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Metabolism of caffeine and other components of coffee
... Thanks to its lipophilic properties, it easily penetrates the blood-brain barrier and the placenta and also passes into the amniotic fluid or milk [3]. The maximum plasma concentration of caffeine (4-5 mg/kg) is observed within 30-120 minutes after ingestion, and the half-life is usually from 2.5 to 5 hours [6]. The binding of caffeine to plasma proteins is limited because its blood/plasma ratio is almost equal to 1. Physiologically, long-term accumulation of this substance or its metabolites is not observed [7,8]. ...
... Data were normally distributed and unpaired t-tests were used. T. Tzakri et al. considering that caffeine distributes freely into the total body water (Arnaud, 1993). The mean normalized caffeine kinetic curves obtained in fasted state show that, after taking the caffeine-containing tablet, the gastric emptying water is comparable for the two population groups (Fig. 6). ...
... Prior reports have already discovered the connection between daily coffee consumption and caffeine metabolism through the polymorphism of CYP1A2 and CYP2A6 [23,24]. The second phase conjugated-metabolism produces a mixture of di-and tri-methylated xanthine, uric acid, and acetylated uracil derivatives, all being excreted through urine [25]. Previous studies have established that the biological effects of caffeine are tightly associated at three primary modulatory points: an antagonistic action on adenosine receptors, calcium mobilization, and phosphodiesterases inhibition [26,27]. ...
Cancer is a complicated and ever-evolving disease that remains a significant global cause of disease and mortality. Its complexity, which is evident at the genetic and phenotypic levels, contributes to its diversity and resistance to treatment. Numerous scientific investigations on human and animal models demonstrate the potential of phytochemicals in cancer prevention. Coffee has been shown to possess potent anti-carcinogenic properties, and studies have documented the consumption of coffee as a beverage reduces the risk of cancer occurrence. The major secondary metabolites of coffee, named caffeine and chlorogenic acid, have been linked to anti-inflammatory and antineoplastic effects through various signaling. In light of this, this review article provides a comprehensive analysis based on studies in anticancer effects of coffee, chlorogenic acid, and caffeine published between 2010 and 2023, sourced from Scopus, Pubmed, and Google Scholar databases. We summarize recent advances and scientific evidence on the association of phytochemicals found in coffee with a special emphasis on their biological activities against cancer and their molecular mechanism deemed potential to be used as a novel therapeutic target for cancer prevention and therapy.
... Caffeine is found in over 60 plants. Its most used product is found in coffee with an estimated 1.6 billion cups consumed daily worldwide (413,414). Other commonly used sources are found in tea, chocolate, cocoa beverages, soft drinks, and energy drinks. ...
Background:
Opioid prescribing in the United States is decreasing, however, the opioid epidemic is continuing at an uncontrollable rate. Available data show a significant number of opioid deaths, primarily associated with illicit fentanyl use. It is interesting to also note that the data show no clear correlation between opioid prescribing (either number of prescriptions or morphine milligram equivalent [MME] per capita), opioid hospitalizations, and deaths. Furthermore, the data suggest that the 2016 guidelines from the Centers for Disease Control and Prevention (CDC) have resulted in notable problems including increased hospitalizations and mental health disorders due to the lack of appropriate opioid prescribing as well as inaptly rapid tapering or weaning processes. Consequently, when examined in light of other policies and complications caused by COVID-19, a fourth wave of the opioid epidemic has been emerging.
Objectives:
In light of this, we herein seek to provide guidance for the prescription of opioids for the management of chronic non-cancer pain. These clinical practice guidelines are based upon a systematic review of both clinical and epidemiological evidence and have been developed by a panel of multidisciplinary experts assessing the quality of the evidence and the strength of recommendations and offer a clear explanation of logical relationships between various care options and health outcomes.
Methods:
The methods utilized included the development of objectives and key questions for the various facets of opioid prescribing practice. Also utilized were employment of trustworthy standards, and appropriate disclosures of conflicts of interest(s). The literature pertaining to opioid use, abuse, effectiveness, and adverse consequences was reviewed. The recommendations were developed after the appropriate review of text and questions by a panel of multidisciplinary subject matter experts, who tabulated comments, incorporated changes, and developed focal responses to questions posed. The multidisciplinary panel finalized 20 guideline recommendations for prescription of opioids for chronic non-cancer pain. Summary of the results showed over 90% agreement for the final 20 recommendations with strong consensus. The consensus guidelines included 4 sections specific to opioid therapy with 1) ten recommendations particular to initial steps of opioid therapy; 2) five recommendations for assessment of effectiveness of opioid therapy; 3) three recommendations regarding monitoring adherence and side effects; and 4) two general, final phase recommendations.
