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Molecules, Volume 29, Issue 12 (June-2 2024) – 235 articles

Cover Story (view full-size image): HBV remains a global health threat. Inhibition of Ribonuclease H (RNase H) activity terminates the viral life cycle. RNase H, though promising, remains an under-explored drug target against HBV. We previously reported the identification of a series of N-hydroxypyridinedione (HPD) imines that effectively inhibit the HBV RNase H. To further explore the HPD scaffold, we designed, synthesized and evaluated several HPD oximes. The new analogues were docked on the RNase H active site, and all proved able to coordinate the two Mg2+ ions in the catalytic site. All new HPDs effectively inhibited viral replication exhibiting EC50 values in the low μM range with low cytotoxicity and significant selectivity indexes. Our findings expand the SARs on the HPD scaffold, facilitating the development of more potent anti-HBV agents. View this paper
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12 pages, 2298 KiB  
Article
Supercritical Water: A Simulation Study to Unravel the Heterogeneity of Its Molecular Structures
by Joseph Guy Gérard Ndongo Assomo, Sadollah Ebrahimi, Jean-Paul Jay-Gerin and Armand Soldera
Molecules 2024, 29(12), 2947; https://doi.org/10.3390/molecules29122947 - 20 Jun 2024
Viewed by 363
Abstract
(1) Background: In the quest to accurately model the radiolysis of water in its supercritical state, a detailed understanding of water’s molecular structure, particularly how water molecules are arranged in this unique state, is essential. (2) Methods: We conducted molecular dynamics simulations using [...] Read more.
(1) Background: In the quest to accurately model the radiolysis of water in its supercritical state, a detailed understanding of water’s molecular structure, particularly how water molecules are arranged in this unique state, is essential. (2) Methods: We conducted molecular dynamics simulations using the SPC/E water model to investigate the molecular structures of supercritical water (SCW) over a wide temperature range, extending up to 800 °C. (3) Results: Our results show that at a constant pressure of 25 MPa, the average intermolecular distance around a reference water molecule remains remarkably stable at ~2.9 Å. This uniformity persists across a substantial temperature range, demonstrating the unique heterogeneous nature of SCW under these extreme conditions. Notably, the simulations also reveal intricate patterns within SCW, indicating the simultaneous presence of regions with high and low density. As temperatures increase, we observe a rise in the formation of molecular clusters, which are accompanied by a reduction in their average size. (4) Conclusions: These findings highlight the necessity of incorporating the molecular complexity of SCW into traditional track-structure chemistry models to improve predictions of SCW behavior under ionizing radiation. The study establishes a foundational reference for further exploration of the properties of supercritical water, particularly for its application in advanced nuclear technologies, including the next generation of water-cooled reactors and their small modular reactor variants that utilize SCW as a coolant. Full article
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12 pages, 11468 KiB  
Article
Curvature-Insensitive Transparent Surface-Enhanced Raman Scattering Substrate Based on Large-Area Ag Nanoparticle-Coated Wrinkled Polystyrene/Polydimethylsiloxane Film for Reliable In Situ Detection
by Meng Sun, Lili Huang, Hongjun Wang, Zhaoyi Zhang, Huijuan Niu, Zhenshan Yang and Hefu Li
Molecules 2024, 29(12), 2946; https://doi.org/10.3390/molecules29122946 - 20 Jun 2024
Viewed by 252
Abstract
Flexible and transparent surface-enhanced Raman scattering (SERS) substrates have attracted considerable attention for their ability to enable the direct in situ detection of analytes on curved surfaces. However, the curvature of an object can impact the signal enhancement of SERS during the measurement [...] Read more.
Flexible and transparent surface-enhanced Raman scattering (SERS) substrates have attracted considerable attention for their ability to enable the direct in situ detection of analytes on curved surfaces. However, the curvature of an object can impact the signal enhancement of SERS during the measurement process. Herein, we propose a simple approach for fabricating a curvature-insensitive transparent SERS substrate by depositing silver nanoparticles (Ag NPs) onto a large-area wrinkled polystyrene/polydimethylsiloxane (Ag NP@W-PS/PDMS) bilayer film. Using rhodamine 6G (R6G) as a probe molecule, the optimized Ag NP@W-PS/PDMS film demonstrates a high analytical enhancement factor (AEF) of 4.83 × 105, excellent uniformity (RSD = 7.85%) and reproducibility (RSD = 3.09%), as well as superior mechanical flexibility. Additionally, in situ measurements of malachite green (MG) on objects with diverse curvatures, including fish, apple, and blueberry, are conducted using a portable Raman system, revealing a consistent SERS enhancement. Furthermore, a robust linear relationship (R2 ≥ 0.990) between Raman intensity and the logarithmic concentration of MG detected from these objects is achieved. These results demonstrate the tremendous potential of the developed curvature-insensitive SERS substrate as a point-of-care testing (POCT) platform for identifying analytes on irregular objects. Full article
(This article belongs to the Special Issue State-of-the-Art Analytical Technologies for Food Safety, Quality and Authenticity Assessment)
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13 pages, 3302 KiB  
Article
Unveiling the Unusual Mn(CO)3 Migration in a Manganese Cyclohexenyl Complex by DFT Computations
by Guangchao Liang and Min Zhang
Molecules 2024, 29(12), 2945; https://doi.org/10.3390/molecules29122945 - 20 Jun 2024
Viewed by 310
Abstract
Homogeneous catalysis involving a transition metal agostic interaction (TM…H…C) is an attractive strategy for C–H bond activation, in which the transition metal agostic intermediates serve as the critical component. To investigate the roles of manganese agostic intermediates in the [...] Read more.
Homogeneous catalysis involving a transition metal agostic interaction (TM…H…C) is an attractive strategy for C–H bond activation, in which the transition metal agostic intermediates serve as the critical component. To investigate the roles of manganese agostic intermediates in the unusual migration of the Mn(CO)3 fragment in the (exo-phenyl)(η3-cyclohexenyl)manganese tricarbonyl [(Ph)(η3-C6H8)Mn(CO)3] (complex 1) under the protonation of tetrafluoroboric acid–diethyl ether (HBF4.Et2O), a comprehensive density functional theory (DFT) theoretical study was performed. The computational results showed that formation of the [(cyclohex-3-enyl)-η6-benzene]manganese tricarbonyl complex [(C6H9)(η6-Ph)Mn(CO)3+][BF4] (complex 2) was achieved via a series of mono-agostic and di-agostic intermediates. The overall rate-limiting step for this unusual migration of the Mn(CO)3 fragment is the formation of the di-agostic (η2-phenyl)manganese complex 8 (4 → 5 → 8) with a Gibbs barrier of 15.4 kcal mol−1. The agostic intermediates with TM…H…C agostic interactions were well-characterized by geometry parameters, Atoms-In-Molecules (AIM) analyses, and the Natural Adaptive Orbitals (NAdOs). The located pathways in the current study successfully explained the experimental observations, and the findings on the TM…H…C agostic interaction provided a new aspect of the catalytic reaction with the manganese complex. Full article
(This article belongs to the Special Issue Metal Coordination Compounds: Synthesis, Electronic Structure, Properties and Application)
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28 pages, 5831 KiB  
Article
The RNA Helicase Ded1 from Yeast Is Associated with the Signal Recognition Particle and Is Regulated by SRP21
by Hilal Yeter-Alat, Naïma Belgareh-Touzé, Agnès Le Saux, Emmeline Huvelle, Molka Mokdadi, Josette Banroques and N. Kyle Tanner
Molecules 2024, 29(12), 2944; https://doi.org/10.3390/molecules29122944 - 20 Jun 2024
Viewed by 320
Abstract
The DEAD-box RNA helicase Ded1 is an essential yeast protein involved in translation initiation that belongs to the DDX3 subfamily. The purified Ded1 protein is an ATP-dependent RNA-binding protein and an RNA-dependent ATPase, but it was previously found to lack substrate specificity and [...] Read more.
