C-H Bond Research Articles

Effect of inoculating Lactiplantibacillus plantarum Y279 on bacterial community structure and quality of fermented Yujiaosuan

The unique flavor and extended shelf life were identified as essential characteristics of Yu jiaosuan (YJS), while challenges of fermentation control and poor stability were noted to have hindered its industrialization. The effects of Y279 inoculation on the bacterial community structure and quality improvement of YJS were investigated in this study. The results showed that after fermentation with Y279, the total acidity and amino nitrogen concentration of YJS were increased by 0.40 g/kg and 18.45 mg/100 g, respectively, while the pH, TBARS value, and nitrite content were significantly decreased by 0.28, 0.2, and 0.0048 mg/kg, respectively. High-throughput sequencing confirmed that Lactobacillus and Weissella were the dominant genera in the inoculated fermentation group. Forty-five differential metabolites were identified, involving three tastant-related pathways: arginine and proline metabolism, arginine biosynthesis, and purine metabolism. Additionally, molecular docking revealed substances in these differential metabolites that were bound to taste receptors via traditional hydrogen and carbon-hydrogen bonds. The results of sensory evaluation showed that the umami and sourness taste and color of the inoculated fermentation group were enhanced.This study offers theoretical guidance for the use of fermentation agents to improve YJS quality.

Palladium supported on alumina as a highly active heterogeneous catalyst for direct arylation of 6-substituted imidazo[2,1-b]thiadiazole via C[sbnd]H bond activation reaction

Fast, atom-economical, phosphine-free, and eco-friendly microwave-irradiated reactions permitting the “green synthesis” of 5,6-disubstituted imidazo[2,1-b]thiadiazole derivatives using heterogeneous palladium catalyst in triethylammonium 2-(1,1-dioxido-3-oxobenzo[d]isothiazol-2(3H)-yl)acetate ([Et3NH][Sac-CH3CO2]) ionic liquid via CH bond activation reaction of 6-substituted imidazo[2,1-b]thiadiazole derivatives, are reported. This method provides a straightforward route to a wide variety of substituted imidazo[2,1-b]thiadiazoles and has the advantages of reusability of the heterogeneous catalyst, simple methodology, high yields, and easy work-up.

Photosynthesis of CH3OH via oxygen-atom-grafting from CO2 to CH4 enabled by AuPd/GaN

The direct co-conversion of methane and carbon dioxide into valuable chemicals has been a longstanding scientific pursuit for carbon neutrality and combating climate change. Herein, we present a photo-driven chemical process that reforms these two major greenhouse gases together to generate green methanol and CO, two high-valued industrial chemicals. Isotopic labeling and control experiments indicate an oxygen-atom-graft occurs, wherein CO2 transfers one O into the C–H bond of CH4 via photo-activated interfacial catalysis with AuPd nanoparticles supported on GaN. The photoexcited AuPd/GaN interface effectively orchestrates the CH4 oxidation and the CO2 reduction producing 13.66 mmol g−1 of CH3OH yield over 10 h. This design provides a solid scientific basis for the photo-driven oxygen-atom-grafting process to be further extended to visible light region.

Interfacial adsorption and catalysis of single-atom Pt-loaded ZrO2 surfaces for enhancing formaldehyde oxidation

The emerging transition metal single-atom catalysts (SACs) are expected to have high activity for converting detrimental formaldehyde (HCHO) under mild conditions. Currently, the exploitation of novel SACs with designed or modified support surfaces remains largely imperative. Herein, we used density functional theory to explore the catalytic performance for HCHO oxidation on various single-atom Pt-loaded ZrO2 surfaces, in which oxygen vacancy and lattice hydroxyl group were included on the surfaces. The surface modifications could enhance the co-adsorption of HCHO and O2 molecules and provide more active sites due to interfacial electron redistribution. The transition state search approach was applied to investigate the oxidation pathways on various ZrO2-supported SAC surfaces, wherein distinct dehydrogenation mechanisms and intermediates were clarified. The oxygen vacancy defects and hydroxyl groups can enhance the catalytic activity for HCHO oxidation by providing active receptor sites for the H-transfer and facilitating the CH bond breakage. Microkinetic modeling was further used to characterize the reaction rates and kinetics behavior of HCHO oxidation on the SAC surfaces. Our simulation demonstrates the excellent catalytic performance of the modified ZrO2-supported SAC in the HCHO oxidation. Meanwhile, the mechanism is also an important implication for the synthesis and design of novel SACs.

