Applied Chemistry

Chemistry of natural product has contributed significantly towards the improvement of modern medicine. Custard apple (Annona squamosa ) is a nutritional rich fruit and is largely valued for its taste. It is known to have some active ingredients which kills lung, colon, breast and pancreatic cancer cells. Therefore, consumption of this fruit is known to have aided in anti-cancer activities. The investigation is carried out to find the chemical composition, phytochemical analysis and evaluation of crust, pulp and the seed of custard apple. The chemical characteristics such as pH, titratable acidity, total sugar and lipids are also verified. The results revealed that seed, pulp and crust contains adequate amount of vitamin C, citric acid, carbohydrate, protein etc. The phytochemical analysis revealed that custard apple contains tannins, flavonoids, cardiac glycosides and steroids. Standard GC analysis of seed oils contain certain types of essential oils which are mainly aiding in anti-inflammatory, anti-cancer and anti-microbial properties. The antioxidant activity is evaluated using DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) assay. The presence of anthocyanins may also offer anti-cancer, anti-inflammatory and anti-viral benefits of custard apple.

Abstract The development of nanotechnology is making the interest of researchers towards the synthesis of nanoparticles for the bioapplication. Metal oxides such as ZnO have received increasing attention as antibacterial materials in recent years because of their stability under harsh processing conditions, and also because they are generally regarded as safe materials for human beings and animals. Zinc activates 300 enzymes, and it plays a role in many another phenomenons like growth, membrane stability, bone mineralization, tissue growth, and repair, wound healing and cell signaling. Many studies have shown that ZnO nanoparticles have enhanced antibacterial activity. Use of plant and plant materials for the synthesis of Zinc nanoparticles is relatively new and exciting research field. Various plants were used for the synthesis of nanoparticles using green synthesis method

The present maniscrupt aimed to improve the castable refractory castable concretes. Thus, kaolin-based refractory castables investigated were carefully prepared. They are composed of 90 wt. % well-graded (coarse, medium, and fine) kaolin aggregate, 10 wt. % binding matrix and adequate amount of distilled water. The binder mixture was calcium aluminate cement (CAC) containing 80 % Alumina and magnesium-aluminate spinel (MA- spinel) or mullite either preformed or insitu. The castable batches were cast into cubes (25 x 25 x 25 mm), cured for 7 days under water, and followed by drying at 110ºC for 24 hrs. The samples were then subjected to firing at 1550°C for a soaking time of 1 hr. The phase composition of the prepared castable samples were investigated by using X-Ray diffraction (XRD) analysis, scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, differential thermal analysis (DTA) and thermal gravimetric analysis (TGA). Results of these investigations confirm each other.

In the present work, the building waste material Red Kotta was treated with sulphuric acid and formaldehyde and used as an adsorbent for the removal of Methylene red from aqueous solution. The adsorption characteristics of Methylene red dye on untreated and treated Red Kotta powder was evaluated as a function of pH, adsorbent dose, initial concentration of adsorbate, contact time and temperature. The effective adsorption was found to be in pH range 2 to7, adsorbent dose 1gm to 5 gm, initial concentration (100ppm to 500ppm) and temperature range (283K to 313K). The results show that Red Kotta powder holds a great potential in removal of Methylene red dye from industrial wastewater.

New vanillin Schiff bases (A1-A6) have been prepared. The Schiff bases were synthesized via condensation of vanillin with various substituted anilines. Compounds A1-A4 came out as crystals of different colours while A5-A6 were obtained as thick viscous liquid. The organic compounds were characterized by IR spectra, UV/Visible spectra and melting points measurements. Purity of the new compounds was revealed by their sharp melting points. The coordination feasibility of the compounds was tested using compound A1 with Zn2+, Cu2+, Co2+ and Ni2+ salts.