The DEAD-box RNA helicase Ded1 is an essential yeast protein involved in translation initiation that belongs to the DDX3 subfamily. The purified Ded1 protein is an ATP-dependent RNA-binding protein and an RNA-dependent ATPase, but it was previously found to lack substrate specificity and enzymatic regulation. Here we demonstrate through yeast genetics, yeast extract pull-down experiments, in situ localization, and in vitro biochemical approaches that Ded1 is associated with, and regulated by, the signal recognition particle (SRP), which is a universally conserved ribonucleoprotein complex required for the co-translational translocation of polypeptides into the endoplasmic reticulum lumen and membrane. Ded1 is physically associated with SRP components in vivo and in vitro. Ded1 is genetically linked with SRP proteins. Finally, the enzymatic activity of Ded1 is inhibited by SRP21 in the presence of SCR1 RNA. We propose a model where Ded1 actively participates in the translocation of proteins during translation. Our results provide a new understanding of the role of Ded1 during translation. Full article
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13 pages, 18058 KiB  
Article
A Zn(II) Coordination Polymer for Fluorescent Turn-Off Selective Sensing of Heavy Metal Cation and Toxic Inorganic Anions
by Yaxin Li, Mouyi Zhang, Ying Wang, Lei Guan, Di Zhao, **nyu Hao and Yuting Guo
Molecules 2024, 29(12), 2943; https://doi.org/10.3390/molecules29122943 - 20 Jun 2024
Viewed by 264
Abstract
A novel coordination polymer [Zn(atyha)2]n (1) (Hatyha = 2-(2-aminothiazole-4-yl)-2- hydroxyiminoacetic acid) was constructed by hydrothermal reaction of Zn2+ with Hatyha ligand. CP 1 exhibits a 2D (4,4)-connected topological framework with Schläfli symbol of {44·62 [...] Read more.
A novel coordination polymer [Zn(atyha)2]n (1) (Hatyha = 2-(2-aminothiazole-4-yl)-2- hydroxyiminoacetic acid) was constructed by hydrothermal reaction of Zn2+ with Hatyha ligand. CP 1 exhibits a 2D (4,4)-connected topological framework with Schläfli symbol of {44·62}, where atyha− anions serve as tridentate ligands, bridging with Zn2+ through carboxylate, thiazole and oxime groups. CP 1 displays a strong ligand-based photoluminescence at 390 nm in the solid state, and remains significantly structurally stable in water. Interestingly, it can be utilized as a fluorescent probe for selective and sensitive sensing of Fe3+, Cr2O72− and MnO4− through the fluorescent turn-off effect with limit of detection (LOD) of 3.66 × 10−6, 2.38 × 10−5 and 2.94 × 10−6 M, respectively. Moreover, the efficient recyclability for detection of Fe3+ and Cr2O72− is better than that for MnO4−. The mechanisms of fluorescent quenching involve reversible overlap of UV-Vis absorption bands of the analytes (Fe3+, Cr2O72− and MnO4−) with fluorescence excitation and emission bands for CP 1, respectively. Full article
(This article belongs to the Special Issue Chemical Research on Photosensitive Materials)
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31 pages, 8543 KiB  
Article
N-Hydroxypiridinedione: A Privileged Heterocycle for Targeting the HBV RNase H
by Dimitrios Moianos, Maria Makri, Georgia-Myrto Prifti, Aristeidis Chiotellis, Alexandros Pappas, Molly E. Woodson, Razia Tajwar, John E. Tavis and Grigoris Zoidis
Molecules 2024, 29(12), 2942; https://doi.org/10.3390/molecules29122942 - 20 Jun 2024
Viewed by 691
Abstract
Hepatitis B virus (HBV) remains a global health threat. Ribonuclease H (RNase H), part of the virus polymerase protein, cleaves the pgRNA template during viral genome replication. Inhibition of RNase H activity prevents (+) DNA strand synthesis and results in the accumulation of [...] Read more.
Hepatitis B virus (HBV) remains a global health threat. Ribonuclease H (RNase H), part of the virus polymerase protein, cleaves the pgRNA template during viral genome replication. Inhibition of RNase H activity prevents (+) DNA strand synthesis and results in the accumulation of non-functional genomes, terminating the viral replication cycle. RNase H, though promising, remains an under-explored drug target against HBV. We previously reported the identification of a series of N-hydroxypyridinedione (HPD) imines that effectively inhibit the HBV RNase H. In our effort to further explore the HPD scaffold, we designed, synthesized, and evaluated 18 novel HPD oximes, as well as 4 structurally related minoxidil derivatives and 2 barbituric acid counterparts. The new analogs were docked on the RNase H active site and all proved able to coordinate the two Mg2+ ions in the catalytic site. All of the new HPDs effectively inhibited the viral replication in cell assays exhibiting EC50 values in the low μM range (1.1–7.7 μM) with low cytotoxicity, resulting in selectivity indexes (SI) of up to 92, one of the highest reported to date among HBV RNase H inhibitors. Our findings expand the structure–activity relationships on the HPD scaffold, facilitating the development of even more potent anti-HBV agents. Full article
(This article belongs to the Special Issue Design, Synthesis and Biological Evaluation of Heterocyclic Compounds)
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17 pages, 2306 KiB  
Article
Modulation of the Human Erythrocyte Antioxidant System by the 5- and 6-Membered Heterocycle-Based Nitroxides
by Krzysztof Gwozdzinski, Stella Bujak-Pietrek, Anna Pieniazek and Lukasz Gwozdzinski
Molecules 2024, 29(12), 2941; https://doi.org/10.3390/molecules29122941 - 20 Jun 2024
Viewed by 289
Abstract
Nitroxides are stable radicals consisting of a nitroxyl group, >N-O•, which carries an unpaired electron. This group is responsible for the paramagnetic and antioxidant properties of these compounds. A recent study evaluated the effects of pyrrolidine and pyrroline derivatives of nitroxides [...] Read more.
