Molecules

12 pages, 2466 KiB

Open AccessArticle

Identification of the Cytotoxic Transglutaminase from Mycobacterium spp. That Is Involved in RIPK1 Activation

by Xinting Zhang, Yikai Zhang, Xiao Feng, Yueying Wang, Si-Shang Li, Mei-Yi Yan, Yi-Cheng Sun, Qi Jin and Feng Jiang

Molecules 2025, 30(10), 2251; https://doi.org/10.3390/molecules30102251 - 21 May 2025

Viewed by 137

Abstract

Although the global incidence of tuberculosis has declined in recent years, tuberculosis remains a major global public health challenge. The Mycobacterium tuberculosis complex (MTBC) including M. tuberculosis, M. bovis, M. microti, etc., is the deadliest Mycobacterium spp. that needs more [...] Read more.

Although the global incidence of tuberculosis has declined in recent years, tuberculosis remains a major global public health challenge. The Mycobacterium tuberculosis complex (MTBC) including M. tuberculosis, M. bovis, M. microti, etc., is the deadliest Mycobacterium spp. that needs more attention. Research on M. microti is significant as it is a zoonotic pathogen that can spread between animals and humans. By exploring the function of a transglutaminase in M. microti (MmTG), which is widely distributed in Mycobacterium and other species, a potential cytotoxic effector has been characterized. MmTG inhibits cell proliferation by inducing the phosphorylation of RIPK1 (receptor-interacting serine/threonine-protein kinase 1) and the Cys159 of MmTG is the highly conserved residue related to its cytotoxicity. Understanding MmTG and its homologs can provide more insights into the pathogenic mechanisms of mycobacteria and contribute to the development of more effective therapeutic strategies against mycobacterial infections. Full article

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19 pages, 1066 KiB

Open AccessReview

Natural Compounds and Health Benefits of Ganoderma capense

by Longshi Liu, Xinge Shi, Longkang Jia, Ran Wang and Chengwei Liu

Molecules 2025, 30(10), 2250; https://doi.org/10.3390/molecules30102250 - 21 May 2025

Viewed by 103

Abstract

Ganoderma capense, a member of the Ganoderma genus within the Polyporaceae family, has long been recognized for its high nutritional value and extensive use in traditional medicine. Its primary distribution is in China and South Africa, with the type locality being South [...] Read more.

Ganoderma capense, a member of the Ganoderma genus within the Polyporaceae family, has long been recognized for its high nutritional value and extensive use in traditional medicine. Its primary distribution is in China and South Africa, with the type locality being South Africa. This species is rich in a diverse array of bioactive compounds, including various polysaccharides, glycopeptide macromolecules, and various small-molecule compounds, such as sesquiterpenes, triterpenes, steroids, and alkaloids. Research indicates that these chemical constituents exhibit numerous pharmacological properties, including antioxidant, anti-inflammatory, and anti-tumor activities, as well as inhibition of acetylcholinesterase, reduction in blood lipids, and promotion of neural synapse growth. Apart from its use in traditional Chinese medicine, the components of G. capense are utilized globally for the treatment of a wide range of diseases, including Alzheimer’s disease, febrile convulsions, HIV, and diabetes. This underscores the extensive medical applications of G. capense, emphasizing its significance in contemporary and traditional healthcare. This review summarizes the latest research findings on the bioactive compounds and pharmacological effects of G. capense, compiled from databases such as PubMed, Web of Science, and Elsevier. This study aimed at providing researchers in this field with in-depth scientific insights and guidance, promoting further application and development in the pharmaceutical and food industries, and serving as a reference for subsequent exploration of active substances and the development of new disease treatments. Full article

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20 pages, 4474 KiB

Open AccessArticle

Immunotoxicity Study of Cucurbit[n]urils (n = 6, 7, 8) and Modeling of Interaction with Some Monocyte Receptors by a Molecular Docking Method

by Saule B. Zhautikova, Nursipat N. Abdykhanova, Dmitry A. Fedorishin, Yelena G. Shapovalova, Andrei I. Khlebnikov, Abdigali A. Bakibaev, Irina A. Kurzina, Saule K. Kabieva, Nazerke Boranbay and Gaziza M. Zhumanazarova

Molecules 2025, 30(10), 2249; https://doi.org/10.3390/molecules30102249 - 21 May 2025

Viewed by 90

Abstract

In this study, cucurbit[n]urils (n = 6, 7, 8) were carefully evaluated for their cytotoxicity and immunotoxicity to human peripheral blood monocytes. The cytotoxicity was studied by evaluating the survival of monocytes, while the immunotoxicity level was assessed by analyzing the inflammatory mediators [...] Read more.

