Molecules

22 pages, 11540 KiB

Open AccessArticle

Exploration of Specific Fluoroquinolone Interaction with SARS-CoV-2 Main Protease (Mpro) to Battle COVID-19: DFT, Molecular Docking, ADME and Cardiotoxicity Studies

by Muhammad Asim Khan, Sadaf Mutahir, Muhammad Atif Tariq and Abdulrahman A. Almehizia

Molecules 2024, 29(19), 4721; https://doi.org/10.3390/molecules29194721 (registering DOI) - 5 Oct 2024

Abstract

Herein, the pharmacokinetic profiles, binding interactions, and molecular properties of fluoroquinolone derivatives as prospective antiviral drugs are examined using a combination of docking, ADME, and DFT simulations. The effectiveness of the ligands is compared with the clinically tested and FDA-authorized medicine remdesivir. The [...] Read more.

Herein, the pharmacokinetic profiles, binding interactions, and molecular properties of fluoroquinolone derivatives as prospective antiviral drugs are examined using a combination of docking, ADME, and DFT simulations. The effectiveness of the ligands is compared with the clinically tested and FDA-authorized medicine remdesivir. The findings demonstrated encouraging binding energies, indicating possible inhibitory effectiveness against SARS-CoV-2 M^pro. The fluoroquinolone derivatives also exhibit promising ADME characteristics, although compounds 5, 6, 9, 12–20 possess poor values, suggesting that oral administration may be possible. The potential of the selected compounds as SARS-CoV-2 M^pro inhibitors is thoroughly understood because of the integrated analysis of DFT, with compound 11 demonstrating the highest energy gap of 0.2604 eV of, docking with viral targets with docking scores of −7.9 to −5.9 kcal/mol, with compound 18 demonstrating the highest docking score, which is at the 13th position in energy difference in the DFT data. Their favorable electrical properties, robust binding interactions with viral targets, and attractive pharmacokinetic profiles boost their potential as prospective study subjects. These substances have the potential to be transformed into cutting-edge antiviral therapies that specifically target SARS-CoV-2 M^pro and related coronaviruses. Full article

(This article belongs to the Special Issue Spectroscopic, Thermodynamic and Molecular Docking Studies on Molecular Mechanisms of Drug Binding to Proteins II)

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25 pages, 2599 KiB

Open AccessArticle

Structural and Dynamical Effects of the CaO/SrO Substitution in Bioactive Glasses

by Margit Fabian, Matthew Krzystyniak, Atul Khanna and Zsolt Kovacs

Molecules 2024, 29(19), 4720; https://doi.org/10.3390/molecules29194720 (registering DOI) - 5 Oct 2024

Abstract

Silicate glasses containing silicon, sodium, phosphorous, and calcium have the ability to promote bone regeneration and biodegrade as new tissue is generated. Recently, it has been suggested that adding SrO can benefit tissue growth and silicate glass dissolution. Motivated by these recent developments, [...] Read more.

Silicate glasses containing silicon, sodium, phosphorous, and calcium have the ability to promote bone regeneration and biodegrade as new tissue is generated. Recently, it has been suggested that adding SrO can benefit tissue growth and silicate glass dissolution. Motivated by these recent developments, the effect of SrO/CaO–CaO/SrO substitution on the local structure and dynamics of Si-Na-P-Ca-O oxide glasses has been studied in this work. Differential thermal analysis has been performed to determine the thermal stability of the glasses after the addition of strontium. The local structure has been studied by neutron diffraction augmented by Reverse Monte Carlo simulation, and the local dynamics by neutron Compton scattering and Raman spectroscopy. Differential thermal analysis has shown that SrO-containing glasses have lower glass transition, melting, and crystallisation temperatures. Moreover, the addition of the Sr²⁺ ions decreased the thermal stability of the glass structure. The total neutron diffraction augmented by the RMC simulation revealed that Sr played a similar role as Ca in the glass structure when substituted on a molar basis. The bond length and the coordination number distributions of the network modifiers and network formers did not change when SrO (x = 0.125, 0.25) was substituted for CaO (25-x). However, the network connectivity increased in glass with 12.5 mol% CaO due to the increased length of the Si-O-Si interconnected chain. The analysis of Raman spectra revealed that substituting CaO with SrO in the glass structure dramatically enhances the intensity of the high-frequency band of 1110–2000 cm⁻¹. For all glasses under investigation, the changes in the relative intensities of Raman bands and the distributions of the bond lengths and coordination numbers upon the SrO substitution were correlated with the values of the widths of nuclear momentum distributions of Si, Na, P, Ca, O, and Sr. The widths of nuclear momentum distributions were observed to soften compared to the values observed and simulated in their parent metal-oxide crystals. The widths of nuclear momentum distributions, obtained from fitting the experimental data to neutron Compton spectra, were related to the amount of disorder of effective force constants acting on individual atomic species in the glasses. Full article