Nitroxides are stable radicals consisting of a nitroxyl group, >N-O•, which carries an unpaired electron. This group is responsible for the paramagnetic and antioxidant properties of these compounds. A recent study evaluated the effects of pyrrolidine and pyrroline derivatives of nitroxides on the antioxidant system of human red blood cells (RBCs). It showed that nitroxides caused an increase in the activity of superoxide dismutase (SOD) and the level of methemoglobin (MetHb) in cells (in pyrroline derivatives) but had no effect on the activity of catalase and lactate dehydrogenase. Nitroxides also reduced the concentration of ascorbic acid (AA) in cells but did not cause any oxidation of proteins or lipids. Interestingly, nitroxides initiated an increase in thiols in the plasma membranes and hemolysate. However, the study also revealed that nitroxides may have pro-oxidant properties. The drop in the AA concentration and the increase in the MetHb level and in SOD activity may indicate the pro-oxidant properties of nitroxides in red blood cells. Full article
(This article belongs to the Section Medicinal Chemistry)
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18 pages, 4585 KiB  
Review
KCNT1 Channel Blockers: A Medicinal Chemistry Perspective
by Francesca Di Matteo, Francesca Mancuso, Rita Turcio, Tania Ciaglia, Claudio Stagno, Carla Di Chio, Pietro Campiglia, Alessia Bertamino, Salvatore Vincenzo Giofrè, Carmine Ostacolo and Nunzio Iraci
Molecules 2024, 29(12), 2940; https://doi.org/10.3390/molecules29122940 - 20 Jun 2024
Viewed by 520
Abstract
Potassium channels have recently emerged as suitable target for the treatment of epileptic diseases. Among potassium channels, KCNT1 channels are the most widely characterized as responsible for several epileptic and developmental encephalopathies. Nevertheless, the medicinal chemistry of KCNT1 blockers is underdeveloped so far. [...] Read more.
Potassium channels have recently emerged as suitable target for the treatment of epileptic diseases. Among potassium channels, KCNT1 channels are the most widely characterized as responsible for several epileptic and developmental encephalopathies. Nevertheless, the medicinal chemistry of KCNT1 blockers is underdeveloped so far. In the present review, we describe and analyse the papers addressing the issue of KCNT1 blockers’ development and identification, also evidencing the pros and the cons of the scientific approaches therein described. After a short introduction describing the epileptic diseases and the structure–function of potassium channels, we provide an extensive overview of the chemotypes described so far as KCNT1 blockers, and the scientific approaches used for their identification. Full article
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14 pages, 7680 KiB  
Article
N-Containing Porous Carbon-Based MnO Composites as Anode with High Capacity and Stability for Lithium-Ion Batteries
by Yi Cheng, Shiyue Li, Wenbin Luo, Kuo Li and **aofei Yang
Molecules 2024, 29(12), 2939; https://doi.org/10.3390/molecules29122939 - 20 Jun 2024
Viewed by 429
Abstract
MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large application. An effective solution to solve this problem is carbon coating. Biomass carbon materials have aroused much interest [...] Read more.
MnO has attracted much attention as the anode for Li-ion batteries (LIBs) owing to its high specific capacity. However, the low conductivity limited its large application. An effective solution to solve this problem is carbon coating. Biomass carbon materials have aroused much interest for being low-cost and rich in functional groups and hetero atoms. This work designs porous N-containing MnO composites based on the chemical-activated tremella using a self-templated method. The tremella, after activation, could offer more active sites for carbon to coordinate with the Mn ions. And the as-prepared composites could also inherit the special porous nanostructures of the tremella, which is beneficial for Li+ transfer. Moreover, the pyrrolic/pyridinic N from the tremella can further improve the conductivity and the electrolyte wettability of the composites. Finally, the composites show a high reversible specific capacity of 1000 mAh g−1 with 98% capacity retention after 200 cycles at 100 mA g−1. They also displayed excellent long-cycle performance with 99% capacity retention (relative to the capacity second cycle) after long 1000 cycles under high current density, which is higher than in most reported transition metal oxide anodes. Above all, this study put forward an efficient and convenient strategy based on the low-cost biomass to construct N-containing porous composite anodes with a fast Li+ diffusion rate, high electronic conductivity, and outstanding structure stability. Full article
(This article belongs to the Special Issue Materials for Emerging Electrochemical Devices)
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38 pages, 1494 KiB  
Review
One Molecule, Many Faces: Repositioning Cardiovascular Agents for Advanced Wound Healing
by Anna Gościniak, Anna Stasiłowicz-Krzemień, Bożena Michniak-Kohn, Piotr Fiedor and Judyta Cielecka-Piontek
Molecules 2024, 29(12), 2938; https://doi.org/10.3390/molecules29122938 - 20 Jun 2024
Viewed by 280
Abstract
Chronic wound treatments pose a challenge for healthcare worldwide, particularly for the people in developed countries. Chronic wounds significantly impair quality of life, especially among the elderly. Current research is devoted to novel approaches to wound care by repositioning cardiovascular agents for topical [...] Read more.
Chronic wound treatments pose a challenge for healthcare worldwide, particularly for the people in developed countries. Chronic wounds significantly impair quality of life, especially among the elderly. Current research is devoted to novel approaches to wound care by repositioning cardiovascular agents for topical wound treatment. The emerging field of medicinal products’ repurposing, which involves redirecting existing pharmaceuticals to new therapeutic uses, is a promising strategy. Recent studies suggest that medicinal products such as sartans, beta-blockers, and statins have unexplored potential, exhibiting multifaceted pharmacological properties that extend beyond their primary indications. The purpose of this review is to analyze the current state of knowledge on the repositioning of cardiovascular agents’ use and their molecular mechanisms in the context of wound healing. Full article
(This article belongs to the Section Medicinal Chemistry)
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28 pages, 7989 KiB  
Review
Exploring Recent Developments in Graphene-Based Cathode Materials for Fuel Cell Applications: A Comprehensive Overview
by Somya Samantaray, Debabrata Mohanty, Santosh Kumar Satpathy and I-Ming Hung
Molecules 2024, 29(12), 2937; https://doi.org/10.3390/molecules29122937 - 20 Jun 2024
Viewed by 489
Abstract
Fuel cells are at the forefront of modern energy research, with graphene-based materials emerging as key enhancers of performance. This overview explores recent advancements in graphene-based cathode materials for fuel cell applications. Graphene’s large surface area and excellent electrical conductivity and mechanical strength [...] Read more.
Fuel cells are at the forefront of modern energy research, with graphene-based materials emerging as key enhancers of performance. This overview explores recent advancements in graphene-based cathode materials for fuel cell applications. Graphene’s large surface area and excellent electrical conductivity and mechanical strength make it ideal for use in different solid oxide fuel cells (SOFCs) as well as proton exchange membrane fuel cells (PEMFCs). This review covers various forms of graphene, including graphene oxide (GO), reduced graphene oxide (rGO), and doped graphene, highlighting their unique attributes and catalytic contributions. It also examines the effects of structural modifications, do**, and functional group integrations on the electrochemical properties and durability of graphene-based cathodes. Additionally, we address the thermal stability challenges of graphene derivatives at high SOFC operating temperatures, suggesting potential solutions and future research directions. This analysis underscores the transformative potential of graphene-based materials in advancing fuel cell technology, aiming for more efficient, cost-effective, and durable energy systems. Full article
(This article belongs to the Special Issue Materials in Fuel Cell: Design and Electrochemical Application)
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13 pages, 4696 KiB  
Article
High-Performance Macroporous Free-Standing Microbial Fuel Cell Anode Derived from Grape for Efficient Power Generation and Brewery Wastewater Treatment
by **-Zhi Sun, Quan-Cheng Shu, Hong-Wei Sun, Yu-Can Liu, **ao-Yong Yang, Yan-**ang Zhang and Gang Wang
Molecules 2024, 29(12), 2936; https://doi.org/10.3390/molecules29122936 - 20 Jun 2024
Viewed by 408
Abstract
Microbial fuel cells (MFCs) have the potential to directly convert the chemical energy in organic matter into electrical energy, making them a promising technology for achieving sustainable energy production alongside wastewater treatment. However, the low extracellular electron transfer (EET) rates and limited bacteria [...] Read more.