New VO(IV), Mn(II), Co(II) and Ni(II) complexes of the Schiff bases, 2-[(2,3-dihydro-1H-inden-4-ylimino)methyl]-5-nitrophenol (HL1) and 3-[2,4-dihydro-1H-inden-4-ylimino) methyl]napthalen-2-ol (HL2) have been synthesized and characterized by elemental analysis, molar conductance, infrared and electronic spectral measurements. The purity of the ligands is confirmed by microanalyses and 1HNMR. The IR spectra show that the ligands are bidentate coordinating via azomethine N and napthalenol/phenol O atoms, and the metal complexes of HL1 exhibit geometric isomerism being in the Cis-form with a lone vC=N band. The metal complexes all assume a 4-coordinate tetrahedral/square planar geometry with exception of the VO(IV) complex which is 5-coordinate square-pyramidal as corroborated by electronic spectra. None is an electrolyte in nitromethane. The Schiff base, HL2, and its metal complexes have higher molar absorptivities of the ligand bands than HL1 and its metal complexes; due to a closer metal to ligand overlap, a consequence of extended conjugation in the naphthalene ring. The in-vitro antibacterial activities of these complexes and their Schiff bases against Staphylococcus aureus, Bacillus cereus, Escherichia coli, Proteus mirabilis, Klebsiella oxytoca and Pseudomonas aeruginosa shows that HL1 and its metal complexes are more active than HL2 and its metal complexes, and the latter compounds have selective inactivity against Bacillus cereus and Klebsiella oxytoca. It is note worthy that [CoL1]2 exhibited broad-spectrum antibacterial activity like the antibiotic ciprofloxacin (26.0-30.5 mm), although with smaller inhibitory zones in the range 12.5-17.0 mm.

Corrosion inhibition of ethanol stem extract of Costus lucanusianus (ESECL) was studied on mild steel and aluminium by weight loss method. The constituents of the extract identified by Gas Chromatography-Mass Spectroscopy (GC-MS) were forty one (41) compounds with 13-Octadecenal, (Z)-(14.39 %) and 9-Octadecenoic acid, 12-hydroxy-, methyl ester, [R-(Z)]- (11.49 %) as the major compounds. Weight loss method revealed that as the concentration of inhibitor increased, the corrosion rate decreased and inhibition efficiency increased. Maximum corrosion inhibition efficiencies of 91% and 85% were obtained in 1 g/l concentration at low temperatures for mild steel and aluminium, respectively. The adsorption followed physisorption mechanism. Positive values of ?H suggested that the process was endothermic, and negative values of ?S suggested a decrease in the disorderliness of the system from thermodynamic approach. The adsorption model showed that Freundlich adsorption isotherm was the best fit for the process.

Studies were carried out to evaluate the effect of post harvest processing conditions on yield and quality of Curcuma longa (L.) rhizomes infusettes. A material balance was determined for four production processes including or not peeling and blanching. Sliced and dried rhizomes were packaged on tea bags and the products quality was monitored using reference methods. Production yields ranged from 38.39 to 76.87% with higher values obtained from unpeeled and blanched rhizomes. The moisture content varyed from 3.15 to 3.75 % m/m with a significant difference (P< 0.05) between the peeled and blanched samples which got lower values compared to the others. Microbiological analyses revealed that all samples were of satisfactory quality. Phytochemical screening showed that the presence or absence of metabolites was not influenced by these processing conditions. Peel removal caused mass loss of 33% without blanching but the tea bags obtained from this process had higher intensity of yellow-orange color. Peeling, blanching and drying were operations that affect not only the yield but also the quality of Curcuma longa (L.) rhizomes infusettes.

Coal is the major source of electricity in South Africa and a large volume of coal fly ash waste is generated by the thermal fired power stations which have become a serious environmental issue because of the problem of the disposal. The aim of this research is to assess the quality and beneficiation of the coal fly ash samples. The fly ash sample was characterized using analytical techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The morphology of the fly ash is spherical and the XRD identified mullite, gypsum, magnetite, lime, quartz and hematite mineral phases. The elemental composition of the fly ash using XRF containing major elements: SiO2, Al2O3, Fe2O3, CaO, while the minor elements are P2O5, SO3, MgO, NaO, TiO2, and V2O5. The result shows that the coal fly ash sample is class C ash with high pozzolanic properties that is suitable to be used for making concrete or cement.

Two simple and sensitive spectrophotometric methods (Method A& Method B) in the visible region have been developed for determination of Entacapone in bulk and pharmaceutical formulations. Method A is based on Oxidation of Entacapone with Fe(III) under controlled experimental conditions followed by complex formation between Fe(II) and bathophenanthroline to give red colored complex which can be measured at 535 nm. Method B (p-nitroaniline) is based on electrophilic aromatic substitution to form brown colored complex which can be measured at 470 nm. The color obeyed Beer’s law in the concentration range of 2-10 ?g/ml for Method A and 10-50 ?g/ml for Method B respectively. When Pharmaceutical formulations (Tablets) containing Entacapone were analyzed, the results obtained by proposed methods are in good agreement with labeled amounts. Recovery in both methods was 98%-102%.