A comprehensive insight into the molecular effect of theobromine on cardiovascular-related risk factors: A systematic review of in vitro and in vivo studies.

Theobromine may have beneficial effects on cardiovascular risk factors. This study aimed to find molecular effects of theobromine on lipid profile, glycemic status, inflammatory factors, and vascular function through a comprehensive assessment of all in vitro and in vivo studies. The search process was started at 18 July 2022. Databases including PubMed, Scopus, and Web of Science were searched to find all articles published up to 18 July 2022. Nineteen studies were included in this study. In vitro studies showed the improving effects of theobromine on inflammatory markers. Of four animal studies assessing the effect of theobromine on inflammatory markers, two reported favorable effects. Among five animal studies assessing the effects of theobromine on lipid profile, three reported improving effects on either triglyceride, total cholesterol, low- or high-density lipoprotein cholesterol. Of the three human studies, two revealed that theobromine had improving effects on lipid profile. A favorable effect of theobromine on augmentation index was also reported in two RCTs. The results for other outcomes were inconclusive. Theobromine may have favorable effects on inflammatory factors, lipid profile, and vascular function markers. However, studies with a longer duration and lower, dietary-relevant doses are required for future confirmation.

The analysis of methylxanthine fractions obtained from Camellia sinensis cultivated in Turkey and effects on the in vitro inhibition of CYP2D6 enzyme.

Tea is a worldwide consumed herbal beverage and it was aimed in this study to reveal the major fractions of green and black tea in order to enlighten the in vitro inhibition potency on the well-known drug metabolizing enzyme CYP2D6 activity. Methylxanthine fractions were extracted from green and black tea and a yield of 0.265 g (1.06%) for 25 g of dried black tea and 0.302 g (1.2%) for 25 g of green tea was calculated. High-performance liquid chromatography analysis represented that the major components of the methylxanthine fractions were caffeine, theobromine, and theophylline. Methylxanthine content of black tea was 368.25 ± 4.6 µg/ml caffeine, 89.30 ± 2.3 µg/ml theobromine, and 3.40 ± 0.5 µg/ml theophylline, whereas that of green tea was 176.50 ± 3.7 µg/ml caffeine, 53.85 ± 1.4 µg/ml theobromine, and 2.06 ± 0.7 µg/ml theophylline. The results of concentration-dependent inhibition studies were 76% green tea, 75% black tea, and 55% caffeine at concentration of 10 mg/ml. The inhibition rates of green and black tea on CYP2D6 activity were 76% and 75%, respectively, where that of quinidine, the well-known inhibitor of CYP2D6, was 82%. Our results indicate that green and black tea is very likely to modify the CYP2D6 enzyme activity.

Pentoxifylline attenuates nonalcoholic fatty liver by inhibiting hepatic macrophage polarization to the M1 phenotype.

BACKGROUND: Nonalcoholic fatty liver (NAFL), recognized as one of the most common causes of chronic liver diseases, is increasingly prevalent worldwide. Pentoxifylline, a derivative of theobromine extracted from Theobroma cacao and tea, has been studied for effects on blood viscosity, tissue oxygenation and inflammation. However, its effects on hepatic lipid accumulation and the potential mechanisms remain unclear. PURPOSE: This study aimed to investigate the therapeutic effects of pentoxifylline on high-fat diet-induced NAFL and to explore the corresponding molecular mechanisms. METHODS: NAFL mice were injected with or without 25, 50 or 100 mg/kg pentoxifylline for 2 weeks. Hepatic steatosis was observed by haematoxylin-eosin staining and Oil Red O staining, the levels of serum total cholesterol, triglyceride were detected by biochemical kits, and insulin resistance was evaluated by glucose and insulin tolerance tests. In addition, we measured the frequencies of macrophage and its polarization subsets in the liver using flow cytometry and immunofluorescence. The expressions of proteins associated with macrophage polarization signaling pathways were assessed by Western blotting and flow cytometry histograms. Molecular docking and cellular thermal shift assay were conducted to identify and verify the target protein of pentoxifylline in macrophage. RESULTS: Pentoxifylline significantly alleviated hepatic lipid accumulation, reduced blood lipid levels and improved insulin resistance. Strikingly, the excessive M1 macrophages in NAFL development was abolished by pentoxifylline. And pentoxifylline was further evidenced it failed to reduce hepatocyte lipid accumulation in the absence of macrophages in vitro. Mechanistically, pentoxifylline competed with LPS for binding to toll-like receptor 4, dramatically inhibiting the TLR4/MyD88/NF-κB signaling pathway. CONCLUSION: Pentoxifylline attenuated NAFL by inhibiting hepatic macrophage M1 polarization, indicating that pentoxifylline could be a therapeutic candidate for NAFL. This study first observed that M1 macrophages were increased in NAFL mice and then revealed the molecule targeted by pentoxifylline. In addition, we provided evidence that macrophage targeting may be an emerging strategy for NAFL treatment.

