Bulletin of the Chemical Society of Ethiopia

Proximate analysis and mineral contents of atella from traditional tella brewers in Jimma City, Ethiopia

Tesfaye Shifarew, Tsegaye Girma Asere, Menberu Yitibarek , Abebe Diro — Tue, 30 Apr 2024 00:00:00 +0000

Atella is a by-product of Tella, a local brewed beverage. It is used as a food source to promote weight gain, development, and milk yield in cattle and sheep. The aim of this study was to analyze the physicochemical properties, nutritional composition, and mineral content of Atella. The samples of Atella were purposively collected from 25 Tella vendors in Jimma City, Ethiopia. The physicochemical properties and proximate analyses were performed using the AOAC method. The mineral contents of the samples were measured using flame atomic absorption spectrometry (FAAS). The results showed that the pH value was between 3.36 - 4.23, temperature (19.27 - 20.20 °C), conductivity (124.10 - 153.50 μS/cm), dry matter content (15.87 - 20.17%), crude protein content (16.47 - 18.72%), crude fat content (3.73 - 5.43%), crude fiber content (15.52 - 19.73%), total ash content (3.58 - 4.47%), carbohydrate content (35.02 - 40.50%), and gross energy (247.42 -271.13 kcal/g). The average concentrations of Ca, Mg, Fe, Cu, Cr, and Pb were 656.71, 274.74, 79.16, 7.73, 1.55, and 0.41 mg/kg, respectively. The results of the study show that Atella is a nutrient-rich source of essential nutrients, minerals, and energy.

KEY WORDS: Tella, Atella, Physicochemical properties, Proximate analysis, Mineral content

Bull. Chem. Soc. Ethiop. 2024, 38(4), 825-837.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.1

Analytical data of Acacia nilotica var. Nilotica gum

Amira A.E. Satti, Mohammed E. Osman, Elfatih A. Hassan, Saphwan Al-Assaf — Tue, 30 Apr 2024 00:00:00 +0000

This study aimed to characterize the exudate gum from Acacia nilotica var. nilotica in Sudan and compare its physicochemical properties to Acacia seyal var. seyal and Acacia senegal var. senegal (gum Arabic). Samples were collected from six different states in Sudan over three seasons. The gum had a moisture content of 10.50%, ash content of 1.86%, pH value of 5.19, specific optical rotation of +94.70, intrinsic viscosity of 10.44 cm³g^-1, nitrogen content of 0.024%, protein content of 0.16%, acid equivalent weight of 1907.82, and total uronic acid content of 10.18%. Sugar content analysis revealed arabinose (41.20%), galactose (17.43%), and rhamnose (10.68%). Potassium was the predominant cation, followed by calcium, magnesium, sodium, lead, and iron. Acacia nilotica was classified as part of the Gummeferae series and exhibited a positive specific optical rotation. The Number average molecular weight (Mn) was estimated using osmometric measurements and gel permeation chromatography. The gum had a higher molecular weight and lower intrinsic viscosity compared to gum Arabic, suggesting a spheroidal shape of molecule. Amino acid analysis showed similarities with gum Arabic, with hydroxyproline and serine as principal amino acids. Variations in cationic composition were attributed to differences in soil type among collection locations.

KEY WORDS: Physicochemical characterization, Acacia senegal var. senegal gum, Acacia seyal var. seyal gum, Acacia nilotica var. nilotica gum, gammiferae

Bull. Chem. Soc. Ethiop. 2024, 38(4), 839-852.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.2

Quantification of phenolic compounds in dietary supplements and antioxidant activities

Tue, 30 Apr 2024 00:00:00 +0000

Dietary supplements (DS) are products that are recommended for the treatment of various health issues, especially during the global pandemic, and the accuracy of the labeling information of these supplements plays a significant role in human health. In this study, a novel high performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated to determine the accuracy of the labeling information of commercial dietary supplements containing phenolic compounds (rutin, quercetin, and resveratrol). The mobile phase, flow rate, and column temperature were optimized. Validation studies were carried out to prove the validity of the developed method. The limit of detection (LOD) and limit of quantification (LOQ) values of rutin, quercetin, and resveratrol were found in the range of 4.83-6.62 ng/mL and 16.09-22.07 ng/mL, respectively. Recoveries% were calculated in the range of 99.52-100.19% and 99.78-100.34% in the intra-day and inter-day analysis, respectively. The IC₅₀ values of the dietary supplement extracts obtained by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method ranged from 0.08 to 0.76 mg/mL. Total Antioxidant Capacity (TAC) values of DS₁, DS₂, DS₃, DS₄, DS₅, measured employing the Cupric Reducing Antioxidant Capacity (CUPRAC) method, were found to be 0.09, 0.03, 0.10, 0.10 and 0.40 mmol trolox per gram of extract, respectively.

