Structure-Bioactivity Relationships of Methylxanthines: Trying to Make Sense of All the Promises and the Drawbacks

The Impact of the Drying Process on the Antioxidant and Anti-Inflammatory Potential of Dried Ripe Coffee Cherry Pulp Soluble Powder

Coffee fruit cascara, which is the skin and pulp of the coffee cherry, has been authorized as a novel food for commercialization in the European Union. The present research assessed the feasibility of using spray drying to produce a soluble powder called instant cascara (IC), employing sun-dried ripe coffee cherry pulp as a raw material. Although there were no significant differences (p > 0.05) in the overall antioxidant capacity between the freeze-dried and spray-dried samples, after an in vitro simulation of the digestion process, the spray-dried sample was significantly (p < 0.05) more antioxidant. Both samples reduced physiological intracellular ROS and significantly decreased (p < 0.05) the secretion of the pro-inflammatory factor NO. Alkaloids and phenolic compounds were detected in intestinal digests. In conclusion, spray drying is a good technique for producing IC as its use does not affect its properties and causes less environmental impact than freeze drying, as calculated by life cycle assessment. Sensory analysis did not show significant differences between the commercial beverage and the IC beverage in the adult population. IC at 10 mg/mL was significantly less accepted in adolescents than the commercial beverage. Future work will include the reformulation of the IC beverage at 10 mg/mL, which has antioxidant and anti-inflammatory potential, to increase its hedonic acceptance in all consumer segments.

Microbial metabolism of caffeine and potential applications in bioremediation

With increasing global consumption of caffeine-rich products, such as coffee, tea, and energy drinks, there is also an increase in urban and processing waste full of residual caffeine with limited disposal options. This waste caffeine has been found to leach into the surrounding environment where it poses a threat to microorganisms, insects, small animals, and entire ecosystems. Growing interest in harnessing this environmental contaminant has led to the discovery of 79 bacterial strains, eight yeast strains, and 32 fungal strains capable of metabolizing caffeine by N-demethylation and/or C-8 oxidation. Recently observed promiscuity of caffeine-degrading enzymes in vivo has opened up the possibility of engineering bacterial strains capable of producing a wide variety of caffeine derivatives from a renewable resource. These engineered strains can be used to reduce the negative environmental impact of leached caffeine-rich waste through bioremediation efforts supplemented by our increasing understanding of new techniques such as cell immobilization. Here, we compile all of the known caffeine-degrading microbial strains, discuss their metabolism and related enzymology, and investigate their potential application in bioremediation.

Theophylline as a quorum sensing and biofilm inhibitor in Pseudomonas aeruginosa and Chromobacterium violaceum

Quorum sensing (QS) is pivotal in coordinating virulence factors and biofilm formation in various pathogenic bacteria, making it a prime target for disrupting bacterial communication. Pseudomonas aeruginosa is a member of the "ESKAPE" group of bacterial pathogens known for their association with antimicrobial resistance and biofilm formation. The current antibiotic arsenal falls short of addressing biofilm-related infections effectively, highlighting the urgent need for novel therapeutic agents. In this study, we explored the anti-QS and anti-biofilm properties of theophylline against two significant pathogens, Chromobacterium violaceum and P. aeruginosa. The production of violacein, pyocyanin, rhamnolipid, and protease was carried out, along with the evaluation of biofilm formation through methods including crystal violet staining, triphenyl tetrazolium chloride assay, and fluorescence microscopy. Furthermore, computational analyses were conducted to predict the targets of theophylline in the QS pathways of P. aeruginosa and C. violaceum. Our study demonstrated that theophylline effectively inhibits QS activity and biofilm formation in C. violaceum and P. aeruginosa. In P. aeruginosa, theophylline inhibited the production of key virulence factors, including pyocyanin, rhamnolipid, protease, and biofilm formation. The computational analyses suggest that theophylline exhibits robust binding affinity to CviR in C. violaceum and RhlR in P. aeruginosa, key participants in the QS-mediated biofilm pathways. Furthermore, theophylline also displays promising interactions with LasR and QscR in P. aeruginosa. Our study highlights theophylline as a versatile anti-QS agent and offers a promising avenue for future research to develop novel therapeutic strategies against biofilm-associated infections.

Bioactive compounds in coffee and their role in lowering the risk of major public health consequences: A review

This article addresses the bioactive components in coffee aroma, their metabolism, and the mechanism of action in lowering the risk of various potential health problems. The main bioactive components involved in the perceived aroma of coffee and its related health benefits are caffeine, chlorogenic acid (CGA), trigonelline, diterpenes, and melanoids. These compounds are involved in various physiological activities. Caffeine has been shown to have anticancer properties, as well as the ability to prevent the onset and progression of hepatocellular carcinoma and to be anti-inflammatory. CGA exhibits antioxidant action and is implicated in gut health, neurodegenerative disease protection, type 2 diabetes, and cardiovascular disease prevention. Furthermore, together with diterpenes, CGA has been linked to anticancer activity. Trigonelline, on the other side, has been found to lower oxidative stress by increasing antioxidant enzyme activity and scavenging reactive oxygen species. It also prevents the formation of kidney stones. Diterpenes and melanoids possess anti-inflammatory and antioxidant properties, respectively. Consuming three to four cups of filtered coffee per day, depending on an individual's physiological condition and health status, has been linked to a lower risk of several degenerative diseases. Despite their health benefits, excessive coffee intake above the recommended daily dosage, calcium and vitamin D deficiency, and unfiltered coffee consumption all increase the risk of potential health concerns. In conclusion, moderate coffee consumption lowers the risk of different noncommunicable diseases.

Production of 1-methylxanthine via the biodegradation of theophylline by an optimized Escherichia coli strain

1-Methylxanthine is a high-value derivative of caffeine of limited natural availability with many potential pharmaceutical applications. Unfortunately, production of 1-methylxanthine through purely chemical methods of synthesis are unfavorable due to lengthy chemical processes and the requirement of hazardous chemicals, ultimately resulting in low yields. Here, we describe a novel biosynthetic process for the production of 1-methylxanthine from theophylline using engineered Escherichia coli whole-cell biocatalysts and reaction optimization. When scaled-up to 1590 mL, the simple biocatalytic reaction produced approximately 1188 mg 1-methylxanthine from 1444 mg theophylline, constituting gram-scale production of 1-methylxanthine in as little as 3 hours. Following HPLC purification and solvent evaporation, 1163 mg of dried 1-methylxanthine powder was collected, resulting in a 97.9 wt% product recovery at a purity of 97.8%. This is the first report of a biocatalytic process designed specifically for the production and purification of the high-value biochemical 1-methylxanthine from theophylline. This process is also the most robust methylxanthine N-demethylation process featuring engineered E. coli to date, capable of gram-scale production.

Methylxanthine for the prevention and treatment of apnea in preterm infants

BACKGROUND

Very preterm infants often require respiratory support and are therefore exposed to an increased risk of chronic lung disease and later neurodevelopmental disability. Although methylxanthines are widely used to prevent and treat apnea associated with prematurity and to facilitate extubation, there is uncertainty about the benefits and harms of different types of methylxanthines.

OBJECTIVES

To assess the effects of methylxanthines on the incidence of apnea, death, neurodevelopmental disability, and other longer-term outcomes in preterm infants (1) at risk for or with apnea, or (2) undergoing extubation.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, two other databases, and three trial registers (November 2022).

SELECTION CRITERIA

We included randomized trials in preterm infants, in which methylxanthines (aminophylline, caffeine, or theophylline) were compared to placebo or no treatment for any indication (i.e. prevention of apnea, treatment of apnea, or prevention of re-intubation).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods and GRADE to assess the certainty of evidence.