Limitations:
There is a continued paucity of literature of long-term opioid therapy addressing chronic non-cancer pain. Further, significant biases exist in the preparation of guidelines, which has led to highly variable rules and regulations across various states.
Conclusion:
These guidelines were developed based upon a comprehensive review of the literature, consensus among expert panelists, and in alignment with patient preferences, and shared decision-making so as to improve the long-term pain relief and function in patients with chronic non-cancer pain. Consequently, it was concluded - and herein recommended - that chronic opioid therapy should be provided in low doses with appropriate adherence monitoring and understanding of adverse events only to those patients with a proven medical necessity, and who exhibit stable improvement in both pain relief and activities of daily function, either independently or in conjunction with other modalities of treatments.
... In humans, it is metabolized into three distinct dimethylxanthines by hepatic p-450 actions to produce paraxanthine, which stimulates lipolysis; theobromine, which exerts diuretic and vasorelaxation effects, and theophylline, which can dilate airways and thus is often useful in alleviating respiratory conditions where it can improve blood pO2 saturation levels and the efficiency of respiratory exchange. 12 However, caffeine is considered a fairly weak inhibitor of phosphodiesterase enzymes, and the in vivo concentrations at which behavioral effects occur may be insufficient to be associated with meaningful phosphodiesterase inhibition. 13,14 The stimulatory effects of caffeine and methylxanthines in cardiovascular and bronchiolar tissues are much more prominent than those observed in behavioral comparisons, however. ...
To determine the effects of norepinephrine (NE) or of caffeine (CAF) alone or in combination with ephedrine (EPH) were determined in groups of lean and obese LA/Ntul//-cp Rats, Body weights of obese were >> lean littermates (p=<0.01) and measures of RMR of lean > Obese (p=<0.05). The effects of caffeine, ephedrine, a caffeine+ephedrine combo, and the β- agonist epinephrine was examined. Caffeine (CAF) resulted in a 33% increase in VO2, ‘nonephedrine’ (EPH) a 48% increase, the combination CAF+EPH a 53% increase, and the NE a 33% increase in VO2. In obese rats, the increases in VO2 were of a similar percentage (21 vs 48 vs 47 % vs 31% for CAF, EPH, CAF+EPH and NE respectively although the peak responses attained in the obese tended to be of a significantly lesser absolute magnitude than were observed in the lean phenotype. The time to peak thermogenic response was similar in lean and obese phenotypes for each of the 4 treatment regimens, but the duration of the peak responses to each treatment differed between lean and obese phenotypes (Obese > lean) for CAF, EPH and the CAF+EPH combination but duration of the VO2 response was similar in both phenotypes for the NE treatment. Thus, these observations are consistent with a significant CAF-stimulated thermogenic response that was qualitatively similar to that of NE in both lean and obese phenotypes of the congenic LA/Ntul//-cp rat and which thermogenic responses were further augmented with EPH alone or in combination with CAF. Although the mechanisms of action of the pharmacologic and physiologic mechanisms elicited may differ among the three agents studied the results indicate that they are complimentary in nature in bringing about increases in parameters of nonshivering thermogenesis and thus increasing metabolic energy expenditure in both lean and obese rats. In conclusion, while caffeine as monotherapy may bring about limited weight loss, the combination of caffeine plus ephedrine was more effective in the lean and obese phenotypes of the congenic, non-diabetic LA/Ntul//-cp (Corpulent) rat.
