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Molecules, Volume 28, Issue 24 (December-2 2023) – 221 articles

Cover Story (view full-size image): Polyester elastomers have revolutionized biomedical therapeutic strategies and devices, providing scaffolding materials with controllable properties and multifunction that cater to the needs of different applications. This review discusses novel structural modification methods that contribute to the outstanding mechanical behaviors of polyester elastomers. Recent advances in applying polyester elastomers in tissue engineering and bioelectronics are outlined and analyzed. A perspective of the future research and development on polyester elastomers is also provided. View this paper
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15 pages, 8169 KiB  
Article
Step-by-Step Replacement of Cyano Groups by Tricyanovinyls—The Influence on the Acidity
Molecules 2023, 28(24), 8157; https://doi.org/10.3390/molecules28248157 - 18 Dec 2023
Viewed by 754
Abstract
Acid-base properties are the simplest expression of compounds’ coordinating ability. In the present work, we studied in silico how the gas-phase Brønsted acidity (GA) of several polycyano-substituted compounds change when cyano (CN) groups are replaced by 1,2,2-tricyanovinyl (TCNV) groups in (iso)cyanic acid, dicyanoamine, [...] Read more.
Acid-base properties are the simplest expression of compounds’ coordinating ability. In the present work, we studied in silico how the gas-phase Brønsted acidity (GA) of several polycyano-substituted compounds change when cyano (CN) groups are replaced by 1,2,2-tricyanovinyl (TCNV) groups in (iso)cyanic acid, dicyanoamine, cyanoform, and hydrogen tetracyanoborate. Different tautomers and conformers/isomers are included in this study. Gas-phase acidity values are compared with the acidities of various acids, including percyanated protonated monocarba-closo-dodecaborate (carborane acid) and dodecaborate, as well as hydrogen cyanide and 1,2,2-tricyanoethene. An estimation of acetonitrile (MeCN), dimethylsufoxide (DMSO), and 1,2-dichloroethane (DCE) acidities is presented using the COSMO-RS method and correlation analysis. The strongest acid with four TCNV groups shows remarkable acidic properties. Full article
(This article belongs to the Special Issue Computational and Theoretical Studies on Isomeric Organic Compounds)
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14 pages, 5354 KiB  
Article
Novel Lanthanide Complexes Synthesized from 3-Dimethylamino Benzoic Acid and 5,5′-Dimethyl-2,2′ Bipyridine Ligand: Crystal Structure, Thermodynamics, and Fluorescence Properties
Molecules 2023, 28(24), 8156; https://doi.org/10.3390/molecules28248156 - 18 Dec 2023
Viewed by 586
Abstract
Two isostructural lanthanide complexes were synthesized by solvent evaporation with 3-dimethylaminobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine as ligands. The general formula of the structure is a [Ln(3-N,N-DMBA)3(5,5′-DM-2,2′-bipy)]2·2(3-N,N-DMHBA), Ln = (Gd(1), Tb(2)), 3-N,N-DMBA = 3-Dimethylamino benzoate, 5,5′-DM-2,2′-bipy = [...] Read more.
Two isostructural lanthanide complexes were synthesized by solvent evaporation with 3-dimethylaminobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine as ligands. The general formula of the structure is a [Ln(3-N,N-DMBA)3(5,5′-DM-2,2′-bipy)]2·2(3-N,N-DMHBA), Ln = (Gd(1), Tb(2)), 3-N,N-DMBA = 3-Dimethylamino benzoate, 5,5′-DM-2,2′-bipy = 5,5′-dimethyl-2,2′ bipyridine. Both complexes exhibited dimeric structures based on X-ray diffraction analysis. At the same time, infrared spectroscopy and Raman spectroscopy were used to measure the spectra of the complex. A thermogravimetric infrared spectroscopy experiment was performed to investigate the thermal stability and decomposition mechanism of the complexes. Measurements of the low-temperature heat capacity of the complexes were obtained within the temperature range of 1.9 to 300 K. The thermodynamic function was calculated by heat capacity fitting. In addition, the fluorescence spectra of complex 2 were studied and the fluorescence lifetime values were determined, and the energy transfer mechanism of complex 2 was elucidated. Full article
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13 pages, 2174 KiB  
Article
Proteomic Study of Broiler Plasma Supplemented with Different Levels of Copper and Manganese from Different Sources
Molecules 2023, 28(24), 8155; https://doi.org/10.3390/molecules28248155 - 18 Dec 2023
Viewed by 585
Abstract
The aim of the present study was to evaluate the differential expression of plasma proteins in broiler chickens supplemented with different sources (sulfates and hydroxychlorides) and levels of copper (15 and 150 mg kg−1) and manganese (80 and 120 mg kg [...] Read more.
The aim of the present study was to evaluate the differential expression of plasma proteins in broiler chickens supplemented with different sources (sulfates and hydroxychlorides) and levels of copper (15 and 150 mg kg−1) and manganese (80 and 120 mg kg−1). For this, plasma samples from 40 broiler chickens were used, divided into four experimental groups: S15-80 (15 ppm CuSO4 and 80 ppm MnSO4), S150-120 (150 ppm CuSO4 and 120 ppm MnSO4), H15-80 (15 ppm Cu(OH)Cl and 80 ppm Mn(OH)Cl), and H150-120 (150 ppm Cu(OH)Cl and 120 ppm Mn(OH)Cl). From plasma samples obtained from each bird from the same treatment, four pools were made considering 10 birds per group. Plasma proteome fractionation was performed by 2D-PAGE. Concentrations of the studied minerals were also evaluated in both plasma and protein pellet samples. A higher concentration of Cu and Mn was observed in the plasma and protein pellets of groups that received higher mineral supplementation levels compared to those receiving lower levels. Mn concentrations were higher in plasma and protein pellets of the hydroxychloride-supplemented groups than the sulfate-supplemented groups. Analysis of the gels revealed a total of 40 differentially expressed spots among the four treatments. Supplementation with different sources of minerals, particularly at higher levels, resulted in changes in protein regulation, suggesting a potential imbalance in homeostasis. Full article
(This article belongs to the Collection Advances in Food Chemistry)
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18 pages, 8970 KiB  
Review
Recent Progress on Perovskite-Based Electrocatalysts for Efficient CO2 Reduction
Molecules 2023, 28(24), 8154; https://doi.org/10.3390/molecules28248154 - 18 Dec 2023
Viewed by 864
Abstract
An efficient carbon dioxide reduction reaction (CO2RR), which reduces CO2 to low-carbon fuels and high-value chemicals, is a promising approach for realizing the goal of carbon neutrality, for which effective but low-cost catalysts are critically important. Recently, many inorganic perovskite-based [...] Read more.