MAIN RESULTS

We included 18 studies (2705 infants), evaluating the use of methylxanthine in preterm infants for: any indication (one study); prevention of apnea (six studies); treatment of apnea (five studies); and to prevent re-intubation (six studies). Death or major neurodevelopmental disability (DMND) at 18 to 24 months. Only the Caffeine for Apnea of Prematurity (CAP) study (enrolling 2006 infants) reported on this outcome. Overall, caffeine probably reduced the risk of DMND in preterm infants treated with caffeine for any indication (risk ratio (RR) 0.87, 95% confidence interval (CI) 0.78 to 0.97; risk difference (RD) -0.06, 95% CI -0.10 to -0.02; number needed to treat for an additional beneficial outcome (NNTB) 16, 95% CI 10 to 50; 1 study, 1869 infants; moderate-certainty evidence). No other trials reported DMND. Results from the CAP trial regarding DMND at 18 to 24 months are less precise when analyzed based on treatment indication. Caffeine probably results in little or no difference in DMND in infants treated for prevention of apnea (RR 1.00, 95% CI 0.80 to 1.24; RD -0.00, 95% CI -0.10 to 0.09; 1 study, 423 infants; moderate-certainty evidence) and probably results in a slight reduction in DMND in infants treated for apnea of prematurity (RR 0.85, 95% CI 0.71 to 1.01; RD -0.06, 95% CI -0.13 to 0.00; NNTB 16, 95% CI 7 to > 1000; 1 study, 767 infants; moderate-certainty evidence) or to prevent re-intubation (RR 0.85, 95% CI 0.73 to 0.99; RD -0.08, 95% CI -0.15 to -0.00; NNTB 12, 95% CI 6 to >1000; 1 study, 676 infants; moderate-certainty evidence). Death. In the overall analysis of any methylxanthine treatment for any indication, methylxanthine used for any indication probably results in little or no difference in death at hospital discharge (RR 0.99, 95% CI 0.71 to 1.37; I2 = 0%; RD -0.00, 95% CI -0.02 to 0.02; I2 = 5%; 7 studies, 2289 infants; moderate-certainty evidence). Major neurodevelopmental disability at 18 to 24 months. In the CAP trial, caffeine probably reduced the risk of major neurodevelopmental disability at 18 to 24 months (RR 0.85, 95% CI 0.76 to 0.96; RD -0.06, 95% CI -0.10 to -0.02; NNTB 16, 95% CI 10 to 50; 1 study, 1869 infants; moderate-certainty evidence), including a reduction in the risk of cerebral palsy or gross motor disability (RR 0.60, 95% CI 0.41 to 0.88; RD -0.03, 95% CI -0.05 to -0.01; NNTB 33, 95% CI 20 to 100; 1 study, 1810 infants; moderate-certainty evidence) and a marginal reduction in the risk of developmental delay (RR 0.88, 95% CI 0.78 to 1.00; RD -0.05, 95% CI -0.09 to -0.00; NNTB 20, 95% CI 11 to > 1000; 1 study, 1725 infants; moderate-certainty evidence). Any apneic episodes, failed apnea reduction after two to seven days (< 50% reduction in apnea) (for infants treated with apnea), and need for positive-pressure ventilation after institution of treatment. Methylxanthine used for any indication probably reduces the occurrence of any apneic episodes (RR 0.31, 95% CI 0.18 to 0.52; I2 = 47%; RD -0.38, 95% CI -0.51 to -0.25; I2 = 49%; NNTB 3, 95% CI 2 to 4; 4 studies, 167 infants; moderate-certainty evidence), failed apnea reduction after two to seven days (RR 0.48, 95% CI 0.33 to 0.70; I2 = 0%; RD -0.31, 95% CI -0.44 to -0.17; I2 = 53%; NNTB 3, 95% CI 2 to 6; 4 studies, 174 infants; moderate-certainty evidence), and may reduce receipt of positive-pressure ventilation after institution of treatment (RR 0.61, 95% CI 0.39 to 0.96; I2 = 0%; RD -0.06, 95% CI -0.11 to -0.01; I2 = 49%; NNTB 16, 95% CI 9 to 100; 9 studies, 373 infants; low-certainty evidence). Chronic lung disease. Methylxanthine used for any indication reduces chronic lung disease (defined as the use of supplemental oxygen at 36 weeks' postmenstrual age) (RR 0.77, 95% CI 0.69 to 0.85; I2 = 0%; RD -0.10, 95% CI -0.14 to -0.06; I2 = 18%; NNTB 10, 95% CI 7 to 16; 4 studies, 2142 infants; high-certainty evidence). Failure to extubate or the need for re-intubation within one week after initiation of therapy. Methylxanthine used for the prevention of re-intubation probably results in a large reduction in failed extubation compared with no treatment (RR 0.48, 95% CI 0.32 to 0.71; I2 = 0%; RD -0.27, 95% CI -0.39 to -0.15; I2 = 69%; NNTB 4, 95% CI 2 to 6; 6 studies, 197 infants; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Caffeine probably reduces the risk of death, major neurodevelopmental disability at 18 to 24 months, and the composite outcome DMND at 18 to 24 months. Administration of any methylxanthine to preterm infants for any indication probably leads to a reduction in the risk of any apneic episodes, failed apnea reduction after two to seven days, cerebral palsy, developmental delay, and may reduce receipt of positive-pressure ventilation after institution of treatment. Methylxanthine used for any indication reduces chronic lung disease (defined as the use of supplemental oxygen at 36 weeks' postmenstrual age).

Theophylline reverses oxycodone's but not fentanyl's respiratory depression in mice while caffeine is ineffective against both opioids

RATIONALE

The opioid epidemic remains a pressing public health crisis in the United States. Most of these overdose deaths are a result of lethal respiratory depression. In recent years the increasing incidence of opioid-involved overdose deaths has been driven by fentanyl, which is more resistant to adequate reversal by naloxone (NARCAN ®) than semi-synthetic or classical morphinan predecessors like oxycodone and heroin. For this and other reasons (e.g., precipitating withdrawal) non-opioidergic pharmacotherapies to reverse opioid-depressed respiration are needed. Methylxanthines are a class of stimulant drugs including caffeine and theophylline which exert their effects primarily via adenosine receptor antagonism. Evidence suggests methylxanthines can stimulate respiration by enhancing neural activity in respiratory nuclei in the pons and medulla independent of opioid receptors. This study aimed to determine whether caffeine and theophylline can stimulate respiration in mice when depressed by fentanyl and oxycodone.

METHODS

Whole-body plethysmography was used to characterize fentanyl and oxycodone's effects on respiration and their reversal by naloxone in male Swiss Webster mice. Next, caffeine and theophylline were tested for their effects on basal respiration. Finally, each methylxanthine was evaluated for its ability to reverse similar levels of respiratory depression induced by fentanyl or oxycodone.

RESULTS AND CONCLUSIONS

Oxycodone and fentanyl dose-dependently reduced respiratory minute volume (ml/min; MVb) that was reversible by naloxone. Caffeine and theophylline each significantly increased basal MVb. Theophylline, but not caffeine, completely reversed oxycodone-depressed respiration. In contrast, neither methylxanthine elevated fentanyl-depressed respiration at the doses tested. Despite their limited efficacy for reversing opioid-depressed respiration when administered alone, the methylxanthines safety, duration, and mechanism of action supports further evaluation in combination with naloxone to augment its reversal of opioid-depressed respiration.