Theobromine enhances the conversion of white adipocytes into beige adipocytes in a PPARγ activation-dependent manner.

The adipocytes play an important role in driving the obese-state-white adipose tissue (WAT) stores the excess energy as fat, wherein brown adipose tissue (BAT) is responsible for energy expenditure via the thermoregulatory function of uncoupling protein 1 (UCP1)-the imbalance between these two onsets obesity. Moreover, the anti-obesity effects of brown-like-adipocytes (beige) in WAT are well documented. Browning, the process of transformation of energy-storing into energy-dissipating adipocytes, is a potential preventive strategy against obesity and its related diseases. In the present study, to explore an alternative source of natural products in the regulation of adipocyte transformation, we assessed the potential of theobromine (TB), a bitter alkaloid of the cacao plant, inducing browning in mice (in vivo) and primary adipocytes (in vitro). Dietary supplementation of TB significantly increased skin temperature of the inguinal region in mice and induced the expression of UCP1 protein. It also increased the expression levels of mitochondrial marker proteins in subcutaneous adipose tissues but not in visceral adipose tissues. The microarray analysis showed that TB supplementation upregulated multiple thermogenic and beige adipocyte marker genes in subcutaneous adipose tissue. Furthermore, in mouse-derived primary adipocytes, TB upregulated the expression of the UCP1 protein and mitochondrial mass in a PPARγ ligand-dependent manner. It also increased the phosphorylation levels of PPARγ coactivator 1α without affecting its protein expression. These results indicate that dietary supplementation of TB induces browning in subcutaneous WAT and enhances PPARγ-induced UCP1 expression in vitro, suggesting its potential to treat obesity.

Lipotoxicity-associated inflammation is prevented by guarana (Paullinia cupana) in a model of hyperlipidemia.

Hyperlipidemia causes lipotoxicity which prompts an inflammatory response linked to the development of cardiovascular diseases. Natural compounds have been receiving special attention for its potential to treat diseases, inexpensiveness, and safety. Guarana (Paullinia cupana) has demonstrated notable anti-inflammatory and antioxidant effects, which may prevent chronic diseases caused by changes in lipid profile. Thus, this study aims to evaluate the effect of guarana powder (Paullinia cupana) in the purine metabolism and inflammatory profile in lymphocytes and serum of rats with Poloxamer-407-induced hyperlipidemia. Pretreatment with guarana 12.5, 25, and 50 mg/kg/day or caffeine (0.2 mg/kg/day) by gavage was applied to adult male Wistar rats for a period of 30 days. As a comparative standard, we used simvastatin (0.04 mg/kg) post-induction. Hyperlipidemia was acutely induced with intraperitoneally injection of Poloxamer-407 (500 mg/kg). Guarana powder and caffeine increased the activity of the E-NTPDase (ecto-apyrase), and all pretreatments decreased the E-ADA (ecto-adenosine deaminase) activity, reducing the inflammatory process caused by lipotoxicity. In hyperlipidemic rats, ATP levels were increased while adenosine levels were decreased, guarana and caffeine reverted these changes. Guarana powder, caffeine, and simvastatin also prevented the increase in INF-γ and potentiated the increase in IL-4 levels, promoting an anti-inflammatory profile. Guarana promoted a more robust effect than caffeine. Our results show that guarana powder and caffeine have an anti-inflammatory as seen by the shift from a proinflammatory to an anti-inflammatory profile. The effects of guarana were more pronounced, suggesting that guarana powder may be used as a complementary therapy to improve the lipotoxicity-associated inflammation.

Insoluble-Bound Polyphenols Released from Guarana Powder: Inhibition of Alpha-Glucosidase and Proanthocyanidin Profile.

