Bulletin of the Chemical Society of Ethiopia 2021-01-12T04:22:50+00:00 Prof. B.S. Chandravanshi Open Journal Systems A triannual publication of the Chemical Society of Ethiopia Phytochemical profile and antioxidant properties of leaves extracts from Posidonia oceanica (L.) Delile and their allelopathic potential on terrestrial plant species 2021-01-12T03:01:52+00:00 H. Nakbi W. Dallel S. Hammami Z. Mighri <p>Dichloromethane, chloroform, ethyl acetate and ethanol extracts obtained from <em>Posidonia oceanica</em> (L.) leaves, were examined in order to determine their total phenolic, flavonoid, flavonol, anthocyanin and condensed tannins contents as well as their antioxidant and allelopathic activities. The qualitative phytochemical analysis of crude extracts confirmed the presence of coumarins in dichloromethane, chloroform and ethyl acetate extracts. The antioxidant activity estimated using the DPPH assay was significantly more pronounced for the ethyl acetate extract (IC<sub>50</sub> = 1.19±0.018 mg/mL) than that of the other extracts. The allelopathic effect against the seeds of <em>Carum carvi</em> (L.) and <em>Foeniculum vulgare </em>(Mill.) indicated that, depending on concentration, the extracts from the leaves of <em>P. oceanic </em>(L.) inhibited or stimulated at different concentrations the germination, shoot and root elongation of seedlings growth. The results of this study suggest that <em>P. oceanica</em> (L.) extracts could be useful as a natural source of health-promoting effects and herbicides.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: <em>Posidonia oceanic </em>(L.), Phytochemical profile, Phenolic compounds, Antioxidant activity, <em>Carum carvi </em>(L.), <em>Foeniculum vulgare </em>(Mill)</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 437-447.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Levels of selected metals in teff grain samples collected from three different areas of Ethiopia by microwave plasma-atomic emission spectroscopy 2021-01-12T03:06:10+00:00 A. Gebregewergis B. S. Chandravanshi M. Redi-Abshiro <p>The levels of selected essential and non-essential metals in the white, red, and mixed teff grains collected from Bure, Debre Markos and Bahir Dar (Ethiopia) were determined by microwave plasma-atomic emission spectroscopy (MP-AES). After proper sample pretreatment, the powdered teff was wet digested with the acid mixture (5 mL HNO<sub>3</sub>:1 mL HClO<sub>4</sub>) at 240 <sup>o</sup>C for 2:30 h over Kjeldhal digestion block. The accuracy of the optimized procedure was evaluated by analyzing the digest of the spiked samples with a standard solution of metals, and the percentage recoveries varied from 92% to 104%. The mean concentrations of metals determined (mg/kg, dry weight) were in the ranges of Al (713-1513) &gt; Fe (252-1195) &gt; Ca (233-348) &gt; Zn (69-102) &gt; Mn (20-45) &gt; Cu (13-15) &gt; Pb (1.8-2.8) &gt; Cd (0.8-1.8). In this study, Al and Cd were determined in the teff for the first time. Analysis of variance indicated no significant difference between the mean concentrations of Cu and Mn among the white teff samples, Mn among the red teff samples and Cd and Pb among the mixed teff samples, but there was a significant difference for the other studied metals among the corresponding teff samples at 95% confidence level.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Teff grain, <em>Eragrostistef </em>(Zucc.) Trotter, Essential metals, Non-essential metals, Ethiopia</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 449-462.