KEY WORDS: Dietary supplement, HPLC-DAD, Phenolic compound, Antioxidant activity

Bull. Chem. Soc. Ethiop. 2024, 38(4), 853-862.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.3

Fatty acid and essential oil compositions of seeds of coriander (Coriandrum sativum L.) Cultivated in different regions of Ethiopia

Mekides Assefa, Estifanos Ele Yaya, Bhagwan Singh Chandravanshi, Melaku Assefa — Tue, 30 Apr 2024 00:00:00 +0000

Coriander (Coriandrum sativum L.) seeds are used as spices. In this study, fatty acids extracted from the coriander seeds collected from three places (Sululta, Jimma and Wolaita Sodo) in Ethiopia were determined as their methyl ester using GC-MS. The fatty acid components were assessed using linoleic acid ethyl ester as an external standard. Sululta sample showed five fatty acids, while Wolaita Sodo and Jimma three each with highest amount of petroselinic acid: 68.41%, 72.53%, and 64.4%, respectively, of the total fatty acids. Linoleic acid (omega-6) was found in the range of 18.24-22.37%. The polyunsaturated versus saturated (P/S) index values were found to be 1.69-2.39, which indicated that coriander seeds from the three sites have a good capacity to prevent the development of cardiovascular and some chronic diseases. The number of compounds identified in the essential oils of coriander seeds from Jimma, Sululta, and Wolaita Sodo were 7, 9, and 15 with total percent areas of 99.64, 75.14, and 96.68, respectively. The major component in the essential oils was linalool ranging from 36.72-88.50% of the total amount. In general, the chemical constituents of fatty acids and essential oils of coriander seeds indicates its good nutritional quality and usefulness for human health.

KEY WORDS: Coriander seeds, Fatty acids, P/S index, Essential oils, Nutritional quality, Spice

Bull. Chem. Soc. Ethiop. 2024, 38(4), 863-876.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.4

N-Ligands mediated Co(Ⅱ) coordination polymer incorporating 5-hydroxyisophthalic acid: Syntheses, structures, and theoretical calculations

J. D. Feng, Y. Z. Song, X. Y. Wang, Y. Song, Y. Yu , J. X. Liu — Tue, 30 Apr 2024 00:00:00 +0000

The coordination polymer, [Co(L)(hip)]_n (1), (L = 11-fluoro-pyridine[3,2-a:2',3'-c]phenazine and H₂hip = 5-hydroxyisophthalic acid), has been successfully synthesized under hydrothermal condition. Complex 1 crystallizes in tetragonal, space group P4₃2₁2 and the asymmetric unit consists of one Co(II) ion, one hip^2- anion and one ligand L. The binuclear [Co₂(L)₂(hip)₄]^4- second building unit is formed by the coordination of four different hip^2- anions and two Co(L) moieties. The adjacent Co(Ⅱ) centers are connected by the bridging hip^2- anions to form a one-dimensional helical chain. Finally, a three-dimensional structure is formed by the self-assembly of the coordination bond between the Co centers and the hip^2- anions. The powder X-ray diffraction, thermal analysis, IR analysis, UV-Vis absorption spectrum, photoluminescent properties and theoretical calculation for complex 1 are straight displayed.

KEY WORDS: Co(Ⅱ), 5-hydroxyisophthalic acid, Coordination polymer, Crystal structure

Bull. Chem. Soc. Ethiop. 2024, 38(4), 877-887.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.5

Pd(II), Pt(II), Zn(II), Cd(II) and Hg(II) complexes of the newly prepared 1,2-benzo- isothiazol-3(2H)-dithiocarbamate (BIT-DTC) ligand

Tue, 30 Apr 2024 00:00:00 +0000

In the current work, we report the synthesis and characterization of new dithiocarbamate complexes derived from 1,2-benzoisothiazol-3(2H)-one (BitH). The ligand was synthesized by treating the BitH with carbon disulfide in a basic solution. The NMR technique confirmed the preparation of the ligand. The treatment of the Bit-dtcNa with the metal salt’s solution afforded the complexes of the type [M(Bit-dtc)₂]; M = Zn, Cd, Hg, Pd, and Pt. The complexes were characterized via FT-IR and ¹H-NMR techniques. The Zn, Pd, and Pt complexes were investigated theoretically, and some of their quantum properties were determined. These parameters include HOMO-LUMO energies, electron affinity, ionization potential, chemical hardness, dipole moment and the total energies of the optimized structures. Moreover, the surface structure of Zn and Hg complexes were investigated by SEM and XRD techniques. The SEM pattern showed a cubic structures for the Zn complex while the Hg complex appeared as a nano rods structure. The calculated average particle sizes for Zn and Hg complexes were 23 and 26 nm, respectively.

KEY WORDS: Dithiocarbamate, 1,2-Benzoisothiazol-3(2H)-one, DFT, SEM, XRD

Bull. Chem. Soc. Ethiop. 2024, 38(3), 889-899.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.6

Enhancement of deposition rate by accelerators employing D-Mannitol as complexing agent

S. Jothilakshmi, S. Rekha, B. Vijayakumar — Tue, 30 Apr 2024 00:00:00 +0000

Copper possesses better conductivity which makes it an ideal plating choice for the electronics and semiconductor industries. Copper electroless plating can be carried easily on non-conductors like plastics, ceramics, fabrics, glasses etc. One of the limitations of electroless plating is its very low plating rate, which is further reduced by the addition of stabilizers which is quite essential for the plating process. A stabilizer improves stability of bath and deposit qualities, but slows down the plating rate. The current study focuses on the enhancement of plating rate by the addition of accelerators in eco-friendly copper methane sulphonate bath. It is observed that accelerators like guanidine hydrochloride and 2,6-diaminopyridine improves the rate of deposition with good deposit quality. It was studied with weight gain method and analyzed with tafel polarization studies. The surface of the deposit was analyzed with X-ray diffraction (XRD) and scanning electrode microscope (SEM).