Theophylline-Induced Relaxation Is Enhanced after Testosterone Treatment via Increased KV1.2 and KV1.5 Protein Expression in Guinea Pig Tracheal Smooth Muscle

Theophylline is a drug commonly used to treat asthma due to its anti-inflammatory and bronchodilatory properties. Testosterone (TES) has been suggested to reduce the severity of asthma symptoms. This condition affects boys more than girls in childhood, and this ratio reverses at puberty. We reported that guinea pig tracheal tissue chronic exposure to TES increases the expression of β₂-adrenoreceptors and enhances salbutamol-induced K⁺ currents (IK⁺). Herein, we investigated whether the upregulation of K⁺ channels can enhance the relaxation response to methylxanthines, including theophylline. Chronic incubation of guinea pig tracheas with TES (40 nM, 48 h) enhanced the relaxation induced by caffeine, isobutylmethylxanthine, and theophylline, an effect that was abolished by tetraethylammonium. In tracheal myocytes, chronic incubation with TES increased theophylline-induced IK⁺; flutamide reversed this effect. The increase in IK⁺ was blocked by 4-aminopyridine by ~82%, whereas iberiotoxin reduced IK⁺ by ~17%. Immunofluorescence studies showed that chronic TES exposure increased the expression of K_V1.2 and K_V1.5 in airway smooth muscle (ASM). In conclusion, chronic exposure to TES in guinea pig ASM promotes upregulation of K_V1.2 and K_V1.5 and enhances theophylline relaxation response. Therefore, gender should be considered when prescribing methylxanthines, as teenage boys and males are likely to respond better than females.

Paraxanthine safety and comparison to caffeine

Introduction: Caffeine, one of the most ubiquitous ingredients found in beverages and other ingested food products, has a long history of safe use. As a member of the methylxanthine class of stimulants, caffeine is not devoid of unwanted side effects at any serving level. Caffeine safety has been the subject of a safety workshop by FDA and the Institute of Medicine in the past decade. Thus, investigation into an alternate stimulant with similar pharmacology but improved safety is warranted. Paraxanthine (1,7-dimethylxanthine) is the predominant metabolite of caffeine in humans with similar stimulant properties. The few toxicity studies that are available for paraxanthine suggest that the molecule is relatively safe, although thorough characterization of its safety is required prior to widespread incorporation into foods/beverages. Methods: The aim of this study was to evaluate the toxicity of paraxanthine (Rarebird, Inc.) relative to caffeine through a battery of toxicological studies conducted in accordance with international guidelines. These studies evaluated the potential mutagenicity (bacterial reverse mutation, in vitro mammalian chromosomal aberration), genetic toxicity (in vitro mammalian cell gene mutation) and acute, sub-acute and sub-chronic oral toxicity of paraxanthine in Sprague Dawley rats. Results/Discussion: There was no evidence of genetic toxicity or mutagenicity in the in vitro studies. An acute oral LD₅₀ of 829.20 mg/kg body weight (bw) was established. There was no mortality or treatment-related adverse effects in the 14-day repeat dose oral toxicity study, wherein rats received low, mid, or high doses of paraxanthine (50, 100, or 150 mg/kg bw, n = 5 rats/sex/group). The same findings were observed in the subchronic repeat-dose 90-day oral toxicity study at daily doses of paraxanthine of 100, 150, or 185 mg/kg bw which were compared to caffeine at 150 or 185 mg/kg bw (n = 10 animals/sex/group). However, mortality was reported in two animals in the high dose caffeine-treated animals. Therefore, the no observed adverse effect level (NOAEL) from the 90-day study was determined to be 150 mg/kg bw for caffeine and 185 mg/kg bw for paraxanthine for both male and female Sprague Dawley rats. These findings may suggest that paraxanthine could be a safer alternative to caffeine in humans.

Determination of Caffeine, Theobromine, and Theophylline by HPLC-DAD in Beverages Commonly Consumed in Lima, Peru

The purpose of this study was to determine the content of caffeine, theobromine, and theophylline by high-performance liquid chromatography with diode-array detection (HPLC-DAD) in beverages commonly consumed in Lima, Peru. The samples were divided into 6 groups (herbal teas, coffee powder, chocolate milks, soft drinks, sports drinks, and energy drinks) which included the five most commonly consumed beverages of the different groups. Caffeine was mainly identified in the soft drink and energy drink groups, with the latter having a more significant value (10.38 ± 0.01 vs. 95.50 ± 3.48 mg/L, respectively). In herbal teas, caffeine showed the highest content (0.47 ± 0.01 to 4.91 ± 0.05 mg/L), despite theophylline being a characteristic compound of tea leaves. Sports drinks presented very low caffeine levels (0.03 ± 0.01 to 0.05 ± 0.01 mg/L), and theobromine (0.48 ± 0.01 to 6.00 ± 0.02) was also identified. Caffeine (4.09 ± 0.01 to 5.70 ± 0.01 mg/L) and theobromine (1.70 ± 0.01 to 12.24 ± 0.01 mg/L) were found in the five commercial brands of chocolate milk evaluated. Moreover, the group of coffee powder samples had the highest level of caffeine content (49.25 ± 0.24 to 964.40 ± 4.93 mg/100 g). The results obtained in this study provide reliable information on the composition and quantification of methylxanthines in the beverages most consumed in Lima and impact consumer knowledge.

Design, Synthesis and Assay of Novel Methylxanthine-Alkynylmethylamine Derivatives as Acetylcholinesterase Inhibitors

Xanthine derivatives have been a great area of interest for the development of potent bioactive agents. Thirty-eight methylxanthine derivatives as acetylcholinesterase inhibitors (AChE) were designed and synthesized. Suzuki-Miyaura cross-coupling reactions of 8-chlorocaffeine with aryl(hetaryl)boronic acids, the CuAAC reaction of 8-ethynylcaffeine with several azides, and the copper(I) catalyzed one-pot three-component reaction (A³-coupling) of 8-ethynylcaffeine, 1-(prop-2-ynyl)-, or 7-(prop-2-ynyl)-dimethylxanthines with formaldehyde and secondary amines were the main approaches for the synthesis of substituted methylxanthine derivatives (yield 53-96%). The bioactivity of all new compounds was evaluated by Ellman's method, and the results showed that most of the synthesized compounds displayed good and moderate acetylcholinesterase (AChE) inhibitory activities in vitro. The structure-activity relationships were also discussed. The data revealed that compounds 53, 59, 65, 66, and 69 exhibited the most potent inhibitory activity against AChE with IC₅₀ of 0.25, 0.552, 0.089, 0.746, and 0.121 μM, respectively. The binding conformation and simultaneous interaction modes were further clarified by molecular docking studies.

Diet in the Prevention of Alzheimer's Disease: Current Knowledge and Future Research Requirements

Alzheimer's disease is a progressive brain disease that is becoming a major health problem in today's world due to the aging population. Despite it being widely known that diet has a significant impact on the prevention and progression of Alzheimer's disease, the literature data are still scarce and controversial. The application of the principles of rational nutrition for the elderly is suggested for Alzheimer's disease. The diet should be rich in neuroprotective nutrients, i.e., antioxidants, B vitamins, and polyunsaturated fatty acids. Some studies suggest that diets such as the Mediterranean diet, the DASH (Dietary Approaches to Stop Hypertension) diet, and the MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) diet have a beneficial effect on the risk of developing Alzheimer's disease.

Synthesis, Crystal Structures, and Biological Activity Evaluation of Novel Xanthine Derivatives Containing a Pyrethroid Moiety

On the basis of the structures of natural xanthines and pyrethroid insecticides, a series of novel xanthine derivatives Ia-Is containing pyrethroid motifs were synthesized and identified by means of melting points, ¹H NMR, ¹³C NMR, and HRMS. The single crystals of compounds In and Iq were obtained, which further confirmed the structures and configurations of this type of compounds. The biological tests showed that some of them exhibited favorable insecticidal activities toward Mythimna separata Walker and Plutella xylostella L. and were superior to the natural methylxanthine compound caffeine and comparable with the insecticide tetramethrin (e.g., compound Im: LC₅₀ = 0.6162 mg/L, against P. xylostella). Among others, Im, Ib, Ij, and Ik could serve as new insecticidal leading structures for further study. Moreover, some of the compounds showed favorable fungicidal activities against a broad spectrum of plant pathogenic fungi (e.g., compound Ie: EC₅₀ = 6.0922 μg/mL, against Physalospora piricola; EC₅₀ = 9.0637 μg/mL, against Rhizoctonia cerealis), which in turn would be an exciting new finding in xanthine chemistry; Ie, Ih, and Ii could be novel fungicidal leading compounds for further investigation. The structure-activity relationships of the compounds were also analyzed and discussed in detail. The research results presented in this paper provide a useful reference and guidance for the development of new natural product-based agrochemicals.