An efficient carbon dioxide reduction reaction (CO2RR), which reduces CO2 to low-carbon fuels and high-value chemicals, is a promising approach for realizing the goal of carbon neutrality, for which effective but low-cost catalysts are critically important. Recently, many inorganic perovskite-based materials with tunable chemical compositions have been applied in the electrochemical CO2RR, which exhibited advanced catalytic performance. Therefore, a timely review of this progress, which has not been reported to date, is imperative. Herein, the physicochemical characteristics, fabrication methods and applications of inorganic perovskites and their derivatives in electrochemical CO2RR are systematically reviewed, with emphasis on the structural evolution and product selectivity of these electrocatalysts. What is more, the current challenges and future directions of perovskite-based materials regarding efficient CO2RR are proposed, to shed light on the further development of this prospective research area. Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry 2.0)
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25 pages, 7395 KiB  
Review
A Review on the Morphology, Cultivation, Identification, Phytochemistry, and Pharmacology of Kitagawia praeruptora (Dunn) Pimenov
Molecules 2023, 28(24), 8153; https://doi.org/10.3390/molecules28248153 - 18 Dec 2023
Viewed by 569
Abstract
Kitagawia praeruptora (Dunn) Pimenov, commonly known as Qianhu in China, is a widely used folk Chinese herbal medicine. This article reviews its botanical traits, ethnopharmacology, cultivation techniques, identification, phytochemical compositions, and pharmacological effects. Over 70 coumarin compounds, including simple coumarins, pyranocoumarins, and furanocoumarins, [...] Read more.
Kitagawia praeruptora (Dunn) Pimenov, commonly known as Qianhu in China, is a widely used folk Chinese herbal medicine. This article reviews its botanical traits, ethnopharmacology, cultivation techniques, identification, phytochemical compositions, and pharmacological effects. Over 70 coumarin compounds, including simple coumarins, pyranocoumarins, and furanocoumarins, have been isolated within this plant. Additionally, K. praeruptora contains other components such as flavonoids, fatty acids, benzoic acids, and sterols. This information highlights the importance of utilizing active ingredients and excavating pharmacological effects. With its remarkable versatility, K. praeruptora exhibits a wide range of pharmacological effects. It has been found to possess expectorant and bronchodilator properties, cardiovascular protection, antimicrobial and antioxidant activities, anti-tumor effects, and even antidiabetic properties. It is recommended to focus on the development of new drugs that leverage the active ingredients of K. praeruptora and explore its potential for new clinical applications and holistic utilization. Full article
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24 pages, 6872 KiB  
Article
On the Question of Zwitterionic Intermediates in the [3+2] Cycloaddition Reactions between Aryl Azides and Ethyl Propiolate
Molecules 2023, 28(24), 8152; https://doi.org/10.3390/molecules28248152 - 18 Dec 2023
Viewed by 456
Abstract
The molecular mechanism of the [3+2] cycloaddition reactions between aryl azides and ethyl propiolate was evaluated in the framework of the Molecular Electron Density Theory. It was found that independently of the nature of the substituent within the azide molecule, the cycloaddition process [...] Read more.
The molecular mechanism of the [3+2] cycloaddition reactions between aryl azides and ethyl propiolate was evaluated in the framework of the Molecular Electron Density Theory. It was found that independently of the nature of the substituent within the azide molecule, the cycloaddition process is realized via a polar but single-step mechanism. All attempts of localization as postulated earlier by Abu-Orabi and coworkers’ zwitterionic intermediates were not successful. At the same time, the formation of zwitterions with an “extended” conformation is possible on parallel reaction paths. The ELF analysis shows that the studied cycloaddition reaction leading to the 1,4-triazole proceeds by a two-stage one-step mechanism. It also revealed that both zwitterions are created by the donation of the nitrogen atom’s nonbonding electron densities to carbon atoms of ethyl propiolate. Full article
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18 pages, 6141 KiB  
Article
Construction of Ketoenamine-Based Covalent Organic Frameworks with Electron-Rich Sites for Efficient and Rapid Removal of Iodine from Solution
Molecules 2023, 28(24), 8151; https://doi.org/10.3390/molecules28248151 - 18 Dec 2023
Viewed by 797
Abstract
Porous covalent organic frameworks (COFs) have been widely used for the efficient removal of iodine from solution due to their abundance of electron-rich sites. In this study, two kinds of ketoenamine-based COFs, TpBD-(OMe)2 and TpBD-Me2, are successfully synthesized via Schiff [...] Read more.
Porous covalent organic frameworks (COFs) have been widely used for the efficient removal of iodine from solution due to their abundance of electron-rich sites. In this study, two kinds of ketoenamine-based COFs, TpBD-(OMe)2 and TpBD-Me2, are successfully synthesized via Schiff base reaction under solvothermal conditions using 1, 3, 5-triformylphoroglucinol as aldehyde monomer, o-tolidine and o-dianisidine as amino monomers. The ability of TpBD-(OMe)2 and TpBD-Me2 to adsorb iodine in cyclohexane or aqueous solutions has been quantitatively analyzed and interpreted in terms of adsorption sites. TpBD-Me2 possesses two adsorption sites, -NH- and -C=O, and exhibits an adsorption capacity of 681.67 mg/g in cyclohexane, with an initial adsorption rate of 0.6 g/mol/min with respect to COF unit cell. The adsorption capacity of TpBD-(OMe)2 can be as high as 728.77 mg/g, and the initial adsorption rate of TpBD-(OMe)2 can reach 1.2 g/mol/min in the presence of oxygen atoms between the methyl group and the benzene ring. Compared with TpBD-Me2, the higher adsorption capacity and adsorption rate of TpBD-(OMe)2 towards iodine are not only reflected in organic solvents, but also in aqueous solutions. It is proven through X-ray photoelectron spectroscopy and Raman spectroscopy that iodine exists in the form of I2, I3, and I5 within TpBD-(OMe)2 and TpBD-Me2 after adsorption. This work not only expands the application of COFs in the field of iodine adsorption, but also provides research ideas and important an experimental basis for the optimization of iodine adsorption sites. Full article
(This article belongs to the Special Issue Adsorbents in Treatment of Pollutants)
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20 pages, 1365 KiB  
Review
Recent Progress on Green New Phase Extraction and Preparation of Polyphenols in Edible Oil
Molecules 2023, 28(24), 8150; https://doi.org/10.3390/molecules28248150 - 18 Dec 2023
Viewed by 601
Abstract
With the proposal of replacing toxic solvents with non-toxic solvents in the concept of green chemistry, the development and utilization of new green extraction techniques have become a research hotspot. Phenolic compounds in edible oils have good antioxidant activity, but due to their [...] Read more.