In this study, cucurbit[n]urils (n = 6, 7, 8) were carefully evaluated for their cytotoxicity and immunotoxicity to human peripheral blood monocytes. The cytotoxicity was studied by evaluating the survival of monocytes, while the immunotoxicity level was assessed by analyzing the inflammatory mediators secreted by them using an enzyme-linked immunosorbent assay. It was found that cucurbit[n]urils (n = 6, 7, 8) in the used concentration (10⁻⁵ M) do not cause a negative effect on cell viability, which is maintained at a level above 50%. At the same time, cucurbit[n]urils (n = 6, 7, 8) do not cause pro-inflammatory activation of monocytic macrophages. The absence of stimulation of pro-inflammatory cytokine expression demonstrates the promising biocompatibility of the studied compounds, which is crucial for their successful clinical use. The obtained results of molecular modeling show the possibility of formation of CB[6], CB[7], and CB[8] associates with various Toll-like receptors, which also confirms good prospects for the development of new ways of medical application of cucurbit[n]urils. Full article

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150 pages, 18424 KiB

Open AccessReview

Metal-Free Graphene-Based Derivatives as Oxygen Reduction Reaction Electrocatalysts in Energy Conversion and Storage Systems: An Overview

by Laura Crociani

Molecules 2025, 30(10), 2248; https://doi.org/10.3390/molecules30102248 - 21 May 2025

Viewed by 96

Abstract

Oxygen reduction reaction (ORR) is one of the most important reactions in electrochemical energy storage and conversion devices. To overcome the slow kinetics, minimize the overpotential, and make this reaction feasible, efficient, and stable, electrocatalysts are needed. Metal-free graphene-based systems are considered promising [...] Read more.

Oxygen reduction reaction (ORR) is one of the most important reactions in electrochemical energy storage and conversion devices. To overcome the slow kinetics, minimize the overpotential, and make this reaction feasible, efficient, and stable, electrocatalysts are needed. Metal-free graphene-based systems are considered promising and cost-effective ORR catalysts with adjustable structures. This review is meant to give a rational overview of the graphene-based metal-free ORR electrocatalysts, illustrating the huge amount of related research developed particularly in the field of fuel cells and metal–air batteries, with particular attention to the synthesis procedures. The novelty of this review is that, beyond general aspects regarding the synthesis and characterization of graphene, above 90% of the various graphene (doped and undoped species, composites)-based ORR electrocatalysts have been reported, which represents an unprecedented thorough collection of both experimental and theoretical studies. Hundreds of references are included in the review; therefore, it can be considered as a vademecum in the field. Full article

(This article belongs to the Section Materials Chemistry)

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13 pages, 3483 KiB

Open AccessArticle

Pressure Sensitivity of UiO-66 Framework with Encapsulated Spin Probe: A Molecular Dynamics Study

by Dmitry V. Alimov, Artem S. Poryvaev and Matvey V. Fedin

Molecules 2025, 30(10), 2247; https://doi.org/10.3390/molecules30102247 - 21 May 2025

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Abstract

Probes sensitive to mechanical stress are in high demand for analyzing pressure distributions in materials. Metal–organic frameworks (MOFs) are especially promising for designing pressure sensors due to their structural tunability. In this work, using classical molecular dynamics (MD) simulations, we clarified the mechanism [...] Read more.

Probes sensitive to mechanical stress are in high demand for analyzing pressure distributions in materials. Metal–organic frameworks (MOFs) are especially promising for designing pressure sensors due to their structural tunability. In this work, using classical molecular dynamics (MD) simulations, we clarified the mechanism of exceptional pressure sensitivity of the material based on the UiO-66 framework with a trace amount of spin probes encapsulated in cavities. The role of defects in the MOF structure has been revealed using a combination of electron paramagnetic resonance (EPR) spectroscopy and MD calculations, and potential degradation pathways under mechanical stress have been proposed. The combined MD and EPR study provides valuable insights for further development of new MOF-based sensors applicable for non-destructive pressure mapping in various materials. Full article

(This article belongs to the Section Physical Chemistry)