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Photocatalytic degradation efficiency of azo dye in aqueous phase using different photo catalysts 2021-01-12T03:11:11+00:00 N. Abd Alrazzak S. T. Saad H. Y. Al-gubury M. M. Kareem M. M. Assi <p>The new azo dye [4-(4-hydroxy-2-methylnaphthyl)diazenyl]benzoic acid was synthesized by the reaction of 2-methyl-1-naphthol with<em> p</em>-amino benzoic acid. The photcatalytic degradation of azo dye has been investigated by using zinc oxide and cadmium sulfide. This degradation was carried out by the irradiation of aqueous suspended solutions containing different concentrations of this dye using 0.11 g/100 mL of metal oxide (semiconductors) ZnO and CdS. A mercury lamp 125 W in a Pyrex photoreaction cell of 100 mL at room temperature was used as an irradiation source. The effect of the catalyst on the photocatalytic degradation of the prepared dye was studied via several experiments at different conditions, where they involve the effect of the catalyst mass and the effect of the dye concentrations. The irradiated solutions were studied using UV-Vis spectrophotometer. It has been the performance of photocatalytic system that using ZnO was observed to be better than cadmium sulfide system for degrade the azo compound from its aqueous solution.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Photocatalytic, Degradation, Semiconductors, Zinc oxide; Cadmium sulphide, Azo dye</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 463-469.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Synthesis, characterization and antimicrobial activities of heteroleptic metal chelates of isoniazid and 2,2’-bipyridine 2021-01-12T03:16:33+00:00 O. F. Akinyele E. G. Fakola L. M. Durosinmi T. A. Ajayeoba A. O. Ayeni <p>The Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) complexes of isoniazid (L<sub>1</sub>) mixed with 2,2-bipyridine (L<sub>2</sub>) were synthesized and characterized by solubility studies, percentage metal analysis, UV-Vis spectroscopy, IR spectroscopy, conductivity measurements and magnetic moment measurements. The IR spectra revealed that the isoniazid coordinated as a bidentate ligand. In Co(II) and Ni(II) complex it coordinated&nbsp; via the carbonyl oxygen (C=O) and the amide nitrogen, while in the Cu(II), Mn(II) and Zn(II) complexes it coordinated using the amide and carbonyl oxygen via enolization. Bipyridine also bonded to the metals as a bidentate ligand through the pyridinic nitrogen atoms. The magnetic data showed that all the complexes were paramagnetic with values ranging from 1.70 to 5.0 B.M., except [Zn(Is)(Bipy)(H<sub>2</sub>O)Cl<sub>2</sub>] which was diamagnetic. The conductivity results revealed that the Cu(II), Mn(II), Zn(II) complexes were 1:1 electrolytes while Co(II) was 1:2 electrolyte and [Ni(Is)(Bipy)Cl<sub>2</sub>] was non-electrolytic in nature. The antibacterial activities of the ligands and the complexes as evaluated via the agar diffusion method showed that the complexes displayed moderately high antimicrobial activity in comparison with the free ligands when tested against ten strains of bacteria.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Isoniazid, Electronic structure, Geometry, Antimicrobial activity, Electrolytic nature, Magnetic moment</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 471-478.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Preparation and characterization of a gadolinium compound with high thermal stability 2021-01-12T03:19:37+00:00 W. T. Chen <p>A new lanthanide compound [Gd(2,5-HPA)(2,5-PA)]<em><sub>n</sub></em> (<strong>1</strong>; 2,5-H<sub>2</sub>PA = 2,5-pyridinedicarboxylic acid) was obtained through hydrothermal reactions and structurally characterized by single-crystal X-ray diffraction. It possesses a three-dimensional (3-D) framework structure. Solid-state photoluminescence experiment revealed that it shows dark blue emission band, which can be assigned to the characteristic emission of the 4<em>f</em> electron intrashell transition of<sup> 6</sup><em>P</em><sub>7/2</sub>&nbsp;→&nbsp;<sup>8</sup><em>S</em><sub>7/2</sub> (Gd<sup>3+</sup>). The energy transfer mechanism was explained by an energy level diagram of the gadolinium ion and 2,5-pyridinedicarboxylic acid ligand. It displayed remarkable CIE chromaticity coordinates of 0.1346 and 0.0678. The solid-state UV/Vis diffuse reflectance spectra unveiled that it possesses a wide optical band gap of 3.52 eV. Thermogravimetry (TG) measurements revealed that this compound is highly thermal stable up to around 500 °C.