16 pages, 4069 KiB

Open AccessReview

Review of the Structural Characteristics and Biological Activities of Tricholoma Secondary Metabolites (2018–2023)

by Meili Zhao, Shiqin Yuan, Zhiming Li, Chengwei Liu and Ruiying Zhang

Molecules 2024, 29(19), 4719; https://doi.org/10.3390/molecules29194719 (registering DOI) - 5 Oct 2024

Abstract

Tricholoma are significant medicinal and edible mushrooms within Basidiomycota. Known for their various medicinal properties such as anti-tumor, immune regulation, and antioxidant effects, they are regarded worldwide as health foods of the 21st century. Tricholoma species produce various types of secondary metabolites, which [...] Read more.

Tricholoma are significant medicinal and edible mushrooms within Basidiomycota. Known for their various medicinal properties such as anti-tumor, immune regulation, and antioxidant effects, they are regarded worldwide as health foods of the 21st century. Tricholoma species produce various types of secondary metabolites, which have been extensively studied by the scientific community. In 2018, Clericuzio et al. summarized the structures, biosynthesis, and biological activities of over one hundred different secondary metabolites isolated from the fruiting bodies of 25 Tricholoma species. Building on this, the present article reviews the research progress on Tricholoma secondary metabolites from 2018 to 2023, identifying a total of 101 compounds, 46 of which were newly discovered. These secondary metabolites include a wide range of chemical categories such as terpenoids, steroids, and alkaloids, demonstrating broad biological activities. This article aims to provide in-depth scientific insights and guidance for researchers in this field by summarizing the chemical and biological properties of these secondary metabolites, promoting further applications and development of Tricholoma fungi in the pharmaceutical and food industries. Full article

(This article belongs to the Special Issue Bioelements and Bioactive Metabolites of Natural Origin—Health-Promoting Applications—Volume II)

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13 pages, 3583 KiB

Open AccessArticle

β-Cyclodextrin-Modified Laser-Induced Graphene Electrode for Detection of N6-Methyladenosine in RNA

by Jingyi Guo, Mei Zhao, Xia Kuang, Zilin Chen and Fang Wang

Molecules 2024, 29(19), 4718; https://doi.org/10.3390/molecules29194718 (registering DOI) - 5 Oct 2024

Abstract

Laser-induced graphene (LIG) possesses characteristics of easy handling, miniaturization, and unique electrical properties. We modified the surface of LIG by electropolymerizing β-cyclodextrin (β-CD), which was used to immobilize antibodies on the electrode surface for highly sensitive detection of targets. N6-methyladenosine (m6A) is [...] Read more.

Laser-induced graphene (LIG) possesses characteristics of easy handling, miniaturization, and unique electrical properties. We modified the surface of LIG by electropolymerizing β-cyclodextrin (β-CD), which was used to immobilize antibodies on the electrode surface for highly sensitive detection of targets. N6-methyladenosine (m6A) is the most prevalent reversible modification in mammalian messenger RNA and noncoding RNA, influencing the development of various cancers. Here, β-CD was electropolymerized to immobilize the anti-m6A antibody, which subsequently recognized the target m6A. This was integrated into the catalytic hydrogen peroxide–hydroquinone (H₂O₂-HQ) redox system using phos-tag-biotin to generate electrochemical signals from streptavidin-modified horseradish peroxidase (SA-HRP). Under optimal conditions, the biosensor exhibited a linear range from 0.1 to 100 nM with a minimum detection limit of 96 pM. The method was successfully applied to the recovery analysis of m6A from HeLa cells through spiking experiments and aims to inspire strategies for point-of-care testing (POCT). Full article

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21 pages, 1756 KiB

Open AccessReview

Advances in Extracting Bioactive Compounds from Food and Agricultural Waste and By-Products Using Natural Deep Eutectic Solvents: A Circular Economy Perspective

by Petar Ristivojević, Maja Krstić Ristivojević, Dalibor Stanković and Ilija Cvijetić

Molecules 2024, 29(19), 4717; https://doi.org/10.3390/molecules29194717 (registering DOI) - 5 Oct 2024

Abstract

Due to the urgent need for a transition to sustainable, zero-waste green technology, the extraction of bioactives from food and agricultural by-products and waste has garnered increasing interest. Traditional extraction techniques often involve using organic solvents, which are associated with environmental and health [...] Read more.

