Methylxanthines Research Articles

Dietary natural methylxanthines and colorectal cancer: a systematic review and meta-analysis.

Some evidence suggests that caffeine, theophylline, and theobromine, as natural methylxanthines (MTXs), possess anti-cancer effects. We systematically reviewed the animal and human studies investigating the effect of (or association between) dietary natural MTXs on (and) colorectal cancer (CRC) and performed a meta-analysis of epidemiological studies. Relevant studies were identified by searching MEDLINE, Embase, Scopus, and Web of Knowledge through September 2020. The overall relative risk (RR) and confidence interval (CI) were determined using a random-effects model. Eight animal and eight epidemiological investigations met our inclusion criteria. Animal studies indicated detrimental effects of high levels of caffeine intake on the initiation and promotion of CRC, while showing beneficial or non-significant effects at lower doses. The meta-analysis of six epidemiological studies found no association between dietary caffeine intake and the risk of CRC (RR = 0.98 (95% CI = 0.88-1.10)). Subgroup analysis revealed a direct association between caffeine intake and risk of CRC only in the studies with a moderate risk of bias and a lack of adjustment for smoking. The results of the only epidemiological study investigating the association between the serum levels of MTXs and the risk of CRC showed an inverse association. In conclusion, some animal studies underlined the beneficial effects of caffeine, at regular doses consumed by humans, on CRC. However, current epidemiological evidence does not support an association between caffeine intake and the risk of CRC.

Advances on the mechanism of caffeine in preventing bronchopulmonary dysplasia in preterms

Caffeine citrate, as one type of methylxanthine, is often used to treat apnea in premature infants.Recent studies have found that it is not only used for extubation before weaning, shortening the time of mechanical ventilation, preventing apnea and reducing the occurance of intermittent hypoxic episodes, but also exerting lung protection by inhibiting inflammatory reactions, mitigating oxidative stress, improving pulmonary function and pulmonary angiogenesis.Thus, it could effectively reduce the risk of bronchopulmonary dysplasia in premature infants. Key words: Caffeine; Bronchopulmonary dysplasia; Preterm

Solvent and temperature effect of accelerated solvent extraction (ASE) coupled with ultra-high-pressure liquid chromatography (UHPLC-PDA) for the determination of methyl xanthines in commercial tea and coffee

BackgroundMethyl xanthines (MX), known for its psychostimulant effect, occurs mostly in tea and coffee samples. However most of the market available products does not mention the proper amount and quality of MX present where, its consumption in high amount may pose health risks. Aim of the studyTo develop and validate a fast, efficient and reliable method of MX extraction along with a sensitive, rapid and precise method for simultaneous analysis of MX i.e. Theobromine (TB), Theophylline (TH) and Caffeine (C), with application in commercial tea and coffee samples. Materials and methodsAccelerated Solvent Extraction (ASE) was utilized for the first time to extract MX, whereas UHPLC-DAD was applied in order to quantify MX. ResultsASE resulted a high extract yield (940.22 ± 192.28 mg/g) with optimized conditions of temperature (100 °C) and solvent (MeOH). UHPLC-DAD showed retention time (min) of 1.51 (TB), 1.81 (TH), 2.30 (C) with r2 values (0.980–0.988). Average MX (μg/mL) was as; TB (14.73 ± 20.9), TH (32.05 ± 55.5), C (121.87 ± 32.3). The method application in commercial samples showed a high extract yield with MX concentration (mg/g) as; TB (0.13–0.38), TH (0–0.55), C (7.14–11.20). Temperature and solvent variation showed important correlation with samples in terms of extraction yield. ConclusionASE-UHPLC/DAD revealed a fast and sensitive method of MX extraction, quantification and quality determination in market available tea and coffee samples.

Extraction of methyl xanthines and their UHPLC-DAD determination in consumable beverages used in Eastern province of Saudi Arabia.

