Molecules

19 pages, 2530 KB

Open AccessArticle

Investigation of N-(2-oxo-2H-chromen-3-carbonyl)cytisine’s Molecular Structure in Solution

by Kymbat Kopbalina, Aigerim Adekenova, Zhanar Shaimerdenova, Zhanargul Kairatova, Kuanysh Shakarimova, Dmitrii Pankin, Mikhail Smirnov, Anarkul Kishkentayeva, Makpal Artykbayeva and Roza Jalmakhanbetova

Molecules 2025, 30(20), 4139; https://doi.org/10.3390/molecules30204139 (registering DOI) - 20 Oct 2025

Abstract

Cytisine and coumarin derivatives are promising for the creation of new drugs with antiarrhythmic, antiepileptic, antidiabetic, anti-inflammatory, and antimicrobial effects. In this study, the molecular structure of the cytisine and coumarin derivative in solution, a recently synthesized substance N-(2-oxo-2H-chromen-3-carbonyl)cytisine, was studied by NMR [...] Read more.

Cytisine and coumarin derivatives are promising for the creation of new drugs with antiarrhythmic, antiepileptic, antidiabetic, anti-inflammatory, and antimicrobial effects. In this study, the molecular structure of the cytisine and coumarin derivative in solution, a recently synthesized substance N-(2-oxo-2H-chromen-3-carbonyl)cytisine, was studied by NMR and UV-Vis absorption spectroscopies accompanied by a theoretical study based on density functional theory. The existence of four stable conformers associated with the rotation of the cytisine part relative to the coumarin part due to a sufficiently flexible intermediate part has been demonstrated. Their energy and concentrations were estimated. In the 1H and 13C NMR spectra, peaks were found that correspond to individual conformers and groups of conformers. The UV-visible absorption spectrum also revealed spectral features associated with different conformers. It was shown that the obtained results are consistent with earlier studies about conformational state identification in cytisine derivatives functionalized with flexible parts. The obtained theoretical and experimental results provide useful spectroscopic information for such conformer identification in this and structurally similar substances. Full article

(This article belongs to the Section Molecular Structure)

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29 pages, 2864 KB

Open AccessArticle

TiO₂ and CaCO₃ Microparticles Produced in Aqueous Extracts from Satureja montana: Synthesis, Characterization, and Preliminary Antimicrobial Test

by Federica Valentini, Irene Angela Colasanti, Camilla Zaratti, Dumitrita Filimon, Andrea Macchia, Anna Neri, Michela Relucenti, Massimo Reverberi, Ivo Allegrini, Ettore Guerriero, Marina Cerasa, Marta De Luca, Francesca Santangeli, Roberto Braglia, Francesco Scuderi, Lorenza Rugnini, Roberta Ranaldi, Roberto De Meis and Antonella Canini

Molecules 2025, 30(20), 4138; https://doi.org/10.3390/molecules30204138 (registering DOI) - 20 Oct 2025

Abstract

The possibility of modifying the surface chemistry of materials and synthetizing inorganic particles in natural aqueous extracts of plants (avoiding calcination), opens the doors to undoubtedly interesting scenarios for innovative functionalization strategies that are increasingly eco-sustainable and rich in interesting chemical–physical and biochemical [...] Read more.

The possibility of modifying the surface chemistry of materials and synthetizing inorganic particles in natural aqueous extracts of plants (avoiding calcination), opens the doors to undoubtedly interesting scenarios for innovative functionalization strategies that are increasingly eco-sustainable and rich in interesting chemical–physical and biochemical properties. Among the aerial plants, Satureja montana exhibits interesting antibacterial, antifungal, antimicrobial, and antioxidant activities due to the rich volatile and non-volatile compounds (characterized by gas chromatography–mass spectrometry), contained in the aqueous extracts. For the first time, the latter was applied for the green synthesis of TiO₂ and CaCO₃ particles, characterized by X-ray diffraction, Raman, infrared spectroscopies, and scanning electron microscopy, coupled with microanalysis. Screening through antimicrobial assays under indoor passive sedimentation conditions showed opposite trends for two kinds of particles. TiO₂ anatase spherical particles (400 < φ < 600 nm) increase microbial growth, proportionally to increasing particle concentration. Instead, S. montana-functionalized CaCO₃ prismatic microparticles (1 µm × 1 µm × 1 µm) exhibit strong and dose-dependent antimicrobial activities, achieving near-complete inhibition at 50 mg/mL. Full article

(This article belongs to the Special Issue Synthesized and Functionalized Nanoparticles in Natural Compounds)

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22 pages, 1340 KB

Open AccessArticle

Polarizabilities of Atoms in Molecules: Choice of the Partitioning Scheme and Applications for Secondary Interactions

by Piero Macchi

Molecules 2025, 30(20), 4137; https://doi.org/10.3390/molecules30204137 - 20 Oct 2025

Abstract

This paper reviews methods for partitioning the molecular polarizability into atomic terms. The advantages and disadvantages of hard space or fuzzy partitioning are critically assessed and compared. Polarizability density is proposed as a key function for the in-depth analysis and prediction of molecular [...] Read more.