Due to the urgent need for a transition to sustainable, zero-waste green technology, the extraction of bioactives from food and agricultural by-products and waste has garnered increasing interest. Traditional extraction techniques often involve using organic solvents, which are associated with environmental and health risks. Natural deep eutectic solvents (NADESs) have emerged as a promising green alternative, offering advantages such as low toxicity, biodegradability, and the ability to dissolve a wide range of biomolecules. This review provides a comprehensive overview of recent trends in the application of NADESs for extracting bioactive compounds from sustainable sources. The review explains the composition and principles of preparation and highlights various applications of NADESs in extracting different classes of bioactive compounds, emphasizing their potential to revolutionize extraction processes. By summarizing the latest advancements and trends, this review aims to support research and industrial applications of NADESs, promoting more sustainable and efficient extraction methods in the food and agricultural sectors. Full article

(This article belongs to the Special Issue Bioactive Phenolic and Polyphenolic Compounds, Volume III)

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19 pages, 1804 KiB

Open AccessArticle

Synthesis of Carborane–Thiazole Conjugates as Tyrosinase and 11β-Hydroxysteroid Dehydrogenase Inhibitors: Antiproliferative Activity and Molecular Docking Studies

by Beata Donarska, Joanna Cytarska, Dominika Kołodziej-Sobczak, Renata Studzińska, Daria Kupczyk, Angelika Baranowska-Łączkowska, Karol Jaroch, Paulina Szeliska, Barbara Bojko, Daria Różycka, Agnieszka B. Olejniczak, Wojciech Płaziński and Krzysztof Z. Łączkowski

Molecules 2024, 29(19), 4716; https://doi.org/10.3390/molecules29194716 (registering DOI) - 5 Oct 2024

Abstract

The presented study depicts the synthesis of 11 carborane–thiazole conjugates with anticancer activity, as well as an evaluation of their biological activity as inhibitors of two enzymes: tyrosinase and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). The overexpression of tyrosinase results in the intracellular accumulation [...] Read more.

The presented study depicts the synthesis of 11 carborane–thiazole conjugates with anticancer activity, as well as an evaluation of their biological activity as inhibitors of two enzymes: tyrosinase and 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1). The overexpression of tyrosinase results in the intracellular accumulation of melanin and can be observed in melanoma. The overexpression of 11β-HSD1 results in an elevation of glucocorticoid levels and has been associated with the aggravation of metabolic disorders such as type II diabetes mellitus and obesity. Recently, as the comorbidity of melanomas and metabolic disorders is being recognized as an important issue, the search for new therapeutic options has intensified. This study demonstrates that carborane–thiazole derivatives inhibit both enzymes, exerting beneficial effects. The antiproliferative action of all newly synthesized compounds was evaluated using three cancer cell lines, namely A172 (human brain glioblastoma), B16F10 (murine melanoma) and MDA-MB-231 (human breast adenocarcinoma), as well as a healthy control cell line of HUVEC (human umbilical vein endothelial cells). The results show that 9 out of 11 newly synthesized compounds demonstrated similar antiproliferative action against the B16F10 cell line to the reference drug, and three of these compounds surpassed it. To the best of our knowledge, this study is the first to demonstrate dual inhibitory action of carborane–thiazole derivatives against both tyrosinase and 11β-HSD1. Therefore, it represents the first step towards the simultaneous treatment of melanoma and comorbid diseases such as type II diabetes mellitus. Full article

(This article belongs to the Special Issue Enzyme Inhibitors: Design, Synthesis and Biological Evaluation, 2nd Edition)

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14 pages, 4146 KiB

Open AccessArticle

Acridone Derivatives for Near-UV Radical Polymerization: One-Component Type II vs. Multicomponent Behaviors

by Adel Noon, Francesco Calogero, Andrea Gualandi, Hiba Hammoud, Tayssir Hamieh, Joumana Toufaily, Fabrice Morlet-Savary, Michael Schmitt, Pier Giorgio Cozzi and Jacques Lalevée

Molecules 2024, 29(19), 4715; https://doi.org/10.3390/molecules29194715 (registering DOI) - 5 Oct 2024

Abstract

In this work, two novel acridone-based photoinitiators were designed and synthesized for the free radical polymerization of acrylates with a light-emitting diode emitting at 405 nm. These acridone derivatives were employed as mono-component Type II photoinitiators and as multicomponent photoinitiating systems in the [...] Read more.

In this work, two novel acridone-based photoinitiators were designed and synthesized for the free radical polymerization of acrylates with a light-emitting diode emitting at 405 nm. These acridone derivatives were employed as mono-component Type II photoinitiators and as multicomponent photoinitiating systems in the presence of an iodonium salt or an amine synergist (EDB) in which they achieved excellent polymerization initiating abilities and high final conversions of the acrylate group. Photoinitiation mechanisms through which reactive species are produced were investigated employing different complementary techniques including steady-state photolysis, steady-state fluorescence, cyclic voltammetry, UV–visible absorption spectroscopy, and electron spin resonance spectroscopy. Finally, these molecules were also used in the direct laser writing process for the fabrication of 3D objects. Full article

(This article belongs to the Special Issue Synthesis and Application of Photoactive Compounds)

