RNA binding efficacy of theophylline, theobromine and caffeine

Exploration of the theobromine-water dimer: comparison with DNA microhydration

Understanding the molecular basis of the appearance of life on Earth is an exciting research field. Many factors may have influenced the election of the molecules used by living beings and evolution may have modified those original compounds. In an attempt to understand the role played by intermolecular interactions in the election of CGAT as the alphabet of life, we present here a thorough experimental and computational study on the interaction of theobromine with water. Theobromine is a xanthine derivative, structurally related to the nucleobases, and also present in many living beings. The experimental results demonstrate that the most stable isomer of theobromine-water was formed and detected in supersonic expansions. This isomer very well resembles the structure of the dimers between nucleobases and water, offering similar values of binding energy. A comparison between the results obtained for theobromine-water with those reported in the literature for monohydrates of nucleobases is also offered.

The theory of interceptor-protector action of DNA binding drugs

The review discusses the theory of interceptor-protector action (the IPA theory) as the new self-consistent biophysical theory establishing a quantitative interrelation between parameters measured in independent physico-chemical experiment and in vitro biological experiment for the class of DNA binding drugs. The elements of the theory provide complete algorithm of analysis, which may potentially be applied to any system of DNA targeting aromatic drugs. Such analytical schemes, apart from extension of current scientific knowledge, are important in the context of rational drug design for managing drug's response by changing the physico-chemical parameters of molecular complexation.

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

Methylxanthines are a group of phytochemicals derived from the purine base xanthine and obtained from plant secondary metabolism. They are unobtrusively included in daily diet in common products as coffee, tea, energetic drinks, or chocolate. Caffeine is by far the most studied methylxanthine either in animal or epidemiologic studies. Theophylline and theobromine are other relevant methylxanthines also commonly available in the aforementioned sources. There are many disseminated myths about methylxanthines but there is increased scientific knowledge to discuss all the controversy and promise shown by these intriguing phytochemicals. In fact, many beneficial physiologic outcomes have been suggested for methylxanthines in areas as important and diverse as neurodegenerative and respiratory diseases, diabetes or cancer. However, there have always been toxicity concerns with methylxanthine (over)consumption and pharmacologic applications. Herein, we explore the structure-bioactivity relationships to bring light those enumerated effects. The potential shown by methylxanthines in such a wide range of conditions should substantiate many other scientific endeavors that may highlight their adequacy as adjuvant therapy agents and may contribute to the advent of functional foods. Newly designed targeted molecules based on methylxanthine structure may originate more specific and effective outcomes.

Array-based sensing of purine derivatives with fluorescent dyes

Natural and synthetic purine derivatives such as caffeine, theophylline, 6-mercaptopurine and 8-chlorotheophylline are important drugs. Due to the structural similarity of these compounds, it is intrinsically difficult to prepare chemosensors for their selective optical detection. Here, we describe a sensor array which can be used to differentiate pharmacologically important purine derivatives with good accuracy. The array is composed of four polysufonated fluorescent dyes, all of which can bind purines viaπ-stacking interactions. The complexation of the analytes results in partial quenching of the fluorescence. The fluorescence response of the four dyes provides a characteristic signal pattern, enabling the identification of thirteen purine derivatives at low millimolar concentration. Furthermore, it is possible to use the array for obtaining information about the quantity and purity of purine samples.

The relevance of theobromine for the beneficial effects of cocoa consumption

Cocoa consumption began in America and in the mid sixteenth Century it quickly spread to Europe. Beyond being considered a pleasant habit due to its rich sweet lingering taste, chocolate was considered a good nutrient and even a medicine. Traditionally, health benefits of cocoa have been related with the high content of antioxidants of Theobroma cocoa beans. However, the direct psychoactive effect due to methylxanthines in cocoa is notable. Theobromine and caffeine, in the proportions found in cocoa, are responsible for the liking of the food/beverage. These compounds influence in a positive way our moods and our state of alertness. Theobromine, which is found in higher amounts than caffeine, seems to be behind several effects attributed to cocoa intake. The main mechanisms of action are inhibition of phosphodiesterases and blockade of adenosine receptors. Further mechanisms are being explored to better understand the health benefits associated to theobromine consumption. Unlike what happens in other mammals -pets- included, theobromine is safe for humans and has fewer unwanted effects than caffeine. Therefore, theobromine deserves attention as one of the most attractive molecules in cocoa.

Spectral analysis of naturally occurring methylxanthines (theophylline, theobromine and caffeine) binding with DNA

Nucleic acids exist in a dynamic equilibrium with a number of molecules that constantly interact with them and regulate the cellular activities. The inherent nature of the structure and conformational integrity of these macromolecules can lead to altered biological activity through proper targeting of nucleic acids binding ligands or drug molecules. We studied the interaction of naturally occurring methylxanthines such as theophylline, theobromine and caffeine with DNA, using UV absorption and Fourier transform infrared (FTIR) spectroscopic methods, and especially monitored their binding affinity in the presence of Mg(2+) and during helix-coil transitions of DNA by temperature (T(m)) or pH melting profiles. The study indicates that all these molecules effectively bind to DNA in a dose dependent manner. The overall binding constants of DNA-theophylline = 3.5×10(3) M(-1), DNA-theobromine = 1.1×10(3) M(-1), and DNA-Caffeine = 3.8×10(3) M(-1). On the other hand T(m)/pH melting profiles showed 24-35% of enhanced binding activity of methylxanthines during helix-coil transitions of DNA rather than to its native double helical structure. The FTIR analysis divulged that theophylline, theobromine and caffeine interact with all the base pairs of DNA (A-T; G-C) and phosphate group through hydrogen bond (H-bond) interaction. In the presence of Mg(2+), methylxanthines altered the structure of DNA from B to A-family. However, the B-family structure of DNA remained unaltered in DNA-methylxanthines complexes or in the absence of Mg(2+). The spectral analyses indicated the order of binding affinity as "caffeine≥theophylline>theobromine" to the native double helical DNA, and "theophylline≥theobromine>caffeine to the denatured form of DNA and in the presence of divalent metal ions.