KEY WORDS: Copper, Methane sulphonic acid, Accelerators, Guanidine hydrochloride, 2,6- Diaminopyridine

Bull. Chem. Soc. Ethiop. 2024, 38(4), 901-908.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.7

Synthesis of substituted heterocyclic with their cobalt(Ⅱ) complexes from 2-amino- thiazoles and evaluation of their biological activity

Amra Zuhair Husain, Yassir S. Al-Jawaheri, Amaal Y. Al-Assafe — Tue, 30 Apr 2024 00:00:00 +0000

In this research, acetophenone and thiourea reacted in the presence of iodine to produce 2-amino-4-phenylthiazoles (1, 2). These compounds were then used in three different reactions to create substituted Schiff-bases (3-5) by further reactions with substituted benzaldehyde. To produce thiazole, they were first reacted with sodium azide (6). After adding maleic anhydride, they interacted with thioglycolic acid to yield oxazepine (7), and lastly, thiazolidine (8). The synthesised compounds (1-8) were confirmed to have their structures clarified by CHNS and spectroscopic methods such as infrared, ¹H NMR and ¹³C NMR. After being produced (1-4, 6-8), these compounds were used in 2:1 ratio reaction with CoCl₂.6H₂O to generate cobalt complexes (9-15). These complexes' magnetic characteristics, thermal analysis (TGA), and differential thermal analysis (DTA) were investigated. Several produced compounds were also tested against the growth of four different types of bacteria.

KEY WORDS: Schiff-bases, Thiazole, Oxazepine, Thiazolidine, Cobalt complexes

Bull. Chem. Soc. Ethiop. 2024, 38(4), 909-922.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.8

Effect of surfactants (cetyl trimethyl ammonium-bromide, ethyl di-tetra amine and polyacrylamide) on the synthesis of zinc oxide for photocatalytic application

Tue, 30 Apr 2024 00:00:00 +0000

In this work, we report the effect of cetyl trimethyl ammonium bromide (CTAB), ethyl di-tetra amine (EDTA) and polyacrylamide as surfactants on synthesis of zinc oxide for photocatalytic application. The ZnO nanoparticles were synthesized with and without the surfactants and characterized using powder X-ray diffraction (PXRD), and Fourier transform infrared spectroscopy (FTIR). In addition to this, the morphology of zinc oxide prepared in the absence and presence of these surfactants investigated through scanning electron microscopy (SEM). As confirmed from XRD and FTIR characterization results, the use of different surfactants did not affect the composition of ZnO nanomaterials. The photocatalytic activities were investigated by the degradation of methylene blue (MB) dye under sunlight irradiation. To optimize the effects of operational parameters, the study was carried out as a function of dye concentration, catalyst dose, and pH on the degradation efficiency of the photocatalysts. The optimum values of catalyst dose, dye concentration and pH of solution were found to be 0.09 g, 5 mg/L and 10, respectively. The ZnO nanomaterials prepared with CTAB surfactant showed highest degradation efficiency of 98% indicating potential application for practical decontamination of wastewater from toxic organic pollutants.

KEY WORDS: Surfactants, Zinc oxide nanoparticles, Photocatalysis, Methylene blue

Bull. Chem. Soc. Ethiop. 2024, 38(4), 923-935.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.9

Synthesis, spectroscopic, biological and structural characterizations for the gold(III), platinum(IV), and Ruthenium(III) ceftriaxone drug complexes

Eid H. Alosaimi — Tue, 30 Apr 2024 00:00:00 +0000

Three new metal complexes of ceftriaxone (cef), incorporating platinum(IV), gold(III), and ruthenium(III), were prepared. The complexes were prepared using a 1:2 molar ratio between ceftriaxone sodium salt (Na₂cef) to AuCl₃, PtCl₄, and RuCl₃ salts in methanol solvent. The as-synthesized complexes were characterized using microanalytical techniques for C, H, N, and S elements, magnetic and molar conductance measurements, as well as spectroscopic methods including FTIR, ¹H NMR, and UV-Vis. The shape, morphology and size calculations have been examined using SEM, TEM, and X-ray diffraction data. The cef complexes were six-coordinate systems possessing a distorted octahedral geometry. Through the oxygen of both triazine and carboxylate moieties with the chemical formulae [Au(cef)₂(Cl)(H₂O)] (I), [Pt(cef)₂(Cl)₂] (II), and [Ru(cef)₂(Cl)(H₂O)] (III) the antibiotic cef acts as a bidentate ligand towards three metal ions. The newly created complexes demonstrated antibacterial activity showing efficacy in comparison to the cef sodium ligands. In vitro, antibacterial assays against specific microorganisms were evaluated to assess the antibacterial activities of the complexes. Cytotoxicity assays for cef complexes were conducted for HepG-2 and MCF-7 cell lines, representing human hepatocellular carcinoma and breast cancer, respectively. A value of 22.4 g and 26.2 g for 50% inhibitory concentration (IC₅₀), respectively, for HepG-2 and MCF-7 were obtained for [Ru(cef)₂(Cl)(H₂O)] (III).

KEY WORDS: Ceftriaxone sodium, Gold, Ruthenium, Platinum, Complexes, FTIR, IC₅₀

Bull. Chem. Soc. Ethiop. 2024, 38(4), 937-948.

_{DOI: https://dx.doi.org/10.4314/bcse.v38i4.10}

Synthesis, characterization and antibacterial studies of ciprofloxaci-imines and their complexes with oxozirconium(IV), dioxomolybdenum(VI), and dioxotungsten(VI)

Amaal Y. Al-Assafe, Rana A.S. Al-Quaba — Tue, 30 Apr 2024 00:00:00 +0000

We synthesized and characterized ciprofloxacin-imine complexes, generated from ciprofloxacin and either 4-nitro-1,2-phenylenediamine (NO₂PD) or 1,3-propanediamine (PD), in conjunction with zirconyl nitrate dihydrate, sodium molybdate dihydrate, and sodium tungstate dihydrate. Characterization involved numerous analytical methods, containing melting point determination, conductance dimensions, elemental analysis (CHN), metal content determination (%), infrared, electronic spectra, nuclear magnetic resonance, and mass spectrometry. Our findings reveal that the ligand as functions a tetra-dentate chelate binding to metal ions via azomethine and deprotonated carboxylate group. Additionally, the complexes and ligands were tested in contradiction of two types of bacteria (Staphylococcus aureus, Bacillus subtilis) and all prepared compounds showed good spectrum activity.

