Caffeine molecular structures

The molecular structure of ephedra resembles that of amphetamine, a stimulant. Dietary supplement product manufacturers often mixed caffeine with ephedra. Some experts believe that caffeine probably enhances or heightens ephedra s stimulant effects. Ephedra may also be combined with other herbs in supplements, depending on the desired effects. 

Figure 16-1. Molecular structures of caffeine (left), theophylline (center), and theobromine (right)...

One of a number of basic compounds found in living matter and having a purine-type molecular structure. See adenine base pair guanine hypoxanthine xanthine uric acid caffeine theobromine. 

The allosteric activators (like AMP) or inhibitors (like ATP, G6P, glucose or caffeine) can alter the equilibrium between a lower active T state to a more active R state or vice versa [4,10]. The molecular structures of T and R states of GP have been illustrated through the X-ray diffraction studies, which have shown that the conformational transformations take place following the commencement of the muscle enzyme and its translation from the T to R state by phosphorylation or AMP [4,11-15]. 

The molecular structures of alkaloids vary from simple to complex. Two common and relatively simple alkaloids are nicotine, which is found in tobacco, and caffeine, which is present in coffee and cola drinks ... 

Figure 4.4 From left to right, molecular structures of caffeine, succinic acid and 4-aminobenzoic acid.

Photoresponsive molecularly imprinted membranes are based on the ability of cis-trans isomers of the polymers which have azobenzene in their molecular structure to undergo conformational rearrangement reaction, a fact which can be speculated for controlled release applications. Two such systems were developed for the controlled release of caffeine, the first by using 4-[(4-methacryloyloxy) phenylazo]-benzoic acid as a functional monomer and trimethylolpropane trimethacrylate [63], and the second by using 4-[(4-methacryloyloxy) phenylazo] benzenesulfonic add as a functional monomer and N,N - hexylenebismethacrylamide as a crosslinker [64]. In the case of the first system, it was foimd that by irradiation at 365 nm for 120 min, 58% of the active substance is released (in the same time period, by exposine to 440 nm, 94% of the caffeine quantity is released), while for the second system, by irradiation at 353 nm for 120 min, 84% of the caffeine quantity is released (94% by irradiation at 440 nm for 90 min). 

Single-crystal X-ray diffraction and ultrahigh-field (21 T) solid-state C NMR were used to reveal new features of the molecular structure of caffeine. Two... 

Darenthin, molecular formula and structure, 5 96t Dark chocolate, 6 361 minerals content, 6 371t theobromine and caffeine content, 6 367t tocopherols, 6 370t typical formulation, 6 362t Dark conductivity ( D), of a-Si H, 22 ... 

Tea leaves consist primarily of cellulose this is the principle structural material of all plant cells. Fortunately, the cellulose is insoluble in water, so that by using a hot water extraction, more soluble caffeine can be separated. Also dissolved in water are complex substances called tannins. These are colored phenolic compounds of high molecular weight (500 to 3000) that have acidic behavior. If a basic salt such as Na2C03 is added to the water solution, the tannins can react to form a salt. These salts are insoluble in organic solvents, such as chloroform or dichloromethane, but are soluble in water. 

The modes of action of different alkaloids are diverse. For example, nicotine binds to and affects nicotinic acetylcholine receptors and shows toxicity. A recent molecular 3D model suggests that both acetylcholine and nicotine bind to the same pocket formed in a nicotinic acetylcholine receptor.15 Morphine binds to and activates opioid receptors, transmembrane-spanning G protein-coupled receptors, in the central nervous system of humans.16 Caffeine, which is structurally similar to adenine, inhibits cyclic AMP phosphodiesterase activity and inhibits the degradation of cAMP, thus exerting a toxic effect on insects 17 in human beings, binding of caffeine to the adenosine A2A receptor induces wakefulness.18 Atropine binds to muscarinic acetylcholine receptors, competing with acetylcholine, and blocks neurotransmission.1... 

Co is available as an isomorphous replacement for Fe in haems (cobaltmyoglobin, for example, still binds oxygen) and structural information has been obtained about cobalt porphyrin molecular complexes with steroids [89] and caffeine [90] in solution. 

Ghosh, M. Basak, A.K. Mazumdar, S.K. Structure and conformation of the 1 1 molecular complex of sulfaproxy-line-caffeine. Acta Crystallogr. 1991, C47, 577-580. 

The first example, depicted in Fig. 6, describes the synthesis and evaluation of a polymer imprinted with the bronchodilating drug theophylline, which is used in the treatment of asthma. Originally published in the journal Nature [2], this work drew considerable attention to the field of molecular imprinting because it was the first study to show that an MIP could be substituted for a natural antibody in a standard clinical assay. The MIP and antibody-based assays exhibit similar selectivities, and both can discriminate between theophylline and structurally related compounds. An equilibrium binding assay is described which uses radiolabeled theophylline as a marker. Data are presented for which nonradioactive theophylline, caffeine, and theobromine are used in competitive binding assays. These assays provide valuable information about the capacity and selectivity of the MIP. 

It is known that structurally diverse low-molecular weight compounds modulate the calcium conductance of ryanodine-sensitive calcium release channels (RyR) in mammals. For example, methylxanthines such as caffeine induce RyR-mediated Ca release from the sarcoplasmic reticulum and decrease the apparent dissociation constant of ryanodine ( /7J. 

Fig. 2.36 The coffee shrub and its berries, cocoa beans and tea flowers. Shown below are the 3D molecular models of caffeine, theobromine and theophylline. The difference between the chemical structures is the number and position of methyl groups (highlighted by dark shacMng). (Authors own work and copyright-free pictures from the book Bessette, Alan E., Chapman, William K. (eds.) Plants and flowers. 1761 Illustrations for artists and designers. Dover Publications, Inc., New York, 1992)...

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