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14 pages, 2682 KiB

Open AccessArticle

A Natural Inhibitor, 1′S-1′-Acetoxychavicol Acetate, Against Testosterone-Induced Alopecia via NADPH Oxidase Regulation

by Kkotnara Park, Isoo Youn, Jung Min Suh, Min Hye Choi, Da-Woon Bae, Soo-Bong Park, Mi Hee Kwack, Sun-Shin Cha, Dae Sik Jang, Young Kwan Sung, Yun Soo Bae and Eun Kyoung Seo

Molecules 2025, 30(10), 2246; https://doi.org/10.3390/molecules30102246 - 21 May 2025

Viewed by 113

Abstract

Androgenetic alopecia is associated with testosterone-mediated anagen-to-catagen transition and matrix keratinocyte apoptosis in hair follicle cells. Activation of Nox isozymes is involved in testosterone-mediated keratinocyte apoptosis, leading to androgenetic alopecia. This indicates that Nox isozymes can serve as therapeutic targets for androgenetic alopecia. [...] Read more.

Androgenetic alopecia is associated with testosterone-mediated anagen-to-catagen transition and matrix keratinocyte apoptosis in hair follicle cells. Activation of Nox isozymes is involved in testosterone-mediated keratinocyte apoptosis, leading to androgenetic alopecia. This indicates that Nox isozymes can serve as therapeutic targets for androgenetic alopecia. The isolated compounds from natural products were screened to evaluate their ROS-inhibition efficacy and it was found that 1′S-1′-acetoxychavicol acetate (ACA, 26), a natural compound isolated from Alpinia galanga (L.) Willd. (Zingiberaceae), exhibits inhibitory activity on Nox isozymes. Nox inhibition by ACA suppressed testosterone-dependent H₂O₂ generation and cell death in keratinocytes. Incubation with ACA in human hair follicle organ culture mitigated testosterone-dependent suppression of hair growth. We validated that ACA regulates androgenetic alopecia in a mouse model. Local application of ACA on the dorsal skin in an androgenetic alopecia model of C57BL/6 mice significantly suppressed testosterone-induced hair loss in a dose-dependent manner. Moreover, hair follicle length in ACA-treated mice was enhanced compared to that in control mice. These findings provide a molecular mechanism in which ACA inhibits Nox activity in hair follicle cells, indicating its potential as an effective treatment of AGA. Full article

(This article belongs to the Special Issue Bioactive Compounds from Roots, Stems, Leaves, Flowers, Fruits, and Seeds: 2nd Edition)

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34 pages, 2331 KiB

Open AccessReview

Imidazole Hybrids: A Privileged Class of Heterocycles in Medicinal Chemistry with New Insights into Anticancer Activity

by Zarifa Murtazaeva, Azizbek Nasrullaev, Anvarjon Buronov, Shukhrat Gaybullaev, Lifei Nie, Sodik Numonov, Zohidjon Khushnazarov, Davron Turgunov, Rustamkhon Kuryazov, Jiangyu Zhao and Khurshed Bozorov

Molecules 2025, 30(10), 2245; https://doi.org/10.3390/molecules30102245 - 21 May 2025

Viewed by 189

Abstract

Imidazole is a five-membered heterocyclic system featuring two nitrogen heteroatoms at the 1- and 3-positions of the ring. The imidazole scaffold is particularly suited for kinase inhibition concepts. This further confirms that this scaffold is a privileged structure in the development of anticancer [...] Read more.

Imidazole is a five-membered heterocyclic system featuring two nitrogen heteroatoms at the 1- and 3-positions of the ring. The imidazole scaffold is particularly suited for kinase inhibition concepts. This further confirms that this scaffold is a privileged structure in the development of anticancer drugs. Considering these key factors and the recent focus of scientists on imidazole compounds, we discuss the anticancer activities of imidazole-containing hybrids and related compounds, highlighting articles published in 2023 that serve as a basis for medicinal chemistry leads. From a chemical perspective, the present review emphasizes hybrid molecules with an imidazole ring in the side chain, imidazole-centered hybrid molecules, condensed imidazole hybrids, hybrid compounds containing two or more imidazole rings, polycyclic imidazole hybrids, imidazole-containing metal complexes, and benzimidazole hybrids. Full article

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20 pages, 4077 KiB

Open AccessArticle

Systematic Optimization of Complex Salt Roasting and Leaching Conditions for Efficient Extraction of Lithium, Rubidium and Cesium from Lepidolite

by Jihan Gu, Binjun Liang, Xianping Luo, Weiquan Yuan, Bin Xiao and Xuekun Tang

Molecules 2025, 30(10), 2244; https://doi.org/10.3390/molecules30102244 - 21 May 2025

Viewed by 65

Abstract

A complex salt roasting–water leaching process was developed and optimized for the efficient extraction of lithium (Li), rubidium (Rb), and cesium (Cs) from lepidolite. The effects of roasting parameters (temperature, time, and complex salt composition) and leaching parameters (temperature, time, and liquid–solid ratio) [...] Read more.