Pancreatic lipase inhibitory and anti‐acne activity of Piper betle: Kinetic studies, in silico docking, and chemical characterization of bioactive compounds

AbstractLipases play important roles in obesity and skin infections. Piper betle (Piperaceae) is widely cultivated and used in daily life. It is a rich source of lead compounds used in skin infections. This study reveals anti‐acne and pancreatic lipase inhibitory potential of leaf extract of Piper betle using in‐vitro and in‐silico molecular docking. The inhibitory potential of 13 selected plant extracts was evaluated at various concentrations (5–25 µg/mL). Ethyl‐acetate extract of Piper betle with strong pancreatic lipase inhibitory activity was further fractionated by preparative thin layer chromatography and eluted bands showing strong inhibitory activity were characterized by high performance liquid chromatography and gas chromatography. The purified compounds, namely, anodendroside E,2‐monoacetate, and 5H‐cyclopropa (3, 4) benz (1, 2‐ejazulen‐5‐one), were identified and showed over 90% pancreatic lipase inhibition. The isolated compounds showed strong dose‐dependent inhibitory effects on Propionibacterium acnes. These observations were consistent with molecular docking studies, which showed that anodendroside E,2‐monoacetate binds to the allosteric site with a binding energy of –7.0 kcal/mol, and this binding site is stabilized by hydrogen and carbon hydrogen bonds contributed by Phe 354 and Asp130, ser103. These findings suggest that the pancreatic lipase inhibitory and anti‐acne effects of Piper betle are attributed to anodendroside E,2‐monoacetate.

Defective TiOx overlayers catalyze propane dehydrogenation promoted by base metals.

The industrial catalysts utilized for propane dehydrogenation (PDH) to propylene, an important alternative to petroleum-based cracking processes, either use expensive metals or metal oxides that are environmentally unbenign. We report that a typically less-active oxide, titanium oxide (TiO2), can be combined with earth-abundant metallic nickel (Ni) to form an unconventional Ni@TiOx catalyst for efficient PDH. The catalyst demonstrates a 94% propylene selectivity at 40% propane conversion and superior stability under industrially relevant conditions. Complete encapsulation of Ni nanoparticles was allowed at elevated temperatures (>550°C). A mechanistic study suggested that the defective TiOx overlayer consisting of tetracoordinated Ti sites with oxygen vacancies is catalytically active. Subsurface metallic Ni acts as an electronic promoter to accelerate carbon-hydrogen bond activation and hydrogen (H2) desorption on the TiOx overlayer.

Iridium(III) complexes with cyclometalated imidazolylidene ligands: sp2 phenyl C[sbnd]H activation vs sp2 benzyl C[sbnd]H activation and catalytic transfer hydrogenation reactions

Cyclometalated N-heterocyclic carbene (NHC) complexes possess fascinating electronic and catalytic properties. A series of cyclometalated iridium(III) complexes have been synthesized from the corresponding imidazolium salts via the aryl sp2 CH bond activation at the N1-phenyl/N3-benzyl wingtips of the imidazolylidene moiety. The electronic tuning towards the competitive formation of cyclometalated complexes (sp2 phenyl CH activation vs sp2 benzyl CH activation) has been discussed. These complexes have been utilized for the transfer hydrogenation (TH) reaction of 4-bromobenzaldehyde and 4-bromoacetophenone. These complexes showed excellent yields of the aryl-alcohols from 4-bromobenzaldehyde or 4-bromoacetophenone.

Programmed alternating current optimization of Cu-catalyzed C-H bond transformations.

Direct current (DC) electrosynthesis, which has undergone optimization over the past century, plays a pivotal role in a variety of industrial processes. Alternating current (AC) electrosynthesis, characterized by polarity reversal and periodic fluctuations, may be advantageous for multiple chemical reactions, but apparatus, principles, and application scenarios remain underdeveloped. In this work, we introduce a protocol for programmed AC (pAC) electrosynthesis that systematically adjusts currents, frequencies, and duty ratios. The application of representative pAC waveforms facilitates copper-catalyzed carbon-hydrogen bond cleavage in cross-coupling and difunctionalization reactions that exhibit suboptimal performance under DC and chemical oxidation conditions. Moreover, observing catalyst dynamic variation under diverse waveform applications provides mechanistic insight.

