coffee at temperatures ranging from 147.9 to 178.8°C for light roasting, and 190.2 to 200°C for dark roasting (10 minutes each). The color of the coffee beans, concentration of phenolic acid in the coffee extract, and total phenolic in the coffee extract were analyzed using a colorimeter, HPLC, and spectro-photometer respectively. The results showed that roasting significantly intensified the dark color of Bogor arabica coffee. Among the phenolic acids, the 5-CQA isomer emerged as the most dominant and was also the most susceptible to degradation during roasting. As the roasting level increased, the concentration of phenolic acid consistently decreased. Interestingly, the total phenolic initially increased in light roasted coffee but decreased in dark roasted coffee. Green coffee beans exhibited the highest proportion of phenolic acid (83%), whereas dark roasted coffee had the lowest proportion (19%). Although light roasted coffee had the highest total phenolic, its phenolic acid concentration decreased significantly compared to green coffee beans.
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Background The chloroplast genome of plants is known for its small size and low mutation and recombination rates, making it a valuable tool in plant phylogeny, molecular evolution, and population genetics studies. Codon usage bias, an important evolutionary feature, provides insights into species evolution, gene function, and the expression of exogenous genes. Coffee, a key crop in the global tropical agricultural economy, trade, and daily life, warrants investigation into its codon usage bias to guide future research, including the selection of efficient heterologous expression systems for coffee genetic transformation. Results Analysis of the codon utilization patterns in the chloroplast genomes of three Coffea species revealed a high degree of similarity among them. All three species exhibited similar base compositions, with high A/T content and low G/C content and a preference for A/T-ending codons. Among the 30 high-frequency codons identified, 96.67% had A/T endings. Fourteen codons were identified as ideal. Multiple mechanisms, including natural selection, were found to influence the codon usage patterns in the three coffee species, as indicated by ENc-GC3s mapping, PR2 analysis, and neutral analysis. Nicotiana tabacum and Saccharomyces cerevisiae have potential value as the heterologous expression host for three species of coffee genes. Conclusion This study highlights the remarkable similarity in codon usage patterns among the three coffee genomes, primarily driven by natural selection. Understanding the gene expression characteristics of coffee and elucidating the laws governing its genetic evolution are facilitated by investigating the codon preferences in these species. The findings can enhance the efficacy of exogenous gene expression and serve as a basis for future studies on coffee evolution.
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Coffee grown in Indonesia has been proven for its quality made Indonesian coffee consumption continues to increase from year to year in many countries. However, the coffee business has not reached its maximum potential due to numerous barriers and supply chain management is one of them. This research aimed to identify the potential cause for blocked chains as one of the business threats that will significantly impact the entire business process in the long term also identifies the success factors related to the coffee supply chain to improve the performance of the business processes. This research utilized an inductive study with quantitative and qualitative approaches using primary and secondary data collection strategies. The research result indicated the low weight for dimensions in “Deliver” and “Return” performance with indicators including “Shipping”, “Good relation with customers”, “Mutual relation with suppliers”, “Return procedure”, “Processing time”, “Ease of process”, and “Complaints that quickly resolved”. Therefore, to the result, the factors that are considered as a direct risk to the blocked chains are “Shipping”, “Processing time”, and “Ease of process”. While the score for supply chain performance in West Java Coffee is 71% for KPIs in Reliability and Responsiveness. This research also provides a coffee supply chain model that will positively contribute to knowledge especially for identifying potentially blocked chains in the coffee business.
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Background: To examine the relationship between the frequency of physical activities and food product consumption with body composition change after two years in a sample of older people. Methods: Body composition, mass change, frequency of physical activity, and food products consumption were measured. Depression severity, health self-assessment, cognitive function, and demographic data were included as confounders. Results: There were no significant changes in body composition except for a reduction in visceral fat level within two years (p < 0.05). Drinking beer and eating sweets a few times per week were associated with a significant increase in body fat percentage (p < 0.05). Drinking green or white tea more frequently than a few times per year was related to an increase in body fat (3.18 to 3.88%, p < 0.05). Contrarily, daily consumption of coffee was related to a decrease in body fat (p = 0.029). Subjects who ate sweets once a week or more frequently consumed coffee more often. Conclusions: More frequent drinking of beer or of green or white tea and consumption of sweets were related to an increase in body fat percentage, while daily coffee consumption was related to a decrease in body fat percentage after two years in older, healthy subjects. Noteworthily, the frequencies of food product consumption are interrelated.