With the proposal of replacing toxic solvents with non-toxic solvents in the concept of green chemistry, the development and utilization of new green extraction techniques have become a research hotspot. Phenolic compounds in edible oils have good antioxidant activity, but due to their low content and complex matrix, it is difficult to achieve a high extraction rate in a green and efficient way. This paper reviews the current research status of novel extraction materials in solid-phase extraction, including carbon nanotubes, graphene and metal–organic frameworks, as well as the application of green chemical materials in liquid-phase extraction, including deep eutectic solvents, ionic liquids, supercritical fluids and supramolecular solvents. The aim is to provide a more specific reference for realizing the green and efficient extraction of polyphenolic compounds from edible oils, as well as another possibility for the future research trend of green extraction technology. Full article
(This article belongs to the Section Green Chemistry)
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16 pages, 3514 KiB  
Article
Graphitic Carbon Nitride/MOFs Hybrid Composite as Highly Selective and Sensitive Electrodes for Calcium Ion Detection
Molecules 2023, 28(24), 8149; https://doi.org/10.3390/molecules28248149 - 18 Dec 2023
Viewed by 537
Abstract
The metal–organic framework (MOF) is a class of materials that exhibits a notable capacity for electron transfer. This unique framework design offers potential applications in various fields, including catalysis, gas storage, and sensing. Herein, we focused on a specific type of MOF called [...] Read more.
The metal–organic framework (MOF) is a class of materials that exhibits a notable capacity for electron transfer. This unique framework design offers potential applications in various fields, including catalysis, gas storage, and sensing. Herein, we focused on a specific type of MOF called Ti-MOF. To enhance its properties and functionality, the composite material was prepared by incorporating graphitic carbon nitride (g-C3N4) into the Ti-MOF structure. This composite, known as g-C3N4@Ti-MOF, was selected as the active material for ion detection, specifically targeting calcium ions (Ca2+). To gain a comprehensive understanding of the structural and chemical properties of the g-C3N4@Ti-MOF composite, several analytical techniques were employed to characterize the prepared g-C3N4@Ti-MOF composite, including X-ray diffraction (XRD), SEM-EDX, and FT-IR. For comparison, different pastes were prepared by mixing Ti-MOF or g-C3N4@Ti-MOF, graphite, and o-NPOE as a plasticizer. The divalent Nernstian responses of the two best electrodes, I and II, were 28.15 ± 0.47 and 29.80 ± 0.66 mV decade−1, respectively, with concentration ranges of 1 µM–1 mM and 0.1 µM–1 mM with a content 1.0 mg Ti-MOF: 250 mg graphite: 0.1 mL o-NPOE and 0.5 mg g-C3N4@Ti-MOF: 250 mg graphite: 0.1 mL o-NPOE, respectively. The electrodes showed high sensitivity and selectivity for Ca2+ ions over different species. The suggested electrodes have been successfully employed for Ca2+ ion measurement in various real samples with excellent precision (RSD = 0.74–1.30%) and accuracy (recovery = 98.5–100.2%), and they exhibited good agreement with the HPLC. Full article
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18 pages, 4149 KiB  
Article
Probing Antibacterial and Anticancer Potential of Selenicereus undatus, Pistacia vera L. and Olea europaea L. against Uropathogens, MCF-7 and A2780 Cancer Cells
Molecules 2023, 28(24), 8148; https://doi.org/10.3390/molecules28248148 - 18 Dec 2023
Viewed by 911
Abstract
Urinary tract infection is an infectious disease that requires immediate treatment. It can occur in any age group and involves both genders equally. The present study was to check the resistance of some antibiotics and to assess the antibacterial potential of three extracts [...] Read more.
Urinary tract infection is an infectious disease that requires immediate treatment. It can occur in any age group and involves both genders equally. The present study was to check the resistance of some antibiotics and to assess the antibacterial potential of three extracts of three plants against notorious bacteria involved in urinary tract infections. Along with assessing the antibacterial activity of plant extracts, we checked for the anticancer potential of these extracts against the cancer cell lines MCF-7 and A2780. Cancer is the leading cause of mortality in developed countries. Determinations of total flavonoid content, total phenolic content, total alkaloid content, total tannin content, total carotenoid content, and total steroid content were performed. The disk diffusion method was used to analyze the antibacterial activity of plant extracts. Ethanolic extract of Selenicereus undatus showed sensitivity (25–28 mm) against bacteria, whereas chloroform and hexane extracts showed resistance against all bacteria except Staphylococcus (25 mm). Ethanolic extract of Pistacia vera L. showed sensitivity (22–25 mm) against bacteria, whereas chloroform and hexane extracts showed resistance. Ethanolic extract of Olea europaea L. showed sensitivity (8–16 mm) against all bacteria except Staphylococcus, whereas chloroform and hexane extracts showed resistance. Positive controls showed variable zones of inhibition (2–60 mm), and negative control showed 0–1 mm. The antibiotic resistance was much more prominent in the case of hexane and chloroform extracts of all plants, whereas ethanolic extract showed a sensitivity of bacteria against extracts. Both cell lines, MCF-7 and A2780, displayed decreased live cells when treated with plant extracts. Full article
(This article belongs to the Special Issue Phytochemical Profile and Biological Evaluation of Plant Extracts)
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12 pages, 1578 KiB  
Article
Accelerating Kinetics with Time-Reversal Path Sampling
Molecules 2023, 28(24), 8147; https://doi.org/10.3390/molecules28248147 - 18 Dec 2023
Viewed by 478
Abstract
In comparison to numerous enhanced sampling methods for equilibrium thermodynamics, accelerating simulations for kinetics and nonequilibrium statistics are relatively rare and less effective. Here, we derive a time-reversal path sampling (tRPS) method based on time reversibility to accelerate simulations for determining the transition [...] Read more.
In comparison to numerous enhanced sampling methods for equilibrium thermodynamics, accelerating simulations for kinetics and nonequilibrium statistics are relatively rare and less effective. Here, we derive a time-reversal path sampling (tRPS) method based on time reversibility to accelerate simulations for determining the transition rates between free-energy basins. It converts the difficult uphill path sampling into an easy downhill problem. This method is easy to implement, i.e., forward and backward shooting simulations with opposite initial velocities are conducted from random initial conformations within a transition-state region until they reach the basin minima, which are then assembled to give the distribution of transition paths efficiently. The effects of tRPS are demonstrated using a comparison with direct simulations of protein folding and unfolding, where tRPS is shown to give results consistent with direct simulations and increase the efficiency by up to five orders of magnitude. This approach is generally applicable to stochastic processes with microscopic reversibility, regardless of whether the variables are continuous or discrete. Full article
(This article belongs to the Section Physical Chemistry)
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15 pages, 6103 KiB  
Article
Monometallic and Bimetallic Catalysts Supported on Praseodymium-Doped Ceria for the Water–Gas Shift Reaction
Molecules 2023, 28(24), 8146; https://doi.org/10.3390/molecules28248146 - 18 Dec 2023
Viewed by 640
Abstract
The water–gas shift (WGS) performance was investigated over 5%Ni/CeO2, 5%Ni/Ce0.95Pr0.05O1.975, and 1%Re4%Ni/Ce0.95Pr0.05O1.975 catalysts to decrease the CO amount and generate extra H2. CeO2 and Pr-doped CeO2 [...] Read more.