KEY WORDS: 4-Nitro-1,2-phenylenediamine, Ciprofloxacin-imine, In-vitro antimicrobial activity, Zr complexes

Bull. Chem. Soc. Ethiop. 2024, 38(4), 949-962.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.11

Co(II) and Ni(II) complexes with bis(4-((E)-(4,5-diphenyl-1H-imidazol-2-yl)diazenyl) phenyl)methane: synthesis, characterization and anti-corrosion effect investigation

Suad Taha Saad — Tue, 30 Apr 2024 00:00:00 +0000

Bright coloured Co (II) and Ni (II) complexes of an azo ligand were synthesized. This ligand was previously synthesized from the coupling reaction between 4,5-diphenyl imidazole and 4,4-diaminodiphenylmethane in 1:2 molar ratio (4,4-diaminodiphenylmethane and 4,5-diphenyl imidazole). The synthesis process of the complexes involved the reflux reaction between the azo ligand with both metal salts. The synthesized complexes were characterized by FTIR, UV.-Visible, molar conductivity and atomic absorption. From the obtained characteristic data of the FTIR spectra, the coordination between the two metals and the azo ligand occurs by the coordination with the nitrogen atom of the azo group and one of the nitrogen atoms in the imidazole both rings. The molar conductivity test confirm the non- electrolytic nature of both complexes, while the atomic absorption agrees with the expected complexes formula. Therefore, the octahedral structure for the two complexes is suggested. The anti-corrosion activity of the synthesized compounds were investigated under two temperatures (298 and 308 K) with 0.03 gm of each compound was tested. According to the results cobalt (II) complex shows a better anti-corrosion activity (93%) in comparison with the ligand and nickel (II) complex.

KEY WORDS: Cobalt(II) and nickel(II) azo complexes, Imidazole derivative, Anti-corrosion effect

Bull. Chem. Soc. Ethiop. 2024, 38(4), 963-971.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.12

Thermal, X-ray spectroscopy, morphological, density functional theory and molecular modeling studies on yttrium(III), germanium(IV), tungsten(VI), and silicon penicillinate antibiotic complexes

Abeer A. El-Habeeb, Sonam Shakya, Mohamed Y. El-Sayed, Moamen S. Refat — Tue, 30 Apr 2024 00:00:00 +0000

This manuscript elucidates the thermal stability analysis of four distinct penicillinate complexes, comprising yttrium(III), germanium(IV), tungsten(VI), and silicon, over a temperature ranging from 25 to 800°C. Thermal data revealed the high thermal stability nature of the decomposition steps. According to the spectroscopic measurements, the chemical formula of penicillinate complexes were [Y(Pin)₂].Cl.6H₂O complex (1), [Ge(Pin)₂].2Cl.2H₂O complex (2), [W(Pin)₂].4Cl complex (3), and [Si(Pin)₂].2Cl.2H₂O complex (4). The powder XRD pattern revealed crystalline to polycrystalline natures. The synthesized penicillinate complexes were subjected to theoretical calculations utilizing density functional theory (DFT) calculations, employing the lanL2DZ/6-311G++ level of theory. The optimized geometry of each penicillinate complex was discerned, and a comprehensive evaluation of various properties, including the HOMO→LUMO electronic energy gap, molecular electrostatic potential map, and additional physical parameters, was conducted and validated against experimental findings. Molecular docking tool was used to explore the anticancer activity of the synthesized penicillinate complexes in comparison with penicillin potassium drug (Pin). For the computational investigation, two kinases — CSF1R (PDB ID: 7MFC) and MEK2 (PDB ID: 1S9I) associated with breast cancer progression and estrogen-dependent breast cancer were utilized. This comprehensive analysis provides a deeper understanding of the synthesized penicillinate complexes and their potential applications.

KEY WORDS: Penicillinate complexes, TGA-DrTGA, TEM, XRD, DFT/TD-DFT, Molecular docking

Bull. Chem. Soc. Ethiop. 2024, 38(4), 973-988.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.13

A theoretical study on a new drug combines between vanadyl sulfate and vitamin E in a single component: A novel antioxidant medication in female reproductive health

Tue, 30 Apr 2024 00:00:00 +0000

This study explores the theoretical properties of a novel complex formed by combining vitamin E (VitE) and vanadyl(II) sulfate. The complex, [VO(VitE)₂(H₂O)₂]2H₂O (Vcom), was synthesized in solid form through a reaction between VitE and VOSO₄.xH₂O in a specific solvent mixture and pH. VitE binds to the vanadyl ion as a single ligand via its deprotonated phenolic oxygen. To characterize the complex, various analytical techniques were employed, including elemental analysis, spectral analysis, conductivity measurements, thermal analysis, X-ray diffraction, and microscopy. Electronic and magnetic properties were also investigated. Theoretical calculations - molecular docking simulations were used to assess the binding affinity of Vcom with two receptors known to interact with vitamin E: α-tocopherol transfer protein (α-TTP) and p105 subunit of nuclear factor NF-kappa-B p105 subunit (NF-κB). The findings revealed a square pyramidal geometry for the Vcom complex. Additionally, Density Functional Theory (DFT) were performed on both VitE and Vcom, focusing on their optimized structures, electrostatic properties, and HOMO-LUMO energy gaps. In summary, this research delves into the theoretical aspects of a newly formed VitE-vanadyl complex, providing insights into its structure, properties, and potential interactions with relevant receptors.