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13 pages, 2510 KiB

Open AccessArticle

Sandwich-Type Electrochemical Aptasensor with Supramolecular Architecture for Prostate-Specific Antigen

by Anabel Villalonga, Raúl Díaz, Irene Ojeda, Alfredo Sánchez, Beatriz Mayol, Paloma Martínez-Ruiz, Reynaldo Villalonga and Diana Vilela

Molecules 2024, 29(19), 4714; https://doi.org/10.3390/molecules29194714 (registering DOI) - 5 Oct 2024

Abstract

A novel sandwich-type electrochemical aptasensor based on supramolecularly immobilized affinity bioreceptor was prepared via host–guest interactions. This method utilizes an adamantane-modified, target-responsive hairpin DNA aptamer as a capture molecular receptor, along with a perthiolated β-cyclodextrin (CD) covalently attached to a gold-modified electrode surface [...] Read more.

A novel sandwich-type electrochemical aptasensor based on supramolecularly immobilized affinity bioreceptor was prepared via host–guest interactions. This method utilizes an adamantane-modified, target-responsive hairpin DNA aptamer as a capture molecular receptor, along with a perthiolated β-cyclodextrin (CD) covalently attached to a gold-modified electrode surface as the transduction element. The proposed sensing strategy employed an enzyme-modified aptamer as the signalling element to develop a sandwich-type aptasensor for detecting prostate-specific antigen (PSA). To achieve this, screen-printed carbon electrodes (SPCEs) with electrodeposited reduced graphene oxide (RGO) and gold nanoferns (AuNFs) were modified with the CD derivative to subsequently anchor the adamantane-modified anti-PSA aptamer via supramolecular associations. The sensing mechanism involves the affinity recognition of PSA molecules on the aptamer-enriched electrode surface, followed by the binding of an anti-PSA aptamer–horseradish peroxidase complex as a labelling element. This sandwich-type arrangement produces an analytical signal upon the addition of H₂O₂ and hydroquinone as enzyme substrates. The aptasensor successfully detected the biomarker within a concentration range of 0.5 ng/mL to 50 ng/mL, exhibiting high selectivity and a detection limit of 0.11 ng/mL in PBS. Full article

(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)

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13 pages, 2958 KiB

Open AccessArticle

Effective Synthesis of mRNA during In Vitro Transcription with Fewer Impurities Produced

by Wei He, Qi Geng, Guiying Ji, Ji Li, Dan Wang, Yucai He, Qiuheng Jin and Jianren Ye

Molecules 2024, 29(19), 4713; https://doi.org/10.3390/molecules29194713 (registering DOI) - 5 Oct 2024

Abstract

The remarkable efficacy of COVID-19 vaccines has established mRNA as a highly promising biomedical technology. However, the adequate application of mRNA therapeutics necessitates additional measures to mitigate the inherent immunogenicity, which is predominantly caused by dsRNA. As a byproduct of the in vitro [...] Read more.

The remarkable efficacy of COVID-19 vaccines has established mRNA as a highly promising biomedical technology. However, the adequate application of mRNA therapeutics necessitates additional measures to mitigate the inherent immunogenicity, which is predominantly caused by dsRNA. As a byproduct of the in vitro transcription of mRNA, dsRNA was reported to be originated through several distinct mechanisms, including the extension of 3′ loop-back hairpins, the extension of hybridized abortive transcripts, and promoter-independent transcription. The intricate mechanisms involved pose a dilemma as the reduction in dsRNA results in a concomitant decrease in other critical quality attributes of mRNA. Here, we demonstrate that the promoter binding motifs of T7 RNA polymerase directly impact the production of promoter-independent transcription-based dsRNA. Specifically, the G753A mutation significantly reduces the formation of dsRNA byproducts, which can further combine with modified nucleotides to enhance the effectiveness of dsRNA mitigation and with previously reported high-integrity mutation K389A to minimize side effects. Accordingly, the present study reports a cost-effective approach to synthesize high-purity, less immunostimulatory mRNA by using an engineered T7 RNA polymerase mutant. Full article

(This article belongs to the Special Issue Recent Progress in Biocatalysis and Enzyme Engineering for Manufacturing Pharmaceutical Intermediates)

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20 pages, 1524 KiB

Open AccessReview

Fluorescence Polarization Assay for Infection Diagnostics: A Review

by Sergei A. Eremin, Liliya I. Mukhametova, Vadim B. Krylov and Nikolay E. Nifantiev

Molecules 2024, 29(19), 4712; https://doi.org/10.3390/molecules29194712 (registering DOI) - 5 Oct 2024

Abstract

Rapid and specific diagnosis is necessary for both the treatment and prevention of infectious diseases. Bacteria and viruses that enter the bloodstream can trigger a strong immune response in infected animals and humans. The fluorescence polarization assay (FPA) is a rapid and accurate [...] Read more.