The water–gas shift (WGS) performance was investigated over 5%Ni/CeO2, 5%Ni/Ce0.95Pr0.05O1.975, and 1%Re4%Ni/Ce0.95Pr0.05O1.975 catalysts to decrease the CO amount and generate extra H2. CeO2 and Pr-doped CeO2 mixed oxides were synthesized using a combustion method. After that, Ni and Re were loaded onto the ceria support via an impregnation method. The structural and redox characteristics of monometallic Ni and bimetallic NiRe materials, which affect their water–gas shift performance, were investigated. The results show that the Pr addition into Ni/ceria increases the specific surface area, decreases the ceria crystallite size, and improves the dispersion of Ni on the CeO2 surface. Furthermore, Re addition results in the enhancement of the WGS performance of the Ni/Ce0.95Pr0.05O1.975 catalyst. Among the studied catalysts, the ReNi/Ce0.95Pr0.05O1.975 catalyst showed the highest catalytic activity, reaching 96% of CO conversion at 330°. It was established that the occurrence of more oxygen vacancies accelerates the redox process at the ceria surface. In addition, an increase in the Ni dispersion, Ni surface area, and surface acidity has a positive effect on hydrogen generation during the water–gas shift reaction due to favored CO adsorption. Full article
(This article belongs to the Special Issue New Materials and Catalysis in Environmental Protection)
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5 pages, 204 KiB  
Editorial
Study on Physicochemical Properties of Food Protein
Molecules 2023, 28(24), 8145; https://doi.org/10.3390/molecules28248145 - 18 Dec 2023
Viewed by 574
Abstract
As the global population continues to grow, the demand for sustainable and nutritious food sources has never been higher [...] Full article
(This article belongs to the Special Issue Study on Physicochemical Properties of Food Protein)
21 pages, 2073 KiB  
Article
Effect of Linear Energy Transfer on Cystamine’s Radioprotective Activity: A Study Using the Fricke Dosimeter with 6–500 MeV per Nucleon Carbon Ions—Implication for Carbon Ion Hadrontherapy
Molecules 2023, 28(24), 8144; https://doi.org/10.3390/molecules28248144 - 18 Dec 2023
Viewed by 650
Abstract
(1) Background: Radioprotective agents have garnered considerable interest due to their prospective applications in radiotherapy, public health medicine, and situations of large-scale accidental radiation exposure or impending radiological emergencies. Cystamine, an organic diamino–disulfide compound, is recognized for its radiation-protective and antioxidant properties. This [...] Read more.
(1) Background: Radioprotective agents have garnered considerable interest due to their prospective applications in radiotherapy, public health medicine, and situations of large-scale accidental radiation exposure or impending radiological emergencies. Cystamine, an organic diamino–disulfide compound, is recognized for its radiation-protective and antioxidant properties. This study aims to utilize the aqueous ferrous sulfate (Fricke) dosimeter to measure the free-radical scavenging capabilities of cystamine during irradiation by fast carbon ions. This analysis spans an energy range from 6 to 500 MeV per nucleon, which correlates with “linear energy transfer” (LET) values ranging from approximately 248 keV/μm down to 9.3 keV/μm. (2) Methods: Monte Carlo track chemistry calculations were used to simulate the radiation-induced chemistry of aerated Fricke–cystamine solutions across a broad spectrum of cystamine concentrations, ranging from 10−6 to 1 M. (3) Results: In irradiated Fricke solutions containing cystamine, cystamine is observed to hinder the oxidation of Fe2+ ions, an effect triggered by oxidizing agents from the radiolysis of acidic water, resulting in reduced Fe3+ ion production. Our simulations, conducted both with and without accounting for the multiple ionization of water, confirm cystamine’s ability to capture free radicals, highlighting its strong antioxidant properties. Aligning with prior research, our simulations also indicate that the protective and antioxidant efficiency of cystamine diminishes with increasing LET of the radiation. This result can be attributed to the changes in the geometry of the track structures when transitioning from lower to higher LETs. (4) Conclusions: If we can apply these fundamental research findings to biological systems at a physiological pH, the use of cystamine alongside carbon-ion hadrontherapy could present a promising approach to further improve the therapeutic ratio in cancer treatments. Full article
(This article belongs to the Section Medicinal Chemistry)
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9 pages, 2538 KiB  
Communication
Concerns on the Effects of Electrode Positions in Electrolyte Container for the Oxygen Evolution Reaction
Molecules 2023, 28(24), 8143; https://doi.org/10.3390/molecules28248143 - 18 Dec 2023
Viewed by 602
Abstract
Water electrolysis is currently a major technique to produce clean hydrogen, which is regarded as a promising and sustainable energy carrier. The efficiency of water electrolysis is highly dependent on the oxygen evolution reaction (OER) on the anode. The evaluation of an OER [...] Read more.
Water electrolysis is currently a major technique to produce clean hydrogen, which is regarded as a promising and sustainable energy carrier. The efficiency of water electrolysis is highly dependent on the oxygen evolution reaction (OER) on the anode. The evaluation of an OER electrocatalyst is frequently carried out on a three-electrode system in a container of electrolyte. Herein, we found that the electrode positions in the electrolyte container could significantly affect the data acquisition of OER performance. After a detailed investigation, we reveal that the difference of the OER activity of an electrocatalyst at a different position is originated from their different iRu drop and the gas diffusion resistance. For the first time, this work evokes concerns on the accurate evaluation of electrocatalysts regarding the electrode position. For fair comparisons and reliable results, it is strongly suggested to keep the electrode position unchanged in the electrochemical measurements. In addition, the establishment of a standard electrolyzer setup for electrocatalysis evaluation in the electrochemical community is also called for. Full article
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15 pages, 14174 KiB  
Article
Dapoxetine, a Selective Serotonin Reuptake Inhibitor, Suppresses Zika Virus Infection In Vitro
Molecules 2023, 28(24), 8142; https://doi.org/10.3390/molecules28248142 - 17 Dec 2023
Viewed by 920
Abstract
Zika virus (ZIKV) belongs to the Flavivirus genus of the Flaviviridae family, and is a pathogen posing a significant threat to human health. Currently, there is a lack of internationally approved antiviral drugs for the treatment of ZIKV infection, and symptomatic management remains [...] Read more.