Microbial fuel cells (MFCs) have the potential to directly convert the chemical energy in organic matter into electrical energy, making them a promising technology for achieving sustainable energy production alongside wastewater treatment. However, the low extracellular electron transfer (EET) rates and limited bacteria loading capacity of MFCs anode materials present challenges in achieving high power output. In this study, three-dimensionally heteroatom-doped carbonized grape (CG) monoliths with a macroporous structure were successfully fabricated using a facile and low-cost route and employed as independent anodes in MFCs for treating brewery wastewater. The CG obtained at 900 °C (CG-900) exhibited excellent biocompatibility. When integrated into MFCs, these units initiated electricity generation a mere 1.8 days after inoculation and swiftly reached a peak output voltage of 658 mV, demonstrating an exceptional areal power density of 3.71 W m−2. The porous structure of the CG-900 anode facilitated efficient ion transport and microbial community succession, ensuring sustained operational excellence. Remarkably, even when nutrition was interrupted for 30 days, the voltage swiftly returned to its original level. Moreover, the CG-900 anode exhibited a superior capacity for accommodating electricigens, boasting a notably higher abundance of Geobacter spp. (87.1%) compared to carbon cloth (CC, 63.0%). Most notably, when treating brewery wastewater, the CG-900 anode achieved a maximum power density of 3.52 W m−2, accompanied by remarkable treatment efficiency, with a COD removal rate of 85.5%. This study provides a facile and low-cost synthesis technique for fabricating high-performance MFC anodes for use in microbial energy harvesting. Full article
(This article belongs to the Section Nanochemistry)
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14 pages, 8192 KiB  
Article
Effects of TiO2 Nanoparticles Synthesized via Microwave Assistance on Adsorption and Photocatalytic Degradation of Ciprofloxacin
by Debora Briševac, Ivana Gabelica, Davor Ljubas, Arijeta Bafti, Gordana Matijašić and Lidija Ćurković
Molecules 2024, 29(12), 2935; https://doi.org/10.3390/molecules29122935 - 20 Jun 2024
Viewed by 319
Abstract
In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol [...] Read more.
In this study, the optimal microwave-assisted sol-gel synthesis parameters for achieving TiO2 nanoparticles with the highest specific surface area and photocatalytic activity were determined. Titanium isopropoxide was used as a precursor to prepare the sol (colloidal solution) of TiO2. Isopropanol was used as a solvent; acetylacetone was used as a complexation moderator; and nitric acid was used as a catalyst. Four samples of titanium dioxide were synthesized from the prepared colloidal solution in a microwave reactor at a temperature of 150 °C for 30 min and at a temperature of 200 °C for 10, 20, and 30 min. The phase composition of the TiO2 samples was determined by X-ray diffraction analysis (XRD) and Fourier-transform infrared spectroscopy (FTIR). Nitrogen adsorption/desorption isotherms were used to determine the specific surface area and pore size distributions using the Brunauer–Emmett–Teller (BET) method. The band-gap energy values of the TiO2 samples were determined by diffuse reflectance spectroscopy (DRS). The distribution of Ti and O in the TiO2 samples was determined by SEM-EDS analysis. The effects of adsorption and photocatalytic activity of the prepared TiO2 samples were evaluated by the degradation of ciprofloxacin (CIP) as an emerging organic pollutant (EOP) under UV-A light (365 nm). The results of the photocatalytic activity of the synthesized TiO2 nanoparticles were compared to the benchmark Degussa P25 TiO2. Kinetic parameters of adsorption and photocatalysis were determined and analyzed. It was found that crystalline TiO2 nanoparticles with the highest specific surface area, the lowest energy band gap, and the highest photocatalytic degradation were the samples synthesized at 200 °C for 10 min. The results indicate that CIP degradation by all TiO2 samples prepared at 200 °C show a synergistic effect of adsorption and photocatalytic degradation in the removal process. Full article
(This article belongs to the Special Issue The Application of Microwave-Assisted Technology in Chemical Reaction)
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14 pages, 1745 KiB  
Review
Ameliorative Effects of Curcumin on Type 2 Diabetes Mellitus
by Yu** Gu, Qun Niu, Qili Zhang and Yanfang Zhao
Molecules 2024, 29(12), 2934; https://doi.org/10.3390/molecules29122934 - 20 Jun 2024
Viewed by 263
Abstract
Type 2 diabetes mellitus (T2DM), a multifactorial and complicated metabolic disorder, is a growing public health problem. Numerous studies have indicated that bioactive compounds from herbal medicine have beneficial effects on T2DM prevention and treatment, owing to their numerous biological properties. Curcumin, the [...] Read more.
Type 2 diabetes mellitus (T2DM), a multifactorial and complicated metabolic disorder, is a growing public health problem. Numerous studies have indicated that bioactive compounds from herbal medicine have beneficial effects on T2DM prevention and treatment, owing to their numerous biological properties. Curcumin, the major curcuminoid of turmeric, is one of the most studied bioactive components of herbal supplements, and has a variety of biological activities. Clinical trials and preclinical research have recently produced compelling data to demonstrate the crucial functions of curcumin against T2DM via several routes. Accordingly, this review systematically summarizes the antidiabetic activity of curcumin, along with various mechanisms. Results showed that effectiveness of curcumin on T2DM is due to it being anti-inflammatory, anti-oxidant, antihyperglycemic, anti-apoptotic, and antihyperlipidemic, among other activities. In light of these results, curcumin may be a promising prevention/treatment choice for T2DM. Full article
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17 pages, 3378 KiB  
Article
Preparation of Ultra-High Temperature Resistant Cyclodextrin-Based Filtration Loss Reducer for Water-Based Drilling Fluids
by Yilin Liu, Lesly Dasilva Wandji Djouonkep, Boyang Yu, Chenyang Li and Chao Ma
Molecules 2024, 29(12), 2933; https://doi.org/10.3390/molecules29122933 - 20 Jun 2024
Viewed by 415
Abstract
In the development of ultra-deep wells, extremely high temperatures can lead to inefficiency of additives in drilling fluids. Hence, there is a need to prepare additives with a simple preparation process and good effects at ultra-high temperatures to ensure stable drilling fluid performance. [...] Read more.
In the development of ultra-deep wells, extremely high temperatures can lead to inefficiency of additives in drilling fluids. Hence, there is a need to prepare additives with a simple preparation process and good effects at ultra-high temperatures to ensure stable drilling fluid performance. In this study, a high temperature resistant filtration loss polymer (LY-2) was prepared using γ-methacryloyloxypropyltrimethoxysilane (KH570), N,N-dimethylallyl ammonium chloride (DMDAAC), sodium p-styrenesulfonate (SSS), and β-cyclodextrin (β-CD). The impact of the different monomer ratios on particle size, rheology, and filtration performance was systematically investigated. Infrared spectroscopy afforded the structural features. Thermogravimetric Analysis detected the temperature stability, and scanning electron microscopy characterized the polymer micromorphology. LY-2 was completely decomposed at a temperature above 600 °C. Experiments showed FLAPI of the drilling fluid containing 3% LY-2 aged at 260 °C/16 h was only 5.1 mL, which is 85.4% lower compared to the base fluid. This is attributed to the synergistic effect of the polymer adsorption through chemical action at high temperatures and the blocking effect of carbon nanoparticles on the filter cake released by cyclodextrin carbonization at high temperatures. Comparing LY-2 with commercial filter loss reducers shows that LY-2 has excellent temperature resistance, which exhibited five times higher filtration performance and relatively low cost, making it possible to be applied to ultra-high temperature drilling operations in an industrial scale-up. Full article
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14 pages, 959 KiB  
Article
High-Yield Production of Dihydroxyacetone from Crude Glycerol in Fed-Batch Cultures of Gluconobacter oxydans
by Katarzyna Górska and Zbigniew Garncarek
Molecules 2024, 29(12), 2932; https://doi.org/10.3390/molecules29122932 - 20 Jun 2024
Viewed by 209
Abstract
The strain Gluconobacter oxydans LMG 1385 was used for the bioconversion of crude glycerol to dihydroxyacetone. The suitability of fed-batch cultures for the production of dihydroxyacetone was determined, and the influence of the pH of the culture medium and the initial concentration of [...] Read more.