Flow is an intrinsically rewarding state characterised by positive affect and total task absorption. Because cognitive and physical performance are optimal in flow, chemical means to facilitate this state are appealing. Caffeine, a non-selective adenosine receptor antagonist, has been emphasized as a potential flow-inducer. Thus, we review the psychological and biological effects of caffeine that, conceptually, enhance flow. Caffeine may facilitate flow through various effects, including: i) upregulation of dopamine D1/D2 receptor affinity in reward-associated brain areas, leading to greater energetic arousal and ‘wanting’; ii) protection of dopaminergic neurons; iii) increases in norepinephrine release and alertness, which offset sleep-deprivation and hypoarousal; iv) heightening of parasympathetic high frequency heart rate variability, resulting in improved cortical stress appraisal, v) modification of striatal endocannabinoid-CB1 receptor-signalling, leading to enhanced stress tolerance; and vi) changes in brain network activity in favour of executive function and flow. We also discuss the application of caffeine to treat attention deficit hyperactivity disorder and caveats. We hope to inspire studies assessing the use of caffeine to induce flow.
Caffeine is an ergogenic substance that is consumed globally in many forms. The use of buccally absorbable formulations instead of gastrointestinal uptake has become increasingly popular over the years, especially when accelerated absorption with minimal gastrointestinal stress is desired. This study investigated the impact of five different formulations and administration routes of caffeine on the whole blood concentrations of caffeine, paraxanthine, and theobromine: caffeinated capsules, tablets, shots, pouches, and chewing gums. A uniform dose of caffeine (200 mg) was administered to 16 healthy recreational athletes (26.0 ± 2.1 years) using a randomized crossover design. Samples were taken in the form of dried blood spots at 16 different time points in a 2-hr timeframe after drug administration. The samples were analyzed using a validated liquid chromatography–tandem mass spectrometry method. The results for caffeine showed no significant differences in the overall bioavailability (area under the concentration–time curve), maximal concentration, and time to maximum concentration. However, when analyzing the bioavailability of caffeine in the first 5, 10, and 15 min, the liquid caffeine formulation was superior to other administered forms ( p < .05). This indicates that caffeine solubility has a major influence on its absorption rate. In sports, the rate of caffeine absorption must be considered, not only when ingesting anhydrous caffeine, but also when choosing buccal absorption. These findings imply that general guidelines for ergogenic caffeine use should consider the formulation used and, accordingly, the corresponding route of absorption.
Xanthines such as caffeine and theobromine are among the most consumed psychoactive stimulants in the world, either as natural components of coffee, tea and chocolate, or as added ingredients. The present study assessed if xanthines affect liver sinusoidal endothelial cells (LSEC). Cultured primary rat LSEC were challenged with xanthines at concentrations typically obtained from normal consumption of xanthine-containing beverages, food or medicines; and at higher concentrations below the in vitro toxic limit. The fenestrated morphology of LSEC were examined with scanning electron and structured illumination microscopy. All xanthine challenges had no toxic effects on LSEC ultrastructure as judged by LSEC fenestration morphology, or function as determined by endocytosis studies. All xanthines in high concentrations (150 μg/mL) increased fenestration frequency but at physiologically relevant concentrations, only theobromine (8 μg/mL) showed an effect. LSEC porosity was influenced only by high caffeine doses which also shifted the fenestration distribution towards smaller pores. Moreover, a dose-dependent increase in fenestration number was observed after caffeine treatment. If these compounds induce similar changes in vivo, age-related reduction of LSEC porosity can be reversed by oral treatment with theobromine or with other xanthines using targeted delivery.
Caffeine is an active ingredient of energy drinks that is often consumed to improve cognizance and physical cum mental alertness. This research aims to quantitatively analyze the caffeine content in serving volumes of energy drinks by spectrophotometric and iodometric back titration methods. In the spectrophotometric method, the determination of caffeine content was carried out using a maximum wavelength of 270 nm. The results show that the caffeine contents of the energy drinks were 37.40 mg/200 mL (Passion) < 64.73 mg/250 mL (Bullet) < 82.70 mg/355 mL (Power Horse) < 86.30 mg/400 mL (Predator) < 114.68 mg/500 mL (Fearless) while the iodometric back titration method showed 57.50 mg/250 mL, 165.00 mg/500 mL, 160.00 mg/400 mL, 117.15 mg/355 mL and 40 mg/200 mL respectively for Bullet, fearless, Predator, Power Horse and Passion. The labeled claims on the energy drinks were 78.75 mg/250 mL, 157.50 mg/500 mL, 120.00 mg/400 mL, 133.60 mg/355 mL and 50 mg/200 mL respectively for Bullet, fearless, Predator, Power Horse and Passion which indicates that manufacturers reported higher values of caffeine content in their product possibly to make it attractive to consumers.
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