The Brazilian Food Supplement Law recently recognized that guarana (Paullinia cupana) contains bioactive substances, hence supporting its role as a functional food ingredient. The health benefits of guarana are associated, at least in part, to its phenolic compounds. However, to the best of our knowledge, there is no literature addressing the presence of phenolic compounds in the fraction containing insoluble-bound compounds and its contribution in terms of alpha-glucosidase inhibition. The concentration of phenolic extracts released from the insoluble-bound fraction required to inhibit 50% of alpha-glucosidase (IC50) activity was 5.8-fold lower than that present in the soluble counterpart. Both fractions exhibited a mixed inhibition mode. Fourteen proanthocyanidins (dimers to tetramers) present in the insoluble-bound fraction were tentatively identified by MALDi-TOF-MS. Future studies aiming at increasing the concentration of the soluble counterpart are deemed necessary. The results presented here enhance the phenolic database of guarana and have a practical impact on the procurement of nutraceuticals and functional ingredients related to the prevention and/or management of type 2 diabetes. The Brazilian normative on food supplements has been recently revised. This study lends support to the future inclusion of guarana powder in the list of sources of proanthocyanidins for the industry of food supplements.

Theobromine Improves Working Memory by Activating the CaMKII/CREB/BDNF Pathway in Rats.

Theobromine (TB) is a primary methylxanthine found in cacao beans. cAMP-response element-binding protein (CREB) is a transcription factor, which is involved in different brain processes that bring about cellular changes in response to discrete sets of instructions, including the induction of brain-derived neurotropic factor (BDNF). Ca2+/calmodulin-dependent protein kinase II (CaMKII) has been strongly implicated in the memory formation of different species as a key regulator of gene expression. Here we investigated whether TB acts on the CaMKII/CREB/BDNF pathway in a way that might improve the cognitive and learning function in rats. Male Wistar rats (5 weeks old) were divided into two groups. For 73 days, the control rats (CN rats) were fed a normal diet, while the TB-fed rats (TB rats) received the same food, but with a 0.05% TB supplement. To assess the effects of TB on cognitive and learning ability in rats: The radial arm maze task, novel object recognition test, and Y-maze test were used. Then, the brain was removed and the medial prefrontal cortex (mPFC) was isolated for Western Blot, real-time PCR and enzyme-linked immunosorbent assay. Phosphorylated CaMKII (p-CaMKII), phosphorylated CREB (p-CREB), and BDNF level in the mPFC were measured. In all the behavior tests, working memory seemed to be improved by TB ingestion. In addition, p-CaMKII and p-CREB levels were significantly elevated in the mPFC of TB rats in comparison to those of CN rats. We also found that cortical BDNF protein and mRNA levels in TB rats were significantly greater than those in CN rats. These results suggest that orally supplemented TB upregulates the CaMKII/CREB/BDNF pathway in the mPFC, which may then improve working memory in rats.

Different behavior of polyphenols in energy metabolism of lipopolysaccharide-stimulated cells.

Energy metabolism is one of the main sources of reactive oxygen species leading to oxidation and inflammation in pathophysiological processes. Lipopolysaccharide (LPS)-activated mouse embryonic fibroblast (MEF) cell lines from knock-out mice for paraoxonase-1 and from transgenic mice overexpressing monocyte chemoattractant protein-1 were obtained as model of pro-oxidant and pro-inflammatory scenarios. Theobroma cacao and Lippia citriodora (worldwide consumed and common ingredient of many food products) were tested in these cell models to assess the action of polyphenols in the energy management. Our metabolomics experiments show a different behavior of polyphenols: T. cacao extract partially reverts the effect of LPS in a pro-oxidant scenario through the antioxidant properties of theobromine, flavonols and procyanidins, while L. citriodora seems to act mainly in a pro-inflammatory cell model through the action of verbascoside decreasing the production of pro-inflammatory cytokines and MCP-1. Nevertheless, the action of polyphenols cannot be attributed only to a mechanism of action but the sum of different modulations in biological pathways. The capacity of both plant extracts to decrease α-ketoglutarate levels merits special attention due to the implications in future medicine. The action of polyphenols modulating oxidative stress, cytokine production and epigenetic changes make an interesting source of bioactive compounds for nutraceutical or functional food purposes.