The strain Gluconobacter oxydans LMG 1385 was used for the bioconversion of crude glycerol to dihydroxyacetone. The suitability of fed-batch cultures for the production of dihydroxyacetone was determined, and the influence of the pH of the culture medium and the initial concentration of glycerol on maximizing the concentration of dihydroxyacetone and on the yield and speed of obtaining dihydroxyacetone by bioconversion was examined. The feeding strategy of the substrate (crude glycerol) during the process was based on measuring the dissolved oxygen tension of the culture medium. The highest concentration of dihydroxyacetone PK = 175.8 g·L−1 and the highest yield YP/Sw = 94.3% were obtained when the initial concentration of crude glycerol was S0 = 70.0 g·L−1 and the pH of the substrate was maintained during the process at level 5.0. Full article
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8 pages, 2049 KiB  
Communication
Density Function Theory Study on the Energy and Circular Dichroism Spectrum for Methylene-Linked Triazole Diads Depending on the Substitution Position and Conformation
by Masaki Nakahata and Akihito Hashidzume
Molecules 2024, 29(12), 2931; https://doi.org/10.3390/molecules29122931 - 20 Jun 2024
Viewed by 246
Abstract
Since the discovery of metal-catalyzed azide–alkyne cycloadditions, 1,2,3-triazoles have been widely used as linkers for various residues. 1,2,3-Triazole is an aromatic five-membered cyclic compound consisting of three nitrogen and two carbon atoms with large dipoles that absorb UV light. In the past decade, [...] Read more.
Since the discovery of metal-catalyzed azide–alkyne cycloadditions, 1,2,3-triazoles have been widely used as linkers for various residues. 1,2,3-Triazole is an aromatic five-membered cyclic compound consisting of three nitrogen and two carbon atoms with large dipoles that absorb UV light. In the past decade, we have been working on the synthesis of dense triazole polymers possessing many 1,2,3-triazole residues linked through a carbon atom in their backbone as a new type of functional polymer. Recently, we reported that stereoregular dense triazole uniform oligomers exhibit a circular dichroism signal based on the chiral arrangement of two neighboring 1,2,3-triazole residues. In this study, to investigate the chiral conformation of two neighboring 1,2,3-triazole residues in stereoregular dense triazole uniform oligomers, density functional theory (DFT) calculations were performed using 1,2,3-triazole diads with different substitution positions and conformations as model compounds and compared with our previous results. Full article
(This article belongs to the Section Computational and Theoretical Chemistry)
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18 pages, 2934 KiB  
Article
Traceability Research on Geographic Erigeron breviscapus Based on High-Resolution Mass Spectrometry and Chemometric Analysis
by Jiao Zhang, Heng Tian, Tao Lin, **angzhong Huang and Hongcheng Liu
Molecules 2024, 29(12), 2930; https://doi.org/10.3390/molecules29122930 - 20 Jun 2024
Viewed by 505
Abstract
A method was developed to identify and trace the geographic sources of Erigeron breviscapus using high-resolution mass spectrometry and chemometrics. The representative samples were collected from the geographic area of Honghe Dengzhanhua and other areas in Yunnan province and Guizhou province. The data [...] Read more.
A method was developed to identify and trace the geographic sources of Erigeron breviscapus using high-resolution mass spectrometry and chemometrics. The representative samples were collected from the geographic area of Honghe Dengzhanhua and other areas in Yunnan province and Guizhou province. The data points could be determined well using the PCA and PLS-DA diagram. A total of 46 characteristic compounds were identified from Honghe Dengzhanhua and within Guizhou province, but 37 compounds were different from Honghe Dengzhanhua and other counties in Yunnan province. Two biomarkers were found from three regions. Their structures were inferred as 8-amino-7-oxononanoic acid and 8-hydroxyquinoline, and they had the same molecular composition. This may suggest that a possible synthesis pathway can be proven in the future. Full article
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12 pages, 2246 KiB  
Article
Blue Phosphorescent Pt(II) Compound Based on Tetradentate Carbazole/2,3′-Bipyridine Ligand and Its Application in Organic Light-Emitting Diodes
by Hakjo Kim, Chan-Hee Ryu, Miso Hong, Kang Mun Lee, Unhyeok Jo and Young** Kang
Molecules 2024, 29(12), 2929; https://doi.org/10.3390/molecules29122929 - 20 Jun 2024
Viewed by 401
Abstract
The tetradentate ligand, merging a carbazole unit with high triplet energy and dimethoxy bipyridine, renowned for its exceptional quantum efficiency in coordination with metals like Pt, is expected to demonstrate remarkable luminescent properties. However, instances of tetradentate ligands such as bipyridine-based pyridylcarbazole derivatives [...] Read more.
The tetradentate ligand, merging a carbazole unit with high triplet energy and dimethoxy bipyridine, renowned for its exceptional quantum efficiency in coordination with metals like Pt, is expected to demonstrate remarkable luminescent properties. However, instances of tetradentate ligands such as bipyridine-based pyridylcarbazole derivatives remain exceptionally scarce in the current literature. In this study, we developed a tetradentate ligand based on carbazole and 2,3′-bipyridine and successfully complexed it with Pt(II) ions. This novel compound (1) serves as a sky-blue phosphorescent material for use in light-emitting diodes. Based on single-crystal X-ray analysis, compound 1 has a distorted square-planar geometry with a 5/6/6 backbone around the Pt(II) core. Bright sky-blue emissions were observed at 488 and 516 nm with photoluminescent quantum yields of 34% and a luminescent lifetime of 2.6 μs. TD-DFT calculations for 1 revealed that the electronic transition was mostly attributed to the ligand-centered (LC) charge transfer transition with a small contribution from the metal-to-ligand charge transfer transition (MLCT, ~14%). A phosphorescent organic light-emitting device was successfully fabricated using this material as a dopant, along with 3′-di(9H-carbazol-9-yl)-1,1′-biphenyl (mCBP) and 9-(3′-carbazol-9-yl-5-cyano-biphenyl-3-yl)-9H-carbazole-3-carbonitrile (CNmCBPCN) as mixed hosts. A maximum quantum efficiency of 5.2% and a current efficiency of 15.5 cd/A were obtained at a do** level of 5%. Full article
(This article belongs to the Special Issue Structure, Spectroscopic Characterization and Application of Crystals)
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16 pages, 3825 KiB  
Article
Ciprofloxacin Removal via Acid-Modified Red Mud: Optimizing the Process, Analyzing the Adsorption Features, and Exploring the Underlying Mechanism
by **gzhuan Shi, Wanqiong Wang, Ziyi Li and Yingjuan Shi
Molecules 2024, 29(12), 2928; https://doi.org/10.3390/molecules29122928 - 20 Jun 2024
Viewed by 247
Abstract
In this study, RM (red mud) was acidified with sulfuric acid, and the acidified ARM (acidified red mud) was utilized as an innovative adsorption material for treating antibiotic-containing wastewater. The adsorption conditions, kinetics, isotherms, thermodynamics, and mechanism of ARM for CIP (ciprofloxacin) were [...] Read more.
