Amplified cathodic electrochemiluminescence of luminol based on zinc oxide nanoparticle modified Ni-foam electrode for ultrasensitive detection of amoxicillin

Journal of Solid State Electrochemistry - Here is reported a new feasible and facile method for the determination of amoxicillin by the electrochemiluminescence (ECL) method. The ECL signal was...     

Beyond p-Hexaphenylenes: Synthesis of Unsubstituted p-Nonaphenylene by a Precursor Protocol

The synthesis of unsubstituted oligo-para-phenylenes ( OPP ) exceeding para-hexaphenylene—in the literature often referred to as p-sexiphenyl—has long remained elusive due to their insolubility. We report the first preparation of unsubstituted para-nonaphenylenes ( 9PP s) by extending our precursor route to poly-para-phenylenes ( PPP ) to a discrete oligomer. Two geometric isomers of methoxylated syn- and anti-cyclohexadienylenes were synthesized, from which 9PP was obtained via thermal aromatization in thin films. 9PP was characterized via optical, infrared and solid-state ¹³C NMR spectroscopy as well as atomic force microscopy and mass spectrometry, and compared to polymeric analogues. Due to the lack of substitution, para-nonaphenylene, irrespective of the precursor isomer employed, displays pronounced aggregation in the solid state. Intermolecular excitonic coupling leads to formation of H-type aggregates, red-shifting emission of the films to greenish. 9PP allows to study the structure–property relationship of para-phenylene oligomers and polymers, especially since the optical properties of PPP depend on the molecular shape of the precursor.     

Synthesis and antimicrobial activity of new 1,2,4-triazole, 1,3,4-oxadiazole, 1,3,4-thiadiazole,thiopyrane, thiazolidinone,and azepine derivatives

4-oxo-4-phenylbutanehydrazide 3 was reacted with aryl or alkyl isothiocyanates to give the corresponding N-substituted-2-(4-oxo-4-phenylbutanoyl) hydrazine-1-carbothioamide 4a-c . Cyclization of thiosemicarbazides 4a-c with sodium hydroxide led to the formation of 3-(4-sub-5-thioxo-1,2,4-triazol-3-yl)-propanone 5a-c . Desulfurization of thiosemicarbazides 4a-c by mercuric oxide afforded 3-(5-(sub-amino)-1,3,4-oxadiazol-2-yl)-propanone 6a-c . The reaction of 4a-c with phosphorus oxychloride gave 3-(5-(sub-amino)-1,3,4-thiadiazol-2-yl)-propanone 7a-c . Treatment of 4a-c with ethyl-bromoacetate or α-bromopropionic acid gave N′-(3-sub-thiazolidin-2-ylidene)-butanehydrazide 8a-c and (N′-(3-sub-oxothiazolidin-2-ylidene)-butanehydrazide 9a-c . Chlorination of oxothiazolidine-hydrazide 9a-c by phosphorus oxychloride afforded N-(3-sub-4-oxothiazolidine)-butane-hydrazonoyl-chloride 10a-c . The reaction of 10a-c with mercaptoacetyl-chloride yielded 2-((4-benzoyl-thiopyrane) hydrazono)-3-sub-thiazolidinone 11a-c . Also, reacted of 10a-c with hydrazine hydrate afforded N″-(3-sub-oxothiazolidine)-butane-hydrazon-hydrazide 12a-c . The 3-sub-2-((pyridazine) hydrazono) thiazolidinone 13a-c was obtained by cyclization of 12a-c via refluxing in DMF. The reaction and cyclized of 9a-c with chloroacetyl-chloride in ethanolic KOH afforded 1-((3-sub-4-oxothiazolidine) amino)-azepine-dione 14a-c . The chemical structures of the new compounds have been confirmed by diverse spectroscopy analyses such as IR, NMR, MS, and elemental analysis. The synthesized compounds were tested for their antimicrobial activity and these compounds were considered (Pyridazin-hydrazono-thiazolidinone 13a-c , oxothiazolidin-azepinedione 14a-c , N-thiazolidin-hydrazon-hydrazide 12a-c , and thiopyran-hydrazono-thiazolidinone 11a-c ) the most effective as antimicrobial activity.     

Phytochemical Profiling of Lavandula coronopifolia Poir. Aerial Parts Extract and Its Larvicidal,Antibacterial, and Antibiofilm Activity Against Pseudomonas aeruginosa

Infections associated with the emergence of multidrug resistance and mosquito-borne diseases have resulted in serious crises associated with high mortality and left behind a huge socioeconomic burden. The chemical investigation of Lavandula coronopifolia aerial parts extract using HPLC–MS/MS led to the tentative identification of 46 compounds belonging to phenolic acids, flavonoids and their glycosides, and biflavonoids. The extract displayed larvicidal activity against Culex pipiens larvae (LC₅₀ = 29.08 µg/mL at 72 h). It significantly inhibited cytochrome P-450 monooxygenase (CYP450), acetylcholinesterase (AChE), and carboxylesterase (CarE) enzymes with the comparable pattern to the control group, which could explain the mode of larvae toxification. The extract also inhibited the biofilm formation of Pseudomonas aeruginosa by 17–38% at different Minimum Inhibitory Concentrations (MICs) (0.5–0.125 mg/mL) while the activity was doubled when combined with ciprofloxacin (ratio = 1:1 v:v). In conclusion, the wild plant, L. coronopifolia, can be considered a promising natural source against resistant bacteria and infectious carriers.     