Study on the thermodynamic mechanism of external magnetic field on gas explosion characteristics

To investigate the thermodynamic mechanism of the magnetic field on the explosion characteristics of gases, experiments were carried out to study the influence of the applied magnetic field of 300 mT on the explosion characteristics of 5.7 % C2H6, 6.5 % C2H4 and 7.7 % C2H2 by volume. CHEMKIN-PRO software was used to simulate the three kinds of gas explosion chain reaction process. The chemical bond strength, stability and bond energy of the three gases were calculated and analyzed by Materials Studio software to derive the strength of chemical bond stability of the three gas molecules in the explosion process. The results show that the magnetic field weakened the breaking rate of CC, CC, and CC, the maximum explosion pressures of C2H6, C2H4, and C2H2 were reduced by 12.14 %, 16.47 %, and 18.71 %. The three gases carbon–carbon bond strength was weaker than the strength of the carbon-hydrogen bond, carbon-hydrogen bond was not easy to break, which in turn reduced the rate of generation of ·H in the chain initiation stage of the cleavage reaction, thus presenting a significant inhibitory effect of the magnetic field on C2H6, C2H4, and C2H2 explosions. The COOP of CC is 0.377 Ha, and the bond energy is 839 KJ/mol, which was greater than CC and CC, so the number of free radicals generated in the C2H2 cleavage reaction was lower, leading to a slower chain reaction rate which led to a stronger inhibitory effect of the magnetic field on C2H2 explosions than that on C2H6 and C2H4.

In vitro inhibitor effect and molecular docking of thiamine (vitamin B1), riboflavin (vitamin B2), and reference inhibitor captopril on angiotensin-converting enzyme purified from sheep plasma

Objective Angiotensin-converting enzyme (ACE, EC 3.4.15.1) is a very important factor in the regulation of blood pressure. Also, the inhibition of ACE with natural compounds has been a very important research area in the treatment of high blood pressure. ACE was purified and characterized from sheep plasma. Molecular docking studies and the inhibition effect of thiamine, riboflavin, and captopril on ACE were investigated. Methods Herein, ACE was purified from sheep plasma by affinity chromatography. The effect of thiamine and riboflavin on ACE was researched. Molecular docking studies were performed to understand the molecular interactions between thiamine, riboflavin, and captopril with ACE. Results The purification coefficient was found to be 8636 fold. The binding energy of thiamine, riboflavin, and captopril was found to be -6.7 kcal/mol, -8.1 kcal/mol, and -5.5 kcal/mol, respectively. Thiamine conformed to three conventional hydrogen bonds with ASP:415, HIS:513, and LYS:454. Riboflavin formed four conventional hydrogen bonds with GLN:281, GLU:376, THR:282, and TYR:520. Captopril formed two conventional hydrogen bonds with ARG:124, one conventional hydrogen bond with TYR:62 and ASN:85, and one carbon-hydrogen bond with ASN:66. Molecular docking results showed that thiamine, riboflavin, and captopril interacted with ACE through hydrogen bonding and hydrophobic interactions. Thiamine and riboflavin indicated significant inhibition effects on ACE. The IC50 values of thiamine, riboflavin, and captopril were found as 960.56 µM, 11.02 µM, and 1.60 nM, respectively. Ki values for thiamine, riboflavin, and captopril were determined as 1352.04 µM, 12.30 µM, and 1.06 nM, respectively. Conclusion In this work, it was concluded that thiamine and riboflavin may have preventive and therapeutical impacts against high blood pressure with their ACE inhibitor effect. Thiamine and riboflavin showed a lower inhibitory effect with a higher IC50 than captopril. However, when the inhibitory effect of thiamine and riboflavin vitamins is compared to captopril, it is concluded that they may be natural inhibitors with fewer side effects.

An Active and Versatile Electron Transport System for Cytochrome P450 Monooxygenases from the Alkane Degrading Organism Acinetobacter sp. OC4.