Effect of Stress and Caffeine on Male Infertility

Caffeine is a natural psychoactive chemical found in beverages made from coffee. In addition, it is added by the manufacturers of a large number of sodas and energy drinks. It does this by stimulating both the brain and the central nervous system, enabling you to avoid being sleepy while still keeping you attentive. A state of emotional or physical tension is defined as stress. It can be induced through the experience of something or thinking of something that causes you to feel uncomfortable, irritated, or nervous. Your body's response to adversity or demand is what we call stress. Among couples, male infertility is common. A failure in spermatogenesis is accountable for nearly half of all occurrences of infertility in marriage. Ageing, psychological stress, diet, physical exercise, coffee, hot water, hot scrotum, and cell phone usage are some of the few modifiable lifestyle variables that have a role in the development of infertility. Many hypotheses have been proposed to establish the link between stress in the workplace, life events (war, earthquake, etc.), and inability to conceive have been linked to inferior or degraded semen quality. In this review, we will discuss the effect on male fertility of elements including quality of life (such as exercise, diet, and other alterations to one's daily routine) and psychological stress. In addition, the effects on male fertility of elevated scrotal temperature, improper dietary habits, and physical inactivity will be discussed. The loss in male fertility, mainly due to ageing, inappropriate lifestyles, and environmental factors, is a significant public health concern in this century. Couples can enhance their quality of life and increase their chances of naturally conceiving a child by altering their way of life and supplementing it with nutraceutical antioxidants and an organised educational, environmental, dietary, and physical exercise program.

A BRET Ca2+ sensor enables high-throughput screening in the presence of background fluorescence

The intrinsic fluorescence of samples confounds the use of fluorescence-based sensors. This is of particular concern in high-throughput screening (HTS) applications using large chemical libraries containing intrinsically fluorescent compounds. To overcome this problem, we developed a bioluminescence resonance energy transfer (BRET) Ca2+ sensor, CalfluxCTN. We demonstrated that it reliably reported changes in intracellular Ca2+ concentrations evoked by an agonist and an antagonist of the human muscarinic acetylcholine receptor M1 (hM1R) even in the presence of the fluorescent compound fluorescein, which interfered with a standard fluorescent HTS sensor (Fluo-8). In an HTS using a chemical library containing fluorescent compounds, CalfluxCTN accurately identified agonists and antagonists that were missed or miscategorized using Fluo-8. Moreover, we showed that a luciferase substrate that becomes activated only when inside cells generated long-lasting BRET signals in HTS, enabling results to be reliably compared among replicate samples for hours. Thus, the use of a self-luminescent sensor instead of a fluorescent sensor could facilitate the complete screening of chemical libraries in a high-throughput context and enable analysis of autofluorescent samples in many different applications.

Neuroprotective Effects of Theobromine in permanent bilateral common carotid artery occlusion rat model of cerebral hypoperfusion

Cerebral hypoperfusion (CH) is a common underlying mechanism of dementia disorders linked to aberrations in the neurovascular unit. Hemodynamic disturbances adversely affect cellular energy homeostasis that triggers a sequence of events leading to irrevocable damage to the brain and neurobehavioral discrepancies. Theobromine is a common ingredient of many natural foods consumed by a large population worldwide. Theobromine has shown health benefits in several studies, attributed to regulation of calcium homeostasis, phosphodiesterase, neurotransmission, and neurotrophins. The current study evaluated the neuroprotective potential of theobromine against CH in the permanent bilateral common carotid artery occlusion (BCCAO) prototype. Wistar rats were distributed in Sham-operated (S), S + T100, CH, CH + T50, and CH + T100 groups. Animals received permanent BCCAO or Sham treatment on day 1. Theobromine (50, 100 mg/kg) was given orally in animals subjected to BCCAO for 14 days daily. CH caused neurological deficits (12-point scale), motor dysfunction, and memory impairment in rats. Treatment with theobromine significantly attenuated neurological deficits and improved sensorimotor functions and memory in rats with CH. In biochemistry investigation of the entire brain, findings disclosed reduction in brain oxidative stress, inflammatory intermediaries (tumor necrosis factor-α, interleukin-1β and - 6, nuclear factor-κB), markers of cell demise (lactate dehydrogenase, caspase-3), acetylcholinesterase activity, and improvement in γ-aminobutyric acid quantity in rats that were given theobromine for 14 days daily after CH. Histopathological analysis substantiated attenuation of neurodegenerative changes by theobromine. The findings of this study indicated that theobromine could improve neurological scores, sensorimotor abilities, and memory in CH prototype.

Imidazole-Based Monomer as Functional Unit for the Specific Detection of Paraxanthine in Aqueous Environments

In the context of personalized medicine, the paraxanthine-to-caffeine ratio is an accepted standard for the optimization of the dose-response effect of many pharmaceuticals in individual patients. There is a strong drive towards the development of cheaper and portable devices for the detection of biomarkers, including paraxanthine and caffeine, which requires materials with high binding efficiency and specificity. We designed a recognition unit specific for paraxanthine which can discriminate molecules with small structural differences and can be used to increase the sensitivity of sensors. A number of functional units were screened by nuclear magnetic resonance for their ability to form specific binding interactions with paraxanthine in water and negligible interactions with its structural analogue caffeine. Imidazole was identified as the unit showing the most promising results and its two polymerizable derivatives were evaluated by isothermal titration calorimetry to identify the best monomer. The data suggested that 4-vinylimidazole was the most promising unit forming specific and strong binding interaction with paraxanthine. The calorimetry experiments allowed also the determination of the thermodynamic parameters of all interactions and the association constant values. Optimization of polymerization protocols in water, achieving high monomer conversions and chemical yields, demonstrate the suitability of the selected functional monomer for polymer preparations, targeting the detection of paraxanthine in aqueous environments.

Purinergic Signaling in Oral Tissues

The role of the purinergic signal has been extensively investigated in many tissues and related organs, including the central and peripheral nervous systems as well as the gastrointestinal, cardiovascular, respiratory, renal, and immune systems. Less attention has been paid to the influence of purines in the oral cavity, which is the first part of the digestive apparatus and also acts as the body’s first antimicrobial barrier. In this review, evidence is provided of the presence and possible physiological role of the purinergic system in the different structures forming the oral cavity including teeth, tongue, hard palate, and soft palate with their annexes such as taste buds, salivary glands, and nervous fibers innervating the oral structures. We also report findings on the involvement of the purinergic signal in pathological conditions affecting the oral apparatus such as Sjögren’s syndrome or following irradiation for the treatment of head and neck cancer, and the use of experimental drugs interfering with the purine system to improve bone healing after damage. Further investigations are required to translate the results obtained so far into the clinical setting in order to pave the way for a wider application of purine-based treatments in oral diseases.

Caffeine, Paraxanthine, Theophylline, and Theobromine Content in Human Milk

This study aimed to assess the content of caffeine and its metabolites—paraxanthine, theophylline, and theobromine—in breast milk according to selected factors. Samples of human milk were collected from 100 women living in the east–northeast region of Poland. Information on the consumption of beverages and foods containing caffeine was collected using a 3 day food record. The determination of caffeine and its metabolite content was performed using liquid chromatography–mass spectrometry (LC–MS/MS). This study research showed that more caffeine was found in the milk of women living in cities, with secondary education, aged 34–43, and also in milk from the 3rd and 4th lactation periods (p ≤ 0.05). Factors such as place of residence, level of education, age, and stage of lactation influenced the nutritional choices of breastfeeding women, which had an impact on the level of caffeine and its metabolites in breast milk. A positive correlation was found between the consumption of caffeine with food and drinks and its level in human milk.

