Applied Chemistry

The inhibition efficiency of coffee husk extract and extract of Ziziphusspina Christi on the corrosion of aluminum in 0.5 M NaOH solutions was investigated using weight loss method at 25 and 45°C. Surface was examined using energy dispersive X-ray analysis (EDX), and scanning electron microscopy (SEM). Experimental investigations showed that coffee husk extract and Ziziphusspina Christi extract reduce the corrosion of aluminum in 0.5M NaOH solutions. The inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. The adsorption of two extracts on the aluminum surface was found to obey Langmuir, Temkin and thermodynamic/kinetic model of adsorption isotherms. The obtained results are consistent with physisorption adsorption.

The ligand, 2-methyl-1,3-oxazole-4-carbaldehyde thiosemicarbazone (HL) was synthesized by reacting equimolar amounts of thiosemicarbazide with the corresponding aldehyde. The synthesized ligand was reacted with Ni(II) and Co(II) chlorides in the 2:1 mole ratio of ligand: metal. These led to the isolation of two new complexes, namely [Ni(HL)2]Cl2 (1), [Co(L)2].1.3Cl (2), the ligand and its metal(II) complexes were characterized by elemental analysis, IR, 1H NMR, 13C NMR spectroscopic methods, UV-Vis spectrophotometry and X-ray diffraction. The X-ray structural studies of the ligand and their corresponding metal complexes 1, 2 revealed that: The free ligand exist in the thione form and remain as neutral tridentate with NNS donor atoms in the complex (1) but in the complex (2) the HL acted as uninegative tridentate ligand, beside Presence of uncoordinated chloride ions in the cavities of the crystal lattice of the complex (2). One of these chlorides is hydrogen bonded to a proton of the amine of the ligand. The coordination environment of Ni(II) and Co(II) metal complexes 1, 2, has a distorted octahedral structure. The oxazole N and S atoms in the two complexes are cis to each other whereas the azomethine N atoms are trans coordinated. The ligand and its metal complexes were tested for their in vitro biological activity against seven standard microorganisms: two Gram positive namely Bacillus subtilis and Micrococcus luteus, and one Gram negative bacteria Escherichia coli and four fungi: Saccharomyces cerevisiae (Baker’s yeast), Candida maltosa, Mucor spec., and Aspergillus niger, at a concentration 100µg/ml. The results showed that the ligand HL and its Ni(II) Co(II) complexes appear inhibition activity for Mucor spec. only.

The ligand 2,5-bis(phenylcarbamoyl)terephthalicacid (bpctpa) was synthesized and characterized. Novel co-ordination polymers were prepared by using ligand (bpctpa) and transition metal ions viz. Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). The co-ordination polymers and parent ligand were characterized by elemental analysis, spectral studies, thermogravimetry, number-average molecular weights ( ), diffuse reflectance spectral studies and magnetic susceptibilities. The biological activity of all the samples has also been monitored against plant pathogens.

Ni-Al₂O₃-Cr metal matrix hybrid composite coatings were developed in a conventional Watt electroplating solution, containing suspended nanoparticles of alumina and chromium. The characterization of the composite layer was carried out by scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Energy-dispersive X-ray spectroscopy (EDX) facilities. SEM, XRD and EDX studies showed that a novel hybrid Ni-Al₂O₃-Cr metal matrix composite (MMC) coating formed successfully on a pure copper substrate with about 11.5 % and 4.4 % vol. Al₂O₃ and Cr dispersed nanoparticles respectively. A texture modification and grain refinement were found in composite layers. The incorporation of nanoparticles of Al₂O₃ and Cr changed the preferential nickel growth orientation from (220) to the (200) plane. The SEM studies on the morphology of a Ni- Al₂O₃-Cr composite surface illustrated that the nickel column growth slowed down in the composite film and the composite coating had a more condensed and smoother surface compared to pure nickel coatings. The mean grain sizes of the pure nickel and composite coats were determined as 103 and 19 nm respectively. The SEM micrographs showed that the nano particles were uniformly dispersed in the electrodeposited nano-structured Ni matrix and the alumina particles agglomerated in sizes of above 100 nm. The micro-hardness and wear resistance test results showed a remarkable improvement in the mechanical properties of the electroplated nickel by creating a nano composite structure of Ni-Al₂O₃-Cr.

Previous studies have shown that the physiochemical properties of urine could change after ingestion of medicinal plants, and may provide significant clinical and diagnostic information. This study examined the urinary profile of healthy subjects who consumed Cymbopogon citratus (C. citratus) infusion. Urine samples were obtained from 105 participants at days 0, 10 and 30 after treatment with infusions prepared from 2, 4 and 8g of C. citratus powder. Biochemical analyses of the urine to determine its chemical constituents were performed using standard procedures. Results obtained on days 10 and 30 were compared with baseline values. UV and UF increased in all groups. Urinary excretion of some electrolytes (Na⁺ and K⁺) and DA increased at day 10 only, whereas others (Ca²⁺ and Cl^-) increased at both days 10 and 30. USG and colour remained unchanged. Urinary creatinine levels significantly increased (p<0.05) in all groups, whereas urinary urea significantly (p<0.05) increased in all groups except the group treated with 8g for 30 days. Urine uric acid and pH decreased in all groups. Urinary protein, glucose, bilirubin and bicarbonate were undetected. Ingestion of C. citratus infusion is associated with some physiochemical changes in urinary composition and could provide significant clinical information on the systemic effects of the plant in humans.