Guarana (Paullinia cupana Mart.) alters gut microbiota and modulates redox status, partially via caffeine in Wistar rats.

Microbiota alterations are observed in pathological conditions, and their regulation is a subject of great interest. Gut microbes are affected by diet, and plant polyphenols may have positive effect on gut microbiota; however, plant-derived extracts may have toxic effects. Guarana (Paullinia cupana Mart.) is a nontraditional medicinal plant applied worldwide. Guarana yields an alkaloid and polyphenol-rich seed with antimicrobial, antioxidant, and anti-inflammatory properties, where caffeine is the major compound. We evaluated the effects of guarana seed powder (GSP) and purified caffeine on gut microbial composition and redox and inflammatory parameters in Wistar rats after 21 days of treatment. Fecal microbiota was analyzed utilizing 16S rDNA sequencing. Antioxidant enzymes activities from liver, kidney, and colon, as well as oxidative damage markers, were evaluated. Total nonenzymatic antioxidant potential was also evaluated. Microbiota was altered by both treatments, GSP and caffeine, without loss of diversity. In the liver, the kidney, and the colon, we observed a decrease in the antioxidant enzymes activities in the GSP group with no increase in the expression of oxidative damage markers, although some enzymes were also regulated by caffeine. Taken together, these results suggested that GSP ameliorates redox parameters but negatively affected gut microbiota, partially via caffeine.

Theobromine Is Responsible for the Effects of Cocoa on the Antibody Immune Status of Rats.

Background: A 10% cocoa-enriched diet influences immune system functionality including the prevention of the antibody response and the induction of lower immunoglobulin (Ig) concentrations. However, neither cocoa polyphenols nor cocoa fiber can totally explain these immunoregulatory properties. Objectives: This study aimed to establish the influence of cocoa theobromine in systemic and intestinal Ig concentrations and to determine the effect of cocoa or theobromine feeding on lymphoid tissue lymphocyte composition. Methods: Three-week-old female Lewis rats were fed either a standard diet (AIN-93M; RF group), a 10% cocoa diet (CC group), or a 0.25% theobromine diet (the same amount provided by the cocoa diet; TB group) in 2 separate experiments that lasted 19 (experiment 1) or 8 (experiment 2) d. Serum IgG, IgM, IgA, and intestinal secretory IgA (sIgA) concentrations were determined. In addition, at the end of experiment 2, thymus, mesenteric lymph node (MLN), and spleen lymphocyte populations were analyzed. Results: Both CC and TB groups in experiments 1 and 2 showed similar serum IgG, IgM, and IgA and intestinal sIgA concentrations, which were lower than those in the RF group (46-98% lower in experiment 1 and 23-91% lower in experiment 2; P < 0.05). In addition, in experiment 2, the cocoa and theobromine diets similarly changed the thymocyte composition by increasing CD4-CD8- (+133%) and CD4+CD8- (+53%) proportions (P < 0.01), changed the MLN composition by decreasing the percentage of T-helper (Th) lymphocytes (-3%) (P = 0.015), and changed the spleen composition by increasing the proportion of Th lymphocytes (+9%) (P < 0.001) after 1 wk of diet treatment. Conclusions: The theobromine in cocoa plays an immunoregulatory role that is responsible for cocoa's influence on both systemic and intestinal antibody concentrations and also for modifying lymphoid tissue lymphocyte composition in young healthy Lewis rats. The majority of these changes are observed after a single week of being fed a diet containing 0.25% theobromine.

Health benefits of methylxanthines in neurodegenerative diseases.

Methylxanthines (MTXs) are consumed by almost everybody in almost every area of the world. Caffeine, theophylline and theobromine are the most well-known members of this family of compounds; they are present, inter alia, in coffee, tea, cacao, yerba mate and cola drinks. MTXs are readily absorbed in the gastrointestinal tract and are able to penetrate into the central nervous system, where they exert significant psychostimulant actions, which are more evident in acute intake. Coffee has been paradigmatic, as its use was forbidden in many diseases, however, this negative view has radically changed; evidence shows that MTXs display health benefits in diseases involving cell death in the nervous system. This paper reviews data that appraise the preventive and even therapeutic potential of MTXs in a variety of neurodegenerative diseases. Future perspectives include the use of MTXs to advance the understanding the pathophysiology of, inter alia, Alzheimer's disease (AD) and Parkinson's disease (PD), and the use of the methylxanthine chemical moiety as a basis for the development of new and more efficacious drugs.

