Current Perspectives on Chemical Sciences Vol. 11

Various bioactive compounds were extensively found at different levels in many medicinal plants. This study mainly focuses on identification and separation of antioxidants from the different extract of leaves of Melia dubia. Soxhlet extraction was adopted for extraction using solvents namely hexane, chloroform, ethyl acetate, methanol, water and 70% ethanol. Anti-oxidant capacity of six extracts was analyzed by quick and convenient DPPH method. Extracts which possess high scavenging activity were taken for separation and are achieved by chromatographic techniques, then, characterized by spectral methods. Compound owing highest antioxidant efficacy were tested for its inhibitory potential against Urolithiatic activity via In-silico and In-vitro analysis. On antioxidant activity the methanol and 70% ethanol extracts revealed greater antioxidant potential from which two antioxidants were isolated and characterized namely MDL-1 and MDL-2. The antioxidant MDL-1 exhibited highest scavenging potential than MDL-2 and its antiurolithiatic potentials were confirmed with molecular docking (In-silico) as well as single diffusion gel method (In-vitro).

A smallest amount of petrol adulterated with kerosene can cause adverse effect on the functioning of a vehicle engine. In this work, a simple, low cost, sensitive and miniature sensor based on fiber optic coupler and an optoelectronic detection system is developed. The sensor is modeled and simulated. It is found that the present sensor is capable of detecting less than 5 percent of kerosene adulteration in petrol. It is capable of detecting 1 percent variation in the adulteration. The sensor has micrometer dimension.

Ti-doped zinc oxide and pure zinc oxide nanoparticles were synthesized by a modified oxalate route using Averrhoa carambola fruit juice as a natural source of oxalate. The characteristics of the precursors have been investigated by FTIR, TGA, and XRD. The results from the investigation revealed that the precursors are zinc oxalate and Ti-doped zinc oxalate which readily decompose at 450°C. The as-prepared precursors were calcined at 450°C for 4 hours, and the decomposition products have been characterized by XRD, SEM, EDX, and VSM. XRD results revealed crystallinity with hexagonal wurtzite structure, while the average grain size was found to be 26 nm for Ti-doped ZnO and 29 nm for ZnO, using calculations based on Debye-Scherrer equation. Furthermore, the morphological studies by SEM showed particle agglomeration, while the presence of Ti³⁺ in the zinc oxide lattice is indicated by EDS analysis. Finally the hysteresis loop from VSM results shows that Ti-doped ZnO exhibits ferromagnetism. The precursors were identified as the expected metal oxalates, and the decomposition products were found to be pure ferromagnetic nanoparticles.  

The solvents used in chemistry are a fundamental element of the environmental performance of processes in corporate and academic laboratories. Their influence on costs, health safety, and nature cannot be neglected. Quantitatively, solvents are the most abundant constituents of chemical transformations; therefore, acting on solvents and replacing standard solvents with safer products can have a great ecological impact. However, not all green solvents are suitable for the wide scope of organic chemistry reactions. A second point to consider is that 50% of pharmaceutical drugs are nitrogen heterocycles compounds. It therefore appeared important to provide an overview of the more ecological methodologies for synthesizing this class of compounds. In this review, all publications since 2000 that describe green reactions leading to the formation of nitrogen heterocycles using safe solvents were considered. We chose water, PEG, and bio-based solvents for their negligible toxicity. The synthesis of five-, six-, and seven-membered aromatic nitrogen heterocycles using green reactions reported in the literature to date is described. We describe biologically based solvents that have been reported as valid alternatives in the synthesis of N-heterocycles, which are; Meglumine, Gluconic acid, Ethyl lactate and Lactic acid.

Quantitative indication of a complex formation comes from the estimation of the stability or formation constants characterizing the equilibria corresponding to the successive addition of ligands.  Paper ionophoresis is used for the study of equilibria in binary complex systems in solution. This method is based on the movement of a spot of metal ion in an electric field at various pH of background electrolyte. A graph of pH versus mobility was used to obtain information on the binary complexes and to calculate its stability constants. At an ionic strength of 0.1 M and 35ºC, the stability constants of ML and ML₂ complex species of certain metal ions copper(II), manganese(II), and uranyl(II) with - $\alpha$-Aminobutenoic acid and hydroxyproline were determined. The stability constants of ML and ML₂ complex species of metal(II)-$\alpha$-aminobutenoic acid and metal(II)– hydroxyproline were found to be [(7.70 ± 0.03, 6.38 ± 0.11), (3.19 ± 0.02, 2.07 ± 0.09), (7.32 ± 0.05, 5.49 ± 0.12)] and [(8.23 ± 0.05, 7.05 ± 0.03), (3.74 ± 0.06, 3.15 ± 0.09), (7.39 ± 0.11, 6.67 ± 0.02)] for copper(II), manganese(II) and uranyl(II) complexes, respectively. The present paper electrophoretic technique has proved to be useful in deciding whether a complex system is formed or not, and if it is formed its stability constants can also be determined.

This work is Unrestricted Hartree Fock (UHF) quantum mechanical calculations of proton transfer and reaction path of (O-R) bond rupture energies in nine cefpodoxime prodrug derivatives of different substituted organic groups, at their optimize geometries. The calculation included geometrical structure, some of physical properties such as standard heat of formation, dipole moment and total energies, using Gaussian-09 program. Comparison was done between the total energies of the reactants, activation energies, transition states and end products. All the calculations are reported in the vacuum phase. The results showed that some of the substituted organic groups can be used as carrier linkages for the acidic cefpodoxime drug. The calculations revealed that using a quantum mechanics account to assess the organic groups can be substituted in drug derivatives as drug-related carrier groups and used as treatment drugs is a strong possibility.