Zika virus (ZIKV) belongs to the Flavivirus genus of the Flaviviridae family, and is a pathogen posing a significant threat to human health. Currently, there is a lack of internationally approved antiviral drugs for the treatment of ZIKV infection, and symptomatic management remains the primary clinical approach. Consequently, the exploration of safe and effective anti-ZIKV drugs has emerged as a paramount imperative in ZIKV control efforts. In this study, we performed a screening of a compound library consisting of 1789 FDA-approved drugs to identify potential agents with anti-ZIKV activity. We have identified dapoxetine, an orally administered selective serotonin reuptake inhibitor (SSRI) commonly employed for the clinical management of premature ejaculation (PE), as a potential inhibitor of ZIKV RNA-dependent RNA polymerase (RdRp). Consequently, we conducted surface plasmon resonance (SPR) analysis to validate the specific binding of dapoxetine to ZIKV RdRp, and further evaluated its inhibitory effect on ZIKV RdRp synthesis using the ZIKV Gluc reporter gene assay. Furthermore, we substantiated the efficacy of dapoxetine in suppressing intracellular replication of ZIKV, thereby demonstrating a concentration-dependent antiviral effect (EC50 values ranging from 4.20 μM to 12.6 μM) and negligible cytotoxicity (CC50 > 50 μM) across diverse cell lines. Moreover, cell fluorescence staining and Western blotting assays revealed that dapoxetine effectively reduced the expression of ZIKV proteins. Collectively, our findings suggest that dapoxetine exhibits anti-ZIKV effects by inhibiting ZIKV RdRp activity, positioning it as a potential candidate for clinical therapeutic intervention against ZIKV infection. Full article
(This article belongs to the Special Issue Strategies in the Design and Development of Antiviral Drugs)
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28 pages, 4538 KiB  
Review
Quercetin: A Potential Polydynamic Drug
Molecules 2023, 28(24), 8141; https://doi.org/10.3390/molecules28248141 - 17 Dec 2023
Viewed by 1898
Abstract
The study of natural products as potential drug leads has gained tremendous research interest. Quercetin is one of those natural products. It belongs to the family of flavonoids and, more specifically, flavonols. This review summarizes the beneficial pharmaceutical effects of quercetin, such as [...] Read more.
The study of natural products as potential drug leads has gained tremendous research interest. Quercetin is one of those natural products. It belongs to the family of flavonoids and, more specifically, flavonols. This review summarizes the beneficial pharmaceutical effects of quercetin, such as its anti-cancer, anti-inflammatory, and antimicrobial properties, which are some of the quercetin effects described in this review. Nevertheless, quercetin shows poor bioavailability and low solubility. For this reason, its encapsulation in macromolecules increases its bioavailability and therefore pharmaceutical efficiency. In this review, a brief description of the different forms of encapsulation of quercetin are described, and new ones are proposed. The beneficial effects of applying new pharmaceutical forms of nanotechnology are outlined. Full article
(This article belongs to the Section Macromolecular Chemistry)
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21 pages, 6033 KiB  
Article
Reactive Molecular Dynamics Study of Pollutant Formation Mechanism in Hydrogen/Ammonia/Methanol Ternary Carbon-Neutral Fuel Blend Combustion
Molecules 2023, 28(24), 8140; https://doi.org/10.3390/molecules28248140 - 17 Dec 2023
Viewed by 727
Abstract
Hydrogen, ammonia, and methanol are typical carbon-neutral fuels. Combustion characteristics and pollutant formation problems can be significantly improved by their blending. In this paper, reactive molecular dynamics were used to investigate the pollutant formation characteristics of hydrogen/ammonia/methanol blended fuel combustion and to analyze [...] Read more.
Hydrogen, ammonia, and methanol are typical carbon-neutral fuels. Combustion characteristics and pollutant formation problems can be significantly improved by their blending. In this paper, reactive molecular dynamics were used to investigate the pollutant formation characteristics of hydrogen/ammonia/methanol blended fuel combustion and to analyze the mechanisms of CO, CO2, and NOX formation at different temperatures and blending ratios. It was found that heating can significantly increase blending and combustion efficiency, leading to more active oxidizing groups and thus inhibiting N2 production. Blended combustion pollutant formation was affected by coupling effects. NH3 depressed the rate of CO production when CH4O was greater than 30%, but the amount of CO and CO2 was mainly determined by CH4O. This is because CH4O provides more OH, H, and carbon atoms for CO and CO2 to collide efficiently. CH4O facilitates the combustion of NH3 by simplifying the reaction pathway, making it easier to form NOX. Full article
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22 pages, 1722 KiB  
Review
A Review on Bioactive Anthraquinone and Derivatives as the Regulators for ROS
Molecules 2023, 28(24), 8139; https://doi.org/10.3390/molecules28248139 - 17 Dec 2023
Viewed by 902
Abstract
Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development [...] Read more.
Anthraquinones are bioactive natural products, which are often found in medicinal herbs. These compounds exert antioxidant-related pharmacological actions including neuroprotective effects, anti-inflammation, anticancer, hepatoprotective effects and anti-aging, etc. Considering the benefits from their pharmacological use, recently, there was an upsurge in the development and utilization of anthraquinones as reactive oxygen species (ROS) regulators. In this review, a deep discussion was carried out on their antioxidant activities and the structure-activity relationships. The antioxidant mechanisms and the chemistry behind the antioxidant activities of both natural and synthesized compounds were furtherly explored and demonstrated. Due to the specific chemical activity of ROS, antioxidants are essential for human health. Therefore, the development of reagents that regulate the imbalance between ROS formation and elimination should be more extensive and rational, and the exploration of antioxidant mechanisms of anthraquinones may provide new therapeutic tools and ideas for various diseases mediated by ROS. Full article
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28 pages, 2241 KiB  
Review
Shade of Innovative Food Processing Techniques: Potential Inducing Factors of Lipid Oxidation
Molecules 2023, 28(24), 8138; https://doi.org/10.3390/molecules28248138 - 17 Dec 2023
Viewed by 940
Abstract
With increasing environmental awareness and consumer demand for high-quality food products, industries are strongly required for technical innovations. The use of various emerging techniques in food processing indeed brings many economic and environmental benefits compared to conventional processes. However, lipid oxidation induced by [...] Read more.