Theobromine up-regulates cerebral brain-derived neurotrophic factor and facilitates motor learning in mice.

Theobromine, which is a caffeine derivative, is the primary methylxanthine produced by Theobroma cacao. Theobromine works as a phosphodiesterase (PDE) inhibitor to increase intracellular cyclic adenosine monophosphate (cAMP). cAMP activates the cAMP-response element-binding protein (CREB), which is involved in a large variety of brain processes, including the induction of the brain-derived neurotrophic factor (BDNF). BDNF supports cell survival and neuronal functions, including learning and memory. Thus, cAMP/CREB/BDNF pathways play an important role in learning and memory. Here, we investigated whether orally administered theobromine could act as a PDE inhibitor centrally and affect cAMP/CREB/BDNF pathways and learning behavior in mice. The mice were divided into two groups. The control group (CN) was fed a normal diet, whereas the theobromine group (TB) was fed a diet supplemented with 0.05% theobromine for 30 days. We measured the levels of theobromine, phosphorylated vasodilator-stimulated phosphoprotein (p-VASP), phosphorylated CREB (p-CREB), and BDNF in the brain. p-VASP was used as an index of cAMP increases. Moreover, we analyzed the performance of the mice on a three-lever motor learning task. Theobromine was detectable in the brains of TB mice. The brain levels of p-VASP, p-CREB, and BDNF were higher in the TB mice compared with those in the CN mice. In addition, the TB mice performed better on the three-lever task than the CN mice did. These results strongly suggested that orally administered theobromine acted as a PDE inhibitor in the brain, and it augmented the cAMP/CREB/BDNF pathways and motor learning in mice.

Theobromine Upregulates Osteogenesis by Human Mesenchymal Stem Cells In Vitro and Accelerates Bone Development in Rats.

Theobromine (THB) is one of the major xanthine-like alkaloids found in cacao plant and a variety of other foodstuffs such as tea leaves, guarana and cola nuts. Historically, THB and its derivatives have been utilized to treat cardiac and circulatory disorders, drug-induced nephrotoxicity, proteinuria and as an immune-modulator. Our previous work demonstrated that THB has the capacity to improve the formation of hydroxyl-apatite during tooth development, suggesting that it may also enhance skeletal development. With its excellent safety profile and resistance to pharmacokinetic elimination, we reasoned that it might be an excellent natural osteoanabolic supplement during pregnancy, lactation and early postnatal growth. To determine whether THB had an effect on human osteoprogenitors, we subjected primary human bone marrow mesenchymal stem cells (hMSCs) to osteogenic assays after exposure to THB in vitro and observed that THB exposure increased the rate of osteogenesis and mineralization by hMSCs. Moreover, THB exposure resulted in a list of upregulated mRNA transcripts that best matched an osteogenic tissue expression signature as compared to other tissue expression signatures archived in several databases. To determine whether oral administration of THB resulted in improved skeletal growth, we provided pregnant rats with chow supplemented with THB during pregnancy and lactation. After weaning, offspring received THB continuously until postnatal day 50 (approximately 10 mg kg-1 day-1). Administration of THB resulted in neonates with larger bones, and 50-day-old offspring accumulated greater body mass, longer and thicker femora and superior tibial trabecular parameters. The accelerated growth did not adversely affect the strength and resilience of the bones. These results indicate that THB increases the osteogenic potential of bone marrow osteoprogenitors, and dietary supplementation of a safe dose of THB to expectant mothers and during the postnatal period could accelerate skeletal development in their offspring.

Genoprotective and hepatoprotective effects of Guarana (Paullinia cupana Mart. var. sorbilis) on CCl4-induced liver damage in rats.