This current work presents a meta-analysis to determine coffee bean specifications [types (Arabica and Robusta), roasting degree (light, medium and dark), roasting condition (time and temperature) and geo- graphical origins by countries (Brazil, India and Thailand)] with the highest antioxidant activity. A total of 12 articles and 189 data points were employed for meta-analysis of subgroups. The results showed that the Arabica coffee bean was reported to have the highest antioxidant activity as assessed by ferric reduc- ing antioxidant power (FRAP) and 2,2-azinobis-3 ethyl benzothiazoline-6-sulfonic acid (ABTS). In addi- tion, the light roasting degree of coffee beans produced the highest antioxidant activity as assessed by FRAP and 2,2-diphenyl-1-picrylhydrazyl (DPPH). Roasting degree is a better parameter to obtain coffee beans with higher antioxidant activity compared to roasting conditions. Coffee from Brazil and India was found to have higher antioxidant activity compared with coffee from Thailand. This study concludes that Arabica coffee beans from Brazil or India with a light roasting degree are expected to have high antioxi- dant activity.
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Background: Coffee is a widely available beverage that is enjoyed by individuals of many cultures. The publication of new studies prompts a review of the clinical updates regarding the association between coffee consumption and cardiovascular disease. Methods: We present a narrative review of the literature related to coffee consumption and cardiovascular disease. Results: Recent (2000-2021) studies have shown that regular coffee consumption is associated with a decreased risk of developing hypertension, heart failure, and atrial fibrillation. However, results are inconsistent with regard to coffee consumption and risk of developing coronary heart disease. Most studies show a J-shaped association, wherein moderate coffee consumption resulted in decreased risk of coronary heart disease and heavy coffee consumption resulted in increased risk. In addition, boiled or unfiltered coffee is more atherogenic than filtered coffee because of its rich diterpene content that inhibits bile acid synthesis and ultimately affects lipid metabolism. On the other hand, filtered coffee, which is essentially devoid of the aforementioned compounds, exerts antiatherogenic properties by increasing high-density lipoprotein–mediated cholesterol efflux from macrophages through the influence of plasma phenolic acid. As such, cholesterol levels are principally influenced by the manner of coffee preparation (boiled vs filtered). Conclusion: Our findings suggest that moderate coffee consumption leads to a decrease in all-cause and cardiovascular-related mortality, hypertension, cholesterol, heart failure, and atrial fibrillation. However, no conclusive relationship between coffee and coronary heart disease risk has been consistently identified.
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Purpose of review This review summarizes and highlights recent advances in current knowledge of the relationship between coffee and caffeine consumption and risk of coronary heart disease. Potential mechanisms and genetic modifiers of this relationship are also discussed. Recent findings Studies examining the association between coffee consumption and coronary heart disease have been inconclusive. Coffee is a complex mixture of compounds that may have either beneficial or harmful effects on the cardiovascular system. Randomized controlled trials have confirmed the cholesterol-raising effect of diterpenes present in boiled coffee, which may contribute to the risk of coronary heart disease associated with unfiltered coffee consumption. A recent study examining the relationship between coffee and risk of myocardial infarction incorporated a genetic polymorphism associated with a slower rate of caffeine metabolism and provides strong evidence that caffeine also affects risk of coronary heart disease. Several studies have reported a protective effect of moderate coffee consumption, which suggests that coffee contains other compounds that may be beneficial. Summary Diterpenes present in unfiltered coffee and caffeine each appear to increase risk of coronary heart disease. A lower risk of coronary heart disease among moderate coffee drinkers might be due to antioxidants found in coffee.