KEY WORDS: New drug, Vanadyl sulfate, Vitamin E, Antioxidant, Female, Reproductive health, DFT

Bull. Chem. Soc. Ethiop. 2024, 38(4), 989-1001.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.14

Metal-urea complexes as primary precursors to generate VO2, ZrO2, NbO2, TaO2, Ga2O3 and TeO2 oxides in the nanoscale range by thermal decomposition route

Abdulrahman A. Almehizia, Mohamed A. Al-Omar, Ahmed M. Naglah, Mashooq A. Bhat — Tue, 30 Apr 2024 00:00:00 +0000

Six metal chlorides of vanadium, zirconium, niobium, tantalum, gallium, and tellurium (i.e., VCl₃, ZrOCl₂×8H₂O, NbCl₅, TaCl₅, GaCl₃, and TeCl₄) were reacted with urea (referred to as U) in aqueous media at ~ 50 ^oC. The resulting metal-urea complexes were characterized using CHN elemental analyses, infrared (IR) spectroscopy, and thermogravimetry. After the synthesized metal-urea complexes were characterized, their ability to form stable metal oxides was examined. The vanadium(IV) oxide; VO₂, zirconium(IV) oxide; ZrO₂, niobium(IV) oxide, NbO₂, tantalum(IV) oxide; TaO₂, gallium(III) oxide; Ga₂O₃, and tellurium(IV) oxide; TeO₂, were generated by the thermal decomposition route of the synthesized metal-urea complexes at low temperature 600 °C in static air atmosphere. The transmission electron microscopy (TEM) revealed that the oxides contain uniform spherical nanoparticles.

KEY WORDS: Metal chloride, Metal-urea complex, Urea, FTIR, TEM

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1003-1012.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.15

Synthesis, characterization, and antibacterial studies of some of first transition series metals and zinc complexes with mixed ligands of trimethoprim-isatin and nitrogen base

Amaal Y. Al-Assafe , Rana A.S. Al-Quaba — Tue, 30 Apr 2024 00:00:00 +0000

Complexes of mixed-ligand Schiff bases [trimetho-prim (TMP) with isatin] (L₁) and nitrogen bases [2,2′-bipyridine (bipy)] (L₂), [1,10-phenanthroline (phen) (L₃)] with metal chlorides: M = Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺ were prepared and characterized by metal content determination (%), FT-IR, electronic, nuclear magnetic resonance, mass spectroscopy, magnetic susceptibility, conductance measurements and elemental analysis (CHN). The bacterial activity of the ligands and their metal compounds was evaluated via various microorganisms. Infrared spectra of Schiff base showed an azomethine peak shifted in complexes that coincide synthesis and coordination of Schiff base through the nitrogen atom of azomethine C=N) and the oxygen atom of the carbonyl group of L₁ with metal ions. L₂, L₃(bipy, phen) coordinated through the di imine nitrogen atoms. Conductance dimensions suggested the non-conductance nature of all the compounds except Cr(III) complexes, this outcome fits in with the molar conductance value estimated for 1:1 electrolyte in DMF. Magnetic susceptibility analysis and electronic spectra indicated an octahedral geometry for all complexes. Biological study for prepared compounds have been evaluated towards pathogenic microbes Staphylococcus aureus and Bacillus subtilis. Some compounds have stronger antibacterial action than Schiff base towards tested microbes.

KEY WORDS: Antimicrobial, Heterocyclic compounds, Schiff base, Trimethoprim drug, 2,2-Bipyridyl, 1,10-Phenanthroline

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1013-1025.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.16

Secondary metabolites and essential oil analysis of Clematis simensis with antioxidant and antibacterial activities

Tue, 30 Apr 2024 00:00:00 +0000

Clematis simensis is one of the most commonly used folk medicines in Ethiopia. This study was aimed to investigate the chemical constituents, antioxidant and antibacterial activities of the aerial part of Clematis simensis, and analysis of the composition of its essential oil. The phytochemical study led to the isolation of five compounds: 1-tricosanol (1), 1-hexacosanol (2), 2-deoxy-D-ribono-1,4-lactone (3), 5-hydroxylevulinic acid (4), and β-sitosterol-3-O-β-D-glucoside (5). Their chemical structures were determined by a comprehensive analysis of HR-ESI-MS, FT-IR, UV-Vis, and 1D/2D NMR experiments. The chemical compositions of the essential oils obtained by hydrodistillation from the aerial part of Clematis semenses were determined by GC-MS, which led to the detection of ten major compounds: (E)-2-nonen-1-ol (38.33%), 4-cyclopentene-1,3-dione (28.69%), cyclofenchene (5.65%), benzene acetaldehyde (4.74%), methyl salicylate (2.77%), salicylaldehyde (2.68%), benzaldehyde (2.60%), α-terpineol (2.10%), eucalyptol (1.21%), and 2,6-dimethylcyclohexanol (1.15%). Compound 4 showed high antioxidant activity (IC₅₀ 14.89 μg/mL) but has no antibacterial activity against both Gram-positive and Gram-negative bacterial strains. According to the antimicrobial parameters, crude extract showed very weak activity at 500 mg/mL, 250 mg/mL, and 125 mg/mL. To our knowledge, this is the first report on the isolation of secondary metabolites from Clematis simensis.