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: CIE, Energy transfer, Lanthanide, Photoluminescence, Thermal stability</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 479-488.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Toxicological assessment of synthesized and characterized transition metal(II) complexes of eflornithine hydrochloride hydrate on albino rats 2021-01-12T03:24:27+00:00 W. A. Osunniran J. A. Obaleye A. C. Tella Y. O. Ayipo A. T. Bale A. O. Rajee <p>Transition metal complexes of Cu(II), Co(II) and Ni(II) with eflornithine hydrochloride hydrate (EFN), an antitrypanosomiasis drug, as ligand have been synthesized and characterized by melting point, elemental analysis, Fourier transform infrared (FTIR), electronic spectra, magnetic susceptibility and electrospray ionization mass spectrometry (ESI-MS). The FTIR spectral data suggested the coordination modes of the ligand to be bidentate, coordinated to the metal ions through its carboxylate oxygen atom and an amino nitrogen atom. From the microanalytical data, the stoichiometry of the metal complexes is 1:2 (metal to ligand). The electronic absorption and magnetic susceptibility studies generally suggested octahedral geometry for the metal complexes. Toxicological evaluation of the ligand (EFN) and complexes were carried out using albino rats. Twenty-five albino rats that were used for the experiment were randomly divided into five groups and animals in group 1 served as a control. All the animals were sacrificed twenty-four hours after completion of their doses. The results revealed a high level of toxicity of EFN than the synthesized metal complexes.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Eflornithine hydrochloride hydrate, Carboxylate moiety, Antitrypanosomiasis drug, Toxicological evaluation, Albino rats</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 489-500.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Nicotine metal complexes: synthesis, characterization and bioactivities of some main group and some transition metals 2021-01-12T03:30:56+00:00 N. S. Awwad H. A. Ibrahium A. A. Shati M. Y. Alfaifi Y. H. Ju A. E. Fazary <p>A number of some main group and transition metal nicotine complexes were synthesized and fully characterized using detailed structural and spectroscopic analysis techniques such as elemental analysis, molar conductivities, magnetic susceptibilities, IR, Raman and NMR techniques. Moreover, scanning electron micrographs and thermogravimetric analyses were also done. Cytotoxic activities of the binary nicotine metal complexes were tested and evaluated against HepG2 (human hepatocellular carcinoma), HPC3 (human prostate cancer), and HCT116 (human colorectal carcinoma) tumor cell lines. The antioxidant activities were examined by free radical scavenging assay. The antimicrobial activities of the synthesized complexes were evaluated against <em>Escherichia coli</em> (gram-negative) and <em>Staphylococcus aureus </em>(gram-positive) microbes. The relationship between the chemical structure of the synthesized complexes and their biological influence as antimicrobial drugs was studied and evaluated.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Nicotine metal complexes, Cytotoxicity, Antioxidant, Antimicrobial</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 501-521.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Synthesis, characterization, structure determination from powder X-ray diffraction data, and biological activity of azo dye of 3-aminopyridine and its complexes of Ni(II) and Cu(II) 2021-01-12T03:33:47+00:00 H. S. Mohammed <p>In the present work azo dye ligand of 3-aminopyridine (L) and its complexes of Ni<sup>II</sup> and Cu<sup>II</sup> were synthesized, characterized and evaluated for antibacterial and antifungal activities <em>in vitro</em>. The L ligand was synthesized by reacting diazonium ion of 3-aminopyridine with 1-naphthole in presence of sodium acetate. The ligand (L) and its complexes were characterized by elemental analysis (CHN), magnetic susceptibility, molar conductivity, UV-Vis spectra, and infrared technique. The (L) azo dye