Anti-oxidative action of resveratrol: Implications for human health

Resveratrol, the red-wine polyphenol, is intensively studied polyphenols for its pleiotropic biological effects. A plethora of health beneficial effects of this stilbene has been reported including cardio-protective, neuro-protective, anti-cancer, anti-diabetic and interesting anti-aging. Though it has been proposed that these effects of resveratrol arise from its capacity to interact with multiple molecular targets involved in diverse intracellular pathways including activation of sirtuins, the antioxidant property of this compound is the most described one to attribute its diverse health beneficial effects. In the present review we have explained the biological activities of resveratrol with the latest laboratory evidences towards its antioxidant effects.     

Trichloroisocyanuric acid (TCCA) and carboxamide interactions in TCCA/NaNO2 triggered nitration of pyrrole and indole in aqueous aprotic media: A kinetic correlation of solvent properties with reactivity

This study deals with the trichloroisocyanuric acid (TCCA) interactions with carboxamides like formamide (FMA), N,N′‐dimethyl formamide (DMF), and N,N′‐dimethyl acetamide (DMA) interactions during the nitration of heterocyclic compounds (HC) like pyrrole and indole in the presence of excess of [NaNO₂] over the concentrations of all other reactants. All the reactions were performed in aqueous acetonitrile media containing carboxamide under acid‐free conditions. Kinetics of the reactions revealed first order in [nitrating agent] and [HC] under otherwise similar conditions. To gain an insight into the reactive species and role of added carboxamide (FAA, DMF, DMA, etc.), the observed rates of the nitration reaction (log k) were analyzed as a function of (1/D), ([D ? 1]/[2D + 1]), mole fraction (n_x), and volume (%) of carboxamide, 1/viscosity, density refractive index function), and Hildebrand solubility parameter plots. Linear regression analysis gave very good correlation coefficients (R² values), which indicate the importance of several solvent properties in addition to the role of dielectric constant (D) of the reaction media. Multiple linear solvent energy relationships suggested by Abraham, Koppel, Palm, and Taft also afforded very good correlation coefficient (R² values), showing the importance of cumulative effect of solvent properties. Besides these features, the negative entropies of activation (?S^#) suggest greater solvation in the transition state. Isokinetic temperature (β) values for different protocols were very close to the experimental temperature range (303‐323 K), indicating the importance of both enthalpy and entropy factors in controlling the reaction.     

Hydrogen bonds and polymerization in acrylamide under pressure

Acrylamide (C₃H₅NO), a hydrogen‐bonded amide, is an important compound from the point of view of basic and material research. It can be used as a model system for studying hydrogen bonding interactions in amides under pressure. As it is a monomer of polyacrylamide, an important polymer, high pressure investigation of polymerization in this material is also of interest. Our in‐situ high pressure Raman spectroscopic investigations of acrylamide carried out up to 17 GPa under quasi‐hydrostatic conditions indicate possible structural variations through the reconstruction of the N‐H‐‐‐O hydrogen bonds at pressures above 2.6 GPa. Emergence of several new spectral features at higher pressures indicate onset of polymerization. The characteristic polymer band becomes discernible at ~17 GPa. The increase in the relative intensity of the polymer peaks with respect to the monomer peaks on release to ambient conditions suggests that higher fraction of polymer is obtained on decompression. Copyright © 2013 John Wiley & Sons, Ltd.     

Ferric reducing, antiradical and beta-carotene bleaching activities of nicotinic acid and picolinic acid bioconjugates of curcumin

Although curcumin displays several beneficial properties, its medicinal use is limited by its low bioavailability. In the present study we report the antioxidant potentials of two bioconjugates of curcumin with nicotinic acid and picolinic acid: di-O-nicotinoyl curcumin [1,7-bis (4-O nicotinoyl-3-methoxyphenyl)-1,6-heptadiene-3, 5-dione] and di-O-picolinoyl curcumin [1,7-bis (4-O-picolinoyl-3-methoxyphenyl)-1,6-heptadiene-3, 5-dione], in terms of ferric reducing, radical scavenging and beta-carotene bleaching abilities, and comparing the observed activity with that of curcumin. Results demonstrate that both the bioconjugates possess higher antioxidant potentials as evidenced by enhanced ferric reducing, radical scavenging and beta-carotene bleaching abilities, in comparison with curcumin. On the basis of our results we conclude that these bioconjugates of curcumin may be better than curcumin for medicinal and pharmacological applications.     

Dialkyl bicyclic heterocycles with a bridgehead nitrogen as purine analogs possessing significant cardiac inotropic activity

A number of 5,7-dialkyl-s-triazolo[1,5-a]pyrimidines and 5,7-dialkylpyrazolo[1,5-a]pyrimidines and related heterocycles containing a bridgehead nitrogen have been prepared and studied as cardiovascular agents in the anesthetized dog. A number of these compounds have exhibited significant inotropic activity with little effect on heart rate. Especially active were 5,7-dialkyl-2-amino or 2-alkylthio-s-triazolo[1,5-a]pyrimidines. In contrast, highly polar purine analogs in these ring systems compounds such as 5,7-di-n-propyl-2-benzylthio-1,3,4-thiadiazolo[3,2-a]pyrimidine bromide 45 containing a charge on the bridgehead nitrogen, were inactive. The detailed structure activity relationship of the dialkyl derivatives of related ring systems are discussed. The presence of certain ring nitrogen atoms are vital to potent in vivo activity, presumably due to specific enzyme binding at these sites. Several of the compounds studied, showed oral activity and are excellent can-diates for further evaluation in man.     

Dispersion of Polymers in Metallic Gallium

This work examines the concept of dispersing polymers in metals. Herein, this was mainly studied with molten gallium, in which 5‐18 wt % of various short‐chain polymers were incorporated and mixed. The nature of the solidified products was examined by using X‐ray diffraction, electron microscopy, UV/Vis, differential scanning calorimetry, and thermal gravimetric analyses. It was found that some polymers can be dispersed as small domains within molten metals to form a heterogeneous solid. The ability to dope Ga with large polymers opens a new avenue to electronic materials.