This paper reviews methods for partitioning the molecular polarizability into atomic terms. The advantages and disadvantages of hard space or fuzzy partitioning are critically assessed and compared. Polarizability density is proposed as a key function for the in-depth analysis and prediction of molecular recognition and chemical reactivity. Applications in the study of secondary interactions are illustrated, particularly in electron donor–acceptor complexes and other molecular adducts. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Physical Chemistry, 3rd Edition)

23 pages, 3441 KB

Open AccessArticle

Tuning of Photocatalytic and Piezophotocatalytic Activity of Bi₃TiNbO₉ via Synthesis-Controlled Surface Defect Engineering

by Farid F. Orudzhev, Asiyat G. Magomedova, Sergei A. Kurnosenko, Vladislav E. Beklemyshev, Wei Li, Chuanyi Wang and Irina A. Zvereva

Molecules 2025, 30(20), 4136; https://doi.org/10.3390/molecules30204136 - 20 Oct 2025

Abstract

In this work, we investigate advanced photocatalyst Bi₃TiNbO₉ as promising piezophotocatalyst in terms of the effect of synthesis methods on the surface chemistry, structure, and catalytic performance in process of contaminant removal. Samples were prepared via solid-state reaction (BTNO-900) and [...] Read more.

In this work, we investigate advanced photocatalyst Bi₃TiNbO₉ as promising piezophotocatalyst in terms of the effect of synthesis methods on the surface chemistry, structure, and catalytic performance in process of contaminant removal. Samples were prepared via solid-state reaction (BTNO-900) and molten salt synthesis (BTNO-800), leading to distinct morphologies and defect distributions. SEM imaging revealed that BTNO-900 consists of agglomerated, irregular particles, while BTNO-800 exhibits well-faceted, plate-like grains. Nitrogen adsorption analysis showed that the molten-synthesized sample possesses a significantly higher specific surface area (5.9 m²/g vs. 1.4 m²/g) and slightly larger average pore diameter (2.8 nm vs. 2.6 nm). High-resolution XPS revealed systematic shifts in binding energies for Bi 4f, Ti 2p, Nb 3d, and O 1s peaks in BTNO-900, accompanied by a higher content of adsorbed oxygen species (57% vs. 7.2%), indicating an increased concentration of oxygen vacancies and surface hydroxylation due to the solid-state synthesis route. Catalytic testing demonstrated that BTNO exhibits enhanced piezocatalytic efficiency of Methylene Blue degradation (~78% for both samples), whereas BTNO-800 shows significantly reduced photocatalytic activity (45.6%) compared to BTNO-900 (84.1%), suggesting recombination effects dominate in the more defective material. Synergism of light and mechanical stress results in piezophotocatalytic degradation for both samples (92.4% and 93.4%, relatively). These findings confirm that synthesis-controlled defect engineering is a key parameter for optimizing the photocatalytic behavior of Bi₃TiNbO₉-based layered oxides and crucial role of its piezocatalytic activity. Full article

(This article belongs to the Special Issue Advanced Photocatalysts for Environmental Remediation and Contaminant Removal)

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15 pages, 14094 KB

Open AccessArticle

Impact of Mg Doping on Structural, Morphological and Thermoelectric Properties of SnO₂ Nanoparticles: A Combined Experimental-Theoretical Investigation

by Muhammad Isram, Matteo Barduzzi, Valeria Demontis, Daniele Goldoni, Pino D’Amico, Luigi Rovati, Alberto Vomiero, Alice Ruini and Francesco Rossella

Molecules 2025, 30(20), 4135; https://doi.org/10.3390/molecules30204135 - 20 Oct 2025

Abstract

Recent advances in nanotechnology, including the development of nanoparticles, thin films, and superlattices, have revitalized research in thermoelectricity by enabling independent control of thermal and electrical transport, overcoming longstanding efficiency limitations and expanding opportunities for sustainable energy generation and miniaturized device applications. Tin [...] Read more.

Recent advances in nanotechnology, including the development of nanoparticles, thin films, and superlattices, have revitalized research in thermoelectricity by enabling independent control of thermal and electrical transport, overcoming longstanding efficiency limitations and expanding opportunities for sustainable energy generation and miniaturized device applications. Tin dioxide (SnO₂) has recently attracted increasing attention as a thermoelectric material owing to its properties, such as high-temperature chemical and structural stability, non-toxicity, and the abundance of constituent elements. Current research efforts have been directed toward enhancing its thermoelectric performance through strategies such as elemental doping, nanostructuring, strain engineering, and the development of composite systems. In this study, we investigate the effects of Mg substitutional doping on the thermoelectric characteristics of SnO₂. We synthesize undoped and Mg-doped SnO₂ nanoparticles (0.05%, 0.10%, and 0.15%) using a straightforward hydrothermal technique. The investigation of the undoped and doped materials revealed that SnO₂ possesses a tetragonal rutile-type structure, as determined through structural and morphological examination. The crystalline size of all of the samples decreases as the Mg doping concentration is increased. Hall measurement and Seebeck coefficient measurements have been employed for assessing the thermoelectric characteristics. As the Mg content increased, both the Seebeck coefficient and electrical conductivity value increased from −20