Chemical speciation and mobility factor indices of Pb, Cd, Zn and Mn were assessed in a crude oil contaminated soil and compared with control (uncontaminated) soil. The assessment was done to evaluate the impact of crude oil contamination on the bioavailability of metals in a soil matrix. Soil was collected in triplicate from four locations (three reflecting the crude oil impacted area and one uncontaminated soil as control). Soil was collected around a crude oil transfer pipeline within Bdere community in Ogoniland, Nigeria, within the month of August 2017. Fractional concentration of metals was determined using a GBC Avanta PM6600 atomic absorption spectrophotometer. In the oil contaminated soil, Zn (41.13%) and Mn (77.54%) were predominantly associated to the residual fractions while Pb (29.45%) and Cd (25.53%) were prevalent in the amorphous Fe-oxide and plant available fractions respectively. Similarly, the uncontaminated soil depicted the residual fractions of Zn (49.43%) and Mn (48.63%) to be the most important while Pb (56.17%) and Cd (62.16%) were both predominantly affiliated to plant available fractions. Heavy metal mobility factor indices reflected the order: (Zn>Cd>Pb>Mn) and (Cd>Mn>Zn>Pb) for crude oil impacted and uncontaminated soils respectively. Despite the prevalence of heavy metals to the inert fractions, the significant affiliation of metals to the readily mobile fractions of crude oil contaminated soil reflected the order: Pb (10.71%), Cd (25.53%), Zn (40.22%) and Mn (3.52%) which further suggested that these metals may have emanated from the introduction of crude oil into the soil matrix.

The chemical composition of the essential oils from the leaves of Acalypha hispida and Acalypha wilkesiana obtained by hydro distillation, were analyzed by Gas chromatography linked with Mass spectrometry. The main constituents of the essential oil from A. hispida were neral (11.04%), citral (12.87%), 6,10,14, trimethyl-2-pentadecanone (13.43%) and n-hexadecanoic acid (14.69%) while neral (30.66%) and citral (36.10%) which are monoterpenes were the major compounds in the oil of A. wilkesiana. The essential oils were tested for toxicity against brine shrimps larvae (Artemia salina) and showed LC50 values of 122.28µg/mL and 212µg/mL respectively while their activity against Anophelis gambiae reveal LC50 values of 125µg/mL and 83.33µg/mL respectively.

100 g of dried leaves of Mentha spicata produced 1.1% of volatile oil by hydro distillation method. GC-MS, method used to identified the chemical compound of the volatile oil, it contained eighteen compounds, ten of them constituted as the major compounds, carvone (58.3%), cis-carveol 14.99%), limonene (8.5%), carvyl acetate (3.10%), ?-pinene (1.22%), ß –Pinene (2.11%), Menthone (1.08%), Menthol (1.01%), ß- bourbonene (1.98) and trans-Caryophyllene (1.75). The spearmint volatile oil more actively against gram positive bacteria (Staphylococcus aurous and Bacillus cereus) than gram negative bacteria,( Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa and Salmonella typhimurium). The activity of antibiotic Chloramphenicol, Ciprofloxacin, Tetracycline Ceftriaxone, and Gentamycin against bacteria found differences inhibition zoon. Among all antibiotic. ciprofloxacin have more activity against bacteria while Ceftriaxone have the lower activity.

Azanza garckeana is a wild edible indigenous fruit tree species in western Sudan locally named (Jakhjakh). The physiochemical and analytical study of Azanza garckeana fruit, physical parameters of fruits determined length ranges 2.52 – 3.52 cm, Width 2.07 – 2.68 cm, Thickness 2.00 – 2.72 cm, Weight 4.05 – 7.98 g, Edible part + peels 2.89 – 5.92 g, Seeds 1.15 – 2.06 g. The chemical contents Crude Protein 9.21%, Moisture 3.82%, Fat 1.19%, Crude Fiber 45.23%, Ash 22.2%, Carbohydrates 42.17%, Energy Value 219.28%, Total Sugar 31.36%, Reducing Sugars 17.72%, Total treatable acidity 0.13%, Vitamin C 41.92%, B-carotene(IU/100g) Vitamin A 18.50% and Pectin 0.26%. The elements determined using ICP-OES the metal levels are decreasing in order Sr > Mn > Ti > Ba > As > Zn > Cu > Cr > V > Co. And essential elements found in higher level order degrease as Ca > K > Mg > P > Na > Si > Fe > Al > Li = Be.

Chemical analysis of the leaf of Bryophyllym pinnanun was carried out. The moisture content and the ash content were found to be 83.91% ± 0.21 and 13.30% ± 0.41. The leave of the plant was found to contain Na, Ca, K, Mn, Mg, Fe, Cu, Cr and Zn. The level of these mineral in mg/ l00g sample were found to be 0.13% ±0.3, 599.97%, ± 24.54; 5.51% ± 0.08; 4.71% ±0.27; 247.11% ± 33.11; 6.62% ± 1.72; 82.96% ± 6.96: 60.%% ± 8.01 and 0.10% ± 0.01 respectively. The elemental analysis using sodium fusion test shows that the leave contain nitrogen, chlorine, and bromine. The present of these mineral elements in the plant could be part of the contributing factors which suggest the use of the plant for various therapeutic applications.