exhibited high sensing for the pH changes. The color of L dye changed from red in basic medium to yellow color in acidic medium. The data of CHN, UV-Vis and magnetic susceptibility indicate that the complexes [Ni(L)<sub>2</sub>Cl<sub>2</sub>] and [Cu(L)<sub>2</sub>Cl<sub>2</sub>] are tetrahedral. The complexes of Ni(II) and Cu(II) exhibited potent activity against growth of <em>Staphylococcus aureus </em>and <em>Escherichia Coli </em>as well as against <em>Penicillium Sp. </em>And <em>Aspergillus niger</em>. Under visible irradiation (395 nm), the (L) azo dye of pyridine exhibited a significant change in the spectra under irradiation.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Pyridine, Photoisomerization, Pyridylazo, Biological activity, pH sensor</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 523-532.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Mixed isatin with 3-(2-(aryl)hydrazono)acetylacetone Mn(II), Co(II) and Ni(II) complexes: antibacterial evaluation and molecular properties prediction 2021-01-12T03:36:36+00:00 A. S. Hassan <p>The metal complexes {Ni (II), Co (II) and Mn (II)} of 3-(2-(aryl)hydrazono)acetylacetone with isatin were synthesized and screened for their <em>in vitro</em> antibacterial activity against four pathogenic microorganisms {two Gram‐positive and two Gram negative}. The results of antibacterial activities revealed that all the metal complexes <strong>1-9 </strong>exhibited moderate activities. Also, Lipinski's rule of five (RO5) of the mixed ligand metal complexes were calculated by SwissADME website.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Isatin, 3-(2-(Aryl)hydrazono)acetylacetone, Metal complexes, Antibacterial activities, Lipinski rules</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 533-541.&nbsp;</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Synthesis, structural elucidation and electrochemical behavior of some oxime-phenylalanine mixed ligand complexes 2021-01-12T03:41:55+00:00 U. T. Öztoprak S. P. Özkorucuklu G. Y. Baştemur M. E. Tunçmen F. Karipcin <p>Four new mixed ligand complexes Me(II)/phenylalanine (phe)/HL [HL =4-(4-bromophenyl- aminoisonitrosoacetyl)biphenyl and Me = Co, Ni, Cu, Zn] were synthesized. These complexes are formulated as: [CoL(phe)(H<sub>2</sub>O)<sub>2</sub>], [NiL(phe)(H<sub>2</sub>O)<sub>2</sub>], [CuL(phe)(H<sub>2</sub>O)<sub>2</sub>] and [ZnL(phe)(H<sub>2</sub>O)<sub>2</sub>]. All the compounds were characterized by elemental analyses, FT-IR, magnetic susceptibility measurements, TG/DTA and cyclic voltammetry (CV) experiments. IR spectral data confirmed the coordination of the oxime ligand to the metal ions through the oxime and carbonyl oxygen. The geometrical structures of the complexes have been found to be octahedral. The measured molar conductance values of the complexes in DMF are in agreement with the non-electrolytic nature ofthe complexes. The elemental analyses confirm a 1:1:1 [metal:HL:L(phenylalanine)] molar ratio. Thermal behavior of the compound was investigated by thermal gravimetric analysis (TG) and differential thermal analysis (DTA) techniques. All the complexes were transformed into metal oxides after thermal degradation. The electrochemical properties of both ligand and their complexes were analyzed by cyclic voltammetry (CV) using glassy carbon electrode in DMF solution containing 0.1 M TBAP as supporting electrolyte.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Oxime, electrochemical characterization, mixed ligand complexes, amino acid, phenylalanine</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 543-556.