Identification of Potential SARS-CoV-2 Main Protease and Spike Protein Inhibitors from the Genus Aloe: An In Silico Study for Drug Development

Severe acute respiratory syndrome coronavirus (SARS-CoV-2) disease is a global rapidly spreading virus showing very high rates of complications and mortality. Till now, there is no effective specific treatment for the disease. Aloe is a rich source of isolated phytoconstituents that have an enormous range of biological activities. Since there are no available experimental techniques to examine these compounds for antiviral activity against SARS-CoV-2, we employed an in silico approach involving molecular docking, dynamics simulation, and binding free energy calculation using SARS-CoV-2 essential proteins as main protease and spike protein to identify lead compounds from Aloe that may help in novel drug discovery. Results retrieved from docking and molecular dynamics simulation suggested a number of promising inhibitors from Aloe. Root mean square deviation (RMSD) and root mean square fluctuation (RMSF) calculations indicated that compounds 132, 134, and 159 were the best scoring compounds against main protease, while compounds 115, 120, and 131 were the best scoring ones against spike glycoprotein. Compounds 120 and 131 were able to achieve significant stability and binding free energies during molecular dynamics simulation. In addition, the highest scoring compounds were investigated for their pharmacokinetic properties and drug-likeness. The Aloe compounds are promising active phytoconstituents for drug development for SARS-CoV-2.     

A New Nanocomposite Based on Pt-rGO Embedded Polymelamine Formaldehyde Nanocomposite for Reduction of Carbon Dioxide

Here, polymelamine formaldehyde was decorated on the surface of reduced graphene oxide whose surface was then electrodeposited with a sub-monolayer of platinum nanoparticles. The nanocomposite thus prepared was characterized using several spectroscopic methods. Using the nanocomposite as a potential electrocatalyst for carbon dioxide reduction, the products were detected by Raman spectroscopy, gas chromatography, ¹³C-NMR spectroscopy, and gas chromatography-mass spectrometry. The analytical results identified methanol as the main product of CO₂ reduction. Moreover, analysis of the liquid products confirmed methanol as the predominant product with a current density of 0.4 mA/cm and a Faradaic efficiency of 93 %.     

Electrochemical Biosensor Design with Multi-walled Carbon Nanotube to Display DNA-Schiff Base Interaction

This paper demonstrates a Schiff base i. e. 5-(diethylamino)-2-((2,6-diethylphenylimino)methyl)phenol (5-DDMP) that was sensed by DNA biosensor. dsDNA was immobilized onto GCE modified with functionalized multi-walled carbon nanotubes to prepare a biosensor. The efficiency of dsDNA biosensor was determined and binding of 5-DDMP with dsDNA was searched by UV-vis spectrophotometry and differential pulse voltammetry. Molecular docking simulations between 5-DDMP and dsDNA were explored and as a result, a hydrogen bond and a π-π contact were observed between 5-DDMP and deoxyguanosine base (dG22) of the strand B, deoxyadenosine base (dA5) of the strand A, respectively. These studies could be useful for new anticancer drug design and development.     

Insecticidal Activity and Free Radical Scavenging Properties of Isolated Phytoconstituents from the Saudi Plant Nuxia oppositifolia (Hochst.)

Chromatographic purification of the alcoholic extract from the aerial parts of the Saudi plant Nuxia oppositifolia (Hochst.), Benth., resulted in five isolated phenolic compounds. Two flavones, hispidulin (1) and jaceosidin (2), and the phenylethanoid glycosides, verbascoside (3), isoverbascoside (4), and conandroside (5), were identified and their chemical structures were determined by spectroscopic analyses. The insecticidal activity of compounds 1 and 2, in addition to 11 compounds isolated in a previous research (6–16), was evaluated against the Yellow Fever mosquito, Aedes aegypti. Four compounds displayed adulticidal activity with LD₅₀ values of 2–2.3 μg/mosquito. Free radical scavenging properties of the plant extracts and compounds (1–5) were evaluated by measuring the 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate radical cation (ABTS^•+) scavenging activity. All compounds exhibited notable activity, compared with the positive control, l-Ascorbic acid. This study suggests that N. oppositifolia could be a promising source of secondary metabolites, some with lethal adulticidal effect against Ae. aegypti.