With increasing environmental awareness and consumer demand for high-quality food products, industries are strongly required for technical innovations. The use of various emerging techniques in food processing indeed brings many economic and environmental benefits compared to conventional processes. However, lipid oxidation induced by some “innovative” processes is often “an inconvenient truth”, which is scarcely mentioned in most studies but should not be ignored for the further improvement and optimization of existing processes. Lipid oxidation poses a risk to consumer health, as a result of the possible ingestion of secondary oxidation products. From this point of view, this review summarizes the advance of lipid oxidation mechanism studies and mainly discloses the shade of innovative food processing concerning lipid degradation. Sections involving a revisit of classic three-stage chain reaction, the advances of polar paradox and cut-off theories, and potential lipid oxidation factors from emerging techniques are described, which might help in developing more robust guidelines to ensure a good practice of these innovative food processing techniques in future. Full article
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18 pages, 3961 KiB  
Article
Upgrading Pyrolytic Residue from End-of-Life Tires to Efficient Heterogeneous Catalysts for the Conversion of Glycerol to Acetins
Molecules 2023, 28(24), 8137; https://doi.org/10.3390/molecules28248137 - 17 Dec 2023
Viewed by 641
Abstract
Recovered carbon blacks (rCBs) produced from end-of-life tires using pyrolysis were transformed into solid acid catalysts for the synthesis of acetins, i.e., products with a wide spectrum of practical applications. Tuning the chemical properties of the surface of samples and introducing specific functional [...] Read more.
Recovered carbon blacks (rCBs) produced from end-of-life tires using pyrolysis were transformed into solid acid catalysts for the synthesis of acetins, i.e., products with a wide spectrum of practical applications. Tuning the chemical properties of the surface of samples and introducing specific functional groups on the rCBs were achieved through carbon functionalization with concentrated H2SO4. The initial and modified rCBs were thoroughly characterized using techniques such as elemental analysis, potentiometric back titration, thermogravimetric technique, scanning and transmission microscopy, X-ray photoelectron spectroscopy, etc. The catalytic activities of the samples were measured via batch mode glycerol acetylation performed at 110 °C and compared to the catalytic performance of the functionalized commercial carbon black. The modified rCBs were found to show a significant catalytic effect in the tested reaction, giving high glycerol conversions (above 95%) and satisfactory combined yields of diacetins and triacetin (~72%) within 4 h; this behavior was attributed to the presence of -SO3H moieties on the surface of functionalized rCBs. The reusability tests indicated that the modified samples were catalytically stable in subsequent acetylation runs. The obtained results evidenced the feasibility of using end-of-life tires for the production of effective acid catalysts for glycerol valorization processes. Full article
(This article belongs to the Special Issue Design, Synthesis and Application of Heterogeneous Catalysts)
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13 pages, 6713 KiB  
Article
Mild and Efficient One-Step Synthesis of Nitrogen-Doped Multistage Porous Carbon for High-Performance Supercapacitors
Molecules 2023, 28(24), 8136; https://doi.org/10.3390/molecules28248136 - 17 Dec 2023
Viewed by 686
Abstract
Biomass-derived carbon materials have broad application prospects in energy storage, but still face problems such as complex synthesis paths and the massive use of corrosive activators. In this study, we proposed a mild and efficient pathway to prepare nitrogen-doped porous carbon material (N-YAC) [...] Read more.
Biomass-derived carbon materials have broad application prospects in energy storage, but still face problems such as complex synthesis paths and the massive use of corrosive activators. In this study, we proposed a mild and efficient pathway to prepare nitrogen-doped porous carbon material (N-YAC) using one-step pyrolysis with solid K2CO3, tobacco straw, and melamine. The optimized material (N-YAC0.5) was not only enriched with nitrogen, but also exhibited a high specific surface area (2367 m2/g) and a reasonable pore size distribution (46.49% mesopores). When utilized in electrodes, N-YAC0.5 exhibited an excellent capacitance performance (338 F/g at 1 A/g) in the three-electrode system, and benefitted from a high mesopore distribution that maintained a capacitance of 85.2% (288 F/g) at high current densities (20 A/g). Furthermore, the composed symmetric capacitor achieved an energy density of 14.78 Wh/kg at a power density of 400 W/kg. In summary, our work provides a novel and eco-friendly approach for converting biomass into high-performance energy-storage materials. Full article
(This article belongs to the Special Issue Modern Materials in Energy Storage and Conversion)
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15 pages, 2767 KiB  
Article
An Aptamer-Based Lateral Flow Biosensor for Low-Cost, Rapid and Instrument-Free Detection of Ochratoxin A in Food Samples
Molecules 2023, 28(24), 8135; https://doi.org/10.3390/molecules28248135 - 17 Dec 2023
Viewed by 611
Abstract
In this work, a simple and cost-efficient aptasensor strip is developed for the rapid detection of OTA in food samples. The biosensor is based on the lateral flow assay concept using an OTA-specific aptamer for biorecognition of the target analyte. The strip consists [...] Read more.
In this work, a simple and cost-efficient aptasensor strip is developed for the rapid detection of OTA in food samples. The biosensor is based on the lateral flow assay concept using an OTA-specific aptamer for biorecognition of the target analyte. The strip consists of a sample pad, a conjugate pad, a nitrocellulose membrane (NC) and an absorbent pad. The conjugate pad is loaded with the OTA-specific aptamer conjugated with gold nanoparticles (AuNPs). The test line of the NC membrane is loaded with a specific OTA-aptamer probe and the control line is loaded with a control probe. The assay is based on a competitive format, where the OTA present in the sample combines with the OTA aptamer-AuNP conjugate and prevents the interaction between the specific probe immobilized on the test line and the OTA aptamer-AuNP conjugates; therefore, the color intensity of the test line decreases as the concentration of OTA in the sample increases. Qualitative detection of OTA is performed visually, while quantification is performed by reflectance colorimetry using a commercial scanner and image analysis. All the parameters of the assay are investigated in detail and the analytical features are established. The visual limit of detection (LOD) of the strip is 0.05 ng mL−1, while the LOD for semi-quantitative detection using reflectance colorimetry is 0.02 ng mL−1. The lateral flow strip aptasensor is applied to the detection of OTA in wine, beer, apple juice and milk samples with recoveries in the range from 91 to 114%. The assay exhibits a satisfactory selectivity for OTA with respect to other mycotoxins and lasts 20 min. Therefore, the lateral flow strip aptasensor could be useful for the rapid, low-cost and fit-for-purpose on-site detection of OTA in food samples. Full article
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21 pages, 7329 KiB  
Review
A Review of Dual-Emission Carbon Dots and Their Applications
Molecules 2023, 28(24), 8134; https://doi.org/10.3390/molecules28248134 - 17 Dec 2023
Viewed by 767
Abstract
Carbon dots (CDs), as a rising star among fluorescent nanomaterials with excellent optical properties and fascinating dual-emission characteristics, have attracted increasing attention in sensing, bio-imaging, drug delivery, and so on. The synthesis of dual-emission CDs (DE-CDs) and the establishment of ratiometric fluorescence sensors [...] Read more.