μ

V/K to −91

μ

V/K and 29.8 S/cm to 112.6 S/cm, confirming the presence of semiconductor behavior. The 0.15% Mg-doped sample demonstrates the highest power factor when evaluated at a temperature of 150 K, yielding a value of 9.4

\times 10^{- 5}

WK⁻²m⁻¹. Full article

(This article belongs to the Special Issue Exclusive Papers of Editorial Board Members and Invited Scholars in “Materials Chemistry”, 2nd Edition)

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20 pages, 4722 KB

Open AccessFeature PaperArticle

Targeting Melanogenesis with Postbiotics: An Integrated Zebrafish-Based Assessment of Lactobacillus salivarius BGHO-1 and Lactobacillus paracasei BGSJ2-8

by Gabor Katona, Natasa Jovanovic Ljeskovic, Ivana Strahinic, Nemanja Stanisavljevic, Sladjana Vojvodic, Jelena Djuris and Aleksandar Pavic

Molecules 2025, 30(20), 4134; https://doi.org/10.3390/molecules30204134 - 20 Oct 2025

Abstract

Skin hyperpigmentation disorders represent a major dermatological challenge, and safe alternatives to conventional depigmenting agents remain scarce. Probiotics and their postbiotic derivatives have emerged as promising natural candidates; however, only a few bacterial strains have been investigated for melanogenesis-inhibitory activity, and their true [...] Read more.

Skin hyperpigmentation disorders represent a major dermatological challenge, and safe alternatives to conventional depigmenting agents remain scarce. Probiotics and their postbiotic derivatives have emerged as promising natural candidates; however, only a few bacterial strains have been investigated for melanogenesis-inhibitory activity, and their true potential remains largely unexplored. Here, we report for the first time the biosafety profile and anti-melanogenic activity of Lactobacillus salivarius BGHO-1 and Lactobacillus paracasei BGSJ2-8, and assess their possible use in the treatment of skin hyperpigmentation. Two complementary zebrafish-based approaches were employed: (i) image-assisted analysis of pigmentation patterns, melanocyte morphology, and melanocytotoxicity, and (ii) quantitative melanin analysis, enabling integrated safety and efficacy evaluation. We investigated both native and heat-inactivated preparations, including whole cultures, cell-free supernatants, isolated cells, and separated cell walls/membranes and cytoplasmic fractions. While several fractions demonstrated the ability to inhibit melanogenesis, the cell wall/membrane fraction was the most potent, reducing melanin content by 64% compared to untreated embryos, while causing no systemic side effects and preserving melanocyte structure. Furthermore, this fraction did not elicit inflammatory responses or neutropenia, underscoring its favorable safety profile at anti-melanogenic doses. Collectively, this study identifies specific postbiotics as effective and safe modulators of melanogenesis and highlights their translational potential in developing novel approaches for treating skin hyperpigmentation. Full article

19 pages, 2015 KB

Open AccessReview

Development of Nanotechnological Approaches to Improving the Antimalarial Potential of Natural Substances

by Yoana Yoncheva, Lyubomira Radeva and Krassimira Yoncheva

Molecules 2025, 30(20), 4133; https://doi.org/10.3390/molecules30204133 - 20 Oct 2025

Abstract

Malaria is one of the diseases that is a serious threat to global health, with millions of cases reported worldwide in recent years. The treatment of malaria is still a challenge due to its complex pathogenesis, resistance to many of the antimalarial drugs, [...] Read more.

Malaria is one of the diseases that is a serious threat to global health, with millions of cases reported worldwide in recent years. The treatment of malaria is still a challenge due to its complex pathogenesis, resistance to many of the antimalarial drugs, and adverse toxicity. Nowadays, the possibilities of applying new natural molecules alone or in combination is being researched. However, many of these substances possess low aqueous solubility, which limits their bioavailability. The solubility of such substances could be improved by applying various techniques for their nanoencapsulation, e.g., incorporation in nanocapsules, liposomes, lipid nanoparticles, etc. The current review emphasizes studies on the nanoencapsulation of some of the well-known natural antimalarial agents (quinine, artemisinin) as well as substances with newly demonstrated antimalarial potential (piperine, quercetin, etc.). The review also discusses the opportunity to simultaneously load two natural agents in nanoparticles. Special focus is given to the metal nanoparticles (e.g., silver, gold, etc.) obtained by green synthesis from plants. Full article

(This article belongs to the Special Issue Natural Compounds for Disease and Health, 3rd Edition)

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14 pages, 2451 KB

Open AccessArticle

Kaempferol and Kaempferin Alleviate MRSA Virulence by Suppressing β-Lactamase and Inflammation

by Junlu Liu, Jingyao Wen, Jiahui Lu, Hanbing Zhou and Guizhen Wang

Molecules 2025, 30(20), 4132; https://doi.org/10.3390/molecules30204132 - 20 Oct 2025

Abstract

Methicillin-resistant S. aureus (MRSA) possesses broad resistance, biofilm formation, and high virulence characteristics. Therefore, developing new therapeutic strategies against this pathogen is urgent. This work reports kaempferol (kol) and kaempferin (kin) bound to the active site of β-lactamase and interacting with key residues, [...] Read more.