KEY WORDS: Clematis simensis, Essential oil, Phytochemical investigation, Biological activities

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1037-1049.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.18

Phytochemical profiling, antidiabetic, antiobesity, and antibacterial activities of Cometes abyssinica

Ahmed A.M. Abdelgawad — Tue, 30 Apr 2024 00:00:00 +0000

This study aims to complete my chemical and biological studies on Cometes abyssinica (CA). The chemical profile was reported by LC-ESI-TOF-MS and GC-MS analyses. Antidiabetic (α-Glucosidase and a-amylase inhibitory activity assay), antiobesity (Lipase inhibitory activity assay), and antibacterial activity (agar well diffusion assay) were determined. The GC-MS analysis led to the identification of 27 hydrocarbons representing 93.4% of the total hydrocarbon content in hexane extract. 11-Octadecenoic acid, methyl ester (28.07%), citronellol (9.31%), hexadecanoic acid, methyl ester (7.64%), phytol (5.93%), and 10-epi-γ-eudesmol (4.91%) were the major components. The LC-ESI-TOF-MS analyses of aqueous-methanolic extract led to the identification of 99 secondary metabolites including phenolics, flavonoids, alkaloids, and vitamins. The percentages of inhibition of the n-hexane, chloroform, ethyl acetate, and methanol extracts of CA were evaluated against α-glucosidase, α-amylase, and pancreatic lipase enzymes at different concentrations. Hexane extract showed the most powerful α-glucosidase and α-amylase inhibitory activity with IC₅₀ value of 0.22 and 0.27 mg/ml comparing with acarbose (IC₅₀ 0.43 and 0.38), respectively. Among all CA extracts, only ethyl acetate extract revealed potent antiobesity as a lipase inhibitory activity with IC₅₀ value of 0.079 mg/ml comparing with orlistat (IC₅₀ 0.11 mg/ml). CA extracts showed mild-weak antibacterial effect against Pseudomonas aeruginosa and Bacillus cereus.

KEY WORDS: Cometes abyssinica, Chemical constituents, α-Amylase inhibitors, α-Glucosidase inhibitors, Lipase inhibitors

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1051-1067.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.19

Synthesis of bioactive heterocyclic compounds using camphor

Ensaf Sultan Alwan, Rafat Milad Mohareb — Tue, 30 Apr 2024 00:00:00 +0000

The aim of the work was to synthesize novel heterocyclic compounds derived from camphor with antibacterial activity. The pyridazine, xanthene, pyranothiazole, pyridinothiazole, thiophene and pyrazole derivatives were produced from 4,11,11-trimethyl-9-phenyl-7-(2-phenylhydrazono)-3,4,5,6,7,9-hexahydro-1H-1,4-methanoxanthen-8(2H)-one (1). Thiophene derivatives 6a,b were produced according to the Gewald’s reaction for thiophene synthesis. On the other hand, pyranothiazol derivatives 8a,b were synthesized by the multicomponent reactions between xanthene derivative 5, benzaldehyde and ethylcyanoacetate or malononitrile in ethanol/triethylamine. Whereas, pyridinothiazole derivative 9 was produced in ethanol/ammonium acetate by the multicomponent reaction between xanthene derivative 5, benzaldehyde and malononitrile. The antibacterial activity of the synthesized compounds was evaluated against E. coli bacteria. All synthesized compounds showed moderate activity against E. coli bacteria.

KEY WORDS: Anti-microbial, Camphor, Heterocyclic, Pyrazol-3(2H)-one, Thiazol-4(5H)-one, Thieno[3,2-d]thiazole, Xanthenes

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1069-1076.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.20

Green chemistry approach for rapid synthesis of indol-3-yl-4H-pyran derivatives, biological assessments, and toxicological activities against Cowpea aphid (Aphis craccivora)

Tue, 30 Apr 2024 00:00:00 +0000

From diverse or indole-3-carbaldehyde, certain unique indol-3-yl-4H-pyran derivatives were generated by condensing with different nucleophiles. IR, ¹HNMR, and elemental studies have all confirmed their chemical structures. The green catalyst for the formation of indol-3-yl-4H-pyran derivatives is a zinc-linked amino acid complex [Zn(L-proline)₂]. Furthermore, the environmental friendliness of this synthetic technique was investigated by assessing the reusability of the Zn(L-proline)₂ complex over five consecutive cycles with no significant loss of catalytic activity. This novel process has showed substantial advantages in terms of safety, simplicity, stability, mild conditions, a short reaction time, excellent yields, and good purity without the use of organic solvents. The antibacterial properties of the compounds produced were investigated and discovered to be promising. To determine whether compounds are appropriate as possible insecticidal agents, the toxicological activity of the synthesized compounds against Cowpea aphid, Aphis craccivora, was tested using leaf dip bioassay technique toxicity studies performed in the laboratory.

KEY WORDS: One pot synthesis, Zn(L-proline)₂, Indole-3-carbaldehyde, Aqueous media, Microwave irradiation, Cowpea aphid, toxicological activity

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1077-1090.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.21

Cerric ammonium nitrate catalyzed eco-friendly green synthesis of chitosan Schiff base using PEG-400 as an anticancer agent against gastric cancer cells via inhibiting EGFR

Wei Geng, Xinwei Feng, Chunfeng Li , Sifeng Ni — Tue, 30 Apr 2024 00:00:00 +0000

The present study was conducted to scrutinize the pharmacological effect of oxazole-embedded Chitosan as an anticancer agent against gastric cancer cells. This compound was synthesized using the classical Schiff base reaction but utilizing the novel green chemical process where cerric ammonium nitrate (CAN) was used as a catalyst in the PEG-400 as solvent media. The target compound was obtained with an excellent yield at the catalyst loading of 5% CAN concentration in 15 min. The Kinase-Glo Plus luminescence kinase assay kit was used to determine the EGFR inhibitory activity of compound 1 where it showed potent activity with IC₅₀ of 2.14 µM. Its effect was also determined on the cellular viability of the Human gastric cancer cell line (SGC7901), liver cancer cell line (HepG2), and lung cancer cell line (A549), where it exhibits potent activity against SGC7901. The compound further showed the concentration-dependent inhibitory effect on migration and invasion of SGC7901. In RT-qPCR analysis, the compound showed induction of apoptosis of SGC7901 cells possibly by restoring the expression of Bcl-2 and Bax near to normal, and inhibition of the mRNA expression of EGFR in a concentration-dependent manner.