CONTEXT: Several biological effects of Paullinia cupana (guarana) have been demonstrated, but little information is available on its effects on the liver. OBJECTIVE: The current study was designed to evaluate the hepatoprotective and genoprotective effects of powder seeds from guarana on CCl4-induced liver injury in rats. MATERIALS AND METHODS: Male Wistar rats were pretreated with guarana powder (100, 300 and 600 mg/kg) or silymarin 100 mg/kg daily for 14 days before treatment with a single dose of CCl4 (50% CCl4, 1 mL/kg, intraperitoneally). RESULTS: The treatment with CCl4 significantly increased the serum activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In addition, CCl4 increased the DNA damage index in hepatocytes. Guarana in all concentrations was effective in decreasing the ALT and AST activities when compared with the CCl4-treated group. The treatment with guarana decreased DNA damage index when compared with the CCl4-treated group. In addition, the DNA damage index showed a significant positive correlation with AST and ALT. DISCUSSION AND CONCLUSION: These results indicate that the guarana has hepatoprotective activity and prevents the DNA strand breakage in the CCl4-induced liver damage in rats.

Hypercholesterolemia and Ecto-enzymes of Purinergic System: Effects of Paullinia cupana.

Hypercholesterolemia is a metabolic disorder characterized by high levels of low-density lipoprotein and blood cholesterol, causing inflammatory lesion. Purinergic signaling modulates the inflammatory and immune responses through adenine nucleotides and nucleoside. Guaraná has hypocholesterolemic and antiinflammatory properties. Considering that there are few studies demonstrating the effects of guaraná powder on the metabolism of adenine nucleotides, we investigated its effects on the activity of ecto-nucleoside triphosphate diphosphohydrolase (E-NTPDase) and ecto-adenosine deaminase activity in lymphocytes of rats with diet-induced hypercholesterolemia. The rats were divided into hypercholesterolemic and normal diet groups. Each group was subdivided by treatment: saline, guaraná powder 12.5, 25, or 50 mg/kg/day and caffeine concentration equivalent to highest dose of guaraná, fed orally for 30 days. An increase in adenosine triphosphate hydrolysis was observed in the lymphocytes of rats with hypercholesterolemia and treated with 25 or 50 mg/kg/day when compared with the other groups. The hypercholesterolemic group treated with the highest concentration of guaraná powder showed decreased ecto-adenosine deaminase activity compared with the normal diet groups. Guaraná was able to reduce the total cholesterol and low-density lipoprotein cholesterol to basal levels in hypercholesterolemic rats. High concentrations of guaraná associated with a hypercholesterolemic diet are likely to have contributed to the reduction of the inflammatory process.

Antinociceptive effects of incarvillateine, a monoterpene alkaloid from Incarvillea sinensis, and possible involvement of the adenosine system.

Incarvillea sinensis is a Bignoniaceae plant used to treat rheumatism and relieve pain in traditional Chinese medicine. As a major component of I. sinensis, incarvillateine has shown analgesic activity in mice formalin tests. Using a series of animal models, this study further evaluated the effects of incarvillateine against acute, inflammatory, and neuropathic pain. Incarvillateine (10 or 20 mg/kg, i.p.) dose-dependently attenuated acetic acid-induced writhing, but did not affect thermal threshold in the hot plate test. In a Complete Freund's Adjuvant model, incarvillateine inhibited both thermal hyperalgesia and paw edema, and increased interleukin-1ß levels. Additionally, incarvillateine attenuated mechanical allodynia induced by spared nerve injury or paclitaxel, whereas normal mechanical sensation was not affected. Incarvillateine did not affect locomotor activity and time on the rotarod at analgesic doses, and no tolerance was observed after 7 consecutive daily doses. Moreover, incarvillateine-induced antinociception was attenuated by theophylline, 1,3-dipropyl-8-cyclopentylxanthine, and 3,7-dimethyl-1-propargylxanthine, but not naloxone, indicating that the effects of incarvillateine on chronic pain were related to the adenosine system, but not opioid system. These results indicate that incarvillateine is a novel analgesic compound that is effective against inflammatory and neuropathic pain, and that its effects are associated with activation of the adenosine system.

The Role of Uric Acid and Methyl Derivatives in the Prevention of Age-Related Neurodegenerative Disorders.

High uric acid (UA levels have been correlated with a reduced risk of many neurodegenerative diseases through mechanisms involving chelating Fenton reaction transitional metals, antioxidant quenching of superoxide and hydroxyl free radicals, and as an electron donor that increases antioxidant enzyme activity (e.g. SOD. However, the clinical usefulness of UA is limited by its' low water solubility and propensity to form inflammatory crystals at hyperuricemic levels. This review focuses on the role of UA in neuroprotection, as well as potential strategies aimed at increasing UA levels in the soluble range, and the potential therapeutic use of more water-soluble methyl-UA derivatives from the natural catabolic end-products of dietary caffeine, theophylline, and theobromine.