Methicillin-resistant S. aureus (MRSA) possesses broad resistance, biofilm formation, and high virulence characteristics. Therefore, developing new therapeutic strategies against this pathogen is urgent. This work reports kaempferol (kol) and kaempferin (kin) bound to the active site of β-lactamase and interacting with key residues, thereby inhibiting its activity. In addition, kol and kin reduced the secretion of β-lactamase to the external environment, then the shielding effect of β-lactamase to β-lactam antibiotics was weakened, and finally, the bactericidal ability of ampicillin (Amp) to MRSA was enhanced. Kol and kin relieved the inflammatory responses of J774 cells induced by MRSA and improved the survival of Galleria mellonella (G. mellonella) infected by MRSA when combined with or without Amp. These data suggest that kol and kin have the potential to be developed as anti-MRSA infection agents, which would broaden the application prospects of these compounds. Full article

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18 pages, 4813 KB

Open AccessArticle

Machine Learning-Assisted DFT Screening of Nitrogen-Doped Graphene Diatomic Catalysts for Nitrogen Reduction Reaction

by Xiulin Wang, Suofu Nie, Huichao Yao, Sida Wu, Yanze Li, Junli Feng, Yiyan Sui, Yuqing Zhang, Xinwei Wang and Xiuxia Zhang

Molecules 2025, 30(20), 4131; https://doi.org/10.3390/molecules30204131 (registering DOI) - 20 Oct 2025

Abstract

This research seeks to investigate extremely efficient catalysts for the nitrogen reduction process (NRR), utilizing machine learning (ML)-aided density functional theory (DFT) computations. Specifically, we investigate dual transition metal atoms anchored on hexagonal nitrogen-doped graphene (TM₁-TM₂@N₆G) as [...] Read more.

This research seeks to investigate extremely efficient catalysts for the nitrogen reduction process (NRR), utilizing machine learning (ML)-aided density functional theory (DFT) computations. Specifically, we investigate dual transition metal atoms anchored on hexagonal nitrogen-doped graphene (TM₁-TM₂@N₆G) as prospective high-activity catalysts for the NRR. The findings indicate that the synergistic effect of dual transition metal atoms in the TM₁-TM₂@N₆G catalyst overcomes the intrinsic constraints of the linear relationship among intermediates, facilitating the activation and adsorption of N₂, thereby exhibiting significant potential for ammonia synthesis through N₂ reduction. Particularly, four catalysts screened by ML and DFT exhibit good stability and excellent selectivity and activation towards N₂. Among them, the catalysts Ti-Cr@N₆G, Ti-Mo@N₆G, and Ti-Pd@N₆G possess two reaction pathways with minimum reaction energies of 0.55 eV, 0.50 eV, and 0.40 eV, respectively. Remarkably, Ti-Co@N₆G, which features a single reaction pathway, exhibits a reaction energy lower than 0.05 eV, allowing the NRR to proceed spontaneously. It is noteworthy that incorporating ML into DFT calculations facilitates the rapid screening of all transition metal combinations, significantly accelerating the research on catalytic performance and optimizing the selection of catalysts. Full article

(This article belongs to the Special Issue Renewable Energy, Fuels and Chemicals from Biomass, 2nd Edition)

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37 pages, 1680 KB

Open AccessReview

The Role of Probiotics and Their Postbiotic Metabolites in Post-COVID-19 Syndrome

by Monika E. Jach, Ewa Sajnaga, Marharyta Bumbul, Anna Serefko, Kinga K. Borowicz, Hieronim Golczyk, Marek Kieliszek and Adrian Wiater

Molecules 2025, 30(20), 4130; https://doi.org/10.3390/molecules30204130 - 20 Oct 2025

Abstract

Post-COVID-19 syndrome, also known as long-COVID, is characterized by a wide spectrum of persistent symptoms involving multiple body organs and systems, including fatigue, gastrointestinal disorders, and neurocognitive dysfunction. Emerging evidence suggests that gut microbiota dysbiosis and disruption of the gut–brain axis play a [...] Read more.

Post-COVID-19 syndrome, also known as long-COVID, is characterized by a wide spectrum of persistent symptoms involving multiple body organs and systems, including fatigue, gastrointestinal disorders, and neurocognitive dysfunction. Emerging evidence suggests that gut microbiota dysbiosis and disruption of the gut–brain axis play a central role in the pathophysiology of this condition. Probiotics and their metabolites (postbiotics) have gained increasing attention as potential therapeutic agents given their immunomodulatory, anti-inflammatory, and antiviral properties. In this review, we discuss the current understanding of the antiviral mechanisms of probiotics, including reinforcement of intestinal epithelial barrier function, direct virus inhibition, receptor competition, and immune system modulation. Special emphasis is placed on short-chain fatty acids (SCFAs), lactic acid, hydrogen peroxide, and bacteriocins as key factors that contribute to these effects. SCFAs appear to be essential postbiotic compounds during post-COVID recovery. We also highlight recent clinical trials involving specific probiotic species, such as Lactiplantibacillus plantarum, Lacticaseibacillus rhamnosus, and Bifidobacterium longum, and their potential role in alleviating long-term COVID symptoms. Although the current results are promising, further research is needed to clarify the most effective strains, dosages, and mechanisms of action in post-COVID therapeutic strategies. Full article

