Environmental Fate and Transformations of Aniline-Based Herbicides with Special Reference to Chlorpropham

The work described in this thesis is principally an investigation into the fate and possible transformations of the aniline-based herbicides or phenylamides with particular reference to chlorpropham in potatoes. This xenobiotic chemical also known as isopropyl N-3-chlorophenylcarbamate or CIPC, has been widely used since the early 50's as a selective herbicide. It is also used on staple food-potatoes, which are often eaten without peeling, to suppress sprouting during storage. Special attention has been focussed on three aspects including: (1) Analysis of the peel of laboratory and commercially treated and stored potatoes for residual chlorpropham and three of its potential metabolites, (2) Photolysis of chlorpropham in aqueous and organic solvents, and (3) The effect of horseradish peroxidase, HRP, system on chlorpropham and related anilines. A comprehensive review of the literature pertaining to the environmental fate of phenylamides revealed that chemicals belonging to this group all have in common an amide linkage which Is susceptible to hydrolysis at least enzymatically especially where no organophosphorus or methylcarbamate insecticides exist. Hydrolysis of the aniline-based herbicides produces aniline or substituted aniline(s), which are very unstable and may undergo various competing reactions with the possibility of forming ultimately more or less toxic derivatives than their precursors. In chapter three analytical methods with high precision and good overall recoveries were developed which allowed simultaneous determination of chlorpropham and three suspected metabolites viz. 3,3-dichloroazobenzene, 3,3-dichloroazoxybenzene and 4-methoxy-chlorpropham. Some effort was given to synthesising and identifying these metabolites. Quantification of the chlorpropham was made possible by GC-ECD or GC-FID, while for the azo and azoxy derivatives quantification was best made only by GC-ECD and for the methoxy metabolite by GC-FID. The minimum detection limits were 4, 8, 8 and 20 ng g-1 for the chlorpropham, the azo, azoxy and methoxychlorpropham respectively. Analysis results revealed on the one hand the existence of significant amounts of chlorpropham in potato peel, on the other hand, that none of the analysed peel samples from laboratory and commercially treated and stored potatoes contain any of the questionable metabolites within the detection limits already stated even after long periods of storage. The photolysis investigation in chapter four demonstrated that chlorpropham is a photolabile chemical especially under the uv-lamp. The rate of its phototransformation followed first order kinetics with the highest rate at the lowest concentration, and was affected by the nature of the solvent in the order, water>hexane>methanol. The principal pathways of chlorpropham photolysis in the various media were reductive dechlorination to the more stable propham, solvolysis and coupling or dimerization with the formation of chlorpropham-propham or propham-propham biphenyl dimers. Finally, the enzymatic work in this study clarified that chlorpropham did not respond to the peroxidase even after a long period of incubation, similar to the behaviour of nitroaniline and sulfanilamide, probably because chlorpropham hydrolyses too slowly if at all in the buffer media of the enzyme system providing not sufficient chloroaniline to react with the enzyme. The susceptibility of other tested anilines to react with HRP especially where no efficient reducing agent such as Na2S2O4 or ascorbic acid was present, correlated in a positive manner with the electron densities on the nitrogen atoms. Susceptibilities were in the order: P-anisidine> 2-amino-p-chlorophenol>3-chloro-p-anisidine>> 3-chloroaniline. A complex mixture of products and oligomers such as substituted acylanilide, azo, azoxy, anilino azo, diphenylamine, benzoquinone and phenazine type compounds were successfully isolated from the reaction media by thin layer chromatography and eventually identified by GC-MS and/or mass spectroscopy. The mass spectra of forty compounds are reported. In the light of these findings, together with the controversial and/or undiscovered toxicity of chlorpropham and many of the identified products, it may be adviseable to stay alert to the possibility that such metabolites may contaminate the environment and to suggest that chlorpropham treated potatoes should as a first precaution be peeled before consumption or processing

Synthesis, characterisation, estimation of ground-and excited-state dipole moments using solvatochromic shift and theoretical studies of new iminocoumarin derivatives

The study on the fluorescence and UV–Vis absorption of some iminocoumarins at ambient temperature in several solvents showed a bathochromic shift with the increase of the solvent polarity. The use of the solvathochromic method allowed us to determine the dipole moment in both ground and excited states. The studied molecules exhibit much higher dipole moments in the excited state than in the ground state, which can be due to the redistribution of π-electron densities in the excited state making molecules more polar with higher dipole moments. Furthermore, HOMO–LUMO gap were also estimated theoretically using B3LYP/6–311 + G (d,p) level of theory; the low energy gap indicated the eventual charge transfer interaction occurring in the molecules, and responsible for their light emitting properties.publishe