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Study of the histidine complex of uranium(IV): synthesis, spectrophotometric, magnetic and electrochemical properties 2021-01-12T03:46:18+00:00 M. Nazir R. Khattak M. S. Khan I. I. Naqvi <p>We synthesized the novel histidine complex of uranium(IV). A 1:3 mole ratio was found between metal and ligand by the mole ratio method, while –NH<sub>2</sub> and –COO<sup>–</sup> groups of histidine behave as coordinating sites. The IR spectra confirmed the lone pair donating or coordinating sites. The elemental analysis confirmed the stoichiometry. The bathochromic shift with an increase in the optical density in the UV-Visible range indicated that the compound and its central metal ion hold uniform electronic charge distribution. The electrochemical results indicated a quasi-reversible (neither completely reversible nor completely irreversible) oxidation of the complex to its uranium(V) product at the platinum working electrode. The quasi-reversible process shows a comparatively slow electron transfer (ET) rate with the heterogeneous electron transfer rate constant ‘<em>k<sub>s</sub></em>’ (3.4 × &nbsp;10<sup>–4 </sup>cm s<sup>-</sup><sup>1</sup>) at 50 mV s<sup>-</sup><sup>1</sup> and 305 ± 0.5 K. The kinetics such as diffusion and charge transfer lead the reaction with an ECE (<em>electrochemical</em>–chemical–<em>electrochemical)</em> mechanism. The thermodynamic parameters of activation such as ΔH*; 4.257 kJ mol<sup>–1</sup>, ΔS*; -2.519 × 10<sup>–3</sup> J mol<sup>–1</sup> K<sup>–1</sup> and ΔG* 4.26 kJ mol<sup>–1</sup> helped to propose an associative mechanism of the electron transfer at the platinum working electrode.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Uranium, Histidine, Spectroscopy, Electrochemistry, Kinetics</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 557-569.&nbsp;</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Synthesis and characterization of CdS/UiO-66/Ag3PO4 nanocomposite for photocatalytic degradation of methyl orange under visible light irradiation 2021-01-12T03:50:05+00:00 T. Kebede A. M. Taddesse B. Ergedo <p>Single, binary and ternary nanomaterials were synthesized by precipitation, solvothermal, simple solution and impregnation methods to serve as photocatalysts. The crystal structure, morphology, band gap energy, functional groups and optical properties of these materials were characterized by XRD, SEM-EDX, UV-Vis, FTIR, and PL instrumental techniques, respectively. Photocatalaytic degradation performances of all the as-synthesized photocatalysts were investigated under visible light irradiation using MO as a model organic pollutant. The photocatalytic degradation performances of all the photocatalysts were evaluated on aqueous solution of the model pollutant dye as well as on a real sewage sample solution collected from Bahir Dar Textile Share Company.&nbsp;Results suggested that the optimized ternary&nbsp;nanocomposite photocatalyst exhibited a relatively higher efficiency towards the photodegradation of both the methyl orange (MO) dye solution (90%) and the real sewage sample solution (71.2%). The effect of operational parameters such as pH (4), initial dye concentration (10 mg/L) and photocatalyst load (0.2 g/L) in MO dye degradation were investigated by using the ternary CdS/UiO-66/Ag<sub>3</sub>PO4 (R<sub>4</sub>) nanocomposite.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Metal-organic frameworks, Nanocomposite, Ternary system, Photocatalysts, Methyl orange</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 571-588.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Copper(II) ions mediated crystal formation of 3-(3-hydroxy phenyl)-1-phenyl-1h-pyrazole- 4-carbaldehyde 2021-01-12T03:53:45+00:00 A. R. Banpurkar S. S. Wazalwar F. Perdih <p>Schiff base obtained from 3-hydroxyacetophenone and phenylhydrazine was subjected to Vilsmeier-Haack reaction to obtain 3-(3-hydroxyphenyl)-1-phenyl-1<em>H</em>-pyrazole-4-carbaldehyde (<strong>2</strong>). Successful formation of crystals of <strong>2</strong> was achieved using copper ions (Cu<sup>2+</sup>) as template. Present paper reports study of spectroscopic characterization and single-crystal X-ray study of <strong>2</strong>. Hydrogen bonding network between <strong>2</strong> and water molecules enable the formation of 2D layer along <em>ab</em>-plane supported also by π···π stacking interactions of parallel molecules in head-to-head fashion.