(This article belongs to the Special Issue Exploring Microorganisms and Their Bioactive Secondary Metabolites: From Nature to Application)

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18 pages, 1494 KB

Open AccessArticle

The Evaluation of (1R,4R,7R,10R)-α,α′,α″,α‴-Tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic Acid (DOTMA) as a Chelator for Zirconium-89

by Darpan N. Pandya, Pere Miro, Michael A. Sinnwell, George B. Crull and Thaddeus J. Wadas

Molecules 2025, 30(20), 4129; https://doi.org/10.3390/molecules30204129 - 19 Oct 2025

Abstract

Recently, macrocycles such as 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) have been observed to form zirconium-89 (⁸⁹Zr: t_½ = 78.4 h, β+: 22.8%, E_β+max = 901 keV; EC: 77%, E_γ = 909 keV)-complexes with excellent in vivo stability. In this report, [...] Read more.

Recently, macrocycles such as 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) have been observed to form zirconium-89 (⁸⁹Zr: t_½ = 78.4 h, β+: 22.8%, E_β+max = 901 keV; EC: 77%, E_γ = 909 keV)-complexes with excellent in vivo stability. In this report, we describe (1R,4R,7R,10R)-α,α′,α″,α‴-tetramethyl-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTMA) as an ⁸⁹Zr chelator. Using [⁸⁹Zr]ZrCl₄, [⁸⁹Zr]Zr-DOTMA was prepared in 99% radiochemical yield and a molar activity of 1055 ± 6 MBq/µmol. In vitro studies revealed a LogP value of −2.97± 0.02 and a radiometal complex that was inert when challenged with 1000-fold excess EDTA or high concentrations of biologically relevant metal ions. Finally, biodistribution studies revealed that the radiometal complex demonstrated in vivo behavior that was like [⁸⁹Zr]Zr-DOTA and superior to [⁸⁹Zr]Zr-DFO. Despite these promising observations, the elevated temperature required to form the [⁸⁹Zr]Zr-DOTMA complex and the lack of derivatives available for bioconjugation will require additional ligand engineering to improve its utility for future nuclear medicine applications. Full article

(This article belongs to the Special Issue Advance in Radiochemistry, 2nd Edition)

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15 pages, 2152 KB

Open AccessArticle

Iron(II) and Manganese(II) Coordination Chemistry Ligated by Coplanar Tridentate Nitrogen-Donor Ligand, 2,6-bis(5-isopropyl-1H-pyrazol-3-yl)pyridine

by Kiyoshi Fujisawa, Yurika Minakawa and David James Young

Molecules 2025, 30(20), 4128; https://doi.org/10.3390/molecules30204128 - 19 Oct 2025

Abstract

Coplanar tridentate nitrogen-donor ligands have been extensively employed to stabilize transition metal complexes by chelation. Some complexes exhibit interesting structures and photoluminescent properties. In this work, 2,6-bis(5-isopropyl-1H-pyrazole-3-yl)pyridine (denoted as L), its iron(II) and manganese(II) dichlorido complexes, and its bis-chelate iron(II) [...] Read more.

Coplanar tridentate nitrogen-donor ligands have been extensively employed to stabilize transition metal complexes by chelation. Some complexes exhibit interesting structures and photoluminescent properties. In this work, 2,6-bis(5-isopropyl-1H-pyrazole-3-yl)pyridine (denoted as L), its iron(II) and manganese(II) dichlorido complexes, and its bis-chelate iron(II) complexes, viz. [FeCl₂(L)]·2(MeOH) and [MnCl₂(L)]·2(MeOH), and [Fe(L)₂](PF₆) ·5(thf), respectively, were synthesized and characterized by single-crystal X-ray structural analysis. These solid-state structures contained N–H donors that formed hydrogen bonds with the coordinated halogenide ions and lattice solvent molecules, methanol or tetrahydrofuran. The iron(II) and manganese(II) dichlorido complexes [FeCl₂(L)]·2(MeOH) and [MnCl₂(L)]·2(MeOH) displayed distorted trigonal pyramidal structures in the solid state. However, [FeCl₂(L)]·2(MeOH) was not stable in methanol and formed the bis-chelate iron(II) complex [Fe(L)₂](FeCl₄). Therefore, the bis-chelate iron(II) complex [Fe(L)₂](PF₆)·5(thf) was also synthesized and structurally and spectroscopically authenticated. Full article

(This article belongs to the Special Issue Inorganic Chemistry in Asia, 2nd Edition)

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19 pages, 1324 KB

Open AccessArticle

Loop-Structured PEG-Lipoconjugate Enhances siRNA Delivery Mediated by Liner-PEG Containing Liposomes

by Daniil V. Gladkikh, Elena V. Shmendel, Darya M. Makarova, Mikhail A. Maslov, Marina A. Zenkova and Elena L. Chernolovskaya

Molecules 2025, 30(20), 4127; https://doi.org/10.3390/molecules30204127 (registering DOI) - 19 Oct 2025

Abstract

Therapeutics involving small interfering RNA (siRNA) have enormous potential for treating a number of diseases, but their effective delivery to target cells remains a major challenge. We studied the influence of the structure and combination of targeted (folate conjugated, F13) and shield lipoconjugates [...] Read more.