Rapid and specific diagnosis is necessary for both the treatment and prevention of infectious diseases. Bacteria and viruses that enter the bloodstream can trigger a strong immune response in infected animals and humans. The fluorescence polarization assay (FPA) is a rapid and accurate method for detecting specific antibodies in the blood that are produced in response to infection. One of the first examples of FPA is the non-competitive test for detecting brucellosis in animals, which was followed by the development of other protocols for detecting various infections. Fluorescently labeled polysaccharides (in the case of brucellosis and salmonellosis) or specific peptides (in the case of tuberculosis and salmonellosis, etc.) can be used as biorecognition elements for detecting infections. The availability of new laboratory equipment and mobile devices for fluorescence polarization measurements outside the laboratory has stimulated the development of new fluorescence polarization assays (FPAs) and the emergence of commercial kits on the market for the detection of brucellosis, tuberculosis, and equine infectious anemia viruses. It has been shown that, in addition to antibodies, the FPA method can detect both viruses and nucleic acids. The development of more specific and sensitive biomarkers is essential for the diagnosis of infections and therapy monitoring. This review summarizes studies published between 2003 and 2023 that focus on the detection of infections using FPA. Furthermore, it demonstrates the potential for using new biorecognition elements (e.g., aptamers, proteins, peptides) and the combined use of FPA with new technologies, such as PCR and CRISPR/Cas12a systems, for detecting various infectious agents. Full article

(This article belongs to the Topic Advances in Spectroscopic and Chromatographic Techniques)

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11 pages, 1994 KiB

Open AccessArticle

Epimesatines P–S: Four Undescribed Flavonoids from Epimedium sagittatum Maxim. and Their Cytotoxicity Activities

by Shuang-Shuang Xie, Xiang Yu, Jing-Ke Zhang, Zhi-You Hao, Xiao-Ke Zheng and Wei-Sheng Feng

Molecules 2024, 29(19), 4711; https://doi.org/10.3390/molecules29194711 - 4 Oct 2024

Abstract

In this study, four previously undescribed flavonoids, named epimesatines P (1), Q (2), R (3), and S (4), were isolated from the aerial parts of Epimedium sagittatum Maxim. Their structures and absolute configurations were confirmed [...] Read more.

In this study, four previously undescribed flavonoids, named epimesatines P (1), Q (2), R (3), and S (4), were isolated from the aerial parts of Epimedium sagittatum Maxim. Their structures and absolute configurations were confirmed via spectroscopic analyses, quantum chemical electronic circular dichroism (ECD) calculations, Mo₂(OAc)₄–induced ECD, and Rh₂(OCOCF₃)₄–induced ECD experiments. Epimesatines Q and R were characterized by the presence of furan rings. A cytotoxicity assay demonstrated that epimesatines P–S exhibited significant inhibitory effects on the viability of MCF-7 human breast cancer cells, with IC₅₀ values ranging from 1.27 to 50.3 μM. Notably, epimesatines Q and R exhibited superior efficacy against MCF-7 cells compared to epimesatines P and S, suggesting that the presence of furan rings may enhance their activity against MCF-7 cells. Specifically, epimesatine Q displayed a more potent inhibitory effect at 1.27 μM compared to a positive control, docetaxel, which had an IC₅₀ of 2.13 μM, highlighting its potential as a therapeutic agent for breast cancer. Importantly, none of the tested compounds exhibited obvious toxicity toward MCF-10A human breast epithelial cells. Furthermore, compounds 1, 3, and 4 were found to significantly inhibit the expression of sphingosine kinase 1 (Sphk1) in MCF-7 cells. Full article

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18 pages, 4115 KiB

Open AccessReview

ZnI₂-Mediated cis-Glycosylations of Various Constrained Glycosyl Donors: Recent Advances in cis-Selective Glycosylations

by Akihiro Ishiwata, Xuemei Zhong, Katsunori Tanaka, Yukishige Ito and Feiqing Ding

Molecules 2024, 29(19), 4710; https://doi.org/10.3390/molecules29194710 - 4 Oct 2024

Abstract

An efficient and versatile glycosylation methodology is crucial for the systematic synthesis of oligosaccharides and glycoconjugates. A direct intermolecular and an indirect intramolecular methodology have been developed, and the former can be applied to the synthesis of medium-to-long-chain glycans like that of nucleotides [...] Read more.