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Cu<sup>2+</sup> assisted crystal growth, Pyrazole-4-carbaldehyde, X-ray crystal study, Hydrogen bonding study</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 589-596.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) The effect of graphite composition on polyaniline film performance for formalin gas sensor 2021-01-12T03:57:45+00:00 S. A. Akbar A. Mardhiah N. Saidi D. Lelifajri <p>The invention of formalin gas sensors based on polyaniline (PANI) has been developed which arranged by PANI|graphite composite form. The reaction between amine and formaldehyde produced a Schiff base that alters the resistance of PANI film as a function of formaldehyde concentration. The response of the sensor was measured in variations of graphite composition with 3%, 10%, and 25%. The results showed similar patterns in all concentrations of formalin. However, the sensor response at 10% and 25% graphite decreased dramatically. The formalin with concentration 400 ppm shown the response with 3% graphite was 1.62 times greater than 25%. Addition of too much graphite makes the absorption area on the PANI surface becomes less because the graphite covered it. In this case, the sensor performance was still stable and functional, but the measured resistance seems smaller because the sensor conductivity level more dominated by graphite. Therefore, composites of polyaniline and graphite can be used as sensors to detect the presence of formaldehyde gas.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Formalin, Graphite, Polyaniline, Resistance, Sensors</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 597-604.&nbsp;</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Electrochemical studies of 1-ferrocenylmethyl-3-methyl-imidazolium iodide and 1-(ferrocenylmethyl)-3-mesityl-imidazolium iodide: redox potential and substituent effects 2021-01-12T04:01:47+00:00 N. N. Salah R. Abdelkrim D. F. Pierre D. Samuel L. Fadila <p>The electrochemical behavior of 1-ferrocenylmethyl-3-(methyl)-imidazolium iodide (or mesityl) imidazolium was studied by cyclic voltammetry at glassy carbon electrode in midiums organic to determine the influences of electronic imidazolium group on the ferrocene. The experimental results indicated that the redox reaction was reversible. Mass transport towards the electrode is a simple diffusion process and the diffusion coefficient (<em>D</em>) for redox couple has been also calculated and we have evaluated the heterogeneous charge transfer rate constant (<em>K<sup>0</sup></em>).</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Electrochemical behaviour, Cyclic voltammetry, Imidazolium salts, Diffusion coefficient</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 605-612.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Interactions mechanism of commonly used drugs for the treatment of Covid-19 2021-01-12T04:06:46+00:00 S. Celik A. D. Demirag A. E. Ozel S. Akyuz <p>In this study conformation analysis of seven drugs commonly used in the treatment of COVID-19 was performed. The most stable conformers of the drug molecules were used as initial data for docking analysis. Using the Cavityplus program, the probable most active binding sites of both apo and holo forms of COVID-19 main protease enzyme (M<sup>pro</sup>) and spike glycoprotein of SARSCoV-2 receptors were determined. The interaction mechanisms of the 7 FDA approved drugs (arbidol, colchicine, dexamethasone, favipiravir, galidesivir, hydroxychloroquine, remdesivir) were examined using the AutoDock Vina program. The six of the seven drugs were found to be more stable in binding to apo form of COVID-19 M<sup>pro </sup>and spike glycoprotein. Moreover, a set of molecular mechanics (MM) Poisson-Boltzmann (PB) surface area (SA) calculations on the investigated drugs-protein systems were performed and the estimated binding free energy of remdesivir and the apo form of M<sup>pro </sup>system was found to be the best. The interaction results of FDA drugs with the apo form of COVID-19 M<sup>pro</sup> and spike glycoprotein can play an important role for the treatment of COVID-19.