Coffee and tea are the most widely consumed beverages worldwide. However, the consumer may be unaware of the exact amount of methyl xanthine (MX, i.e. caffeine [C], theobromine [TB] and theophylline [TH]) consumed, as most of the products do not list the proper amounts. This may lead to serious risks including cardiovascular, kidney and stimulant effects. The aim of the study was to determine the MX amount in ready-to-use beverages (coffee and tea) collected from various outlets in the city of Al-Khobar, Saudi Arabia. Forty different samples of espresso, black coffee and red tea were collected. A fast, reliable and efficient UHPLC-DAD method was developed and validated for MX determination. Total lipids were extracted and fractionated in order to determine glycolipids, phospholipids and neutral lipids. The r2 value for the method was 0.980-0.988 in a linearity range of 0.5-200 ppm. The range for MX (C [0.02-2.39 mg/ml], TB [0.00-0.10 mg/ml] and TH [0.00-0.004 mg/ml]) and total lipids was 1-5 g. The amount of glycolipids (3.1 g) was higher among the lipid fractions followed by phospholipids (1.8 g) and neutral lipids (0.25 g). In general, espresso beverages (20-30 ml) contained high amounts of MX whereas black coffee beverages contained high amount of lipids. Most of the beverages expressed C, TB, TH, lipids or their fractions; however, the product with high amounts of MX and lipids at the same time was espresso (brands Chemistry and Wogard). Although the MX and lipid levels in these beverages well below the allowed limits, care must still be taken, especially when using the beverages with high serving volumes (200-250 ml) or coffee prepared via the filter method i.e. black coffee, using a high temperature for a longer time.

Effect of Caffeine and Other Methylxanthines on Aβ-Homeostasis in SH-SY5Y Cells.

Methylxanthines (MTX) are alkaloids derived from the purine-base xanthine. Whereas especially caffeine, the most prominent known MTX, has been formerly assessed to be detrimental, this point of view has changed substantially. MTXs are discussed to have beneficial properties in neurodegenerative diseases, however, the mechanisms of action are not completely understood. Here we investigate the effect of the naturally occurring caffeine, theobromine and theophylline and the synthetic propentofylline and pentoxifylline on processes involved in Alzheimer’s disease (AD). All MTXs decreased amyloid-β (Aβ) level by shifting the amyloid precursor protein (APP) processing from the Aβ-producing amyloidogenic to the non-amyloidogenic pathway. The α-secretase activity was elevated whereas β-secretase activity was decreased. Breaking down the molecular mechanism, caffeine increased protein stability of the major α-secretase ADAM10, downregulated BACE1 expression and directly decreased β-secretase activity. Additionally, APP expression was reduced. In line with literature, MTXs reduced oxidative stress, decreased cholesterol and a decreased in Aβ1-42 aggregation. In conclusion, all MTXs act via the pleiotropic mechanism resulting in decreased Aβ and show beneficial properties with respect to AD in neuroblastoma cells. However, the observed effect strength was moderate, suggesting that MTXs should be integrated in a healthy diet rather than be used exclusively to treat or prevent AD.

Methylxanthines: Potential Therapeutic Agents for Glioblastoma

Glioblastoma (GBM) is the most common and aggressive primary brain tumor. Currently, treatment is ineffective and the median overall survival is 20.9 months. The poor prognosis of GBM is a consequence of several altered signaling pathways that favor the proliferation and survival of neoplastic cells. One of these pathways is the deregulation of phosphodiesterases (PDEs). These enzymes participate in the development of GBM and may have value as therapeutic targets to treat GBM. Methylxanthines (MXTs) such as caffeine, theophylline, and theobromine are PDE inhibitors and constitute a promising therapeutic anti-cancer agent against GBM. MTXs also regulate various cell processes such as proliferation, migration, cell death, and differentiation; these processes are related to cancer progression, making MXTs potential therapeutic agents in GBM.