Cytochrome P450 monooxygenases (CYPs) are valuable biocatalysts for the oxyfunctionalization of non-activated carbon-hydrogen bonds. Most CYPs rely on electron transport proteins as redox partners. In this study, the ferredoxin reductase (FdR) and ferredoxin (FD) for a cytochrome P450 monooxygenase from Acinetobacter sp. OC4 are investigated. Upon heterologous production of both proteins independently in Escherichia coli, spectral analysis showed their reduction capability towards reporter electron acceptors, e. g., cytochrome c. The individual proteins' specific activity towards cytochrome c reduction was 25 U mg-1. Furthermore, the possibility to enhance electron transfer by artificial fusion of the units was elucidated. FdR and FD were linked by helical linkers [EAAAK]n, flexible glycine linkers [GGGGS]n or rigid proline linkers [EPPPP]n of n=1-4 sequence repetitions. The system with a glycine linker (n=4) reached an appreciable specific activity of 19 U mg-1 towards cytochrome c. Moreover, their ability to drive different members of the CYP153A subfamily is demonstrated. By creating artificial self-sufficient P450s with FdR, FD, and a panel of four CYP153A representatives, effective hydroxylation of n-hexane in a whole-cell system was achieved. The results indicate this protein combination to constitute a functional and versatile surrogate electron transport system for this subfamily.

Regularities in mercury cation sorption by a lignin-based sulfur-containing sorbent

The unfavorable environmental situation in the town of Usolye-Sibirskoye (Irkutsk Oblast, Russia) determines the relevance of investigating and applying a new lignin-based sulfur-containing sorbent for purification of groundwater from mercury compounds. The sorbent was synthesized on the basis of waste products of epichlorohydrin (1,2,3-trichloropropane), sulfur, and lignin. The IR spectrum of the sorbent under study showed the presence of an S–S bond in the region of 445–465 cm-1. Intensive absorption of Hg2+ ions in the regions of 2800–2950 cm-1 (valence vibrations of C–H bonds in CH and CH2 groups) and 1460 cm-1 (deformation vibrations in CH2 group) was observed. Absorption of Hg2+ ions by lignin fragments was accompanied by a change in the vibration band of S–S bonds, which splits into two bands of higher frequencies than the νS–S band in the original sorbent. The optimum sulfur content, which ensures the maximum sorption activity of the sorbent, was found to be 53.25%. The mercury sorption isotherms at 20 and 60 °C are described by parabolic dependencies with determination coefficients of 98.9 and 98.6 %, respectively. The kinetic curve at 20 °C and 40 °C is approximated by a hyperbola and a cubic polynomial with determination coefficients of 97.9 and 96.2 %, respectively. The reaction order (first order at 20 °C and second order at 40 °C) and the reaction rate constant (0.0876 min-1 at 20 °C and 0.00014 min-1 at 40 °C) were determined. At 20 °C, the sorption rate of Hg2+ was established to be significantly higher and the sorption time to be faster than those at 40 °C. Therefore, mercury sorption by the proposed sorbent should be carried out at 20 °C in order to reduce energy consumption.

Dry reforming of methane over Ni5 nanocluster supported on double perovskite surface − A DFT study

The opportunity for efficient hydrogen extraction from natural gas through perovskite-supported Ni5 nanocluster has been investigated using first-principles calculations. The reaction dynamics of dry reforming of methane (DRM) has been studied, and all the elementary steps are assessed to locate the transition states. The obtained results demonstrate a high affinity of CH4 and CO2 towards the supported nanocluster as predicted by reasonably large adsorption energies. Chromium and Molybdenum on the perovskite surface play an essential role, in conjunction with Nickel, in methane CH bond activation. Ni2Cr and Ni2Mo are identified as the sites where methane reaction begins and ends, or vice versa. The dissociation of CO2 is also facilitated by the nanocluster, with the rate-limiting step in the two pathways being CH4 dissociation. The study suggests that decorating the anode with Ni-nanoclusters can effectively promote hydrogen extraction from hydrocarbon fuels in solid-oxide fuel cells.