In this study, RM (red mud) was acidified with sulfuric acid, and the acidified ARM (acidified red mud) was utilized as an innovative adsorption material for treating antibiotic-containing wastewater. The adsorption conditions, kinetics, isotherms, thermodynamics, and mechanism of ARM for CIP (ciprofloxacin) were investigated. The characterization of the ARM involved techniques such as scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), X-ray fluorescence (XRF), thermogravimetric analysis (TGA), and NH3-TPD analysis. Adsorption studies employed a response surface methodology (RSM) for the experimental design. The results showed that ARM can absorb CIP effectively. The RSM optimal experiment indicated that the most significant model terms influencing adsorption capacity were solution pH, CIP initial concentration, and ARM dosage, under which the predicted maximum adsorption capacity achieved 7.30 mg/g. The adsorption kinetics adhered to a pseudo-second-order model, while equilibrium data fitted the Langmuir–Freundlich isotherm, yielding maximum capacity values of 7.35 mg/g. The adsorption process occurred spontaneously and absorbed heat, evidenced by ΔGθ values between −83.05 and −91.50 kJ/mol, ΔSθ at 281.6 J/mol/K, and ΔHθ at 0.86 kJ/mol. Analysis using attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR) indicated a complex reaction between the Al–O in the ARM and the ester group –COO in CIP. The C=O bond in CIP was likely to undergo a slight electrostatic interaction or be bound to the internal spherical surface of the ARM. The findings indicate that ARM is a promising and efficient adsorbent for CIP removal from wastewater. Full article
(This article belongs to the Section Analytical Chemistry)
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13 pages, 2059 KiB  
Article
Synthesis and Characterisation of Core–Shell Microparticles Formed by Ni-Mn-Co Oxides
by Javier García-Alonso, Svitlana Krüger, Bilge Saruhan, David Maestre and Bianchi Méndez
Molecules 2024, 29(12), 2927; https://doi.org/10.3390/molecules29122927 - 20 Jun 2024
Viewed by 267
Abstract
In this work, core and core–shell microparticles formed by Ni-Mn-Co oxides with controlled composition were fabricated by an oxalate-assisted co-precipitation route, and their properties were analysed by diverse microscopy and spectroscopy techniques. The microparticles exhibit dimensions within the 2–6 μm range and mainly [...] Read more.
In this work, core and core–shell microparticles formed by Ni-Mn-Co oxides with controlled composition were fabricated by an oxalate-assisted co-precipitation route, and their properties were analysed by diverse microscopy and spectroscopy techniques. The microparticles exhibit dimensions within the 2–6 μm range and mainly consist of NiO and NiMn2O4, the latter being promoted as the temperature of the treatment increases, especially in the shell region of the microparticles. Aspects such as the shell dimensions, the vibrational modes of the spinel compounds primarily observed in the shell region, the oxidation states of the cations at the surface of the microparticles, and the achievement of a Ni-rich 811 core and a Mn-rich 631 shell were thoroughly evaluated and discussed in this work. Full article
(This article belongs to the Special Issue Exclusive Papers of Editorial Board Members and Invited Scholars in “Materials Chemistry”)
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1 pages, 169 KiB  
Correction
Correction: Reyes Romero et al. Computer- and NMR-Aided Design of Small-Molecule Inhibitors of the Hub1 Protein. Molecules 2022, 27, 8282
by Atilio Reyes Romero, Katarzyna Kubica, Radoslaw Kitel, Ismael Rodríguez, Katarzyna Magiera-Mularz, Alexander Dömling, Tad A. Holak and Ewa Surmiak
Molecules 2024, 29(12), 2926; https://doi.org/10.3390/molecules29122926 - 20 Jun 2024
Viewed by 212
Abstract
In the published publication [...] Full article
13 pages, 5409 KiB  
Article
A Dopamine Detection Sensor Based on Au-Decorated NiS2 and Its Medical Application
by Chongchong Ma, Yixuan Wen, Yuqing Qiao, Kevin Z. Shen and Hongwen Yuan
Molecules 2024, 29(12), 2925; https://doi.org/10.3390/molecules29122925 - 20 Jun 2024
Viewed by 458
Abstract
This article reports a simple hydrothermal method for synthesizing nickel disulfide (NiS2) on the surface of fluorine-doped tin oxide (FTO) glass, followed by the deposition of 5 nm Au nanoparticles on the electrode surface by physical vapor deposition. This process ensures [...] Read more.
This article reports a simple hydrothermal method for synthesizing nickel disulfide (NiS2) on the surface of fluorine-doped tin oxide (FTO) glass, followed by the deposition of 5 nm Au nanoparticles on the electrode surface by physical vapor deposition. This process ensures the uniform distribution of Au nanoparticles on the NiS2 surface to enhance its conductivity. Finally, an Au@NiS2-FTO electrochemical biosensor is obtained for the detection of dopamine (DA). The composite material is characterized using transmission electron microscopy (TEM), UV-Vis spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The electrochemical properties of the sensor are investigated using cyclic voltammetry (CV), differential pulse voltammetry (DPV), and time current curves in a 0.1 M PBS solution (pH = 7.3). In the detection of DA, Au@NiS2-FTO exhibits a wide linear detection range (0.1~1000 μM), low detection limit (1 nM), and fast response time (0.1 s). After the addition of interfering substances, such as glucose, L-ascorbic acid, uric acid, CaCl2, NaCl, and KCl, the electrode potential remains relatively unchanged, demonstrating its strong anti-interference capability. It also demonstrates strong sensitivity and reproducibility. The obtained Au@NiS2-FTO provides a simple and easy-to-operate example for constructing nanometer catalysts with enzyme-like properties. These results provide a promising method utilizing Au coating to enhance the conductivity of transition metal sulfides. Full article
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15 pages, 4212 KiB  
Article
Exploring the Antitumor Efficacy of N-Heterocyclic Nitrilotriacetate Oxidovanadium(IV) Salts on Prostate and Breast Cancer Cells
by Katarzyna Chmur, Aleksandra Tesmar, Magdalena Zdrowowicz, Damian Rosiak, Jarosław Chojnacki and Dariusz Wyrzykowski
Molecules 2024, 29(12), 2924; https://doi.org/10.3390/molecules29122924 - 19 Jun 2024
Viewed by 376
Abstract
The crystal structures of two newly synthesized nitrilotriacetate oxidovanadium(IV) salts, namely [QH][VO(nta)(H2O)](H2O)2 (I) and [(acr)H][VO(nta)(H2O)](H2O)2 (II), were determined. Additionally, the cytotoxic effects of four N-heterocyclic nitrilotriacetate oxidovanadium(IV) salts—1,10-phenanthrolinium, [(phen)H][VO(nta)(H [...] Read more.