Carbon dots (CDs), as a rising star among fluorescent nanomaterials with excellent optical properties and fascinating dual-emission characteristics, have attracted increasing attention in sensing, bio-imaging, drug delivery, and so on. The synthesis of dual-emission CDs (DE-CDs) and the establishment of ratiometric fluorescence sensors can effectively diminish background interference and provide more accurate results than single-emission CDs. Although DE-CDs have generated increased attention in many fields, the review articles about DE-CDs are still insufficient. Therefore, we summarized the latest results and prepared this review. This review first provides an overview of the primary synthesis route and commonly used precursors in DE-CDs synthesis. Then, the photoluminescence mechanism behind the dual-emission phenomenon was discussed. Thirdly, the application of DE-CDs in metal cation detection, food safety analysis, biosensing, cell imaging, and optoelectronic devices has been extensively discussed. Finally, the main challenges and prospects for further development are presented. This review presents the latest research progress of DE-CDs synthesis and its application in ratiometric sensing; hopefully, it can help and encourage researchers to overcome existing challenges and broaden the area of DE-CDs research. Full article
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35 pages, 1559 KiB  
Review
Mediterranean Shrub Species as a Source of Biomolecules against Neurodegenerative Diseases
Molecules 2023, 28(24), 8133; https://doi.org/10.3390/molecules28248133 - 16 Dec 2023
Viewed by 1712
Abstract
Neurodegenerative diseases are associated with oxidative stress, due to an imbalance in the oxidation-reduction reactions at the cellular level. Various treatments are available to treat these diseases, although they often do not cure them and have many adverse effects. Therefore, it is necessary [...] Read more.
Neurodegenerative diseases are associated with oxidative stress, due to an imbalance in the oxidation-reduction reactions at the cellular level. Various treatments are available to treat these diseases, although they often do not cure them and have many adverse effects. Therefore, it is necessary to find complementary and/or alternative drugs that replace current treatments with fewer side effects. It has been demonstrated that natural products derived from plants, specifically phenolic compounds, have a great capacity to suppress oxidative stress and neutralize free radicals thus, they may be used as alternative alternative pharmacological treatments for pathological conditions associated with an increase in oxidative stress. The plant species that dominate the Mediterranean ecosystems are characterized by having a wide variety of phenolic compound content. Therefore, these species might be important sources of neuroprotective biomolecules. To evaluate this potential, 24 typical plant species of the Mediterranean ecosystems were selected, identifying the most important compounds present in them. This set of plant species provides a total of 403 different compounds. Of these compounds, 35.7% are phenolic acids and 55.6% are flavonoids. The most relevant of these compounds are gallic, vanillic, caffeic, chlorogenic, p-coumaric, and ferulic acids, apigenin, kaempferol, myricitrin, quercetin, isoquercetin, quercetrin, rutin, catechin and epicatechin, which are widely distributed among the analyzed plant species (in over 10 species) and which have been involved in the literature in the prevention of different neurodegenerative pathologies. It is also important to mention that three of these plant species, Pistacea lentiscus, Lavandula stoechas and Thymus vulgaris, have most of the described compounds with protective properties against neurodegenerative diseases. The present work shows that the plant species that dominate the studied geographic area can provide an important source of phenolic compounds for the pharmacological and biotechnological industry to prepare extracts or isolated compounds for therapy against neurodegenerative diseases. Full article
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9 pages, 901 KiB  
Article
Synthesis of Mixed Chitin Esters via Acylation of Chitin in Deep Eutectic Solvents
Molecules 2023, 28(24), 8132; https://doi.org/10.3390/molecules28248132 - 16 Dec 2023
Cited by 1 | Viewed by 620
Abstract
The development of efficient derivatization methods of chitin, such as acylation, has been identified to confer new properties and functions to chitin. In this study, we investigate the synthesis of mixed chitin esters via the acylation of chitin in deep eutectic solvents (DESs) [...] Read more.
The development of efficient derivatization methods of chitin, such as acylation, has been identified to confer new properties and functions to chitin. In this study, we investigate the synthesis of mixed chitin esters via the acylation of chitin in deep eutectic solvents (DESs) comprising 1-allyl-3-methylimidazolum chloride and 1,1,3,3-tetramethylguanidine based on a previous study that reported the development of efficient acylation of chitin in the DES to obtain single chitin esters. A stearoyl group was selected as the first substituent, which was combined with several bulky acyl and long oleoyl groups as the second substituents. After dissolution of chitin in the DES (2 wt%), the acylation reactions were conducted using stearoyl and the desired acyl chlorides for 1 h + 24 h at 100 °C in the resulting solutions. The IR and 1H NMR spectra of the isolated products confirmed the structures of mixed chitin esters with two different substituents. The substituent ratios in the derivatives, which were estimated via the 1H NMR analysis, were changed according to the feed ratios of two acyl chlorides. Full article
(This article belongs to the Special Issue Organic Reactions in Deep Eutectic Solvents)
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15 pages, 4746 KiB  
Article
Glycyrrhetinic Acid Receptor-Mediated Zeolitic Imidazolate Framework-8 Loaded Doxorubicin as a Nanotherapeutic System for Liver Cancer Treatment
Molecules 2023, 28(24), 8131; https://doi.org/10.3390/molecules28248131 - 16 Dec 2023
Viewed by 603
Abstract
In this study, we designed and developed a DOX nanodrug delivery system (PEG-GA@ZIF-8@DOX) using ZIF-8 as the carrier and glycyrrhetinic acid (GA) as the targeting ligand. We confirmed that DOX was loaded and PEG-GA was successfully modified on the surface of the nanoparticles. [...] Read more.