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Coffee drinking has been associated with increased serum cholesterol levels in some, but not all, studies. A Medline search of the English-language literature published prior to December 1998, a bibliography review, and consultations with experts were performed to identify 14 published trials of coffee consumption. Information was abstracted independently by two reviewers using a standardized protocol. With a random-effects model, treatment effects were estimated by pooling results from individual trials after weighting the results by the inverse of total variance. A dose-response relation between coffee consumption and both total cholesterol and LDL cholesterol was identified (p < 0.01). Increases in serum lipids were greater in studies of patients with hyperlipidemia and in trials of caffeinated or boiled coffee. Trials using filtered coffee demonstrated very little increase in serum cholesterol. Consumption of unfiltered, but not filtered, coffee increases serum levels of total and LDL cholesterol.
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Caffeine is probably the most frequently ingested pharmacologically active substance in the world. It is found in common beverages (coffee, tea, soft drinks), in products containing cocoa or chocolate, and in medications. Because of its wide consumption at different levels by most segments of the population, the public and the scientific community have expressed interest in the potential for caffeine to produce adverse effects on human health. The possibility that caffeine ingestion adversely affects human health was investigated based on reviews of (primarily) published human studies obtained through a comprehensive literature search. Based on the data reviewed, it is concluded that for the healthy adult population, moderate daily caffeine intake at a dose level up to 400 mg day(-1) (equivalent to 6 mg kg(-1) body weight day(-1) in a 65-kg person) is not associated with adverse effects such as general toxicity, cardiovascular effects, effects on bone status and calcium balance (with consumption of adequate calcium), changes in adult behaviour, increased incidence of cancer and effects on male fertility. The data also show that reproductive-aged women and children are 'at risk' subgroups who may require specific advice on moderating their caffeine intake. Based on available evidence, it is suggested that reproductive-aged women should consume </=300 mg caffeine per day (equivalent to 4.6 mg kg(-1) bw day(-1) for a 65-kg person) while children should consume </=2.5 mg kg(-1) bw day(-1).
Coffee drinking has been associated with increased serum cholesterol levels in some, but not all, studies. A Medline search of the English-language literature published prior to December 1998, a bibliography review, and consultations with experts were performed to identify 14 published trials of coffee consumption. Information was ed independently by two reviewers using a standardized protocol. With a random-effects model, treatment effects were estimated by pooling results from individual trials after weighting the results by the inverse of total variance. A dose-response relation between coffee consumption and both total cholesterol and LDL cholesterol was identified (p < 0.01). Increases in serum lipids were greater in studies of patients with hyperlipidemia and in trials of caffeinated or boiled coffee. Trials using filtered coffee demonstrated very little increase in serum cholesterol. Consumption of unfiltered, but not filtered, coffee increases serum levels of total and LDL cholesterol.
Objective: Coffee is a beverage used worldwide. It includes a wide array of components that can have potential implication on health. We have reviewed publications on the impact of coffee on a series of health outcomes. Methods: Articles published between January 1990 and December 2012 were selected after crossing coffee or caffeine with a list of keywords representative of the most relevant health areas potentially affected by coffee intake. Results: Caffeine, chlorogenic acids and diterpenes are important components of coffee. Tolerance often acts as a modulator of the biological actions of coffee. There is a significant impact of coffee on the cardiovascular system, and on the metabolism of carbohydrates and lipids. Contrary to previous beliefs, the various forms of arterial cardiovascular disease, arrhythmia or heart insufficiency seem unaffected by coffee intake. Coffee is associated with a reduction in the incidence of diabetes and liver disease. Protection seems to exist also for Parkinson's disease among the neurological disorders, while its potential as an osteoporosis risk factor is under debate. Its effect on cancer risk depends on the tissue concerned, although it appears to favor risk reduction. Coffee consumption seems to reduce mortality. Conclusion: The information gathered in recent years has generated a new concept of coffee, one which does not match the common belief that coffee is mostly harmful. This view is further supported by the discovery of a series of phyto-components with a beneficial profile. Reasonable optimism needs to be tempered, however, by the insufficiency of the clinical data, which in most cases stem from observational studies.