Therapeutics involving small interfering RNA (siRNA) have enormous potential for treating a number of diseases, but their effective delivery to target cells remains a major challenge. We studied the influence of the structure and combination of targeted (folate conjugated, F13) and shield lipoconjugates (P1500, diP1500) on the ability of cationic liposomal formulations based on the 2X3-DOPE system to deliver siRNA into cells in vitro and in vivo. The loop-structured PEG lipoconjugate equipped with two hydrophobic anchor groups (diP1500) demonstrated superior performance across multiple evaluation criteria. The F13/diP1500 composition maintained a compact particle size (126.0 ± 23.0 nm), while F13/P1500 with the same PEG chain equipped with one anchor group maintained an increased particle size of 241.8 ± 65.7 nm. Most critically, F13/diP1500 preserved substantial positive surface charges (21.6–30.5 mV) across all N/P ratios, demonstrating superior ability in avoid the “PEG dilemma”, whereas F13/P1500 suffered substantial charge neutralization (3.9–9.1 mV). Competitive inhibition with free folate confirmed receptor-mediated cellular accumulation of siRNA mediated by F13 containing liposomal compositions. In vivo biodistribution revealed statistically significant circulation advantages: DSPE-PEG2000/diP1500 achieved the highest plasma concentration at 15 min (1.84 ± 0.01 pmol/mL), representing the first direct in vivo comparison of compositions with PEG lipoconjugates of the same length, but formed different structures in the liposomes due to the presence of one or two anchor groups. Our findings provide critical insights for the rational design of targeted liposomal delivery systems, highlighting the importance of balanced optimization between folate targeting functionality and PEG shielding for effective siRNA delivery both in vitro and in vivo. Full article

(This article belongs to the Special Issue Advances in Targeted Delivery of Nanomedicines)

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14 pages, 16405 KB

Open AccessArticle

Influence of Arabic Gum/Gelatin/Ascorbyl Palmitate Coating on Quality Parameters of Hazelnut Kernels Stored in Plastic Boxes

by Dariusz Kowalczyk, Katarzyna Niedźwiadek, Tomasz Skrzypek, Emil Zięba and Jaromir Jarecki

Molecules 2025, 30(20), 4126; https://doi.org/10.3390/molecules30204126 - 19 Oct 2025

Abstract

Edible coatings enriched with antioxidants offer a promising approach to prolong the shelf life of oxidation-sensitive foods such as nuts. Nonetheless, not all formulations provide the expected protection, and understanding why is equally important. The aim of this study was to assess the [...] Read more.

Edible coatings enriched with antioxidants offer a promising approach to prolong the shelf life of oxidation-sensitive foods such as nuts. Nonetheless, not all formulations provide the expected protection, and understanding why is equally important. The aim of this study was to assess the effect of an Arabic gum/gelatin/ascorbyl palmitate (GAR/GEL/AP) coating on the quality of hazelnut kernels during storage at 23 °C and ~40% relative humidity. The coating was applied by dipping hazelnuts in a 20% ethanolic solution containing GAR/GEL 75/25 blend (10% w/w), glycerol (1% w/w), Tween 80 (0.25% w/w), and AP (2% w/w), followed by drying. Control (uncoated) and coated hazelnuts were stored in plastic containers and evaluated at 1, 2, 4, 8, and 16 weeks for weight loss, moisture content, hardness, color, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH*) scavenging activity, acid and peroxide values, and thiobarbituric acid reactive substances (TBARS) level. Coated hazelnuts showed higher initial moisture content (8.17%), stabilizing at 4.80% after one week, compared to 3.35% in uncoated samples. This increased moisture led to greater storage-related weight loss. The coating darkened the nuts and reduced their yellow hue. It had no significant effect on hardness, peroxide value, or TBARS index, but notably enhanced the antiradical potential. After 16 weeks, coated nuts had an acid value ~10 mg KOH/g lower than the control. In conclusion, the coating improved antioxidant capacity and reduced hydrolytic, but not oxidative, rancidity in hazelnuts. Therefore, further optimization of the coating formulation or application method is necessary to more effectively improve the shelf life of hazelnuts. Full article

(This article belongs to the Special Issue 30th Anniversary of Molecules—Recent Advances in Food Chemistry)

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34 pages, 1121 KB

Open AccessReview

Sodium-Glucose Cotransporter-2 Inhibitors in Diabetes and Beyond: Mechanisms, Pleiotropic Benefits, and Clinical Use—Reviewing Protective Effects Exceeding Glycemic Control

by Julia Hanke, Katarzyna Romejko and Stanisław Niemczyk

Molecules 2025, 30(20), 4125; https://doi.org/10.3390/molecules30204125 - 18 Oct 2025

Abstract

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, also known as gliflozins, are a class of antidiabetic agents that act independently of insulin by promoting renal glucose excretion. They modulate glucose reabsorption in proximal renal tubules. Initially, they were used for the treatment of type 2 diabetes [...] Read more.