Addiction and human male fertility: A systematic review and a critical appraisal

BACKGROUND

Addiction is a global problem that has many negative consequences on human health as well as the quality of life.

OBJECTIVES

This review aimed to assess the effect of addiction on human male fertility.

METHODS

A systematic review was conducted on various electronic sites.

RESULTS

The initial literature search identified a total of 5239 articles in all searched databases. After removing duplicates and application of inclusion/exclusion criteria,177 were potential articles, 112 were omitted because no direct relevance was encountered. Finally, 65 studies were retained for review. They were classified according to the type of addiction into; opioids and cannabinoids (18 articles), alcohol (7 articles), cocaine (2 articles), Androgenic Anabolic steroids AAS (15 articles), tobacco (10 articles) and caffeine (13 articles). Most of these recruited articles demonstrated a negative impact of the addressed substance on male fertility with variable levels of evidence.

CONCLUSIONS

It was concluded that addiction harms human male fertility that should be put into consideration. More future studies are needed after a proper methodological and statistical approach, including logistic regression analysis, to predict the effect of a specific substance on human male fertility. This article is protected by copyright. All rights reserved.

Synthesis and evaluation of novel xanthine-acrylamides and xanthine-acrylates as insecticidal agents

BACKGROUND

The design and discovery of novel pesticidal agents according to bioactive natural products is an important aspect of agrochemical innovation. New xanthine derivatives derived from natural xanthine or methylxanthines are rich resources that possess great potential to afford new active pesticidal molecules. Herein novel xanthine derivatives were designed through a strategy of combining the methylxanthine caffeine skeleton with the acrylamide or acrylate motif of cinnamic acid derivatives.

RESULTS

A series of novel (E)-3-(1,3,7-trimethyl-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-8-yl)acrylic acid derivatives, caffeine-(E)-acrylamides and caffeine-(E)-acrylates, were synthesized and confirmed via melting points, ¹ H NMR, ¹³ C NMR and high-resolution mass spectrometry. A single crystal of compound I12 was obtained to illustrate the trans-configuration of the vinyl double bond. Preliminary insecticidal evaluations showed that some of the compounds had favorable insecticidal potentials against Mythimna separata Walker at 200 mg L^-1 . Some of the compounds exhibited excellent insecticidal activity against Plutella xylostella L. at low test concentrations, e.g. I18 and I24 with LC₅₀ values of 0.0435 and 0.0133 mg L^-1 , respectively, were found to be more potent than the insecticide control triflumuron. The structure-activity relationship (SAR) analysis is also given in detail.

CONCLUSION

Compounds I12, I18, I24 and I26 generated from the integration of natural methylxanthine (caffeine) and acrylate moieties could be novel insecticidal leading compounds for further structural optimization. The SAR analysis may bring a new inspiration to the extensive and deep investigations on new xanthine derivatives in the agrochemical area.

Abiotic Factors from Different Ecuadorian Regions and Their Contribution to Antioxidant, Metabolomic and Organoleptic Quality of Theobroma cacao L. Beans, Variety "Arriba Nacional"

Fine flavor cocoa is a unique category of cocoa that produces almonds with high aromatic potential and several sensory benefits that make it different from the basic or ordinary cocoas. Ecuador is the world's leader in the production and export of fine flavor cocoa, responsible for 63% of the world's total production due to the commercialization of the Arriba Nacional variety, known to possess an intense aroma that is unique in the cocoa world market. Besides its organoleptic specificity, this variety represents a source of important bioactive compounds associated with both sensory and health properties. This study evaluates the influence of an abiotic factor, nutritional soil status, on the phytochemical composition (methylxantines and phenolic compounds), and antioxidant and sensory properties of Arriba variety cocoa beans originating from three different geographical regions of Ecuador. We used the Diagnosis and Recommendation Integrated System (DRIS), Folin-Ciocalteau, high-performance liquid chromatography (HPLC), ABTS free-radical-scavenging activity, the α, α-diphenyl-β-picrylhydrazyl free-radical-scavenging method (DPPH), and Ferric reducing antioxidant power (FRAP) analysis to reveal a significant correlation between Mn ions and total phenolic content, a positive implication of N in methylxanthine composition and antioxidant properties, and the importance of Ca, Mg, and K ions in increasing the flavonoid and anthocyanin content of raw cocoa beans. We showed that these nutritional elements can interfere with the nutraceutical and sensory properties of cocoa beans, as Cu, Mg, and K are correlated with anthocyaninic content, while Fe, Ca, P and Zn influenced the flavonoid content. We underline that the Arriba variety is suitable not only for the production of high-quality chocolate, but also for the increasing worldwide nutraceutical market, generating qualitative and competitive products.

Influence of methylxanthines isolated from Bancha green tea on the pharmacokinetics of sildenafil in rats

BACKGROUND

Sildenafil is used to treat erectile dysfunction and pulmonary arterial hypertension and is metabolized in the liver mainly by CYP3A4, thus co-administration with drugs or herbal extracts that affect CYP3A4 activity may lead to drug-drug or drug-herb interactions, respectively. The aim of the present study was to evaluate the influence of single and multiple oral doses of methylxanthine fraction, isolated from Bancha green tea leaves on the pharmacokinetics of sildenafil in rats.

METHODS

Rats were given sildenafil alone as well as simultaneously with methylxanthines or ketoconazole. The plasma concentrations of sildenafil were measured with high-performance liquid chromatography method with ultraviolet detection. The pharmacokinetic parameters of sildenafil were calculated by non-compartmental analysis.

RESULTS

Concomitant use of sildenafil with a single oral dose of methylxanthines resulted in a decrease in C_max (p > 0.05), AUC_0-t (p < 0.05) and AUC_0-inf (p < 0.05), while the administration of sildenafil after methylxanthines pretreatment resulted in an increase in C_max (p < 0.0001), AUC_0-t (p < 0.0001) and AUC_0-inf (p < 0.001) compared to the sildenafil group. After co-administration of sildenafil and ketoconazole, a significant increase in C_max, AUC_0-t and AUC_0-inf was observed in both of the experiments.

CONCLUSION

Drug-herb interactions were observed when sildenafil was co-administered with Bancha methylxanthines in rats. Further in vivo studies about the potential drug interactions between sildenafil and methylxanthines, especially caffeine, are needed to clarify mechanisms underlying the observed changes in sildenafil pharmacokinetics.

Appraising the potency of small molecule inhibitors and their graphene surface-mediated organizational attributes on uric acid-melamine clusters

Uric acid (UA) and melamine (MM) crystallization in humans is associated with adverse medical conditions, including the germination of kidney stones, because of their low solubility. The growth of kidney stones, usually formed on renal papillary facades, is accomplished on the matrix-coated surface by the aggregation of preformed crystals or secondary crystal nucleation. Therefore, the effects of inhibitors such as theobromine (TB) and allopurinol (AP) on MM-UA aggregation are investigated by employing classical molecular dynamics simulations on a graphene surface. This impersonates the exact essence of the precipitation of kidney stones. The interaction between MM-UA is very intense and, thus, large clusters are formed on the surface. The presence of TB and AP will, however, substantially inhibit their aggregation. TB and AP significantly impede UA aggregation in particular. Therefore, lower order UA clusters are formed. These smaller UA clusters then pull a lower number of MM towards themselves, resulting in a smaller order UA-MM cluster. MM and UA aggregation on a 2D graphene surface is found to be spontaneous. There is no difference in these molecules' adsorption with a change in the force field parameters (i.e., GAFF and OPLS-AA) for graphene. Moreover, the greater the surface area of graphene, the more molecules are absorbed. The solute-surface van der Waals interaction energy plays a driving force in the adsorption of solute molecules on the surface. In addition, interactions like hydrogen bonding and π-stacking over the graphene surface involve binding all like molecules. These aggregated solute molecules strongly attract more like molecules until all solute molecules are adsorbed on the graphene surface, as estimated by enhanced sampling. The molecular origin of graphene exfoliation by MM is also described here. The present work helps to design novel kidney stone inhibitors.