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: COVID-19, Drugs, Molecular modelling, Conformational analysis, Molecular docking</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 613-623.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Chemical constituents and acetylcholinesterase inhibitory activity of Piper abbreviatum Opiz 2021-01-12T04:12:06+00:00 W. M. N. H. W. Salleh M. A. Nafiah K. H. Yen H. Kassim A. Tawang <p>Plants of the genus <em>Piper</em> have long been used as medicinal herbs. The chemistry of <em>Piper</em> species has been widely investigated and phytochemical investigations conducted in all parts of the world have led to the isolation of a number of physiologically active compounds. Thus, this study was carried out to investigate the phytochemicals from <em>Piper abbreviatum</em> and their acetylcholinesterase inhibitory activity, which has not been previously investigated. Fractionation and purification of the aerial parts of <em>P. abbreviatum</em> led to the isolation and identification of five methoxylated flavonoids, namely 5,7-dimethoxyflavone, 4ʹ,5,7-trimethoxyflavone, 3',4',5,7-tetramethoxyflavone, 5-hydroxy-7-methoxyflavone, 5-hydroxy-4ʹ,7-dimethoxyflavone, together with lupeol, lupenone, β-sitosterol, and β-sitostenone. The structures of these compounds were obtained by analysis of their spectroscopic data, as well as the comparison with that of reported data. Acetylcholinesterase inhibitory activity revealed that all isolated flavones were found to inhibit AChE with percentage inhibition values ranged from 24.2 to 58.2%. This is the first report on the isolation of methoxylated flavonoid from <em>P. abbreviatum. </em>The high variants of flavonoid compounds from this species may be used as chemotaxonomic markers for this <em>Piper</em> species.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: Piperaceae, <em>Piper</em>,<em> Piper abbreviatum</em>, Flavonoid, Acetylcholinesterase</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 625-632.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c) Chemical constituents of Eremomastax speciosa (Hochst.) Cufod leaves and its cytotoxic potential on NIH-3T3 cells 2021-01-12T04:16:52+00:00 M. O. Eve T. N. Alfred I. I. Akripo E. E. Ubana I. M. Choudhary <p>This study aimed at assessing the cytotoxicity of <em>Eremomastax speciosa </em>crude extract on NIH-3T3 fibroblast cell lines and reporting the chemical constituents in the extract. The MTT assay on NIH-3T3 cells showed a significantly lower (<em>p &lt; 0.05</em>) inhibition from <em>E. speciosa </em>(IC<sub>50</sub> &gt; 30 µg/mL) compared to cyclohexamide (IC<sub>50 </sub>&gt; 0.8 µg/mL). This result validates the non-toxicity observed with the use of <em>E. specios</em><em>a</em> on normal cells at low to moderate doses. Four compounds were isolated and identified from their EIMS as well as 1D and 2D NMR spectroscopic data namely hydroxyandrographolide (<strong>1</strong>), stigmasterol glucoside (<strong>2</strong>), (Z)-4-coumaric acid 4-O-β-D-apiofuranosyl-(1’’→2’)-O-β-D-glucopyranoside (<strong>3</strong>) and 5-methoxy-4,4′-di-O-methyl- secolariciresinol-9′-monoacetate (<strong>4</strong>). These compounds are isolated from this species for the first time. Thirteen volatile constituents were detected in the extract using gas chromatography mass spectrometry (GC-MS). Besides 6,10,14-trimethy-2-pentadecanone (12.63%), mostly fatty acid esters were detected in high amounts notably ethyl hexadecanoate (16.00%), ethyl-9,12,15-octadecatrienoate (11.51%) and 9,12-octadecadienoic acid ethyl ester (8.05%). This study revealed many unsaturated fatty acid esters in <em>E. speciosa </em>and is noteworthy that ω-3 and ω-6 fatty acid esters were predominant, hence an added nutritional value to this plant.</p> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</p> <p><strong>KEY WORDS</strong>: <em>Eremomastax speciosa</em>, Secondary metabolites, NIH-3T3 cytotoxicity, NMR, GC-MS</p> <p>&nbsp;</p> <p>Bull. Chem. Soc. Ethiop. <strong>2020</strong>, 34(3), 633-640.</p> <p>DOI: <a href=""></a></p> 2021-01-12T00:00:00+00:00 Copyright (c)