Synthesis and characterization of sustainable polyurethane-amide (PUA)-organoclay bio-nanocomposites for enhanced protective coatings

An effort has been made to synthesize sustainable polyurethane-amide (PUA) organoclay by incorporating natural materials. Polyol derived from castor oil, toluene diisocyanate (TDI), and cetyl pyridinium chloride (CPC) modified Montmorillonite (Mt) clay have been used in this purpose. The modification of Mt clay with CPC serves a dual purpose by increasing the D-spacing between clay layers and enhancing the compatibility of clay with organic polymers. The investigations included varying the percentage of TDI at three different levels to assess its impact on the physical, mechanical and corrosion resistance characteristics of bio-nanocomposite. The presence of characteristics CH bonds at 2854 cm−1 (sym. −CH2) and 2928 cm−1 (asym. −CH2–) in CMC are absent in Mt, confirming formation of CPC modified Mt clay (CMC). Structural investigations of nanobiocomposites were done by Scanning electron microscopy and X-ray diffraction studies and TGA analysis. The findings suggest that the synthesized bio-nanocomposites could serve as a novel and environmentally friendly material for protective coatings.

GC/MS analyses, FTIR and quantum mechanics calculations of poly Vinyl Alcohol in neutral and irradiated state

The products obtained from a poly vinyl alcohol (PVA) at non-irradiated and irradiated state were identified. The analyses were carried out using Head Space (HS) – Gas Chromatography – Mass Spectrometry (HS-GC/MS) instruments. On the other hand, FTIR spectroscopy has been done to explain the functional groups present. Also, the quantum chemical calculations using DFT (Density Function Theory) method were used to confirm the fragmentation process of the GC/MS chromatogram and the mass spectra of non-irradiated and irradiated PVA products. The HS-GC/MS analysis exhibited that fourth according to namely: 2-Butene, 2-methyl- (MW = 70), Cyclohexene (MW = 82), Benzocyclopropene (MW = 90), and Benzene, 1,2,4-trimethyl (MW = 120) have been detected and identified according to its GC/MS chromatogram outcomes. The mass spectrum of each component has been recorded and confirms the molecular ion peak. The obtained results show that the peaks begin to develop as the irradiation dose increases, and that this proportion rises as the gamma dose increases. Furthermore, every component of the fragment appears in the GC/MS chromatogram at a higher relative intensity of Selected ion motoring (SIM) as gamma dosages increase for each molecule. An induced change in the band intensities has been observed in FTIR spectra, which indicates cleavage in the CH bond after irradiation. In both cases, it was found a significant difference between the fragmentation products of the PVA at non-irradiated and irradiated state. Density functional theory (DFT) provides theoretical confirmation of this for both irradiated and non-irradiated PVA states.

Inhibitory effect and the involved mechanism of furaneol on enzymatic browning of potatoes

Enzymatic browning is an important issue impacting the shelf life of fresh-cut potatoes. Using browning inhibitors is an effective method to solve the issue. This research aimed to identify novel and safe inhibitors of enzymatic browning. The research first investigated the inhibitory role of furan compounds in enzymatic browning, then explored the anti-browning effect of furaneol and the involved mechanism. Among the eight tested furan compounds classified as flavorings in food additives, seven showed anti-browning effects, of which three demonstrated superior efficacy in delaying browning compared to the others. Based on the efficacy and odor, furaneol as one natural flavor composition of fresh fruit was selected to be further investigated. At 4 °C, control potatoes browned on day 1. However, furaneol at concentrations of 4 and 8 mM prevented the fresh-cut potatoes from browning for up to 10 d, and their anti-browning efficacies reached that of sodium bisulfite. Sensory evaluation showed the treated fresh-cut potatoes exhibited a slight and acceptable sweet aroma, which quickly disappeared after heat cooking. Further research revealed furaneol reduced the activity of polyphenol oxidase (PPO), chelated Cu2+, and acted as a mixed-type inhibitor of PPO with competitive inhibition being the dominant. Circular dichroism analysis indicated furaneol decreased α-helix content, increased the β-fold content, and altered the secondary structure of PPO. Fluorescence quenching data showed furaneol can form complexes with PPO, quench the fluorescence produced by PPO and change its tertiary structure. Molecular docking suggested that furaneol could enter the active center region near copper ions and interact with surrounding amino residues through van der Waals force, pi-alkyl interactions and carbon-hydrogen bonds. Furaneol can also cause the brown pigment colorless to a certain extent. Moreover, furaneol addition also improved the antioxidant capacity of enzymatic browning reaction system. Our study first reported the inhibitory effect of furan compounds on enzymatic browning and furaneol has great potential as an anti-browning inhibitor for fresh-cut produce in future.