Exploring the potential of a Ephedra alata leaf extract: Phytochemical analysis, antioxidant activity, antibacterial properties, and green synthesis of ZnO nanoparticles for photocatalytic degradation of methylene blue

Ephedra alata leaf extracts have therapeutic properties and contain various natural compounds known as phytochemicals. This study assessed the phytochemical content and antioxidant effects of a Ephedra alata leaf extract, as well as zinc oxide (ZnO) nanoparticle production. The extract contained phenolic acids, including vanillic acid, chlorogenic acid, gallic acid, p-coumaric acid, vanillin and rutin. Its total phenolic content and total flavonoid content were 48.7 ± 0.9 mg.g-1 and 1.7 ± 0.4 mg.g-1, respectively. The extract displayed a DPPH inhibition rate of 70.5%, total antioxidant activity of 49.5 ± 3.4 mg.g-1, and significant antimicrobial activity toward Gram-positive and negative bacteria. The synthesized ZnO nanoparticles had spherical shape, crystallite size of 25 nm, particle size between 5 and 30 nm, and bandgap energy of 3.3 eV. In specific conditions (90 min contact time, pH 7, and 25°C), these nanoparticles efficiently photodegraded 87% of methylene blue, suggesting potential applications for sustainable water treatment and pollution control

Serum insulin and leptin in patients with end stage renal disease on regular hemodialysis treatment (RDT)

This work aimed to study serum insulin and serum leptin in patients with end stage renal disease on regular hemodialysis therapy. The study included two groups: Group I: 20 non diabetic, end stage renal disease male patients on regular hemodialysis therapy. Group II: 12 volunteers non-diabetic males as a control group, they were age and height matched, and of the same socioeconomic class as patients group. The results concluded that, patients with ESRD on RDT showed decrease in mean body mass index (BMI), significant reduction in mean serum insulin  level and non significant increase in mean serum leptin level compared to the control group

Analysis and Characterization of Isopropyl Carbanilate Herbicide and Its Photoproducts

The phototransformation of the herbicide Isopropyl carbanilate (IPC) has been investigated under UV light. Irradiation of the herbicide at room temperature in aqueous and organic solvents such as hexane and methanol afforded new photo-products formed as a consequence of various processes including photo-Fries rearrangement, ring solvolysis, hydrolysis of the amide/carbamoyl and ester bonds, ring coupling and polymerization. The percentage remaining of the herbicide as a function of time was followed periodically starting from zero time up to three hours. Analyses were performed by GC-FID equipped with a semipolar glass column operated at 170˚C. The rate of photo disappearance of IPC under controlled lab condition followed 1st order kinetics and found to be solvent dependent in the manner of non polar> polar solvents. The photo-products were successfully separated by GC and preparative TLC (Silica gel F-254) and were identified using either GC-MS and/or MS. Identifications were assigned on the bases of molecular ions, mass fragmentation pattern and whenever possible by comparison with the mass spectra of literature analogues

Molting hormone-like substances from Ajuga iva (Labiatae), isolation and spectral identification

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Correlation between serum Ca, Mg, Zn & Cu and hypertension in pre-eclampsia

Pre-eclampsia is potentially preventable, but potentially morbid and/or a fatal disease. The aim of this work is to study serum levels of copper, zinc, calcium and magnesium in pregnant patients with pre-eclampsia. 15 patients diagnosed as pre-eclampsia "patient group" (group 1) and two age matched control groups [8 essential hype1tension non pregnant women (group 2)] and [8 normotensive pregnant women (group3 )] were studied. All persons were subjected to full history with special attention to past history of hypertension and renal disease, clinical examination, routine laboratory investigation and estimation of serum levels of copper, zinc, calcium and magnesium by spectrophotometer method. The resul!s revealed significant increase of serum uric acid in group1 (6.64 ± 0.62 mg%) vs. (3 ± 0.55 mg%) in group2 and (4.12 ± 0.5 mg%) fo group3, significant reduction in serum calcium in group1 (92.32 ± 10.94 µg/dl) vs. group 2 & 3 (122.9 ± 8.49 µg/dl & 130.92 ± 3.91 µg/dl), significant increase in serum magnesium in groupl (59.9 ± ll.18 µg/dl) vs. group 2 & 3 (37.71 ± 4.92 µg/dl & 38.71 ± 1 .4 µg/dl), significant reduction in Ca/Mg ratio in group1 (l.58 ± 0.33) vs group 2 & 3 (3.31 ± 0.49 & 3037 ± 0.07), significant increase in serum copper in group1 (4.83 ± 1.49 µg/dl) vs group 2 (2.64 ± 0.42 µg/dl) and group 3 (2.09 ± 0.68 µg/dl) and significant reduction in serum zinc in group l (1.47 ± 0.49 µg/dl) vs group 2 (3.15 ± 0.46 µg/dl) & group 3 (3.94 ± 1.52 µg/dl). The significance and pathogenic mechanisms of these abnormalities are explained

