Interaction of pharmacologically important anticancer drug cytosine β-D arabinofuranoside with human serum albumin (HSA) at physiological pH 7.4 has been studied by utilizing various spectroscopic and molecular docking strategies. Fluorescence results revealed that cytosine β-D arabinofuranoside interacts with HSA through static quenching mechanism with binding affinity of 2.4×103 M−1. The average binding distance between drug and Trp214 of HSA was found to be 2.23 nm on the basis of the theory of Förster's energy transfer. Synchronous fluorescence data indicated that interaction of drug with HSA changed the microenvironment around the tryptophan residue. UV–visible spectroscopy and circular dichroism results deciphered the complex formation and conformational alterations in the HSA respectively. Dynamic light scattering was utilized to understand the topology of protein in absence and presence of drug. Thermodynamic parameters obtained from isothermal titration calorimetry (ΔH=−26.01 kJ mol−1 and TΔS=6.5 kJ mol−1) suggested the involvement of van der Waal interaction and hydrogen bonding. Molecular docking and displacement study with site specific markers suggested that cytosine β-D arabinofuranoside binds to subdomain IB of HSA which is also known as the hemin binding site. This study will be helpful to understand the binding mechanism of cytosine β-D arabinofuranoside with HSA and associated alterations.

Protein aggregation is associated with many serious diseases including Parkinson's and Alzheimer's. Protein aggregation is a primary problem related with the health of industrial workers who work with the surfactants, metal ions, and cosolvents. We have synthesized rosin-based surfactants, i.e., quaternary amines of rosin diethylaminoethyl esters (QRMAE), which is an ester of rosin acid with polyethylene glycol monomethyl ether. Here, we report the thermal aggregation of lysozyme induced by QRMAE at 65°C and pH 7.4 for a given time period in which amorphous aggregates are formed and confirm that copper-nanoparticles have the ability to inhibit QRMAE-induced aggregation compared with zinc and silver-nanoparticles. Aggregation experiments was evaluated using several spectroscopic methods and dye binding assay, such as turbidity, Rayleigh light scattering, 1-anilino-8-naphthalene sulfonate (ANS), Thioflavin T (Th T), congo red (CR) and circular dichroism (CD), that was further supported by scanning electron microscopy (SEM) and SEM with EDX. The therapeutic use of nanoparticles and the fact that rosin possesses excellent film-forming properties, and that its derivatives have pharmaceuticals application such as micro encapsulation, coating and film forming, it's matrix materials are used for sustained and controlled release tablets, renders importance and application to the present study. Copyright © 2015 Elsevier B.V. All rights reserved.

Abstract.An electrochemical anodic stripping proce-dure for ultra-trace assay of xanthine in Cu 2þ solution at a glassy carbon electrode (GCE) is described. Cyclic voltammetry was used to characterize the nature of the process taking place at the GCE. The anodic stripping response in the presence of Cu 2þ , at 150 mV (peak I) and 600 mV (peak II), is evaluated with respect to various experimental and instrumental conditions. Voltammetric studies show that the mechanism of the overall reaction is similar to that of the oxidation of purine derivatives at a pyrolytic graphite electrode. It is found that the copper metal deposited onto the GCE was oxidized to Cu þ at around 180 mVvs. Ag=AgCl and the generated Cu þ reacted with xanthine to accumulate on the GCE as an insoluble compound. The Cu þ -xanthine compound accumulated on the GCE was redissolved by the oxidation of Cu þ to Cu 2þ at ca. 150 mV, and the concentration of xanthine in the vicin-ity of the GCE increased. The results enabled us to use the measurement of the oxidation peak current as the basis of a simple, accurate and rapid method of deter-mining xanthine within a concentration range of 19.9 to 166 nM for peak (I) and 0.24 to 17.2mM for peak (II). Promising results were obtained for xanthine determination by using an external mixing step prior to stripping measurements, which yielded a detection limit of 0.138mgL 1 (9.110 10 M) xanthine. The effect of some interferences (e.g. purine compounds, amino acids and some metal ions) was considered

Abstract.An electrochemical anodic stripping proce-dure for ultra-trace assay of xanthine in Cu 2þ solution at a glassy carbon electrode (GCE) is described. Cyclic voltammetry was used to characterize the nature of the process taking place at the GCE. The anodic stripping response in the presence of Cu 2þ , at 150 mV (peak I) and 600 mV (peak II), is evaluated with respect to various experimental and instrumental conditions. Voltammetric studies show that the mechanism of the overall reaction is similar to that of the oxidation of purine derivatives at a pyrolytic graphite electrode. It is found that the copper metal deposited onto the GCE was oxidized to Cu þ at around 180 mVvs. Ag=AgCl and the generated Cu þ reacted with xanthine to accumulate on the GCE as an insoluble compound. The Cu þ -xanthine compound accumulated on the GCE was redissolved by the oxidation of Cu þ to Cu 2þ at ca. 150 mV, and the concentration of xanthine in the vicin-ity of the GCE increased. The results enabled us to use the measurement of the oxidation peak current as the basis of a simple, accurate and rapid method of deter-mining xanthine within a concentration range of 19.9 to 166 nM for peak (I) and 0.24 to 17.2mM for peak (II). Promising results were obtained for xanthine determination by using an external mixing step prior to stripping measurements, which yielded a detection limit of 0.138mgL 1 (9.110 10 M) xanthine. The effect of some interferences (e.g. purine compounds, amino acids and some metal ions) was considered

Abstract.An electrochemical anodic stripping proce-dure for ultra-trace assay of xanthine in Cu 2þ solution at a glassy carbon electrode (GCE) is described. Cyclic voltammetry was used to characterize the nature of the process taking place at the GCE. The anodic stripping response in the presence of Cu 2þ , at 150 mV (peak I) and 600 mV (peak II), is evaluated with respect to various experimental and instrumental conditions. Voltammetric studies show that the mechanism of the overall reaction is similar to that of the oxidation of purine derivatives at a pyrolytic graphite electrode. It is found that the copper metal deposited onto the GCE was oxidized to Cu þ at around 180 mVvs. Ag=AgCl and the generated Cu þ reacted with xanthine to accumulate on the GCE as an insoluble compound. The Cu þ -xanthine compound accumulated on the GCE was redissolved by the oxidation of Cu þ to Cu 2þ at ca. 150 mV, and the concentration of xanthine in the vicin-ity of the GCE increased. The results enabled us to use the measurement of the oxidation peak current as the basis of a simple, accurate and rapid method of deter-mining xanthine within a concentration range of 19.9 to 166 nM for peak (I) and 0.24 to 17.2mM for peak (II). Promising results were obtained for xanthine determination by using an external mixing step prior to stripping measurements, which yielded a detection limit of 0.138mgL 1 (9.110 10 M) xanthine. The effect of some interferences (e.g. purine compounds, amino acids and some metal ions) was considered