Design and synthesis of new 8-anilide theophylline derivatives as bronchodilators and antibacterial agents

Theophylline derivatives have long been recognized as potent bronchodilators for the relief of acute asthma. Recently, it was found that bacterial infection has a role in asthma pathogenesis. The present work involves the design and synthesis of 8-substituted theophylline derivatives as bronchodilators and antibacterial agents. The chemical structures of these compounds were elucidated by IR, (1)H-NMR, mass spectrometry, and elemental analyses. The bronchodilator activity was evaluated using acetylcholine-induced bronchospasm in guinea pigs, and most of the compounds showed significant anti-bronchoconstrictive activity in comparison with standard aminophylline. In addition, the antibacterial activity of all the target compounds was investigated in vitro against Gram-positive and Gram-negative bacteria using ampicillin as a reference drug. Results showed that some of the tested compounds possessed significant antibacterial activity. A pharmacophore model was computed to obtain useful insight into the essential structural features of bronchodilator activity. A structure activity relationship was also discussed.

Design and synthesis of some new theophylline derivatives with bronchodilator and antibacterial activities

Methylxanthines especially theophylline have been recognized as potent bronchodilators for the relief of acute asthma for over 65 years. Recently, it was found that bacterial infection plays a role in asthma pathogenesis. Accordingly, the present work involves the synthesis of 6-(4-(un)substituted phenyl)thiazolo[2,3-f]theophyllines 2a-g and different series of 8-(1,2,4-triazol-3-ylmethylthio)theophyllines 6-9. The chemical structures of the target compounds were proved by IR, (1)H NMR, (13)C NMR, EI-MS and HRMS spectroscopic techniques along with elemental analyses. The bronchodilator activity of fifteen compounds was determined in vivo by acetylcholine induced bronchospasm in anaesthetized guinea pigs. Results revealed that all compounds showed moderate to good activity; in addition, five compounds exhibited a bronchodilator activity nearly similar to that of aminophylline as a standard. The antibacterial activity of all the target compounds was investigated in vitro against both Gram-positive and Gram-negative bacterial strains. Results revealed that some compounds showed more potent antibacterial activity than ampicillin as a standard. Acute toxicity study for four target compounds revealed that none of these derivatives showed significant toxicity up to 300 mg/kg. It was found that compound 8c combined both promising bronchodilator and antibacterial activities. This compound could be subjected for further investigations as a new possible candidate in the treatment of bronchial asthma.

Complexation of biologically active aromatic compounds with DNA in the presence of theophylline

(1)H NMR measurements (500 MHz) have been used to determine the equilibrium hetero-association constants of theophylline (THP) with various biologically active aromatic compounds (daunomycin, novantrone, ethidium bromide, proflavine, norfloxacin) and the complexation constants of THP with both single- and double-stranded oligonucleotides in solution. The results provide a quantitative estimation of the effect of THP on the binding of aromatic ligands with DNA, and a determination of the fraction of aromatic ligand removed from DNA on addition of THP.

Analysis of group I intron splicing in the presence of naturally occurring methylxanthines

BACKGROUND

Recent advances in the understanding of RNA structure-function, intricate folding and its affinity to bind small molecules have led to the proposal that RNA can be a fastidious target for drug design. The revelation that RNA can act as enzymes as in group I intron and that has been recognized by small molecule ligands targeting the catalytic activity has necessitated our focus on group I intron as target for RNA binders.

METHODS

We studied the group I intron splicing of Tetrahymena in the presence of naturally occurring methylxanthines (theophylline, theobromine and caffeine) at 5-200 micromol/l concentration, and analyzed the spliced out products. For the first time the interference of splicing was ascertained on the basis of pre-rRNA accumulation.

RESULTS

The gel mobility shift showed the binding of methylxanthines with group I intron RNA in a dose dependent manner. The densitometric analysis of pre-rRNA accumulation showed 50% of splicing interference at 200 micromol/l of theophylline and theobromine, whereas the structurally similar molecule caffeine does not alter splicing.

CONCLUSION

The splicing interference measured from the accumulation of pre-rRNA in group I intron splicing is considered to be an uncomplicated or simple denominator for calculating the splicing interference or relative splicing activity in the presence of above RNA binders or splicing modulators.

Probing RNA–antibiotic interactions: a FTIR study

The crystal structure determination of antibiotic binding sites on the 30S ribosomal subunit and the increasing demand for developing RNA-based drugs has prompted us to study the direct binding of spectinomycin, vancomycin and bleomycin with yeast total RNA using Fourier transform infrared (FTIR) spectroscopy. We report that the OH of spectinomycin and the peptide group of vancomycin can bind to the bases of RNA, which might depend on Mg2+ concentration. Bleomycin on the other hand does not show such a drastic effect on yeast total RNA. This study might help in developing innovative strategies utilizing RNA molecules to perform a variety of essential biological functions.