Sodium-glucose cotransporter-2 (SGLT2) inhibitors, also known as gliflozins, are a class of antidiabetic agents that act independently of insulin by promoting renal glucose excretion. They modulate glucose reabsorption in proximal renal tubules. Initially, they were used for the treatment of type 2 diabetes mellitus (T2DM); however, numerous pleiotropic benefits beyond glycemic control were observed. Large clinical trials confirmed their efficacy in reducing cardiovascular mortality, heart failure hospitalizations, and progression of chronic kidney disease. SGLT2 inhibitors reduce oxidative stress and inflammation and induce favorable metabolic adaptations, including lowering ketosis and upregulation of erythropoiesis. They also exert protective effects on hepatic and cognitive function. Additionally, SGLT2 inhibitors lower serum uric acid and reduce adipose tissue mass, which usually results in weight loss. Although generally well-tolerated, they are associated with increased risk of urogenital infections, euglycemic ketoacidosis, and a potentially enlarged amputation risk. Current guidelines worldwide recommend their use not only for T2DM but also for heart failure and chronic kidney disease, marking a paradigm shift toward organ-protective therapies. This review provides a comprehensive synthesis of current evidence on the mechanisms, clinical benefits, and safety profile of SGLT2 inhibitors, highlighting their expanding role in cardiometabolic and multisystem disease management. Full article

(This article belongs to the Special Issue Natural Compounds for Disease and Health, 3rd Edition)

16 pages, 24100 KB

Open AccessArticle

Structural Engineering in Sn-Doped WO₃ Multi-Phase Systems for Enhanced Transparent Heat Insulation

by Xinyu Song, Ze Wang, Yue Liu, Xin Li, Chun Du and Shifeng Wang

Molecules 2025, 30(20), 4124; https://doi.org/10.3390/molecules30204124 (registering DOI) - 17 Oct 2025

Abstract

Building energy conservation through the development of transparent thermal insulation materials that selectively block near-infrared radiation while maintaining visible light transmittance has emerged as a key strategy for global carbon neutrality. WO₃ is a semiconductor oxide with near-infrared absorption capabilities. However, the [...] Read more.

Building energy conservation through the development of transparent thermal insulation materials that selectively block near-infrared radiation while maintaining visible light transmittance has emerged as a key strategy for global carbon neutrality. WO₃ is a semiconductor oxide with near-infrared absorption capabilities. However, the limited absorption efficiency and narrow spectral coverage of pure WO₃ significantly diminish its overall transparent thermal insulation performance, thereby restricting its practical application in energy-saving glass. Therefore, this study successfully prepared Sn-doped WO₃ materials using a one-step hydrothermal method, controlling the Sn:W molar ratio from 0.1:1 to 2.0:1. Through evaluation of transparent thermal insulation performance of a series of Sn-doped WO₃ samples, we found that Sn:W = 0.9:1 exhibited the most excellent performance, with NIR shielding efficiency reaching 93.9%, which was 1.84 times higher than pure WO₃. Moreover, this sample demonstrated a transparent thermal insulation index (THI) of 4.38, representing increases of 184% and 317%, respectively, compared to pure WO₃. These enhancements highlight the strong NIR absorption capability achieved by Sn-doped WO₃ through structural regulation. When Sn doping reaches a certain concentration, it triggers a structural transformation of WO₃ from monoclinic to tetragonal phase. After reaching the critical solubility threshold, phase separation occurs, forming a multiphase structure composed of a Sn-doped WO₃ matrix and secondary SnO₂ and WSn_0.33O₃ phases, which synergistically enhance oxygen vacancy formation and W⁶⁺ to W⁵⁺ reduction, achieving excellent NIR absorption through small polaron hopping and localized surface plasmon resonance effects. This study provides important insights for developing high-performance transparent thermal insulation materials for energy-efficient buildings. Full article

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22 pages, 3509 KB

Open AccessArticle

Microwave-Assisted Preparation of Coffee-Based Activated Carbons: Characteristics, Properties, and Potential Application as Adsorbents for Water Purification

by Przemysław Pączkowski, Viktoriia Kyshkarova, Viktor Nikolenko, Oksana Arkhipenko, Inna Melnyk and Barbara Gawdzik

Molecules 2025, 30(20), 4123; https://doi.org/10.3390/molecules30204123 - 17 Oct 2025

Abstract

Activated carbons were synthesized from coffee grounds using phosphoric acid as a chemical activator and microwave-assisted carbonization as a rapid and energy-efficient method. Then the prepared carbons were surface-treated with cold plasma to improve their chemical properties and adsorption efficiency. The structural properties [...] Read more.