Caffeic Acid Phenethyl Ester and Its Fluorinated Derivative as Natural Anti-obesity Agents (P06-089-19)

ObjectivesCaffeic acid phenethyl ester (CAPE), an active component of propolis from honeybee hives, is well studied for its beneficial effects on cancer, inflammation and diabetes. There are however limited studies investigating the effects of CAPE on obesity. Currently, several natural products are under investigation for their effects on adipocyte life cycle. A multi-targeted approach for prevention and treatment of obesity includes targeting adipocytes at all the stages of life cycle by decreasing adipocyte differentiation, inducing lipolysis and/or by inducing adipocyte apoptosis. In this study, we examined the effects of CAPE on preadipocyte viability, adipogenesis and lipolysis. Earlier reports on CAPE indicate that CAPE is liable to enzymatic hydrolysis in vivo making this compound unstable for therapeutic applications. In the current study, we compared the anti-adipogenic effects of CAPE with its novel fluorinated derivative (FCAPE), a more stable compound. Methods3T3-L1 pre-adipocytes were differentiated using a cocktail consisting of insulin, dexamethasone, and isobutyl methyl xanthine in DMEM supplemented with 10% FBS following adipogeneic differentiation. Pre- and mature adipocytes were incubated with CAPE or FCAPE for 24–48 hours and their effects on viability, lipolysis, and adipogenesis was tested using Prestoblue, Lipolysis assay (Zen-Bio) and AdipoRed assay respectively. ResultsOur results indicate that neither CAPE nor FCAPE significantly altered preadipocyte viability within the tested dose range. Although both CAPE and FCAPE significantly decreased adipogenesis compared to control, FCAPE decreased lipid content by 73.6 ± 1.6% while CAPE reduced lipid content by only 36.8 ± 9.1% at 25 μM concentration. In contrast to adipogenesis data, our preliminary results with lipolysis assay indicate that only CAPE, but not FCAPE induces lipolysis in mature adipocytes. ConclusionsThese findings suggest that both CAPE and FCAPE possess anti-adipogenic properties. Further studies are needed to elucidate their differential effects on adipogenesis and lipolysis. Funding SourcesThis study was funded by the Department of Research, PCOM.

Caffeine and caffeine metabolites in relation to hypertension in U.S. adults.

Most studies assessing the association between coffee consumption and hypertension ascertained caffeine intake in terms of number of cups per days, and yield mixed results. Although the inter-individuals variability in the caffeine metabolism is known, the relation of caffeine metabolites with hypertension remains unsettled. We examined the association of caffeine and 13 direct and indirect caffeine metabolites with hypertension in U.S. adults. Using data from 2009-2010 National Health and Nutrition Examination Survey, we included 2278 individuals aged 18 to 80 years. Urinary methyluric acids (MU) and methylxanthines (MX) products of caffeine metabolism were measured using high performance liquid chromatography-electrospray ionization-tandem quadrupole mass spectrometry. We used multivariate logistic regression to model hypertension (systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥80 mmHg) as functions of urinary coffee metabolites. The odds of hypertension decreased across quartiles of 3-MU, 7-MU, 3-MX and 7-MX, with 7-MU being the more powerful metabolite. Compared with adults in the bottom quartile of 7-MU, the odds of hypertension decreased by 81% (95% CI: -90 to -22%) in those in the upper quartile. In contrast, the odds ratio for being hypertensive from the bottom to the upper quartile were 4.47 (95% CI: 1.21-16.50) for 1,3-dimethyluric acid, 4.45 (95% CI: 1.48-13.39) for 1,3-dimethylxanthine, and 5.08 (95% CI: 1.11-23.36) for 1,7-dimethylxanthine. Neither insulin resistance nor abdominal obesity were moderators in these associations. Final metabolites of caffeine (namely 3-MU, 7-MU, 3-MX and 7-MX), but not caffeine, significantly reduce the odds for hypertension in this population.