The crystal structures of two newly synthesized nitrilotriacetate oxidovanadium(IV) salts, namely [QH][VO(nta)(H2O)](H2O)2 (I) and [(acr)H][VO(nta)(H2O)](H2O)2 (II), were determined. Additionally, the cytotoxic effects of four N-heterocyclic nitrilotriacetate oxidovanadium(IV) salts—1,10-phenanthrolinium, [(phen)H][VO(nta)(H2O)](H2O)0.5 (III), 2,2′-bipyridinium [(bpy)H][VO(nta)(H2O)](H2O) (IV), and two newly synthesized compounds (I) and (II)—were evaluated against prostate cancer (PC3) and breast cancer (MCF-7) cells. All the compounds exhibited strong cytotoxic effects on cancer cells and normal cells (HaCaT human keratinocytes). The structure–activity relationship analysis revealed that the number and arrangement of conjugated aromatic rings in the counterion had an impact on the antitumor effect. The compound (III), the 1,10-phenanthrolinium analogue, exhibited the greatest activity, whereas the acridinium salt (II), with a different arrangement of three conjugated aromatic rings, showed the lowest toxicity. The increased concentrations of the compounds resulted in alterations to the cell cycle distribution with different effects in MCF-7 and PC3 cells. In MCF-7 cells, compounds I and II were observed to block the G2/M phase, while compounds III and IV were found to arrest the cell cycle in the G0/G1 phase. In PC3 cells, all compounds increased the rates of cells in the G0/G1 phase. Full article
(This article belongs to the Section Inorganic Chemistry)
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23 pages, 4085 KiB  
Article
Characterization and Performance of Peanut Shells in Caffeine and Triclosan Removal in Batch and Fixed-Bed Column Tests
by Cristina E. Almeida-Naranjo, Mayra Frutos, Victor H. Guerrero and Cristina Villamar-Ayala
Molecules 2024, 29(12), 2923; https://doi.org/10.3390/molecules29122923 - 19 Jun 2024
Viewed by 323
Abstract
Peanut shells’ adsorption performance in caffeine and triclosan removal was studied. Peanut shells were analyzed for their chemical composition, morphology, and surface functional groups. Batch adsorption and fixed-bed column experiments were carried out with solutions containing 30 mg/L of caffeine and triclosan. The [...] Read more.
Peanut shells’ adsorption performance in caffeine and triclosan removal was studied. Peanut shells were analyzed for their chemical composition, morphology, and surface functional groups. Batch adsorption and fixed-bed column experiments were carried out with solutions containing 30 mg/L of caffeine and triclosan. The parameters examined included peanut shell particle size (120–150, 300–600, and 800–2000 µm), adsorbent dose (0.02–60 g/L), contact time (up to 180 min), bed height (4–8 cm), and hydraulic loading rate (2.0 and 4.0 m3/m2-day). After determining the optimal adsorption conditions, kinetics, isotherm, and breakthrough curve models were applied to analyze the experimental data. Peanut shells showed an irregular surface and consisted mainly of polysaccharides (around 70% lignin, cellulose, and hemicellulose), with a specific surface area of 1.7 m2/g and a pore volume of 0.005 cm3/g. The highest removal efficiencies for caffeine (85.6 ± 1.4%) and triclosan (89.3 ± 1.5%) were achieved using the smallest particles and 10.0 and 0.1 g/L doses over 180 and 45 min, respectively. Triclosan showed easier removal compared to caffeine due to its higher lipophilic character. The pseudo-second-order kinetics model provided the best fit with the experimental data, suggesting a chemisorption process between caffeine/triclosan and the adsorbent. Equilibrium data were well-described by the Sips model, with maximum adsorption capacities of 3.3 mg/g and 289.3 mg/g for caffeine and triclosan, respectively. In fixed-bed column adsorption tests, particle size significantly influenced efficiency and hydraulic behavior, with 120–150 µm particles exhibiting the highest adsorption capacity for caffeine (0.72 mg/g) and triclosan (143.44 mg/g), albeit with clogging issues. The experimental data also showed good agreement with the Bohart–Adams, Thomas, and Yoon–Nelson models. Therefore, the findings of this study highlight not only the effective capability of peanut shells to remove caffeine and triclosan but also their versatility as a promising option for water treatment and sanitation applications in different contexts. Full article
(This article belongs to the Special Issue Adsorbent Material for Water Treatment)
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16 pages, 3495 KiB  
Article
Enhanced Enzymatic Performance of Immobilized Pseudomonas fluorescens Lipase on ZIF-8@ZIF-67 and Its Application to the Synthesis of Neryl Acetate with Transesterification Reaction
by Qi Wang, Jian **ong, Hanghang Xu, Wenyuan Sun, **aoxu Pan, Shixin Cui, Siting Lv and Yinling Zhang
Molecules 2024, 29(12), 2922; https://doi.org/10.3390/molecules29122922 - 19 Jun 2024
Viewed by 238
Abstract
In this study, hybrid skeleton material ZIF-8@ZIF-67 was synthesized by the epitaxial growth method and then was utilized as a carrier for encapsulating Pseudomonas fluorescens lipase (PFL) through the co-precipitation method, resulting in the preparation of immobilized lipase (PFL@ZIF-8@ZIF-67). Subsequently, it was further [...] Read more.
In this study, hybrid skeleton material ZIF-8@ZIF-67 was synthesized by the epitaxial growth method and then was utilized as a carrier for encapsulating Pseudomonas fluorescens lipase (PFL) through the co-precipitation method, resulting in the preparation of immobilized lipase (PFL@ZIF-8@ZIF-67). Subsequently, it was further treated with glutaraldehyde to improve protein immobilization yield. Under optimal immobilization conditions, the specific hydrolytic activity of PFL@ZIF-8@ZIF-67 was 20.4 times higher than that of the free PFL. The prepared biocatalyst was characterized and analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR). Additionally, the thermal stability of PFL@ZIF-8@ZIF-67 at 50 °C was significantly improved compared to the free PFL. After 7 weeks at room temperature, PFL@ZIF-8@ZIF-67 retained 78% of the transesterification activity, while the free enzyme was only 29%. Finally, PFL@ZIF-8@ZIF-67 was applied to the neryl acetate preparation in a solvent-free system, and the yield of neryl acetate reached 99% after 3 h of reaction. After 10 repetitions, the yields of neryl acetate catalyzed by PFL@ZIF-8@ZIF-67 and the free PFL were 80% and 43%, respectively. Full article
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11 pages, 4175 KiB  
Article
Rapid Determination of Tetracyclines in Drinking and Environmental Waters Using Fully Automatic Solid-Phase Extraction with Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry
by Tongtong Zhang, **angyang Zhang, Jiangmei Yu, Hongmei Hu, Pengfei He, Zhenhua Li, Yi Fang, Tiejun Li and Yuanming Guo
Molecules 2024, 29(12), 2921; https://doi.org/10.3390/molecules29122921 - 19 Jun 2024
Viewed by 336
Abstract
The abuse and irrational use of tetracyclines (TCs) in human medicine and animal husbandry has become a serious concern, affecting the ecological environment and human health. The aim of this study was to develop a sensitive and selective method using fully automatic solid-phase [...] Read more.