In Situ Growth of Mn-Co3O4 on Mesoporous ZSM-5 Zeolite for Boosting Lean Methane Catalytic Oxidation

The low-temperature oxidation of methane gas in coal mine exhaust gas is important for reducing the greenhouse effect and protecting the environment. Unfortunately, the carbon–hydrogen bonds in methane molecules are highly stable, requiring higher reaction temperatures to achieve effective catalytic oxidation. However, metal oxide-based catalysts face the problem of easy sintering and the deactivation of active components at high temperatures, which is an important challenge that catalysts need to overcome in practical applications. In this work, a series of Mn-Co3O4 active components were grown in situ on ZSM-5 zeolite with mesoporous pore structures treated with an alkaline solution via a hydrothermal synthesis method. Due to the presence of polyethylene glycol as a structure-directing agent, manganese can be uniformly doped into the Co3O4 lattice. The large specific surface area of ZSM-5 zeolite allows the active component Mn-Co3O4 to be uniformly dispersed, effectively preventing the sintering and growth of active component particles during the catalytic reaction process. It is worth mentioning that the Mn-Co3O4/meso-ZSM-5-6.67 catalyst has a methane conversion rate of up to 90% at a space velocity of 36,000 mL·g−1·h−1 and a reaction temperature of 363 °C. This is mainly due to the mesoporous ZSM-5 carrier with a high specific surface area, which is conducive to the adsorption and mass transfer of reaction molecules. The active component has an abundance of oxygen vacancies, which is conducive to the activation of reaction molecules and enhances its catalytic activity, which is even higher than that of noble metal-based catalysts. The new ideas for the preparation of metal oxide-based low-temperature methane oxidation catalysts proposed in this work are expected to provide new solutions for low-temperature methane oxidation reactions and promote technological progress in related fields.

Efficient removal of organic pollutants from aqueous environments using activated carbon derived from biomass waste of Calotropis procera fruit: Characterization, kinetics, isotherm, and thermodynamic investigation

In this research, a powder derived from the biomass of the Calotropis Procera fruit (FCP) was utilized to produce an activated carbon (AC). The H3PO4 was the activator agent. After the adsorption test, the AC (AC-FCP1–1) impregnated with a ratio of 1:1 was chosen as the most suitable and efficient for methylene blue (MB) removal in aqueous environments at high rates. The characterization of AC-FCP1–1 and its efficient adsorption of MB was confirmed through various methods and analyses. The SEM image shows and confirms the micropores and mesopores. EDX analysis reveals the elemental composition and then BET analysis using N2 at 77 K indicates a high surface area of 1025.0628 m2.g-1 and prominent microporosity. FT-IR analysis confirmed functional groups such as OH, CO, CH (aromatic), phosphorus bands, and CO bonds. The amorphous structure was confirmed by XRD analysis. Conversely, the batch study, adsorption modeling, and adsorption mechanism were also carried out. The Adsorption of MB onto AC-FCP1–1 follows a pseudo-second-order kinetic and Freundlich isotherm, indicating that the adsorption process of MB onto AC-FCP1–1 was performed in a multilayer with a physisorption process. The interactions between AC and MB were fast, irreversible, and favorable. The thermodynamic parameters show that this adsorption is exothermic. At equilibrium, under optimal conditions, the adsorption rate of MB onto AC-FCP1–1 reaches 99.24 % with a maximum adsorption capacity of 158.98 mg.g−1.