Impact of the functionalized tetrazole ring on the electrochemical behavior and biological activities of novel nickel (II) complexes with a series of tetrazole derivatives

International audienceSix new nickel (II) complexes with a series of tetrazole derivatives functionalized by different substituents {5-(2-(1-Benzyltetrazol-5-yl) phenyl)-2-ethyl-4-methylthiazole (L1), 1-Benzyl-5-(2-(1-methylpyrrol-2-yl)phenyl) tetrazole (L2), 5-(2-(1-Pivalyltetrazol-5-yl)phenyl)-2-ethyl-4-methylthiazole (L3), 5-(2-(1-Methylpyrrol-2-yl) phenyl)-1-pivalyltetrazole (L4), 2-Ethyl-4-methyl-5-(2-(1 methyltetrazol-5-yl) phenyl) thiazole (L5) and 1-Methyl-5-(2-(1-methylpyrrol-2-yl)phenyl) tetrazole (L6)} have been synthesized and characterized by analytical and spectral methods. The data clearly indicated that the nickel (II) complexes are coordinated to the monodentate tetrazole derivatives via nitrogen (N3) atom of the tetrazole ring. The octahedral geometry is observed for all the complexes. The thermogravimetric analysis revealed the presence of coordinated and hydrated water molecules in the coordination sphere. The DFT calculations performed on both the ligands and the complexes allowed to optimize the structures, the stability and to explain the electrochemical behavior and the biological activities of the nickel (II) complexes. The study of the substituents effects on the redox properties of the ligands and their nickel (II) complexes were discussed via cyclic voltammograms. Electron donating substituents shift the reduction potentials toward negative values, while anodic shift of the oxidation potentials is manifested by the substituents having an electron withdrawing effect. The in vitro antimicrobial activities of the ligands and their corresponding nickel (II) complexes have been evaluated against four bacterial and two fungal strains. L1–L6 ligands and their nickel (II) complexes showed a better activity against Gram-positive bacteria. The reactivity of the complexes against Streptococcus group D varied from very sensitive to extremely sensitive activity. No activity has been recorded for the six ligands against the tested fungal strains but their complexes showed extremely sensitive antifungal activity against these strains. The electron donating effect of the substituents was found to weaken the antimicrobial activity of the complexes. The antioxidant activity of the compounds has been evaluated using the DPPH method. The results indicated that the ligands and their nickel (II) complexes exhibited a better activity against the radical DPPH in comparison to the used reference. Electron withdrawing effect of the substituents on the ligands enhanced the antioxidant activity of the ligands and their complexes

Bioequivalence assessment of two formulations of ibuprofen

Zeyad A Al-Talla1, Sabah H Akrawi2, Luke T Tolley3, Salim H Sioud1, Mohammed F Zaater4, Abdul-Hamid M Emwas1 1Analytical and NMR Core Laboratories, King Abdullah University of Science and Technology, Thuwal, Kingdom of Saudia Arabia; 2College of Pharmacy, Al-Ain University, Al-Ain, United Arab Emirates; 3Department of Chemistry and Biochemistry, Southern Illinois University Carbondale, Carbondale, IL, USA; 4Department of Chemistry, Jordan University of Science and Technology, Jordan University of Science and Technology, Irbid, Jordan Background: This study assessed the relative bioavailability of two formulations of ibuprofen. The first formulation was Doloraz®, produced by Al-Razi Pharmaceutical Company, Amman, Jordan. The second forumulation was Brufen®, manufactured by Boots Company, Nottingham, UK. Methods and results: A prestudy validation of ibuprofen demonstrated long-term stability, freeze-thaw stability, precision, and accuracy. Twenty-four healthy volunteers were enrolled in this study. After overnight fasting, the two formulations (test and reference) of ibuprofen (100 mg ibuprofen/5 mL suspension) were administered as a single dose on two treatment days separated by a one-week washout period. After dosing, serial blood samples were drawn for a period of 14 hours. Serum harvested from the blood samples was analyzed for the presence of ibuprofen by high-pressure liquid chromatography with ultraviolet detection. Pharmacokinetic parameters were determined from serum concentrations for both formulations. The 90% confidence intervals of the ln-transformed test/reference treatment ratios for peak plasma concentration and area under the concentration-time curve (AUC) parameters were found to be within the predetermined acceptable interval of 80%–125% set by the US Food and Drug Administration. Conclusion: Analysis of variance for peak plasma concentrations and AUC parameters showed no significant difference between the two formulations and, therefore, Doloraz was considered bioequivalent to Brufen. Keywords: ibuprofen, bioequivalence study, pharmacokinetic