KEY WORDS: Schiff base, Chitosan, EGFR, mRNA, apoptosis, Bcl-2

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1091-1101.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.22

In silico and in vitro study of pyrimidones synthesized with ethylenediamine- modified β-cyclodextrin: potential against ESBL E. coli

Tue, 30 Apr 2024 00:00:00 +0000

Modern organic synthesis is primarily focused on developing environmentally benign synthetic protocols by employing green chemistry principles. Accordingly, in our recent research work, we herein report the use of modified supramolecular host cyclodextrin as an effective solid based green catalyst for accessing structurally diverse and medicinally relevant pyrimidone architectures. The catalyst and the synthesized compounds 4 (a-r) were characterized using FT-IR, NMR and GC-mass spectroscopy. Major highlights of the reported work include the economical atom process, remarkably gentler reaction conditions, ease of operation, high isolated yields, and excellent catalyst turnover numbers. The molecular docking studies suggest that the compound 4n has hydrogen bonding, hydrophobic and π-pair interactions with the active site of the CXT M 15 receptor. Further, the in-vitro antibacterial study as well as the screening of anti-biofilm activity resulted in a BIC value of 76.79 ± 0.785% at a concentration of 10 µg/mL and morphological alterations induced by DHPMs against the ESBL E. coli strain aggregated with a good result.

KEY WORDS: Ethylenediamine modified β-CD, Multicomponent reaction, 3,4-dihydropyrimidin-2(1H)-ones DHPM derivatives, Solvent-free conditions, Reusability, Antibactercidal

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1103-1118.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.23

TCS/ZnCl2 as a controlled reagent for the Michael addition and heterocyclic cyclization based on the phenyl pyrazolone scaffold with docking validation as a Covid-19 protease inhibitor

Tue, 30 Apr 2024 00:00:00 +0000

TCS/ZnCl₂ is presented as a new catalyst for achieving the Michael addition adduct 5a-g by the reaction of phenyl pyrazolone 4 as the Michael donor and arylidene derivatives 3a-g as the Michael acceptor. The one-pot multi-component reaction of the same fragments' scaffolds as aldehydes 1a-g, malononitrile (2), and phenyl pyrazolone 4 with the same catalyst gives pyrano[2,3-c]pyrazole derivatives 6a-g as final products. The prepared compounds undergo docking validation as COVID-19 protease inhibitors and are compared with hydroxychloroquine as a reference drug.

KEY WORDS: Pyranopyrazole, multi-component reactions, TCS/ZnCl₂ catalyst, COVID-19, the energy score, hydroxychloroquine

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1119-1127.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.24

Synthesis of new peptide-based macrocycles: Evaluation of their in vitro anti-proliferative activity and molecular dynamic simulation studies

Tue, 30 Apr 2024 00:00:00 +0000

A simplified synthetic protocol was adopted for the preparation of the six novel cyclo-pentapeptide candidates of the structure cyclo-(m-phthaloyl)-bis-[L-Phe -Gly/Sar]-L-Lys–X, where X = COOMe (9a,b), COOH (10a,b) and NHNH₂(11a,b). The potential cytotoxicity (IC₅₀, μg/mL) for cyclo-pentapeptides (9a,b), (10a,b), (11a,b) and doxorubicin^®as reference drugs, is assayed against eight cell lines of human cancer namely; mamillary MCF-7 and T47D, hepatic HEPG2, colon HCT116, cell line of cervix HELA, larynx HEP2, Prostate PC3, and gut Caco. Cyclo-[m-phthaloyl chloride-bis-(L-phalanine-sar)-L-Lys]-COOH 10b was proved as cytotoxically more potent than doxorubicin against most of the screened cell lines. It can be inferred that the proposed molecular structural characteristics associated with cytotoxicity in these m-phthaloyl-bridged cyclopeptides appear noteworthy and hold promise as potential candidates for further exploration as novel anticancer agents. Molecular dynamics simulation studies of 10b into the binding site of Human Epidermal Growth Factor Receptor tyrosine kinase exhibited the highest MM-GBSA value (-16.59 kcal/mol).