Virulent-MDR-ESBL E. coli and Klebsiella pneumoniae report from North Sinai calves diarrhea and in vitro antimicrobial by Moringa oleifera

The health of calves has a significant impact on the production of cows and livestock. Some desert plants have pharmacological importance, as they can be used to reduce antibiotic resistance. Our hypothesis is designed to detect Virulent- Multidrug-Resistant and Extended- spectrum Beta- lactamase Enterobacteriaceae (Virulent-MDR-ESBL Enterobacteriaceae and to determine whether Moringa oleifera has antibacterial activity against the detected isolates. A total of 39 Enterobacteriaceae isolates from 28 diarrheic samples were collected from calves aged between 20 days and 20 months from 3 different flocks in North Sinai, Sahl-Eltina region, Egypt. E.coli 46% (18/39), O157 13% (5/39), Klebsiella pneumoniae 41% (16/39). MDR members accounted for 87%, while ESBL isolates accounted for 43%. The antibacterial activity is represented by microdilution. Minimum inhibition concentration (MIC) for the methanol extract of Moringa oleifera ranged from 2.5,5,10, and 25mg/ ml among E.coli isolates, and O157 was susceptible to (2.5mg/ ml), Klebsiella pneumoniae isolates were susceptible to (5-50mg/ ml). Analysis of the methanol extract revealed that ferulic acid was the dominant phenolic compound with a concentration of 29,832 parts per million (ppm). In silico docking study expected the active site of ferulic acid to act on the tyrosine bacterial enzyme through Pi-alkyl, Pi-anion, Carbon hydrogen bonds, and extra ionic attractive interactions with copper ions which can stabilize ferulic acid inside the targeted pocket Diverse virulent gene profiles were observed in E. coli. The Shiga toxin-producing Escherichia coli (STEC) was reported in 83% of the isolated E. coli, while the DNA gyrase (gyrA) was harbored in 100% of Klebsiella pneumoniae isolates. Various profiles of antibiotic resistance genes for both E. coli and Klebsiella pneumoniae isolates were distinguished. blaTEM genes were detected in 99% of E. coli and 100% of Klebsiella pneumoniae. Sequence analysis for E. coli strain DRC-North Sinai-Eg was placed in accession numbers (OP955786) for the Shiga toxin 2 gene (Stx2A), (OP997748) and (OP997749) for the Adhesion to host cell gene (Eae). For the hemolysine gene (hylA), the accession number was (OP946183). Klebsiellapneumoniae strain DRC-North Sinai-Eg was placed in (OP946180) for (gyrA). This study has proven the broad range of Moringa oliefera's antibacterial effects in vitro against the virulent-MDR- ESBL E. coli and Klebsiella pneumoniae isolated from North Sinai calves diarrhea. These are congruent with the disability effect on bacterial tyrosinase enzyme through docking study therefore, we recommend the usage of this desert plant as a prospective feed additive, we endorse this as an antibacterial new insight natural source and for the medication of considered pathogens with zoonotic impacts.Graphical

Synthesis, characterization and reactivity of a Mn(III)–hydroxido complex as a biomimetic model for lipoxygenase

Manganese hydroxido (Mn–OH) complexes supported by a tripodal N,N′,N″-[nitrilotris(ethane-2,1-diyl)]tris(P,P-diphenylphosphinic amido) ([poat]3−) ligand have been synthesized and characterized by spectroscopic techniques including UV–vis and electron paramagnetic resonance (EPR) spectroscopies. X-ray diffraction (XRD) methods were used to confirm the solid-state molecular structures of {Na2[MnIIpoat(OH)]}2 and {Na[MnIIIpoat(OH)]}2 as clusters that are linked by the electrostatic interactions between the sodium counterions and the oxygen atom of the ligated hydroxido unit and the phosphinic (P=O) amide groups of [poat]3−. Both clusters feature two independent monoanionic fragments in which each contains a trigonal bipyramidal Mn center that is comprised of three equatorial deprotonated amide nitrogen atoms, an apical tertiary amine, and an axial hydroxido ligand. XRD analyses of {Na[MnIIIpoat(OH)]}2 also showed an intramolecular hydrogen bonding interaction between the MnIII–OH unit and P=O group of [poat]3−. Crystalline {Na[MnIIIpoat(OH)]}2 remains as clusters with Na+---O interactions in solution and is unreactive toward external substrates. However, conductivity studies indicated that [MnIIIpoat(OH)]− generated in situ is monomeric and reactivity studies found that it is capable of cleaving C-H bonds, illustrating the importance of solution-phase speciation and its direct effect on chemical reactivity.Synopsis: Manganese–hydroxido complexes were synthesized to study the influence of H-bonds in the secondary coordination sphere and their effects on the oxidative cleavage of substrates containing C-H bonds.