An efficient and versatile glycosylation methodology is crucial for the systematic synthesis of oligosaccharides and glycoconjugates. A direct intermolecular and an indirect intramolecular methodology have been developed, and the former can be applied to the synthesis of medium-to-long-chain glycans like that of nucleotides and peptides. The development of a generally applicable approach for the stereoselective construction of glycosidic bonds remains a major challenge, especially for the synthesis of 1,2-cis glycosides such as β-mannosides, β-L-rhamnosides, and β-D-arabinofuranosides with equatorial glycosidic bonds as well as α-D-glucosides with axial ones. This review introduces the direct formation of cis-glycosides using ZnI₂-mediated cis-glycosylations of various constrained glycosyl donors, as well as the recent advances in the development of stereoselective cis-glycosylations. Full article

(This article belongs to the Collection Advances in Glycosciences)

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16 pages, 5576 KiB

Open AccessArticle

Reaction Thermodynamic and Kinetics for Esterification of 1-Methoxy-2-Propanol and Acetic Acid over Ion-Exchange Resin

by Xinyu Liu, Shu Wang, Mingxia Wang, Lifang Chen and Zhiwen Qi

Molecules 2024, 29(19), 4709; https://doi.org/10.3390/molecules29194709 - 4 Oct 2024

Abstract

The esterification of 1-methoxy-2-propanol (PM) and acetic acid (AA) is an important reaction for the production of 1-methoxy-2-propyl acetate (PMA). Herein, we used the macroporous ion-exchange resin Amberlyst-35 as a catalyst to explore the effects of reaction conditions on the reaction rate and [...] Read more.

The esterification of 1-methoxy-2-propanol (PM) and acetic acid (AA) is an important reaction for the production of 1-methoxy-2-propyl acetate (PMA). Herein, we used the macroporous ion-exchange resin Amberlyst-35 as a catalyst to explore the effects of reaction conditions on the reaction rate and equilibrium yield of PMA. Under the optimized conditions of a reaction temperature of 353 K, using the initial reactant PM/AA with a molar ratio of 1:3, and a catalyst loading of 10 wt%, the PMA equilibrium yield reached 78%, which is the highest equilibrium yield so far. The reaction equilibrium constants and activity coefficients were estimated to obtain reaction thermodynamic properties, indicating the exothermicity of the reaction. Furthermore, pseudo-homogeneous (PH), Eley–Rideal (ER), and Langmuir–Hinshelwood–Hougen–Watson (LHHW) kinetic models were fitted based on experimental reaction kinetic data. The results demonstrate that the LHHW model is the most consistent with experimental data, indicating a surface reaction-controlled process and exhibiting an apparent activation energy of 62.0 ± 0.2 kJ/mol. This work represents a valuable example of calculating reaction thermodynamics and kinetics, which are particularly essential for promising industrial reactor designs. Full article

(This article belongs to the Special Issue Applied Chemistry in Asia)

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16 pages, 949 KiB

Open AccessArticle

Red Grape By-Products from the Demarcated Douro Region: Chemical Analysis, Antioxidant Potential and Antimicrobial Activity against Food-Borne Pathogens

by Adriana Silva, Raquel Martins, Vanessa Silva, Fátima Fernandes, Rosa Carvalho, Alfredo Aires, Gilberto Igrejas, Virgílio Falco, Patrícia Valentão and Patrícia Poeta

Molecules 2024, 29(19), 4708; https://doi.org/10.3390/molecules29194708 - 4 Oct 2024

Abstract

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act [...] Read more.

Wine production is one of the most important agricultural activities. The winemaking process generates a considerable volume of different residues characterized as by-products, such as pomace, seeds, stems, and skins. By-products are rich in polyphenols with antioxidant and antibacterial properties and may act as bacteriostatic or bactericidal agents against food-borne pathogens, improving food safety by enhancing antibiotic efficacy and reducing bacterial resistance. The aim of this study was to evaluate the phenolic composition and antioxidant activity of grape components (skins, seeds, and stems) from three red grape varieties (Periquita, Gamay, and Donzelinho Tinto) and determine their antibacterial activity against antibiotic-resistant bacteria, including Escherichia coli in food-producing animals and Listeria monocytogenes from food products and food-related environments. Ten phenolic compounds were quantified in these red grape varieties, with specific compounds found in different parts of the grape, including phenolic acids and flavonoids. Flavonoids are abundant in seeds and stems, malvidin-3-O-glucoside being the main anthocyanin in skins. The ethanolic extract from the seeds showed in vitro concentration-dependent activity against reactive species like ^•NO and O₂^•−. Gamay extract was the most effective, followed by Donzelinho Tinto and Periquita. Extracts showed varying antibacterial activity against Gram-positive and Gram-negative bacteria, with stronger effects on Gram-positive bacteria. L. monocytogenes was more susceptible, while E. coli was limited to three strains. Seeds exhibited the strongest antibacterial activity, followed by stems. The results of our study provide evidence of the potential of grape by-products, particularly seeds, as sources of bioactive compounds with antioxidant and antibacterial properties, offering promising avenues for enhancing food safety and combating antibiotic resistance in food production and related environments. Full article

(This article belongs to the Special Issue Food Chemistry and Bioactive Compounds in Relation to Health, 2nd Edition)

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19 pages, 2582 KiB

Open AccessArticle

Extraction, Structural Characterization, and Physicochemical and Biological Properties of Water-Soluble Polysaccharides from Adlay Bran

by Peng Hu and Guangjing Chen

Molecules 2024, 29(19), 4707; https://doi.org/10.3390/molecules29194707 - 4 Oct 2024

Abstract

Adlay bran, often discarded or used as animal feed, holds untapped potential. This study explores the beneficial properties of water-soluble polysaccharides (ABPs), extracted using a hot water method, with the aim of transforming what is commonly regarded as waste into a valuable resource. [...] Read more.