Preparasi Teofilin dalam Pembawa Vesikular Etosom untuk Penggunaan Transdermal

Theophylline is a methyl xanthine of alkaloid derivative compound has been used as a bronchodilator in the treatment of chronic lung disorders, especially asthma. Oral administration of theophylline causes inconvenient for patients including bitter taste, narrow therapeutic range, and indigestion due to increased of gastric acid secretion. Therefore, other administration of theophylline has been developed as transdermal delivery system. This study disscused about preparation of theophylline in ethosome as vesicular carrier. Preparation of ethosome was used hot method (40oC) and cool method (30oC). Characterization of ethosomes includes observation of shape and size of vesicles by microscopic method and the vesicles were fractionated by centrifugation then entrapment efficiency (% EE) were measured by spectrophotometric method. Then optimazed theophylline that entrapped in ethosome. Based on the results, ethosomes preparation by hot method were produced Small Unilamellar Vesicle (SUV), the size were 0,0522-0,100 µm, and the highest value of % EE was 98.95%, while ethosomes preparation by cold method were produced Small Unilamellar Vesicle (SUV), the size were 0.0522-0.100 μm, and the highest value of % EE was 99.80%. The optimum concentration of theophylline was entrapped in etosom was 0.1%. It was concluded that cold method was the appropriate method for preparation of theophylline in ethosome as vesicular carrier.Keywords: Etosome, theophylline, vesicular, transdermal

Evaluation of orthodontic tooth movement by 3D micro-computed tomography (µ-CT) following caffeine administration

Background: The compressive strength of orthodontic tooth movement will be distributed throughout the periodontal ligament and alveolar bone, resulting in bone resorption on the pressure side and new bone formation on the tension side. Caffeine, a member of the methyl xanthine family, represents a widely-consumed psychoactive substance that can stimulate osteoclastogenesis through an increase in RANKL. A 3D Micro-Computed Tomography (µ-CT) x-ray device can be used to measure orthodontic tooth movement and changes in periodontal ligament width. Purpose: The purpose of this research was to analyze the effects of caffeine on the distal movement distance of two mandibular incisors using 3D µ-CT. Methods: The research subjects (guinea pigs) were randomly divided into four groups. Of the two control groups created, one received two weeks of treatment and the other three weeks. The members of these two control groups were subjected to orthodontic movement but received no caffeine. Meanwhile, the other two groups were treatment groups whose members also received either two or three weeks of treatment. In these two treatment groups, the subjects were subjected to orthodontic movement and received a 6 mg/500 BM dose of caffeine. The orthodontic movement of the subjects was induced by installing a band matrix and orthodontic bracket on each mandibular incisor to move distally by means of an open coil spring. Observations were then conducted on days 15 and 22 with µ-CT x-rays to measure the distal movement distance of the two mandibular incisors and the width of the periodontal ligament. Results: The administration of caffeine increased the tooth movement on day 15 (p<0.05) and day 22 (p<0.05). The increase in the tooth movement on day 22 was greater than that on day 15 (p<0.05). The width of the periodontal ligament on the pressure side of the treatment groups experienced greater narrowing than that of the control groups (p<0.05). Meanwhile, the width of periodontal ligament on the tension side of the treatment groups widened more than that of the control groups (p<0.05). Conclusion: µ-CT x-ray can be used to evaluate the extent of orthodontic movement in addition to the width of the mandibular incisor periodontal ligament during orthodontic tooth movement. Moreover, it has been established that the administering of caffeine can improve orthodontic tooth movement.