The abuse and irrational use of tetracyclines (TCs) in human medicine and animal husbandry has become a serious concern, affecting the ecological environment and human health. The aim of this study was to develop a sensitive and selective method using fully automatic solid-phase extraction coupled with ultra-performance liquid chromatography–tandem mass spectrometry for the determination of twelve TCs in water. Four isotope-labeled internal standards for TCs were used to correct matrix effects. Several parameters affecting extraction efficiency were systematically optimized, and the optimum experimental conditions found were 1.0 L water sample with 0.5 g/L Na2EDTA (pH 3.0) extracted and enriched by CNW HLB cartridge and eluted by 4 mL of acetone:methanol (v/v, 1:1). The enrichment factors were up to 798−1059 but only requiring about 60 min per six samples. Under the optimized conditions, the linearity of the method ranged from 0.2 to 100 μg/L for 12 TCs, the detection limits were as low as 0.01−0.15 ng/L, and the recoveries were in the range of 70%–118%, with relative standard deviations less than 15%. The developed method can be successfully utilized for the determination of 12 TCs in pure water, tap water, river water, and mariculture seawater. In summary, three and six TCs were detected in river water and mariculture seawater, respectively, with total concentrations of 0.074–0.520 ng/L (mean 0.248 ng/L) and 0.792–58.369 ng/L (12.629 ng/L), respectively. Tetracycline (TC) and oxytetracycline (OTC) were the dominant TCs in river water, while doxytetracycline (DXC) and OTC were dominant in mariculture seawater. Full article
(This article belongs to the Special Issue Advanced Analytical Techniques for the Detection and Quantification of Emerging Contaminants)
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14 pages, 4225 KiB  
Article
A Theoretical Investigation into the Oligomer Structure of Carbon Dots Formed from Small-Molecule Precursors
by Chunlan Li, Xu Zhu and Maotian Xu
Molecules 2024, 29(12), 2920; https://doi.org/10.3390/molecules29122920 - 19 Jun 2024
Viewed by 246
Abstract
In-depth insights into the oligomers of carbon dots (CDs) prepared from small-molecule precursors are important in the study of the carbonization mechanism of CDs and for our knowledge of their complex structure. Herein, citric acid (CA) and ethylenediamine (EDA) were used as small-molecule [...] Read more.
In-depth insights into the oligomers of carbon dots (CDs) prepared from small-molecule precursors are important in the study of the carbonization mechanism of CDs and for our knowledge of their complex structure. Herein, citric acid (CA) and ethylenediamine (EDA) were used as small-molecule precursors to prepare CDs in an aqueous solution. The structure of oligomers acquired from CA and EDA in different molar ratios and their formation process were first studied using density functional theory, including the dispersion correction (DFT-D3) method. The results showed that the energy barrier of dimer cyclization was higher than that of its linear polymerization, but the free energy of the cyclized product was much lower than that of its reactant, and IPCA (5-oxo-1,-2,3,5-tetrahydroimidazo [1,2-a]pyridine-7-carboxylic acid) could therefore be obtained under certain conditions. The oligomers obtained from different molar ratios of EDA and CA were molecular clusters formed by short polyamide chains through intermolecular forces; with the exception of when the molar ratio of EDA to CA was 0.5, excessive CA did not undergo an amidation reaction but rather attained molecular clusters directly through intermolecular forces. These oligomers exhibited significant differences in their surface functional groups, which would affect the carbonization process and the surface structure of CDs. Full article
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14 pages, 4518 KiB  
Article
Halogenated Boroxine K2[B3O3F4OH] Modulates Metabolic Phenotype and Autophagy in Human Bladder Carcinoma 5637 Cell Line
by Nikolina Elez-Burnjaković, Lejla Pojskić, Anja Haverić, Naida Lojo-Kadrić, Maida Hadžić Omanović, Ajla Smajlović, Svetoslav Kalaydjiev, Milka Maksimović, Bojan Joksimović and Sanin Haverić
Molecules 2024, 29(12), 2919; https://doi.org/10.3390/molecules29122919 - 19 Jun 2024
Viewed by 282
Abstract
Halogenated boroxine K2[B3O3F4OH] (HB), an inorganic derivative of cyclic anhydride of boronic acid, is patented as a boron-containing compound with potential for the treatment of both benign and malignant skin changes. HB has effectively inhibited [...] Read more.
Halogenated boroxine K2[B3O3F4OH] (HB), an inorganic derivative of cyclic anhydride of boronic acid, is patented as a boron-containing compound with potential for the treatment of both benign and malignant skin changes. HB has effectively inhibited the growth of several carcinoma cell lines. Because of the growing interest in autophagy induction as a therapeutic approach in bladder carcinoma (BC), we aimed to assess the effects of HB on metabolic phenotype and autophagy levels in 5637 human bladder carcinoma cells (BC). Cytotoxicity was evaluated using the alamar blue assay, and the degree of autophagy was determined microscopically. Mitochondrial respiration and glycolysis were measured simultaneously. The relative expression of autophagy-related genes BECN1, P62, BCL-2, and DRAM1 was determined by real-time PCR. HB affected cell growth, while starvation significantly increased the level of autophagy in the positive control compared to the basal level of autophagy in the untreated negative control. In HB-treated cultures, the degree of autophagy was higher compared to the basal level, and metabolic phenotypes were altered; both glycolysis and oxidative phosphorylation (OXPHOS) were decreased by HB at 0.2 and 0.4 mg/mL. Gene expression was deregulated towards autophagy induction and expansion. In conclusion, HB disrupted the bioenergetic metabolism and reduced the intracellular survival potential of BC cells. Further molecular studies are needed to confirm these findings and investigate their applicative potential. Full article
(This article belongs to the Topic Bioactive Compounds and Therapeutics: Molecular Aspects, Metabolic Profiles, and Omics Studies)
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14 pages, 1511 KiB  
Article
Enantioselective Synthesis of the Active Sex Pheromone Components of the Female Lichen Moth, Lyclene dharma dharma, and Their Enantiomers
by Yun Zhou, Jianan Wang, Yueru Zhang, **aochen Fu, Hongqing **e, **long Han, Jianhua Zhang, Jiangchun Zhong and Chenggang Shan
Molecules 2024, 29(12), 2918; https://doi.org/10.3390/molecules29122918 - 19 Jun 2024
Viewed by 276
Abstract
The Lichen moth, Lyclene dharma dharma (Arctiidae, Lithosiinae), plays a significant role in forest ecosystem dynamics. A concise and novel method to synthesize the active sex pheromone components, (S)-14-methyloctadecan-2-one ((S)-1), (S)-6-methyloctadecan-2-one (( [...] Read more.
The Lichen moth, Lyclene dharma dharma (Arctiidae, Lithosiinae), plays a significant role in forest ecosystem dynamics. A concise and novel method to synthesize the active sex pheromone components, (S)-14-methyloctadecan-2-one ((S)-1), (S)-6-methyloctadecan-2-one ((S)-2), and their enantiomers has been developed. Key steps in the synthesis include the use of Evans’ chiral auxiliaries, Grignard cross-coupling reactions, hydroboration–oxidation, and Wacker oxidation. The synthesized sex pheromone components hold potential value for studies on communication mechanisms, species identification, and ecological management. Full article
(This article belongs to the Special Issue Synthesis of Bioactive Compounds: Volume II)
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