In this study, we designed and developed a DOX nanodrug delivery system (PEG-GA@ZIF-8@DOX) using ZIF-8 as the carrier and glycyrrhetinic acid (GA) as the targeting ligand. We confirmed that DOX was loaded and PEG-GA was successfully modified on the surface of the nanoparticles. The in vitro release profile of the system was investigated at pH 5.0 and 7.4. The cellular uptake, in vitro cytotoxicity, and lysosomal escape characteristics were examined using HepG2 cells. We established an H22 tumor-bearing mouse model and evaluated the in vivo antitumor activity. The results showed that the system had a uniform nanomorphology. The drug loading capacity was 11.22 ± 0.87%. In acidic conditions (pH 5.0), the final release rate of DOX was 57.73%, while at pH 7.4, it was 25.12%. GA-mediated targeting facilitated the uptake of DOX by the HepG2 cells. PEG-GA@ZIF-8@DOX could escape from the lysosomes and release the drug in the cytoplasm, thus exerting its antitumor effect. When the in vivo efficacy was analyzed, we found that the tumor inhibition rate of PEG-GA@ZIF-8@DOX was 67.64%; it also alleviated the loss of the body weight of the treated mice. This drug delivery system significantly enhanced the antitumor effect of doxorubicin in vitro and in vivo, while mitigating its toxic side effects. Full article
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14 pages, 3861 KiB  
Article
N-Methyl- and N-Phenylpiperazine Functionalized Styryl Dyes Inside Cucurbiturils: Theoretical Assessment of the Factors Governing the Host–Guest Recognition
Molecules 2023, 28(24), 8130; https://doi.org/10.3390/molecules28248130 - 16 Dec 2023
Viewed by 638
Abstract
The family of cucurbiturils (CBs), the unique pumpkin-shaped macrocycles, has received great attention over the past four decades owing to their remarkable recognition properties. They have found diverse applications including biosensing and drug delivery technologies. The cucurbituril complexation of guest molecules can modulate [...] Read more.
The family of cucurbiturils (CBs), the unique pumpkin-shaped macrocycles, has received great attention over the past four decades owing to their remarkable recognition properties. They have found diverse applications including biosensing and drug delivery technologies. The cucurbituril complexation of guest molecules can modulate their pKas, improve their solubility in aqueous solution, and reduce the adverse effects of the drugs, as well as enhance the stability and/or enable targeted delivery of the drug molecule. Employing twelve cationic styryl dyes with N-methyl- and N-phenylpiperazine functionality as probes, we attempted to understand the factors that govern the host–guest complexation of such molecules within CB[7] and CB[8] host systems. Various key factors determining the process were recognized, such as the pH and dielectric constant of the medium, the cavity size of the host, the chemical characteristics of the substituents in the guest entity, and the presence/absence of metal cations. The presented results add to our understanding (at the molecular level) of the mechanism of encapsulation of styryl dyes by cucurbiturils, thus shedding new light on various aspects of the intriguing complexation chemistry and the underlying recognition processes. Full article
(This article belongs to the Special Issue Molecular Modeling: Advancements and Applications II)
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21 pages, 3332 KiB  
Article
Extraction of Pyrrole from Its Mixture with n-Hexadecane Using Ionic Liquids and Their Binary Mixtures
Molecules 2023, 28(24), 8129; https://doi.org/10.3390/molecules28248129 - 16 Dec 2023
Viewed by 690
Abstract
The conventional hydrodenitrogenation method is expensive and involves the use of catalysts and harsh procedures. In the last few years, ionic liquids (ILs) have gained attention as a promising alternative solvent for fuel oil extractive denitrogenation. In this work, the Conductor-like Screening Model [...] Read more.
The conventional hydrodenitrogenation method is expensive and involves the use of catalysts and harsh procedures. In the last few years, ionic liquids (ILs) have gained attention as a promising alternative solvent for fuel oil extractive denitrogenation. In this work, the Conductor-like Screening Model for Real Solvents (COSMO-RS) was used to screen 173 potential ILs as solvents for fuel oil. Two ILs (1-ethyl-3-methylimidazolium dicyanamide ([EMIM][N(CN)2]) and 1-ethyl-3-methylimidazolium methanesulfonate ([EMIM][MeSO3])) were selected for experimental investigation. The experimental liquid–liquid extraction of pyrrole (taken as the model nitrogen compound) from n-hexadecane (the model fuel) was conducted at 298 K and 1 atm with feed concentrations of pyrrole ranging from 10 to 50 wt%, using either the two pure ILs or their mixtures with dimethylformamide or ethylene glycol. Moreover, the NRTL model was effectively used to correlate the experimental tie lines. This work shows that the use of a binary mixture of ILs with a conventional solvent results in good selectivity, but has a low capacity for extracting pyrrole compounds. On the other hand, using an IL-IL mixture exhibits good results for both capacity and selectivity. All the ternary systems tested showed positive slopes, indicating that the nitrogen compounds had a higher affinity for the IL and binary mixture extract phase. In fact, the extraction efficiency for all the systems shows promising results. This characteristic is advantageous, as it requires less solvent to remove nitrogen compounds. Full article
(This article belongs to the Special Issue Recent Advances in Ionic Liquids and Their Applications)
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13 pages, 3663 KiB  
Article
Synthesis and Evaluation of Compound Targeting α7 and β2 Subunits in Nicotinic Acetylcholinergic Receptor
Molecules 2023, 28(24), 8128; https://doi.org/10.3390/molecules28248128 - 16 Dec 2023
Viewed by 590
Abstract
Nicotinic acetylcholine receptors (nAChRs) are involved in various central nervous system functions and have also been implicated in several neurodegenerative disorders. The heteromeric α4β2* and homomeric α7 are two major nAChR subtypes which have been studied in the brain using positron emission tomography [...] Read more.
Nicotinic acetylcholine receptors (nAChRs) are involved in various central nervous system functions and have also been implicated in several neurodegenerative disorders. The heteromeric α4β2* and homomeric α7 are two major nAChR subtypes which have been studied in the brain using positron emission tomography (PET). Our comparative autoradiographic studies of the two receptor types in the mouse and rat brains show major differences in the thalamus (α4β2* >> α7), hippocampus (α7 >> α4β2*), and subiculum (α4β2* >> α7). A relatively newer heteromeric α7β2 nAChR subtype has been identified in the brain which may have a greater role in neurodegeneration. We report the development of KS7 (3-(2-(S)-azetidinylmethoxy)-5-(1,4-diaza-bicyclo[3.2.2]nonane)pyridine) which incorporates structural features of Nifzetidine (high affinity for α4β2* nAChR) and ASEM (high affinity for α7 nAChR) in an effort to target α7 and β2 subunits in α7β2 nAChR. KS7 exhibited higher affinities (IC50 = 50 to 172 nM) for [3H]cytisine radiolabeled sites and weaker affinities (IC50 = 10 μM) for [125I]-α-bungarotoxin radiolabeled rat brain sites in several brain regions. The weaker affinity of KS7 to α7 nAChR may suggest lack of binding at the α7 subunit of α7β2 nAChR. A radiolabeled derivative of KS7 may be required to identify any specific binding to brain regions suggested to contain α7β2 nAChR. Full article
(This article belongs to the Special Issue New Advances in Radiopharmaceutical Sciences)
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