Pharmacological and molecular dynamics analyses of differences in inhibitor binding to human and nematode PDE4: Implications for management of parasitic nematodes

Novel chemical controls are needed that selectively target human, animal, and plant parasitic nematodes with reduced adverse effects on the host or the environment. We hypothesize that the phosphodiesterase (PDE) enzyme family represents a potential target for development of novel nematicides and anthelmintics. To test this, we identified six PDE families present in the nematode phylum that are orthologous to six of the eleven human PDE families. We characterized the binding interactions of family-selective PDE inhibitors with human and C. elegans PDE4 in conjunction with molecular dynamics (MD) simulations to evaluate differences in binding interactions of these inhibitors within the PDE4 catalytic domain. We observed that roflumilast (human PDE4-selective inhibitor) and zardaverine (selective for human PDE3 and PDE4) were 159- and 77-fold less potent, respectively, in inhibiting C. elegans PDE4. The pan-specific PDE inhibitor isobutyl methyl xanthine (IBMX) had similar affinity for nematode and human PDE4. Of 32 residues within 5 Å of the ligand binding site, five revealed significant differences in non-bonded interaction energies (van der Waals and electrostatic interaction energies) that could account for the differential binding affinities of roflumilast and zardaverine. One site (Phe506 in the human PDE4D3 amino acid sequence corresponding to Tyr253 in C. elegans PDE4) is predicted to alter the binding conformation of roflumilast and zardaverine (but not IBMX) into a less energetically favorable state for the nematode enzyme. The pharmacological differences in sensitivity to PDE4 inhibitors in conjunction with differences in the amino acids comprising the inhibitor binding sites of human and C. elegans PDE4 catalytic domains together support the feasibility of designing the next generation of anthelmintics/nematicides that could selectively bind to nematode PDEs.

A new coupling of an acid-base transporter to PKD and cyst formation.

A new coupling of an acid-base transporter to PKD and cyst formation.

Diprophylline inhibits non-small cell lung cancer A549 cell proliferation and migration, and promotes apoptosis, by downregulating PI3K signaling pathway.

Diprophylline (DPL) is identified as a methylxanthine (MX) derivative. A number of MX derivatives are reported to have anti-tumor effects. However, it is not clear whether DPL has a therapeutic effect on non-small cell lung cancer (NSCLC). The aim of the present study was to investigate the effects of DPL on NSCLC and to elucidate the potential underlying mechanism. A Cell Counting Kit-8 assay was used to evaluate the potential effect of DPL on A549 cell proliferation. Transwell invasion and migration assays were performed to assess the effect of DPL on A549 cell migration and invasion. Furthermore, the percentage of apoptotic cells was detected by flow cytometric analysis, and proteins associated with apoptosis, including apoptosis regulator Bcl-2, apoptosis regulator BAX and active caspase-3, were examined by western blotting. Finally, the expression levels of molecules relevant to phosphoinositide 3-kinase (PI3K) signaling were detected by western blot analysis. The present study demonstrated that DPL may significantly inhibit A549 cell proliferation, migration and invasion. Furthermore, treatment with DPL may significantly induce A549 cell apoptosis. Finally, the protein expression levels associated with the PI3K signaling pathway were significantly inhibited in A549 cells following treatment with DPL. In conclusion, DPL may inhibit the proliferation and migration of NSCLC by inactivating the PI3K signaling pathway, and DPL is a promising novel therapeutic drug for NSCLC.

Progress of caffeine in preventing bronchopulmonary dysplasia in preterm infants

Caffeine is a methylxanthine, clinically used to treat apnea in preterm infants.However, it has been found that the drug also has a role in reducing the incidence of bronchopulmonary dysplasia(BPD)in preterm infants in recent years.It may be related to improvement of lung function, improvement of extubation success rate and shortening of ventilator assisted ventilation time.Further study found that caffeine could play a protective role in the prevention and control of BPD by antagonistic adenosine receptors, inhibiting inflammatory mediators, inhibiting the transforming growth factors-β1, and inhibiting matrix metalloproteinases. Key words: Caffeine; Premature infants; Bronchopulmonary dysplasia

CAMP/Protein Kinase A Signaling Inhibits Dlx5 Expression via Activation of CREB and Subsequent C/EBPβ Induction in 3T3-L1 Preadipocytes.

