Theoretical and experimental investigation of thiourea derivatives: synthesis, crystal structure, in-silico and in-vitro biological evaluation

ABSTRACT. In this study, five different thiourea derivatives were synthesized from aryl amines according to the reported method. 1-Benzoyl-3-(4-methoxyphenyl)thiourea (2) was confirmed with single crystal XRD analysis while 1-benzoyl-3-phenylthiourea (1), 1-benzoyl-3-(4-hydroxyphenyl)thiourea (3), 1-benzoyl-3-(2-nitrophenyl) thiourea (4) and 1-benzoyl-3-p-tolylthiourea (5) were elucidated with FTIR and NMR techniques. The geometry optimization of the targeted molecules was accomplished with density functional theory applying B3LYP function. The experimental (XRD) and calculated (DFT) bond angles and bond lengths were compared. The frontier molecular orbitals and molecular electrostatic potential were computed to determine the charge density distribution and possible sites for electrophilic and nucleophilic reactions of the crystalline compound. The synthesized compounds were evaluated as an anti-radical scavenger and enzyme (esterases and protease) inhibitor using in-vitro models. The results confirmed that the synthesized molecules have good anti-oxidant property while a moderate enzyme inhibiting activity. Docking study was conducted with acetylcholine and butyrylcholine esterase which suggested that molecules under study have a potential to inhibit these esterases and protease enzymes. On the basis of in-vitro studies, it is concluded that compound 2 is most active against all tested assays.                     KEY WORDS: Thiourea, 2,2-Diphenyl-1-picrylhydrazyl, Enzyme inhibition, Density functional theory, Docking studies   Bull. Chem. Soc. Ethiop. 2021, 35(3), 587-600. DOI: https://dx.doi.org/10.4314/bcse.v35i3.1

Antimicrobial activities of some medicinal essential oils

S u m m a r y in this study, the antimicrobial properties of essential oils obtained from Coriandrum sativum, Foeniculum vulgare Miller, Salvia triloba, Laurus nobilis L., Citrus limon and Origanum smyrnaeum L. were investigated. A total of eight microbial organisms belonging to six species of bacteria, namely Salmonella typhimurium, Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, Escherichia coli and Enterobacter aerogenes, as well as two fungi, Candida albicans and Aspergillus niger, were studied using a disc-diffusion and agar dilution (minimal inhibition concentration) method. the antimicrobial activity of essential oils obtained from the six plants turned out to be more effective in the case of bacteria than against fungi. the antimicrobial activity against Gram-positive bacteria was more pronounced than against Gram-negative ones. All the investigated plants are known as having healing properties and are used to treat various diseases. the essential oils obtained from L. nobilis and O. smyrnaeum showed the highest antifungal activity against C. albicans and A. niger, while the essential oils obtained from F. vulgare showed the highest antimicrobial activity against P. aeruginosa and E. coli. On the other hand, the essential oils obtained from O. smyrnaeum showed stronger antibacterial activity in the case of E. aerogenes and S. aureus, but were not equally effective against E. coli. the other crude essential oils showed varied levels of antibacterial and antifungal activity. the minimal inhibition concentrations (Mic) of the essential oils obtained from O. smyrnaeum and of those obtained from L. nobilis ranged from 1.17 to 4.71 mg/ml, and 2.4 to 19.2 mg/ml, respectively

Waste to biodiesel: A preliminary assessment for Saudi Arabia

This study presents a preliminary assessment of biodiesel production from waste sources available in the Kingdom of Saudi Arabia (KSA) for energy generation and solution for waste disposal issues. A case study was developed under three different scenarios: (S1) KSA population only in 2017, (S2) KSA population and pilgrims in 2017, and (S3) KSA population and pilgrims by 2030 using the fat fraction of the municipal solid waste. It was estimated that S1, S2, and S3 scenarios could produce around 1.08, 1.10 and 1.41 million tons of biodiesel with the energy potential of 43423, 43949 and 56493 TJ respectively. Furthermore, annual savings of US $55.89, 56.56 and 72.71 million can be generated from landfill diversion of food waste and added to the country's economy. However, there are challenges in commercialization of waste to biodiesel facilities in KSA, including waste collection and separation, impurities, reactor design and biodiesel quality

Carbon dioxide rich microbubble acceleration of biogas production in anaerobic digestion

This paper addresses the use of anaerobic bacteria to convert carbon dioxide to biomethane as part of the biodegradation process of organic waste. The current study utilises gaslift bioreactors with microbubbles generated by fluidic oscillation to strip the methane produced in the gaslift bioreactor. Removal of methane makes its formation thermodynamically more favourable. In addition, intermittent sparging of microbubbles can prevent thermal stratification, maintain uniformity of the pH and increase the intimate contact between the feed and microbial culture with lower energy requirements than traditional mixing. A gaslift bioreactor with microbubble sparging has been implemented experimentally, using a range of carrier gas, culminating in pure carbon dioxide, in the anaerobic digestion process. The results obtained from the experiments show that the methane production rate is approximately doubled with pure carbon dioxide as the carrier gas for intermittent microbubble sparging

Hamujący wpływ frakcji zawierających czerwony barwnik powstały w wyniku mechanicznego uszkodzenia Hippeastrum x hybr. Hort. na wzrost i rozwój form specjalnych Fusarium oxysporum SCHLECHT.