Dietary polyphenols are thought to be beneficial for human health as antioxidants. Coffee beans contain a common polyphenol, chlorogenic acid. Chlorogenic acid is the ester of caffeic acid and quinic acid. Although these polyphenols have received much attention, there is little evidence indicating a relationship between the effect and the rate of absorption. In this study, we focused on the beneficial effects of chlorogenic acid and caffeic acid, a major metabolite of chlorogenic acid. We carried out in vitro and in vivo experiments. In the in vitro study, caffeic acid had stronger antioxidant activity than that of chlorogenic acid. The uptake of chlorogenic acid by Caco-2 cells was much less than that of caffeic acid. The physiological importance of an orally administered compound depends on its availability for intestinal absorption and subsequent interaction with target tissues. We then used an intestinal ischemia-reperfusion model to evaluate antioxidant activities in vivo. We found that both chlorogenic acid and caffeic acid had effects on intestinal ischemia-reperfusion injury. Since caffeic acid has a stronger antioxidant activity than that of chlorogenic acid and chlorogenic acid is hydrolyzed into caffeic acid in the intestine, it is possible that caffeic acid plays a major role in the protective effect of chlorogenic acid against ischemia-reperfusion injury.
Adenosine A(1) and A(2A) receptors are colocalized with dopamine D(1) and D(2) receptors on striatal projection neurons and adenosine antagonists have been proposed as adjunctive therapies to l-DOPA treatment in Parkinson patients. We present here two studies examining the effects of selective and non-selective adenosine antagonists in two rodent models of parkinsonian tremor. Tremulous jaw movements (TJMs) were induced by either the dopamine antagonist pimozide (1.0 mg/kg) or the acetylcholine agonist tacrine (5.0 mg/kg), and were quantified by a trained observer who was blind to the treatment conditions. Animals were treated concomitantly with either caffeine (10.0 mg/kg non-selective adenosine antagonist), 8-cyclopentyltheophylline (CPT; 10.0 mg/kg; selective A(1) antagonist) or SCH58261 (8.0 mg/kg; selective A(2A) antagonist). Caffeine, CPT and SCH58261 all significantly reduced pimozide-induced TJM activity. Surprisingly administration of adenosine antagonists did not reduce tacrine-induced TJMs, and in the case of SCH58261 significantly increased TJMs compared to tacrine alone. These results indicate that antagonism at A(1) receptors may be more important for the reduction of tremor than previously supposed. Furthermore they indicate that dopamine antagonist-induced tremor models and acetylcholine agonist-induced tremor models are not entirely similar, and caution should be taken when using these models to evaluate novel therapeutics.
Among the many reported central nervous system effects of long-term caffeine use is improvement in mood. To examine prospectively the relationship of coffee and caffeine intake to risk of death from suicide. We conducted a 10-year follow-up study (1980 to 1990) in an ongoing cohort of 86 626 US female registered nurses aged 34 to 59 years in 1980, who were free of diagnosed coronary heart disease, stroke, or cancer. Information on coffee and caffeine intake was collected by a semiquantitative food frequency questionnaire in 1980. Deaths from suicide were determined by physician review of death certificates. Fifty-six cases of suicide occurred during 832 704 person-years of observation. Compared with non-drinkers of coffee, the age-adjusted relative risk of suicide in women who consumed two to three cups per day was 0.34 (95% confidence interval [CI, 0.17 to 0.68) and 0.42 (95% CI, 0.21 to 0.86) in women who consumed four or more cups per day (P for linear trend=.002). These findings remained essentially unchanged after adjusting for a broad range of potential confounding factors, including smoking habit, alcohol intake, medication use (diazepam and phenothiazine), history of comorbid disease (hypertension, hypercholesterolemia, or diabetes), marital status, and self-reported stress. A strong inverse relationship was similarly found for caffeine intake from all sources and risk of suicide. The data suggest a strong inverse association between coffee intake and risk of suicide. Whether regular intake of coffee or caffeine has clinically significant effects on the maintenance of affect or the prevention of depression merits further investigation in clinical trials and population-based prospective studies.