The Effect of Toothpastes Containing Natural Ingredients Such As Theobromine and Caffeine on Enamel Microhardness: An In Vitro Study

The current study aimed to investigate the effect of biocompatible kinds of toothpastes containing natural ingredients such as theobromine and caffeine on the enamel microhardness after demineralization. 72 maxillary premolar teeth extracted for orthodontic purposes were used in this study. Primary enamel surface microhardness examinations were performed using a Digital Micro Vickers Hardness Tester following the Knoop technique (50 g load for 15 s with three indentations at various points). The specimens were immersed in lactic acid (pH = 5.4) for 7 days, washed with distilled water, dried, and then retested for microhardness. According to the type of toothpaste used for brushing, all specimens were categorized as follows: Group 1, Theodent classic® toothpaste (theobromine); Group 2, Power Energy toothpaste (caffeine); Group 3, Colgate toothpaste (fluoride); and Group 4, distilled water as the negative control. The specimens were retested for enamel microhardness after brushing 2 times a day for one month. After brushing with different types of toothpaste, for all experiment groups, the increase in microhardness values in the demineralized enamel surfaces was significant and there were significant differences between them (p value <0.05). The fluoride group had the highest microhardness and had a significant difference with the caffeine and distilled water groups, but there was no significant difference with the theobromine group (p value <0.05). In the theobromine group, the hardness was considerably higher than in the caffeine and distilled water groups. There was no significant difference between the caffeine and distilled water groups. Theobromine toothpaste had the same remineralization effect as that of fluoride toothpaste, while caffeine toothpaste had no positive effect on the remineralization process.

Dissecting coffee seeds metabolome in context of genotype, roasting degree, and blending in the Middle East using NMR and GC/MS techniques

With a favored taste and various bioactivities, coffee has been consumed as a daily beverage worldwide. The current study presented a multi-faceted comparative metabolomics approach dissecting commercially available coffee products in the Middle East region for quality assessment and functional food purposes using NMR and GC/MS platforms. NMR metabolites fingerprinting led to identification of 18 metabolites and quantification (qNMR) of six prominent markers for standardization purposes. An increase of β-ethanolamine (MEA) reported for the first time, 5-(hydroxymethyl) furfural (5-HMF), concurrent with a reduction in chlorogenic acid, kahweol, and sucrose levels post roasting as revealed using multivariate data analyses (MVA). The diterpenes kahweol and cafestol were identified in green and roasted Coffea arabica, while 16-O-methyl cafestol in roasted C. robusta. Moreover, GC/MS identified a total of 143 metabolites belonging to 15 different chemical classes, with fructose found enriched in green C. robusta versus fatty acids abundance, i.e., palmitic and stearic acids in C. arabica confirming NMR results. These potential results aided to identify novel quality control attributes, i.e., ethanolamine, for coffee in the Middle East region and have yet to be confirmed in other coffee specimens.

An assessment of mutagenicity, genotoxicity, acute-, subacute and subchronic oral toxicity of paraxanthine (1,7-dimethylxanthine)

Paraxanthine or 1,7-dimethylxanthine is a natural dietary component and the main metabolite of caffeine in humans. A battery of toxicological studies was conducted in accordance with international guidelines to investigate mutagenicity, genotoxicity and acute and repeated-dose oral toxicity in rats of synthetic paraxanthine (ENFINITY™, Ingenious Ingredients, L.P., >99% purity). There was no evidence of mutagenicity in a bacterial reverse mutation as well as in an in vitro mammalian chromosomal aberration test. There was no evidence of genotoxicity in an in vivo mammalian erythrocyte micronucleus test as well as in an in vitro mammalian cell gene mutation test. An acute oral toxicity test resulted in a LD₅₀ value of 1601 mg/kg bw/d. Paraxanthine did not cause mortality or toxic effects in a subacute 28-day repeated-dose oral toxicity study at daily doses of 75, 150, or 300 mg/kg bw/d (each group n = 10 per sex), administered by gavage. Paraxanthine also did not cause mortality or toxic effects in a subchronic 90-day repeated-dose oral toxicity study at daily doses of 75, 150, or 300 mg/kg bw/d (each group n = 10 per sex), administered by gavage. The no observed adverse effect level (NOAEL) determined from the 90-day study was greater than or equal to 300 mg/kg bw/d, the highest dose tested, for both male and female Wistar rats.

Neuroprotective effects of theobromine in transient global cerebral ischemia-reperfusion rat model

Transient global cerebral ischemia (tGCI) is a cerebrovascular disorder characterized by a brief decline in blood flow, neurological deficits, and is often predictive of stroke. Theobromine (TBR) is consumed worldwide in chocolates, tea, and cocoa products. TBR is a natural stimulant and vasoactive alkaloid that may protect against ischemic injury. In this study, neuroprotective potential of theobromine (TBR) was evaluated in 2-vessel occlusion transient global cerebral ischemia-reperfusion (tGCI/R) rat model. Rats were treated with TBR (50, 100 mg/kg, p.o.) for 7 successive days, and subjected to bilateral common carotid artery occlusion (20 min) or sham surgery after last dose of TBR. Severe neurological deficits accompanied by brain infarction, blood-brain barrier abnormalities, and oedema were noted in rats subjected to tGCI/R, and these effects were prevented by TBR. TBR protected against lipid peroxidation and enhanced glutathione level in brain against tGCI/R. TBR pre-treatment for 7 days prevented tGCI/R induced cell death (lactate dehydrogenase, caspase-3), vascular injury (MMP-9), and inflammation (TNF-α, NFκB) in rat whole brain. TBR protected against glutamate excitotoxicity and GABAergic decline in the brain of rats against tGCI/R injury. Findings of this study showed that TBR can alleviate chances of stroke by preventing acute episodes of cerebral ischemia.

Caffeine Has Different Immunomodulatory Effect on the Cytokine Expression and NLRP3 Inflammasome Function in Various Human Macrophage Subpopulations

Besides its well-known psychoactive effects, caffeine has a broad range of actions. It regulates several physiological mechanisms as well as modulates both native and adaptive immune responses by various ways. Although caffeine is assumed to be a negative regulator of inflammation, the effect on the secretion of pro- and anti-inflammatory cytokines is highly controversial. Macrophages are major mediators of inflammatory responses; however, the various subpopulations develop different effects ranging from the initiation to the resolution of inflammation. Here we report a comparative analysis of the effect of caffeine on two subpopulations of human monocyte-derived macrophages differentiated in the presence of macrophage colony-stimulating factor (M-CSF) or granulocyte-macrophage colony-stimulating factor (GM-CSF), resulting in M-MΦs and GM-MΦs, respectively. We showed that although TNF-α secretion was downregulated in both LPS-activated MΦ subtypes by caffeine, the secretion of IL-8, IL-6, and IL-1β as well as the expression of Nod-like receptors was enhanced in M-MΦs, while it did not change in GM-MΦs. We showed that caffeine (1) altered adenosine receptor expression, (2) changed Akt/AMPK/mTOR signaling pathways, and (3) inhibited STAT1/IL-10 signaling axis in M-MΦs. We hypothesized that these alterations play an important modulatory role in the upregulation of NLRP3 inflammasome-mediated IL-1β secretion in LPS-activated M-MΦs following caffeine treatment.