Distal-less homeobox 5 (Dlx5) is a negative regulator of adipogenesis. Dlx5 expression is decreased by adipogenic stimuli, but the mechanisms of Dlx5 downregulation by adipogenic stimuli have not yet been determined. Here, we tested the impact of cAMP/PKA (protein kinase A) signaling induced by 3-isobutyl-1 methyl xanthine (IBMX), forskolin, and 8-CPT-cAMP on the expression of Dlx5 in 3T3-L1 preadipocytes. Significant downregulation of Dlx5 mRNA expression and protein production levels were observed via cAMP/PKA-dependent signaling. Forced expression of cAMP-responsive element-binding protein (CREB) and CCAAT/enhancer-binding protein β (C/EBPβ) was sufficient for downregulation of Dlx5 expression and revealed that CREB functions upstream of C/EBPβ. In addition, C/EBPβ knockdown by siRNA rescued Dlx5 expression in IBMX-treated 3T3-L1 preadipocytes. Luciferase assays using a Dlx5-luc-2935 reporter construct demonstrated the requirement of the Dlx5 promoter region, ranging from −774 to −95 bp that contains two putative C/EBPβ binding elements (site-1: −517 to −510 bp and site-2: −164 to −157 bp), in the suppression of Dlx5 transcription. Consequently, chromatin immunoprecipitation analysis confirmed the importance of site-1, but not site-2, in C/EBPβ binding and transcriptional suppression of Dlx5. In conclusion, we elucidated the underling mechanism of Dlx5 downregulation in IBMX-induced adipogenesis. IBMX activated cAMP/PKA/CREB signaling and subsequently upregulated C/EBPβ, which binds to the Dlx5 promoter to suppress Dlx5 transcription.

Different Catabolism Pathways Triggered by Various Methylxanthines in Caffeine-Tolerant Bacterium Pseudomonas putida CT25 Isolated from Tea Garden Soil.

The degradation efficiency and catabolism pathways of the different methylxanthines (MXs) in isolated caffeine-tolerant strain Pseudomonas putida CT25 were comprehensively studied. The results showed that the degradation efficiency of various MXs varied with the number and position of the methyl groups on the molecule (i.e., xanthine > 7-methylxanthine ≈ theobromine > caffeine > theophylline > 1-methylxanthine). Multiple MX catabolism pathways coexisted in strain CT25, and a different pathway would be triggered by various MXs. Demethylation dominated in the degradation of N-7-methylated MXs (such as 7-methylxanthine, theobromine, and caffeine), where C-8 oxidation was the major pathway in the catabolism of 1-methylxanthine, whereas demethylation and C-8 oxidation are likely both involved in the degradation of theophylline. Enzymes responsible for MX degradation were located inside the cell. Both cell culture and cell-free enzyme assays revealed that N-1 demethylation might be a rate-limiting step for the catabolism of the MXs. Surprisingly, accumulation of uric acid was observed in a cell-free reaction system, which might be attributed to the lack of activity of uricase, a cytochrome c-coupled membrane integral enzyme.

Black Tea: A Possible Multitherapeutic Combinatorics Aiding Neuroprotection in Alzheimer’s Disease

This article aims at reviewing the effectiveness of compounds in black tea in combating neuroinflammation in Alzheimer’s disease (AD). Detailed chemo profiling of black tea showed the presence of theaflavins, different catechins, and amino acids viz., L-theanine and methylxanthines. A literature search showed a multitude of pharmacological activities diversity of black tea. Structural and anti-inflammatory activity relationship studies showed the anti-inflammatory potentials of benzotropolone moiety containing compounds, flavonoids, flavones, phenolics and methylxanthines e.g. caffeine, theobromine, theophylline. Black tea is a good source of several multifunctional pharmacophores and thus can combat neuroinflammation in AD providing neuroprotection from multidimensional perspectives.

