Applied Chemistry

In all developing countries like Benin, medicinal plants were the most widely used especially in rural areas to solve health problems in humans and in animal’s life. But despite this use, all the mysteries of nature were not yet perceived by human. This paper reports the results of the chemical and biological studies of two plants, Khaya senegalensis and Pseudocedrela kotschyi used by farmers in Benin in the treatment of gastro-intestinal diseases in livestock. Throughout the results, we noted in both samples the presence of several secondary metabolites such as saponins, catechic tannins, polyphenols, mucilages, flavonoids, anthocyanins, leuco anthocyanin, reducing compounds, sterols and terpenes. Concerning the extraction yield of metabolites, the binary water-ethanol (50/50) showed the best results compared to each of the two solvents used separately. Concerning the polyphenols content, it varied in the same plant depending of the extraction solvent nature. The test results of the scavenging activity showed a better one with the ethanolic extract of the stem bark of P. kotschyi whereas the stem bark of Khaya senegalensis extracted with semi-ethanol was the most active. Both extracts displayed similar activities (CI50= 4 ?g/ml) more pronounced than that of the reference compound used in this study, the BHA (CI50=4.8 µg/mL). The results of antibacterial activity of the ethanolic and hydroethanolic extracts of trunk bark of P. kotschyi had bactericidal activity against Staphylococcus aureus, Salmonella typhi, Escherichia coli and Klebsiella pneumoniae. Concerning K. senegalensis, the ethanolic and hydroethanolic extracts showed an interesting antibacterial activity against Salmonella typhi, Escherichia coli and Klebsiella pneumonia.

This study intended to verify the feasibility of laser-arc hybrid welding to dissimilar materials joints between high strength steel (AH32) and stainless steel (STS304L). For this, hybrid welding process for dissimilar materials was optimized by varying four parameters (welding speed, welding current, wire feeding rate, welding voltage) through Grey-based Taguchi analysis. A Grey relational analysis of the ultimate tensile strength (UTS), welding depth to width ratio (D/W) and absorbed energy (AE) attained from the Taguchi method can optimize the multiple-performance characteristics of the Grey relational grade. Moreover, hardness values and fatigue strength of welded joints fabricated under welding condition optimized by Grey-based Taguchi analysis were investigated. From the results, it was found that the initial visual test of the welds could be classified as very stringent (Quality B') in quality levels for weld imperfections based on EN ISO 13919-1. In the tensile test of welded joints, the damaged part was in BM of STS304L side. Tensile strength of welded joints in dissimilar materials was comparable to that of STS304L base material. Hardness values at distances of 3mm and 12mm over the bottom surface of welded joints were in the order of WM > HAZ > BM. The hardness of welded joints exhibits within the acceptable range (the maximum value 340Hv~360Hv). Dissimilar materials hybrid welded joints exhibited almost same fatigue strength for similar material STS304L SAW welded joints and lied well above the design curve(level D) for JSSC.

A simple and reliable square wave anodic stripping (SWAS) voltammetric method at carbon paste electrode (CPE) of Mebeverin hydrochloride (MEB) in pharmaceutical dosage forms (tablet) and in biological fluids (spiked and real urine samples) has been developed and evaluated. Different parameters such as medium, supporting electrolyte, pH, accumulation potential, scan rate and accumulation time, were tested to optimize the conditions for the determination of MEB. The adsorbed form is oxidized irreversibly under optimal conditions, viz., 0.1 M Phosphate buffer (pH~8), 0.1M KCl, a linear concentration ranges from 0.233 to 42.406 µg/mL of MEB, at accumulation times 60, 150 s, can be determined successfully. The standard addition method was used to determine the MEB in pure solutions, tablets and in biological fluids with satisfactory results. The data obtained are compared with the standard official method.

The batch tests enabled determination of the degradation of the compounds at different temperatures and times, using various sludge types after characterization. Removal rates of cocaine (91.0%), benzoylecgonine (90.6%), heroin (97.9%), morphine (99.7%), 6 monoacetylmorphine (93.3%) and diazepam (99.7%) were measured after 3 hours equilibration; partition coefficients (Kd) for these six substances ranged from 1.2 – 68.1 Kg L-1. The degradation of compounds at 19 ± 0.5o C was relatively greater but it still occurred slowly at 4 ± 0.5o C, at between 5 and 10%. Work encompassed in this study directly measures illicit drug removal rates in laboratory studies for the first time. The application of batch studies in calculating removal rates in sewage works is an improvement over prior studies where assumptions on removal rates at STW were made.

A new series of Cr(III) and Fe(III) complexes with the Flavone ligand were studied on the growth of Hep-2 (Human hepatocellular ademocarcinoma ),which is the human larynx cancer cell Line by using in vitro system and compared with anticancer drug cisplatin (cis-pt) as appositive control. The cancer cells were treated with different concentration and cis-pt after 72 hr. exposure time. The cytotoxic activity was tested by inhibition rate as parameter. The results showed significant differences (p<0.05) for each three treatments when the inhibition rates were increased. The synthesized compounds were tested for antimicrobial activity by cup plate diffusion method. The results indicate the enhanced activity of metal complexes over the parent ligands.

To evaluate chemical composition, antibacterial, antioxidant and anticancer activity of Pinus wallichiana essential oil. The oil was extracted by hydro-distillation which was analysed through GC-MS. The antibacterial activity was evaluated by agar well diffusion method and antioxidant activity was evaluated through DPPH assay while as anticancer activity was evaluated through MTT method. Beta-pinene and alpha-pinene were the major constituents present in the oil. This oil showed significant antibacterial, antioxidant and anticancer activity.

The nutritional value of the reproductive (alates) and non reproductive (workers/soldiers) termites (Macrotermesbellicosus) were evaluated. The result showed that the non-reproductive termites contain moisture (6.62±0.12mg), crude ash (11.35± 0.01mg), crude fat (13.00± 0.14mg), crude protein (14.58±0.15mg), carbohydrate (462.9 ± 0.01cal)and caloric value (362.48±0,01Kcal), vitamin A (16.30±0.11mg), vitamin C(26.00± 0.13). The mineral element concentration in mg/100g in the non reproductive termites were 22.02±0.01, 14.32±0.03, 6.55±0.03, 13.64±0.02, 4.2± 0.02, 2.08 ± 0.03, 7.16±0.01, 5.35±0.02, 21.40±0.01 and 9.12 ±0.11 for Ca, Mg, Na, K, P,Zn, Mn, Cu, Fe and I2 respectively. The antinutrients content in the non- reproductive termite were HCN; 1.93±0.01mg, phytate; 2.80±0.02mg, Tannins; 2.50±0.03mg, Alkaloids; 1.58±0.02mg and; Saponins; 0.20±0.02mg. Comparatively, the results of this study, show that the reproductive termites contain lesser concentration of toxicants but higher proximate, vitamins and mineral compositions than the non reproductive termites. Hence the reproductive termite (alates) has a higher nutritional value than the non reproductive (soldiers/workers) termites.

A new series of Cr(III) and Fe(III) complexes with the Flavone ligand were prepared and spectroscopic method and elemental analysis verified their structures. All the prepared complexes have been identified by available spectroscopic tools (UV-Visible and IR) in addition the structure of complexes was characterized by magnetic moments and molar conductance in DMSO solution .From the above of these studies and measurements suggest an octahedral geometry around Cr(III) and Fe(III). A theoretical treatment of the formation of complexes in the gas phase was studied, this was done using the HYPERCHEM-6 program for the Molecular mechanics and Semi-empirical calculations.