Adlay bran, often discarded or used as animal feed, holds untapped potential. This study explores the beneficial properties of water-soluble polysaccharides (ABPs), extracted using a hot water method, with the aim of transforming what is commonly regarded as waste into a valuable resource. The response surface methodology (RSM) was employed to fine-tune the extraction parameters, establishing conditions at 80.0 °C, 2.5 h, and a water-to-material ratio of 31.6 mL/g. Structural studies showed that ABPs consist of different monosaccharides, including rhamnose, arabinose, glucosamine, glucose, galactose, xylose, mannose, and glucuronic acid, with respective molar ratios of 2.12%, 2.40%, 0.52%, 77.12%, 7.94%, 3.51%, 2.55%, and 3.82%. The primary component of these polysaccharides has a molecular weight averaging 12.88 kDa. The polysaccharides feature eight distinct linkage types: →3,4)-Rhap-(1→ at 5.52%, →4)-Glcp-(1→ at 25.64%, Glcp-(1→ at 9.70%, →3,4)-Glcp-(1→ at 19.11%, →4)-Xylp-(1→ at 7.05%, →3)-Glcp-(1→ at 13.23%, →3,4)-Galp-(1→ at 9.26%), and →4,6)-Gclp-(1→ at 12.49%. The semi-crystalline properties of ABPs and their shear-thinning characteristics were validated by X-ray diffraction and rheology tests. In vitro assays highlighted the strong antioxidant activities of ABPs, as evidenced by DPPH and ABTS hydroxyl radical scavenging tests, along with significant metal chelating and reducing powers. Additionally, ABPs showed significant inhibition of α-glucosidase and α-amylase, making them attractive as versatile additives or as agents with antioxidant and blood-sugar-lowering properties in both the food and pharmaceutical sectors. These findings support the utilization of adlay bran for higher-value applications, harnessing its bioactive components for health-related benefits. Full article

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20 pages, 1023 KiB

Open AccessArticle

Excess Thermodynamic Properties and FTIR Studies of Binary Mixtures of Toluene with 2-Propanol or 2-Methyl-1-propanol

by Maria Magdalena Naum and Vasile Dumitrescu

Molecules 2024, 29(19), 4706; https://doi.org/10.3390/molecules29194706 - 4 Oct 2024

Abstract

Physical properties of the binary solutions, toluene with 2-propanol and 2-methyl-1-propanol, were measured at T = 293.15, 298.15, 303.15, 308.15, and 313.15 K and P = 100 kPa. The experimental density values were tested with the Emmerling et al. and Gonzalez-Olmos–Iglesias equations. The [...] Read more.

Physical properties of the binary solutions, toluene with 2-propanol and 2-methyl-1-propanol, were measured at T = 293.15, 298.15, 303.15, 308.15, and 313.15 K and P = 100 kPa. The experimental density values were tested with the Emmerling et al. and Gonzalez-Olmos–Iglesias equations. The results indicate that the equation by Emmerling et al. is the best to correlate the density for toluene + 2-methyl-1-propanol system, while for toluene + 2-propanol, both proposed equations are proper to correlate the density with composition and temperature. The viscosity results were verified with different models containing two adjustable parameters. The values of viscosity deviation (

∆ η

), excess molar volume (V^E), excess Gibbs energy (ΔG^*E), partial molar volumes (

\bar{V_{1}}

and

\bar{V_{2}}

), and apparent molar volume (

V_{φ, 1}

and

V_{φ, 2}

) were calculated. The values of the excess molar volume were positive for both systems, while negative values were obtained for the viscosity deviation and the excess Gibbs energy. The excess properties of the mixtures were adjusted to the Redlich–Kister equation. The values of thermodynamic functions of activation of viscous flow were computed and analyzed. Additionally, the Prigogine–Flory–Patterson (PFP) theory was applied to calculate V^E and then compared with experimental values. The values of the percentage absolute average deviation obtained suggest the validity of this theory. The Fourier transform infrared spectroscopy (FTIR) spectra of the binary solutions studied in this work allowed for the understanding of the interactions between the molecules of these systems. Full article

(This article belongs to the Section Applied Chemistry)

33 pages, 9396 KiB

Open AccessReview

Amino Acid-Derived Supramolecular Assembly and Soft Materials

by Shuaishuai Nie, He Zhao, Jiayi Sun, Qingtao Liu, Yongming Cui and Wen Li

Molecules 2024, 29(19), 4705; https://doi.org/10.3390/molecules29194705 - 4 Oct 2024

Abstract

Amino acids (AAs), serving as the primary monomer of peptides and proteins, are widely present in nature. Benefiting from their inherent advantages, such as chemical diversity, low cost, ease of modification, chirality, biosafety, and bio-absorbability, AAs have been extensively exploited to create self-assembled [...] Read more.