Formulation and Penetration Enhancement Activity of Sticks Containing Caffeine

Caffeine is a methyl xanthine alkaloid that has been widely used in cosmetic products as anti-cellulite. Caffeine has a hydrophilic character, thus it has difficulty in penetrating the lipid layer of the skin. The aims of this study were to formulate sticks containing emulsion and microemulsion caffeine (control stick), caffeine emulsions (emulsion stick), and caffeine microemulsion (microemulsion stick) and compare the penetration between them. Caffeine was made in the form of water in oil emulsions and microemulsion then form into sticks-shaped with the lipophilic component. All sticks were physically and chemically evaluated. The penetration of caffeine through Sprague-Dawley rat skin using Franz Diffusion Cell were tested for 12 hours. The penetration result of caffeine from control stick, emulsion stick, and microemulsion stick were 306.42 ± 34.92 µg/cm2, 927.75 ± 57.38 µg/cm2, and 2408.68 ± 81.65 µg/cm2 respectively, with percentage 5.90 ± 0.67%, 12.76 ± 0.78%, and 35.23 ± 1.19%. Physical and chemical stability tests were performed for 8 weeks at room temperature (29±2°C), cold temperature (4±2°C), and hot temperature (40±2°C). Microemulsion stick delivered the highest cumulative amount of caffeine in penetration test for 12 hours, followed by emulsion stick and control stick. Also, all sticks showed physical and chemical relatively stable.

Separation and Detection of Caffeine, Theophylline and Theobromine from Coffee Varieties, Carbonated Soft Drinks and Alcoholic Beverages

The paper evaluates the presence of methyl xanthine compounds: caffeine, theophylline, theobromine used as ingredients in carbonated soft drinks or as color and flavor ingredients in alcoholic beverages. The active components extracted from the selected products (coffee, tea, drinks) was separated and identified chromatographically using plates with silica nano -Sil NH2 / UV-254, mobile phase ethanol - water (50: 1, 50: 3, 50: 5; 50: 7; v / v) and 60 F254 plates, mobile phase acetone-toluene-chloroform (40:30:30 v / v). Separated caffeine and identified by TLC was analyzed using a HelWet Packard 5890 Gas Chromatograph equipped with MS 5972 mass detector and spectral library to confirm identification. This simple and rapid TLC, GC / MS instrumental method is useful in controlling traces of methyl xanthine compounds in food as a food safety measure.is useful in controlling traces compound of food products containing methylxanthines as a food safety measure.

Enhanced anticancer efficacy of histone deacetyl inhibitor, suberoylanilide hydroxamic acid, in combination with a phosphodiesterase inhibitor, pentoxifylline, in human cancer cell lines and in-vivo tumor xenografts.

Vorinostat [suberoylanilide hydroxamic acid (SAHA)], a histone deacetylase inhibitor, shows limited clinical activity against solid tumors when used alone. The methyl xanthine drug, pentoxifylline (PENT), has been described to have antitumor properties. The aim of this study was to look for the enhanced anticancer activities of both agents when used in combination at doses lower than their respective efficacy dose when used alone. We investigated the antitumor potential of this novel combination in vitro and in vivo. The combination index was assessed for these two drugs to look for synergistic antiproliferative activity against a broad spectrum of human cancer cell lines. Consistent additive to synergistic interactions were observed in HCT116 cells when PENT was combined with SAHA at all drug tested concentrations. The combination of SAHA and PENT induces chromatin condensation and apoptosis downstream of the pan histone deacetylase inhibition and phosphodiesterase regulation, leading to subsequent cell cycle arrest at their lower tested concentrations. Further, the ability of this combination to inhibit angiogenesis, both in vitro and in vivo, was examined and a significant inhibition in tube formation in HUVEC cells and neovascularization of Matrigel plug was observed. A significant inhibition in tumor growth was observed in severe combined immunodeficient mice bearing HCT116 (colon) and PC3 (prostate) human xenografts treated with SAHA (30 mg/kg, intraperitoneal) in combination with PENT (60 mg/kg, intraperitoneal), with no loss in body weight and 100% survival. In conclusion, these findings indicate the enhanced anticancer activity of SAHA in combination with PENT both in vitro and in vivo.