Theobromine inhibits differentiation of 3T3-L1 cells during the early stage of adipogenesis via AMPK and MAPK signaling pathways.

Obesity is characterized by hypertrophy and/or by the differentiation or adipogenesis of pre-existing adipocytes. In this study, we investigated the inhibitory effects of theobromine, a type of alkaloid in cocoa, on adipocyte differentiation of 3T3-L1 preadipocytes and its mechanisms of action. Theobromine inhibited the accumulation of lipid droplets, the expression of PPARγ and C/EBPα, and the mRNA expression of aP2 and leptin. The inhibition of adipogenic differentiation by theobromine occurred primarily in the early stages of differentiation. In addition, theobromine arrested the cell cycle at the G0/G1 phase and regulated the expressions of CDK2, p27, and p21. Theobromine treatment increased AMPK phosphorylation and knockdown of AMPKα1/α2 prevented the ability of theobromine to inhibit PPARγ expression in the differentiating 3T3-L1 cells. Theobromine reduced the phosphorylation of ERK and JNK. Moreover, the secretion and the mRNA level of TNF-α and IL-6 were inhibited by theobromine treatment. These data suggest that theobromine inhibits adipocyte differentiation during the early stages of adipogenesis by regulating the expression of PPARγ and C/EBPα through the AMPK and ERK/JNK signaling pathways in 3T3-L1 preadipocytes.

Differing chemical compositions of three teas may explain their different effects on acute blood pressure in spontaneously hypertensive rats.

BACKGROUND: Heavy tea consumption is suggested to be unsuitable for hypertensive people. However, the bioactive substances in different varieties of tea leaves are very different. This study compares the effects of three Chinese teas - C. sinensis, C. ptilophylla and C. assamica var. kucha - on blood pressure (BP) and heart rate in spontaneously hypertensive rats (SHRs). RESULTS: Intragastric administration of C. sinensis extract led to an acute increase in systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate in SHRs. However, C. ptilophylla and C. assamica var. kucha exerted no obvious influences on SBP, DBP or heart rate. Similar to the extract of C. sinensis, intragastric administration of caffeine also led to an acute increase in BP and heart rate in SHRs. In contrast, theobromine and theacrine - purine alkaloids predominantly contained in C. ptilophylla and C. assamica var. kucha, respectively - had no pressor effects. The effect of caffeine on BP was related to the regulation of plasma epinephrine and norepinephrine levels in SHRs. CONCLUSION: The different effects of C. sinensis, C. ptilophylla and C. assamica var. kucha on BP might be explained, at least partially, by the differences in the varieties and contents of purine alkaloids.

Impact of cocoa polyphenol extracts on the immune system and microbiota in two strains of young rats.

A diet containing 10% cocoa, a rich source of polyphenols and fibre, is able to modify intestinal immune status as well as microbiota composition. The present study was aimed at investigating whether cocoa flavonoid content is uniquely responsible for these modulatory effects of cocoa, and to establish whether these effects depend on the rat strain. To this end, 3-week-old Wistar and Brown Norway rats were fed, for 4 weeks, either a standard diet or the following three isoenergetic diets containing increasing proportions of cocoa flavonoids from different sources: one with 0.2% polyphenols (from conventional defatted cocoa), and two others with 0.4 and 0.8% polyphenols (from non-fermented cocoa, very rich in polyphenols). Serum Ig concentrations, faecal IgA levels, microbiota composition and IgA-coating bacterial proportion were evaluated at the beginning and at the end of the study. After the nutritional intervention, the composition of lymphocytes in Peyer's patches and mesenteric lymph nodes was evaluated. In some respects, the Wistar strain was more sensitive to the impact of the cocoa diets than the Brown Norway strain. After 4 weeks of dietary intervention, similar modulatory effects of the diets containing 0.2 and 0.8% polyphenols on mucosal IgA levels and microbiota composition were found, although the 0.2% diet, with a higher proportion of theobromine and fibre, had more impact, suggesting that polyphenols are not the only components involved in such effects.