Activated carbons were synthesized from coffee grounds using phosphoric acid as a chemical activator and microwave-assisted carbonization as a rapid and energy-efficient method. Then the prepared carbons were surface-treated with cold plasma to improve their chemical properties and adsorption efficiency. The structural properties and chemical structure of the carbons were determined using nitrogen adsorption–desorption analysis, X-ray photoelectron spectroscopy, as well as X-ray microanalysis by means of scanning electron microscopy. The effect of cold plasma treatment on surface functionality and porosity was investigated. The resulting activated carbons were tested for their potential use as sorbents for the removal of ciprofloxacin, a commonly used antibiotic, from aqueous solutions. The effects of solution pH, sorption kinetics, and initial concentration were investigated. Adsorption kinetics followed a pseudo-second-order model, and the equilibrium data were well described by both the Langmuir and Freundlich isotherms, indicating a combination of monolayer adsorption on homogeneous sites and multilayer adsorption on heterogeneous surfaces. Plasma-treated carbon demonstrated significantly increased adsorption capacity (42.6–120.6 mg g⁻¹) compared to the unactivated samples (20.2–92.4 mg g⁻¹). Desorption experiments revealed that the plasma-treated carbon retained over 90% efficiency after seven cycles, confirming its excellent reusability and regeneration potential for practical water treatment applications. Full article

(This article belongs to the Special Issue Design and Synthesis of Novel Adsorbents for Pollutant Removal, 2nd Edition)

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30 pages, 2866 KB

Open AccessArticle

Photokinetics of Mixtures of Independent Photoreactions

by Mounir Maafi

Molecules 2025, 30(20), 4122; https://doi.org/10.3390/molecules30204122 - 17 Oct 2025

Abstract

The photokinetic behavior of concomitant and independent photo- and photothermal reactions exposed to monochromatic or polychromatic irradiation, has not yet been described in photochemistry literature. The occurrence of such mixtures is reported in a wide range of fields, from living species to technologically [...] Read more.

The photokinetic behavior of concomitant and independent photo- and photothermal reactions exposed to monochromatic or polychromatic irradiation, has not yet been described in photochemistry literature. The occurrence of such mixtures is reported in a wide range of fields, from living species to technologically designed devices. To address the lack of investigative tools that facilitate better understanding, quantification, and control of such parallel-reaction systems, a new holistic approach is proposed in the present study. It contributes to an effort dedicated to rationalizing photokinetics along the same criteria required for thermal kinetics. The methodology builds on a previously introduced general explicit integrated rate-law formula for single-reaction systems (whose integro-differential rate-equation is not solvable). The extension of its field of applicability to multi-component photoreactive mixtures is demonstrated in the present paper. For this purpose, a large number of combinations of both photo- and photothermal individual reactions, possessing distinctly different features, were studied in binary and ternary mixtures. The data of reactions/mixtures were generated by a fourth-order Runge–Kutta numerical integration. An excellent fitting of the species’ kinetic traces by the adapted explicit formula was obtained for all mixtures. Also, the quantification of the effects of the variation in the initial concentration of one component of the mixture, and/or the presence of inert spectator molecules in the reactor, was successfully performed. The investigative photokinetic tools proposed here are shown to be handy, efficient, and useful. The findings of the present study are also thought to expand the application possibilities of reactive photothermal systems in mixtures. Full article

(This article belongs to the Special Issue Excited State Dynamics, Photokinetics and Photochemistry)

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16 pages, 1250 KB

Open AccessArticle

Almond Shell-Derived Biochar for Lead Adsorption: Comparative Study of Pyrolysis Techniques and Sorption Capacities

by Eva Pertile, Tomáš Dvorský, Vojtěch Václavík, Lucie Berkyová and Petr Balvín

Molecules 2025, 30(20), 4121; https://doi.org/10.3390/molecules30204121 - 17 Oct 2025

Abstract

Lead (Pb(II)) contamination in water poses severe environmental and health risks due to its toxicity and persistence. This study compares almond shell-derived biochars produced by slow pyrolysis (SP) and microwave pyrolysis (MW), with and without KOH activation, focusing on structural properties and Pb(II) [...] Read more.

Lead (Pb(II)) contamination in water poses severe environmental and health risks due to its toxicity and persistence. This study compares almond shell-derived biochars produced by slow pyrolysis (SP) and microwave pyrolysis (MW), with and without KOH activation, focusing on structural properties and Pb(II) adsorption performance. Biochars were characterized by proximate and elemental analysis, BET surface area, FTIR spectroscopy, and adsorption experiments including pH dependence, kinetics, and equilibrium isotherms. Non-activated SP exhibited the highest surface area (S_BET = 693 m²·g⁻¹), pronounced mesoporosity (≈73% of total pore volume), and the largest observed equilibrium capacities. KOH activation increased surface hydroxyl content but degraded textural properties; in MW samples, it induced severe pore collapse. Given the very fast uptake, kinetic modeling was treated cautiously: for non-activated biochars, Elovich adequately captured the time-course trend, whereas activated samples returned non-physical kinetic constants (e.g., negative k₂) likely due to high post-adsorption pH (>11) and probable Pb(OH)₂ precipitation. Equilibrium data (fitted over 50–500 mg·L⁻¹) were better captured by the Freundlich and Redlich–Peterson models, indicating a mixed adsorption behaviour with contributions from heterogeneous site distribution and site-specific interactions. Optimal Pb(II) removal occurred at pH 4, with no measurable leaching from the biochar matrix. Overall, non-activated SP biochar is the most effective, sustainable and low-cost option among the tested materials for Pb(II) removal from water, avoiding aggressive chemical activation while maximizing adsorption performance. Full article

(This article belongs to the Special Issue Green Chemistry Approaches to Analysis and Environmental Remediation)

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