Studies concerned the effect of different fractions obtained from white scales of Hippestrum after drying and from scales after red colouration as a result of wounding of fresh white scales, on the growth and development of formae speciales of Fusarium oxysporum, non-pathogenic fungi for Hippeastrum. Fraction B, at the concentration of 250 and 500 μg・cm⁻³ obtained from red wounded scales of Hippeastmm and containing two red compounds (Hpp-1 and Hpp-2) showed a strong inhibitory effect on the linear growth of mycelium, germination of spores and germ tube growth of Fusarium oxysporum Schlecht, isolated from Fritillaria, F. oxysporum f. sp. callistephi and F. oxysporum f. sp. tulipae. Fractions A, C and D from red wounded scales at the same concentrations did not inhibit or had a slight antifungal activity on mycelium growth of tested pathogens in vitro. Fractions A, B and D obtained in the same way from white scales of Hip- peastrum did not inhibit mycelial growth of F. oxysporiim SCHLECHT, from Fritillaria and F. oxysporum f. sp. tulipae. Fraction C at a concentration of 500 μg・cm⁻³ showed a slight inhibition of the F. oxysporiim from Fritillaria. All fractions (A, B, C and D) at a concentration of 500 μg・cm⁻³ obtained from white scales of Hippeastrum showed a slight inhibition of the F. oxysporum f. sp. callistephi in vitro. Subfractions B₂ and B₃, free from red compounds, and subfraction B₅ (containing mostly red compound Hpp-1), greatly limited the growth of tested pathogens in comparison to the control. Subfraction B₈, containing mostly red compound Hpp-2 and a small amount of red compound Hpp-1, applied at the same concentration did not inhibit or had little antifungal activity against tested formae speciales of F. oxysporum.W pracy przedstawiono wyniki badań nad wpływem różnych frakcji otrzy- mnych z białych łusek bezpośrednio po uszkodzeniu Hippeastrum i z łusek po wytworzeniu czerwonego zabarwienia w wyniku uszkodzenia łusek białych na wzrost i rozwój form specjalnych Fusarium oxysporum, grzybów nie patogenicznych dla Hippeastrum. Frakcja B w stężeniu 250 i 500 μg・cm⁻³ uzyskana z czerwonych łusek Hippeastrum i zawierająca dwa związki o czerwonym zbarwieniu Hpp-1 i Hpp-2 najsilniej ograniczała wzrost grzybni, kiełkowanie zarodników i wzrost strzępki kiełkowej Fusarium oxysporum Schlecht. - patogena Fritillaria, F. oxysporum f. sp. callistephi i F. oxysporum f. sp. tulipae. Frakcja A, C i D w tych samych stężeniach były mało aktywne. Frakcja A, B i D uzyskana w ten sam sposób z białych łusek Hippeastrum, nie wpłynęły hamująco na wzrost liniowy grzybni F. oxysporum Schlecht, izolowanego z Fritillaria i F. oxysporum f. sp. tulipae. Frakcja C uzyskana z białych łusek w niewielkim stopniu hamowała wzrost grzybni F. oxysporum Schlecht, z Fritillaria. Frakcja A, B, C i D w stężeniu 500 μg・cm⁻³ uzyskane z białych łusek Hippeastrum wykazały słaby inhibicyjny wpływ na wzrost grzybni F. oxysporum f. sp. callistephi in vitro. Otrzymane z czerwonych łusek (w wyniku uszkodzenia) Hippeastrum sub- frakcje typu B; B₂ i B₃ (brak barwników Hpp-1 i Hpp-2), i B₅ (zawierająca głównie barwnik Hpp-1), silnie hamowały wzrost grzybni testowanych patogenów w porównaniu do kontroli. Subfrakcja B₈, zawierająca barwnik Hpp-2 i śladowe ilości Hpp-1 nie wykazała takiej aktywności w ograniczaniu wzrostu testowanych form specjalnych F. oxysporum

Recent key technical barriers in solid oxide fuel cell technology

High-temperature solid oxide fuel cells (SOFCs) are considered as suitable components of future large-scale clean and efficient power generation systems. However, at its current stage of development some technical barriers exists which limit SOFC’s potential for rapid large-scale deployment. The present article aims at providing solutions to key technical barriers in SOFC technology. The focus is on the solutions addressing thermal resistance, fuel reforming, energy conversion efficiency, materials, design, and fuel utilisation issues