The New Challenge of Green Cosmetics: Natural Food Ingredients for Cosmetic Formulations

Nowadays, much attention is paid to issues such as ecology and sustainability. Many consumers choose “green cosmetics”, which are environmentally friendly creams, makeup, and beauty products, hoping that they are not harmful to health and reduce pollution. Moreover, the repeated mini-lock downs during the COVID-19 pandemic have fueled the awareness that body beauty is linked to well-being, both external and internal. As a result, consumer preferences for makeup have declined, while those for skincare products have increased. Nutricosmetics, which combines the benefits derived from food supplementation with the advantages of cosmetic treatments to improve the beauty of our body, respond to the new market demands. Food chemistry and cosmetic chemistry come together to promote both inside and outside well-being. A nutricosmetic optimizes the intake of nutritional microelements to meet the needs of the skin and skin appendages, improving their conditions and delaying aging, thus helping to protect the skin from the aging action of environmental factors. Numerous studies in the literature show a significant correlation between the adequate intake of these supplements, improved skin quality (both aesthetic and histological), and the acceleration of wound-healing. This review revised the main foods and bioactive molecules used in nutricosmetic formulations, their cosmetic effects, and the analytical techniques that allow the dosage of the active ingredients in the food.

Novel Facet of an Old Dietary Molecule? Direct Influence of Caffeine on Glucose and Biogenic Amine Handling by Human Adipocytes

Caffeine is a plant alkaloid present in food and beverages consumed worldwide. It has high lipid solubility with recognized actions in the central nervous system and in peripheral tissues, notably the adipose depots. However, the literature is scant regarding caffeine's influence on adipocyte functions other than lipolysis, such as glucose incorporation into lipids (lipogenesis) and amine oxidation. The objective of this study was to explore the direct effects of caffeine and of isobutylmethylxanthine (IBMX) on these adipocyte functions. Glucose transport into fat cells freshly isolated from mice, rats, or humans was monitored by determining [³H]-2-deoxyglucose (2-DG) uptake, while the incorporation of radiolabeled glucose into cell lipids was used as an index of lipogenic activity. Oxidation of benzylamine by primary amine oxidase (PrAO) was inhibited by increasing doses of caffeine in human adipose tissue preparations with an inhibition constant (Ki) in the millimolar range. Caffeine inhibited basal and insulin-stimulated glucose transport as well as lipogenesis in rodent adipose cells. The antilipogenic action of caffeine was also observed in adipocytes from mice genetically invalidated for PrAO activity, indicating that PrAO activity was not required for lipogenesis inhibition. These caffeine inhibitory properties were extended to human adipocytes: relative to basal 2-DG uptake, set at 1.0 ± 0.2 for 6 individuals, 0.1 mM caffeine tended to reduce uptake to 0.83 ± 0.08. Insulin increased uptake by 3.86 ± 1.11 fold when tested alone at 100 nM, and by 3.21 ± 0.80 when combined with caffeine. Our results reinforce the recommendation of caffeine's potential in the treatment or prevention of obesity complications.

Synthesis, Hemolytic Studies, and In Silico Modeling of Novel Acefylline-1,2,4-Triazole Hybrids as Potential Anti-cancer Agents against MCF-7 and A549

A series of novel theophylline-7-acetic acid (acefylline)-derived 1,2,4-triazole hybrids with N-phenyl acetamide moieties (11a-j) have been synthesized and tested for their inhibitory (in vitro) potential against two cancer cell lines, A549 (lung) and MCF-7 (breast), using MTT assay. Among these derivatives, 11a, 11c, 11d, 11g, and 11h displayed remarkable activity against both cancer cell lines having cell viability values in the 21.74 ± 1.60-55.37 ± 4.60% range compared to acefylline (86.32 ± 1.75%) using 100 μg/μL concentration of compounds. These compounds were further screened against the A549 cancer cell line (lung) to find their half-maximal inhibitory concentration (IC₅₀) by applying various concentrations of these compounds. Compound 11g (2-(5-((1,3-dimethyl-2,6-dioxo-2,3-dihydro-1H-purin-7(6H)-yl)methyl)-4-phenyl-4H-1,2,4-triazol-3-ylthio)-N-p-tolylacetamide) with the least IC₅₀ value (1.25 ± 1.36 μM) was discerned as a strong inhibitor of cancer cell multiplication in both cell lines (A549 and MCF-7). Their hemolytic studies revealed that all of them had very low cytotoxicity. Finally, in silico modeling was carried out to find the mode of binding of the highly active compound (11g), which was according to the results of anti-cancer activity.

New framework for a non-animal approach adequately assures the safety of cosmetic ingredients - A case study on caffeine

This case study on the model substance caffeine demonstrates the viability of a 10-step read-across (RAX) framework in practice. New approach methodologies (NAM), including RAX and physiologically-based kinetic (PBK) modelling were used to assess the consumer safety of caffeine. Appropriate animal systemic toxicity data were used from the most relevant RAX analogue while assuming that no suitable animal toxicity data were available for caffeine. Based on structural similarities, three primary metabolites of the target chemical caffeine (theophylline, theobromine and paraxanthine) were selected as its most relevant analogues, to estimate a point of departure in order to support a next generation risk assessment (NGRA). On the basis of the pivotal mode of action (MOA) of caffeine and other methylxanthines, theophylline appeared to be the most potent and suitable analogue. A worst-case aggregate exposure assessment determined consumer exposure to caffeine from different sources, such as cosmetics and food/drinks. Using a PBK model to estimate human blood concentrations following exposure to caffeine, an acceptable Margin of Internal Exposure (MOIE) of 27-fold was derived on the basis of a RAX using theophylline animal data, which suggests that the NGRA approach for caffeine is sufficiently conservative to protect human health.

Natural products targeting into cancer hallmarks: An update on caffeine, theobromine, and (+)-catechin

Natural products have been studied to reveal new therapies against human dysfunctions since they present several medicinal properties. Caffeine, theobromine and (+)-catechin are remarkable natural agents in the class of methylxanthines and flavonoids. These bioactive molecules have several biological activities, for instance, antioxidant, anti-inflammatory, and antitumor capacity. In this sense, studies focusing on these molecules have been performed to discover new treatments against diseases, such as cancer. Cancer is a serious public health problem worldwide responsible for more than 70% of all deaths globally. Industrialized products associated with a sedentary lifestyle and a diet low in antioxidants are related to neoplasms development. Unfortunately, many types of cancers are extremely aggressive and untreatable since, in many cases, they are resistant to chemotherapy. Therefore, revealing new strategies to block cancer growth is one of the biggest challenges to science. In this context, despite the known anticancer actions of caffeine, theobromine and (+)-catechin, it is still essential to elucidate the causal antitumor mechanism of these molecules by analyzing the dysfunctional cancer pathways associated with the hallmarks of cancer. Hence, this review aims to describe the anticancer activity of caffeine, theobromine, and (+)-catechin against the different hallmarks and enabling characteristics of cancer.

Engineering Alternate Ligand Recognition in the PurR Topology: A System of Novel Caffeine Biosensing Transcriptional Antirepressors

Recent advances in synthetic biology and protein engineering have increased the number of allosteric transcription factors used to regulate independent promoters. These developments represent an important increase in our biological computing capacity, which will enable us to construct more sophisticated genetic programs for a broad range of biological technologies. However, the majority of these transcription factors are represented by the repressor phenotype (BUFFER), and require layered inversion to confer the antithetical logical function (NOT), requiring additional biological resources. Moreover, these engineered transcription factors typically utilize native ligand binding functions paired with alternate DNA binding functions. In this study, we have advanced the state-of-the-art by engineering and redesigning the PurR topology (a native antirepressor) to be responsive to caffeine, while mitigating responsiveness to the native ligand hypoxanthine-i.e., a deamination product of the input molecule adenine. Importantly, the resulting caffeine responsive transcription factors are not antagonized by the native ligand hypoxanthine. In addition, we conferred alternate DNA binding to the caffeine antirepressors, and to the PurR scaffold, creating 38 new transcription factors that are congruent with our current transcriptional programming structure. Finally, we leveraged this system of transcription factors to create integrated NOR logic and related feedback operations. This study represents the first example of a system of transcription factors (antirepressors) in which both the ligand binding site and the DNA binding functions were successfully engineered in tandem.