Amino acids (AAs), serving as the primary monomer of peptides and proteins, are widely present in nature. Benefiting from their inherent advantages, such as chemical diversity, low cost, ease of modification, chirality, biosafety, and bio-absorbability, AAs have been extensively exploited to create self-assembled nanostructures and supramolecular soft materials. In this review article, we systematically describe the recent progress regarding amino acid-derived assembly and functional soft materials. A brief background and several classified assemblies of AAs and their derivatives (chemically modified AAs) are summarized. The key non-covalent interactions to drive the assembly of AAs are emphasized based on the reported systems of self-assembled and co-assembled AAs. We discuss the molecular design of AAs and the general rules behind the hierarchical nanostructures. The resulting soft materials with interesting properties and potential applications are demonstrated. The conclusion and remarks on AA-based supramolecular assemblies are also presented from the viewpoint of chemistry, materials, and bio-applications. Full article

(This article belongs to the Special Issue Molecular Self-Assembly in Interfacial Chemistry)

17 pages, 5780 KiB

Open AccessArticle

Characterization and Crystal Structural Analysis of Novel Carvedilol Adipate and Succinate Ethanol-Solvated Salts

by Li Ye, Takayuki Furuishi, Takefumi Yamashita and Etsuo Yonemochi

Molecules 2024, 29(19), 4704; https://doi.org/10.3390/molecules29194704 - 4 Oct 2024

Abstract

Two ethanol-solvated adipate and succinate salts of carvedilol (CVD), a Biopharmaceutics Classification System class 2 drug, were synthesized by crystallizing ethanol with adipic acid (ADP) and succinic acid (SUA). Proton transfer from ADP and SUA to CVD and the presence of ethanol in [...] Read more.

Two ethanol-solvated adipate and succinate salts of carvedilol (CVD), a Biopharmaceutics Classification System class 2 drug, were synthesized by crystallizing ethanol with adipic acid (ADP) and succinic acid (SUA). Proton transfer from ADP and SUA to CVD and the presence of ethanol in the two novel compounds were confirmed using powder X-ray diffraction, Fourier transform infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and single-crystal X-ray diffraction measurements. The two novel ethanol-solvated salts exhibited enhanced solubility and dissolution rates compared with pure carvedilol in phosphate buffer (pH 6.8). Additionally, the morphologies and attachment energies of the two novel compounds and pure CVD were calculated based on their single-crystal structures, revealing a correlation between attachment energy and dissolution rate. Full article

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25 pages, 5564 KiB

Open AccessArticle

The Influence of the Functional Group on the Physicochemical and Biological Properties of New Phenanthro[9,10-d]-Imidazole Derivatives

by Slawomir Kula, Paweł Kalarus, Łukasz Kaźmierski, Anna Biernasiuk and Przemysław Krawczyk

Molecules 2024, 29(19), 4703; https://doi.org/10.3390/molecules29194703 - 4 Oct 2024

Abstract

The search for safe, cheap, and repeatable diagnostic methods is a fundamental research goal. Currently, great hope is placed on fluorescence imaging. However, the development of this method mainly depends on efficient fluorescent probes. Designing and obtaining new probes with potential applications in [...] Read more.

The search for safe, cheap, and repeatable diagnostic methods is a fundamental research goal. Currently, great hope is placed on fluorescence imaging. However, the development of this method mainly depends on efficient fluorescent probes. Designing and obtaining new probes with potential applications in fluorescence imaging is very difficult because compounds of this type must meet several requirements related to their properties. Therefore, this article attempted to obtain and study new phenanthro[9,10-d]-imidazole derivatives (PK1–PK3) with potential application as fluorescent probes for fluorescence imaging. The main goal of the work was to assess the effect of two functional groups (such as the formyl group (PK2) and rhodanine-3-acetic acid (PK3)) on selected physicochemical properties and possibilities of practical application of the considered compounds. The conducted studies proved that the influence of the functional group is significant, as it causes a bathochromic shift in both absorption and emission results (by the order PK1 < PK2 < PK3). Moreover, all compounds could stain live cells cultured in vitro. The staining efficiency was not affected by the cell line, thanks to which we obtained the correct staining of both mouse and human cell lines. PK3 was the most attractive of the tested compounds due to its staining potential of live cells and retention after fixation. Our results also showed some antibacterial and antifungal activity of the newly synthesized compounds (PK1–PK3). Among them, PK3 showed the highest antimicrobial effect, especially against Gram-positive bacteria. Full article

(This article belongs to the Special Issue Synthetic Studies Aimed at Heterocyclic Organic Compounds)

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