KEY WORDS: Anticancer, Cytotoxicity, Cyclopeptides, Cyclopeptides, m-phthaloyl-bis-peptides

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1129-1144.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.25

Study on the engine characteristics (CI) of using pumpkin-maize-blended biodiesel mixed with additive (diethyl ether)

N. Magesh, T. Pushparaj, S. Sabanayagam — Tue, 30 Apr 2024 00:00:00 +0000

This paper focused on the engine characteristics of a diesel engine fuelled using ternary blends. Initially, pumpkin and maize biodiesel were mixed in a volume ratio of 50:50. With a constant 0.5% diethyl ether (DEE) content, the binary combination of pumpkin and maize biodiesel was mixed with diesel at proportions of 10:90, 20:80, 30:70, 40:60, and 50:50 by volume. The prepared ternary mixtures were evaluated at varying engine loads to improve engine performance. Compared to diesel, the tested ternary blends had a reduced brake thermal efficiency (BTE). However, up to a 30% blending ratio, the BTE demonstrated by ternary blends was within the range of less than 0.5% concerning diesel fuel. The ternary blends' BSFC declined as the binary biodiesel mix increased. Diesel has a brake specific fuel consumption (BSFC) of 1.4%, 2.2%, and 3.4% lower than the ternary blends of 10%, 20%, and 30%. The decrease in the heat release rate of the ternary mixes meant that emitted less CO and NO_x than diesel. In contrast, ternary blends exhibited an increasing trend in smoke and HC emissions because of the rise in incomplete combustion that occurs as biodiesel content rises. Therefore, with appropriate engine modifications, the pumpkin and maize binary biodiesel blend can replace diesel by up to 30%.

KEY WORDS: Biodiesels, Binary blend, DEE, Ternary blend, Efficiency

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1145-1161.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.26

Corrosion, wear and machinability studies on scrap aluminium alloy wheel based metal matrix composite

V. P. Ravi, R. A. Sankaran — Tue, 30 Apr 2024 00:00:00 +0000

Recycled materials, especially scrap aluminum alloy wheels with reinforcement castings, are gaining applications in various fields such as aerospace, naval, military, and automobile. In this research, Honda car alloy wheels are stir-cast with 5% alumina as reinforcement and subjected to corrosion, wear, and machinability studies. Corrosion studies were conducted to evaluate the corrosion current density (I_Corr), corrosion potential (E_Corr), and corrosion rate for the cast aluminum metal matrix composite. The wear studies with different loads, i.e., 50 N, 60 N, 70 N, and 80 N, were performed on the specimen and investigated the coefficient of friction, frictional force, and pin temperature. The sliding load has a significant effect on wear performance, and for the sliding load of 80 N, the wear recorded was 2574.83 µm. The electrochemical machinability studies with voltage, duty cycle, and concentration of citric acid electrolyte are performed on the machining rate and surface corrosion factor. Analysis of the electrochemical machining process with PROMETHEE-II shows that 7 V, 60% duty cycle, and 30 g/L electrolyte concentration are estimated to be the best combination for a higher machining rate and a lower surface corrosion factor.

KEY WORDS: Alumina, Machining rate, Nyquist plot, Electrochemical machining, PROMETHEE-II

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1163-1175.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.27

Polyaniline/TiO2 nanocomposite for high performance supercapacitor

Tue, 30 Apr 2024 00:00:00 +0000

A binary polyaniline/TiO₂ and varied weight ratio TiO₂/PANI nanocomposite was successfully fabricated as an electrode for energy storage application. The TiO₂ nanoparticles were synthesized via manual irradiation system with wavelength 256 nm and power 125 W. Polyaniline/TiO₂ was then prepared by in situ polymerizing TiO₂ onto aniline monomer. Polyaniline nanofibers are loaded with TiO₂ to product core-shell system. The polyaniline/TiO₂ nanocomposite were characterized using XRD, XPS, TEM, TGA, CP and LCR measurements. The structure properties were examined by XRD and XPS, which confirmed preparing polyaniline/TiO₂ binary nanocomposite. The thermal stability was investigated using TGA and obtained high stability of polyaniline/TiO₂ compared with polyaniline, while the electrochemical properties were examined by LCR measurements. The LCR measurements were appeared dielectric constant and dielectric loss for incorporating TiO₂ through PANI. Varied weights ratio TiO₂ was worked in increasing the stored energy ability of polyaniline. Notably, the electrochemical investigate results appear that the PANI/TiO₂ has a high specific capacitance (250 F/g) compared with pure PANI (200 F/g).

KEY WORDS: Supercapacitor, UV irradiation, XPS, LCR, nanofibers

Bull. Chem. Soc. Ethiop. 2024, 38(4), 1177-1188.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.28

Chemical constituents of the essential oils from Uvariodendron mbagoi

Slim R. Juma, Cosam C. Joseph , Stephen S. Nyandoro — Tue, 30 Apr 2024 00:00:00 +0000

Several Uvariodendron species are known for their scented leaves and stem bark, hence this study. The leaves, twigs, stem and root barks of the newly described Uvariodendron species, U. mbagoi Dagallier and Couvreur from Kwedijela forest (KF) and Kimboza Forest Reserve (KFR) collected in dry and wet seasons, were steam distilled to yield essential oils that was more abundant in the root bark (2.07-3.85%) than in the leaves, twigs and stem bark (0.09-0.71%). The essential oils from the root bark collected from KF in the wet season (2.07%) was slightly lower than that obtained from the plant part collected from the same locality during the dry season (3.85%). GC-MS analysis indicated that linalool was the most prominent constituent of the leaf (82.18%, KF) and (98.86%, KFR), twig (89.66%, KFR), and stem bark (97.97%, KFR) oil while methyl eugenol (41.08%, KFR) and elemicin (39.28%, KFR) were the major constituents of the root bark oil. The essential oil from the leaves, stem bark, twigs and root bark of U. mbagoi exhibited mild to moderate potency when screened for antioxidant, antibacterial, and protease (trypsin) inhibitory activities.

KEY WORDS: Uvariodendron mbagoi, Annonaceae, Essential oil, Linalool, Elemicin, Methyl eugenol

Bull. Chem. Soc. Ethiop. 2024, 38(3), 1027-1035.

DOI: https://dx.doi.org/10.4314/bcse.v38i4.17