Natural Bioactive Compounds Useful in Clinical Management of Metabolic Syndrome

Metabolic syndrome (MetS) is a clinical manifestation characterized by a plethora of comorbidities, including hyperglycemia, abdominal obesity, arterial hypertension, and dyslipidemia. All MetS comorbidities participate to induce a low-grade inflammation state and oxidative stress, typical of this syndrome. MetS is related to an increased risk of cardiovascular diseases and early death, with an important impact on health-care costs. For its clinic management a poly-pharmaceutical therapy is often required, but this can cause side effects and reduce the patient's compliance. For this reason, finding a valid and alternative therapeutic strategy, natural and free of side effects, could represent a useful tool in the fight the MetS. In this context, the use of functional foods, and the assumption of natural bioactive compounds (NBCs), could exert beneficial effects on body weight, blood pressure and glucose metabolism control, on endothelial damage, on the improvement of lipid profile, on the inflammatory state, and on oxidative stress. This review focuses on the possible beneficial role of NBCs in the prevention and in the clinical management of MetS and its comorbidities.

Protective Effect of Cocoa Bean Shell against Intestinal Damage: An Example of Byproduct Valorization

BACKGROUND

Cocoa bean shell (CBS), a main byproduct of cocoa processing, represents a source of components such as polyphenols and methylxanthines, which have been associated with a reduced risk of several diseases. Therefore, CBS has potential application as a food ingredient. Intestinal mucosa is exposed to immune and inflammatory responses triggered by dietary agents, such as oxysterols, which derive from cholesterol oxidation and are pro-oxidant compounds able to affect intestinal function. We aimed at investigating the capability of the Forastero cultivar CBS, added or not added to ice cream, to protect against the intestinal barrier damage induced by a dietary oxysterol mixture.

METHODS

Composition and antioxidant capacity of in vitro digested CBS and CBS-enriched ice cream were analyzed by high-performance liquid chromatography and 1,1-diphenyl-2-picryl-hydrazyl radical-scavenging assay, respectively. CaCo-2 cells differentiated into enterocyte-like monolayer were incubated with 60 µM oxysterol mixture in the presence of CBS formulations.

RESULTS

The oxysterol mixture induced tight junction impairment, interleukin-8 and monocyte chemoattractant protein-1 cell release, and oxidative stress-related nuclear factor erythroid 2 p45-related factor 2 response Nrf2. Both CBSs protected cells from these adverse effects, probably thanks to their high phenolic content. CBS-enriched ice cream showed the highest antioxidant capacity. Theobromine, which is in high concentrations of CBS, was also tested. Although theobromine exerted no effect on Nrf2 expression, its anti-inflammatory cooperating activity in CBS effect cannot be excluded.

CONCLUSIONS

Our findings suggest that CBS-enriched ice cream may be effective in the prevention of gut integrity damage associated with oxidative/inflammatory reactions.

Electrochemically facilitated oxidative C–H amination enables access to fluorescent N9-fused tricyclic xanthines

An electrochemically enabled intramolecular C−H amination route for accessing a broad range of fluorescent N9-fused tricyclic xanthines with various substitution patterns under simple, green, and mild condition is developed.

Simultaneous Quantification of Antioxidants Paraxanthine and Caffeine in Human Saliva by Electrochemical Sensing for CYP1A2 Phenotyping

The enzyme CYP1A2 is responsible for the metabolism of numerous antioxidants in the body, including caffeine, which is transformed into paraxanthine, its main primary metabolite. Both molecules are known for their antioxidant and pro-oxidant characteristics, and the paraxanthine-to-caffeine molar ratio is a widely accepted metric for CYP1A2 phenotyping, to optimize dose–response effects in individual patients. We developed a simple, cheap and fast electrochemical based method for the simultaneous quantification of paraxanthine and caffeine in human saliva, by differential pulse voltammetry, using an anodically pretreated glassy carbon electrode. Cyclic voltammetry experiments revealed for the first time that the oxidation of paraxanthine is diffusion controlled with an irreversible peak at ca. +1.24 V (vs. Ag/AgCl) in a 0.1 M H₂SO₄ solution, and that the mechanism occurs via the transfer of two electrons and two protons. The simultaneous quantification of paraxanthine and caffeine was demonstrated in 0.1 M H₂SO₄ and spiked human saliva samples. In the latter case, limits of detection of 2.89 μM for paraxanthine and 5.80 μM for caffeine were obtained, respectively. The sensor is reliable, providing a relative standard deviation within 7% (n = 6). Potential applicability of the sensing platform was demonstrated by running a small scale trial on five healthy volunteers, with simultaneous quantification by differential pulse voltammetry (DPV) of paraxanthine and caffeine in saliva samples collected at 1, 3 and 6 h postdose administration. The results were validated by ultra-high pressure liquid chromatography and shown to have a high correlation factor (r = 0.994).

Unique Role of Caffeine Compared to Other Methylxanthines (Theobromine, Theophylline, Pentoxifylline, Propentofylline) in Regulation of AD Relevant Genes in Neuroblastoma SH-SY5Y Wild Type Cells

Methylxanthines are a group of substances derived from the purine base xanthine with a methyl group at the nitrogen on position 3 and different residues at the nitrogen on position 1 and 7. They are widely consumed in nutrition and used as pharmaceuticals. Here we investigate the transcriptional regulation of 83 genes linked to Alzheimer’s disease in the presence of five methylxanthines, including the most prominent naturally occurring methylxanthines—caffeine, theophylline and theobromine—and the synthetic methylxanthines pentoxifylline and propentofylline. Methylxanthine-regulated genes were found in pathways involved in processes including oxidative stress, lipid homeostasis, signal transduction, transcriptional regulation, as well as pathways involved in neuronal function. Interestingly, multivariate analysis revealed different or inverse effects on gene regulation for caffeine compared to the other methylxanthines, which was further substantiated by multiple comparison analysis, pointing out a distinct role for caffeine in gene regulation. Our results not only underline the beneficial effects of methylxanthines in the regulation of genes in neuroblastoma wild-type cells linked to neurodegenerative diseases in general, but also demonstrate that individual methylxanthines like caffeine mediate unique or inverse expression patterns. This suggests that the replacement of single methylxanthines by others could result in unexpected effects, which could not be anticipated by the comparison to other substances in this substance class.

Emerging Roles of SRSF3 as a Therapeutic Target for Cancer

Ser/Arg-rich (SR) proteins are RNA-binding proteins known as constitutive and alternative splicing (AS) regulators that regulate multiple aspects of the gene expression program. Ser/Arg-rich splicing factor 3 (SRSF3) is the smallest member of the SR protein family, and its level is controlled by multiple factors and involves complex mechanisms in eukaryote cells, whereas the aberrant expression of SRSF3 is associated with many human diseases, including cancer. Here, we review state-of-the-art research on SRSF3 in terms of its function, expression, and misregulation in human cancers. We emphasize the negative consequences of the overexpression of the SRSF3 oncogene in cancers, the pathways underlying SRSF3-mediated transformation, and implications of potential anticancer drugs by downregulation of SRSF3 expression for cancer therapy. Cumulative research on SRSF3 provides critical insight into its essential part in maintaining cellular processes, offering potential new targets for anti-cancer therapy.