Carbon fiber-carbon microcoil (CF-CMC) hybrids were formed on carbon fiber (CF)-based fabrics using thermal chemical vapor deposition system. For the CF-based nonwoven fabrics (c-NFs), the shielding effectiveness (SE) values were improved by the CF-CMC hybridization reaction, although the electrical conductivities of the nonwoven fabric were reduced by the CF-CMC hybrid formation. For the CF-based woven fabrics (c-WFs), the SE values were improved by more than twofold throughout the entire range of frequencies, owing to the CF-CMC hybrid formation. This dramatic improvement was partly ascribed to the enhanced electrical conductivity, particularly in the transverse direction to the individual CFs. Because the c-NFs consist of randomly oriented carbon fibers, the SE values of the samples based on c-NFs are higher than those of the samples based on c-WFs. For c-NFs, H₂ plasma treatment was performed on c-NFs to improve the SE values. Consequently, the SE values of the c-NFs was significantly enhanced across the operating frequency range of 0.04 to 20.0 GHz. We compared the SE values of the H₂ plasma-treated c-NFs samples with those of the c-NFs samples coated with nano-sized Ag particles. Despite having a lower surface electrical conductivity, H₂ plasma-treated c-NFs samples exhibited a considerably higher SE than the Ag-coated c-NFs samples did, across the relatively high operating frequency range of 7.0 to 20.0 GHz. The carbon component of H₂ plasma-treated c-NFs samples increased significantly compared with the oxygen component. The H₂ plasma treatment transformed the alcohol-type (C-O-H) compounds formed by carbon-oxygen bonds on the surface of the native c-NFs samples into ether-type (C-O-C) compounds. Based on these results, we proposed a mechanism to explain the SE enhancement observed in H₂ plasma-treated c-NFs.

Excellent wound dressing is essential for effective wound repair and regeneration. This chapter aims to evaluate the effectiveness of bacterial cellulose (BC) and type I collagen (COL) scaffolds conjugated with resveratrol (RSV) for wound management. BC and COL are biodegradable and renewable attractive polymers for medical applications which has a strong affinity for materials containing hydroxyl groups, meanwhile RSV has a 4'-hydroxyl group and exhibits good biocompatibility and no cytotoxicity. The results demonstrated that RSV was effectively released from the BC and COL scaffolds in vitro, and immunofluorescence staining showed that both scaffolds were highly biocompatible and regenerated epithelia. Additionally, Masson’s trichrome staining showed that the both scaffolds preserved the normal collagen-bundling pattern and induced re-epithelialization in defective rat epidermis. These results indicate that RSV-conjugated BC or COL scaffold created a biocompatible environment for stem cell attachment and growth and promoted epithelial regeneration during wound healing.

Industrial processes and used commercial (metallic) products generate large quantity of metallic waste products which are discharged into the water or land-dump sites. It has been estimated that the toxicity due to metallic discharge, into the environments far exceeds the combined total toxicity of all radioactive and organic wastes. The extent to which metals and their compounds are used in industrial operations cannot be overemphasized. Meanwhile, effluents from the industrial operations contain some heavy metal ions which are reported to be harmful to human and plant health when the effluents are discharged untreated into the environment. Therefore the need to remove heavy metal ions from industrial effluents before discharging becomes indispensable. The removal /adsorption of lead (II) ion and cadmium (II) ion from their aqueous solution by Cola nitida pod were investigated. The effects of contact time, initial metal ion concentration, initial pH, adsorbent dose and temperature on metal ions removal were studied, in contact time range of 15- 90 minutes, metal ions initial concentration range of 50- 200 mg/l. pH range of 5-8, adsorbent dose range of 0.1- 0.7 g and temperature range of 303-333 K. The equilibrium time was found to be of the order of 60 minutes. Percentage removal of both Pb²⁺ and Cd²⁺ from their aqueous solution by the adsorbent (Cola nitida pod) was found to be above 90%. The percentage removal of lead (II) ion and cadmium (II) ion by the test adsorbent was affected by changes in initial metal ion concentration, initial pH, adsorbent dose, and temperature. Langmuir and Freundlich adsorption isotherms were used to examine the adsorption mechanisms of the metal ions on the test adsorbent, and the adsorption of both Pb²⁺ and Cd²⁺ on Cola nitida pod fitted perfectly into the adsorption isotherms. The comparison of correlation coefficients values (R²) of the linearized form of both Langmuir and Freundlich models shows that the Langmuir model yields a better fit for the experimental adsorption equilibrium data and the most appropriate isotherm to describe the equilibrium data for lead and cadmium and hence Langmuir adsorption is recommended for the adsorption studies of Pb²⁺ and Cd²⁺. The comparison of correlation coefficients values (R2) of the linearized form of both Langmuir and Freundlich models shows that the Langmuir model yields a better fit for the experimental adsorption equilibrium data and the most appropriate isotherm to describe the equilibrium data for lead and cadmium.

This study was based on current efforts and breakthroughs in customising nano-scale structures of nanostructured conducting polymer materials to improve electrical characteristics, as given in the reviews. The goal of this research is to investigate the a.c electrical response of a PANI/FeNP/Graphene composite made in-situ with adhathodavasica plant extract in an ice-cold bath. Techniques such as FT-IR and SEM were used to characterise the samples.  The AC conductivity measurements were performed in the frequency range 5x10¹–5x10⁶ Hz at 298K with an HIOKI 3532-50 LCR Hi-tester. The layered structure of graphene nanosheets in the composite is depicted in SEM photographs. The homogeneous distribution of iron nanoparticles throughout the PANI matrix, as well as imine stretching frequency, are attributes of IR spectral data. The investigation of a.c conductivity provides evidence for the composites' transport properties. With a stepwise increase in graphene content in the PANI/FeNP/Graphene composites, AC conductivity values increase.