A complex salt roasting–water leaching process was developed and optimized for the efficient extraction of lithium (Li), rubidium (Rb), and cesium (Cs) from lepidolite. The effects of roasting parameters (temperature, time, and complex salt composition) and leaching parameters (temperature, time, and liquid–solid ratio) were systematically investigated. Optimal roasting conditions were found to be 900 °C for 60 min with a complex salt composition of Lepidolite:Na₂SO₄:CaCl₂:CaCO₃ = 1:0.5:0.3:0.05, while optimal leaching conditions were 60 °C, 60 min, and a liquid–solid ratio of 3:1, achieving the highest leaching efficiencies of 94.60%, 83.33%, and 82.95% for Li₂O, Rb₂O, and Cs₂O, respectively. XRD and SEM characterizations confirmed the decomposition of lepidolite, formation of water-soluble phases during roasting, and selective separation of Li, Rb, and Cs from insoluble phases during leaching. The porous structure of the roasted product facilitated the dissolution of target metals. This study provides valuable insights and guidance for the efficient extraction of Li, Rb, and Cs from lepidolite, contributing to the comprehensive utilization of this resource. Full article

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22 pages, 3440 KiB

Open AccessReview

Coherent Vibrational Anti-Stokes Raman Spectroscopy Assisted by Pulse Shaping

by Kai Wang, James T. Florence, Xia Hua, Zehua Han, Yujie Shen, Jizhou Wang, Xi Wang and Alexei V. Sokolov

Molecules 2025, 30(10), 2243; https://doi.org/10.3390/molecules30102243 - 21 May 2025

Viewed by 106

Abstract

Coherent anti-Stokes Raman scattering (CARS) is a powerful nonlinear spectroscopic technique widely used in biological imaging, chemical analysis, and combustion and flame diagnostics. The adoption of pulse shapers in CARS has emerged as a useful approach, offering precise control of optical waveforms. By [...] Read more.

Coherent anti-Stokes Raman scattering (CARS) is a powerful nonlinear spectroscopic technique widely used in biological imaging, chemical analysis, and combustion and flame diagnostics. The adoption of pulse shapers in CARS has emerged as a useful approach, offering precise control of optical waveforms. By tailoring the phase, amplitude, and polarization of laser pulses, the pulse shaping approach enables selective excitation, spectral resolution improvement, and non-resonant background suppression in CARS. This paper presents a comprehensive review of applying pulse shaping techniques in CARS spectroscopy for biophotonics. There are two different pulse shaping strategies: passive pulse shaping and active pulse shaping. Two passive pulse shaping techniques, hybrid CARS and spectral focusing CARS, are reviewed. Active pulse shaping using a programmable pulse shaper such as spatial light modulator (SLM) is discussed for CARS spectroscopy. Combining active pulse shaping and passive shaping, optimizing CARS with acousto-optic programmable dispersive filters (AOPDFs) is discussed and illustrated with experimental examples conducted in the authors’ laboratory. These results underscore pulse shapers in advancing CARS technology, enabling improved sensitivity, specificity, and broader applications across diverse scientific fields. Full article

(This article belongs to the Special Issue From Spectroscopic Insights to Structural Wonders: A Theme Issue Dedicated to Professor Jaan Laane)

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16 pages, 4173 KiB

Open AccessArticle

Valence Bond Insights into the H-Abstraction Barrier in Cytochrome P450

by Enhua Zhang and Hajime Hirao

Molecules 2025, 30(10), 2242; https://doi.org/10.3390/molecules30102242 - 21 May 2025

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Abstract

The valence bond (VB) framework is widely recognized as a powerful tool for elucidating the electronic origins of activation energy barriers in chemical reactions. We employed ab initio VB calculations to investigate the hydrogen abstraction (H-abstraction) barrier in cytochrome P450 enzymes (P450s), using [...] Read more.

The valence bond (VB) framework is widely recognized as a powerful tool for elucidating the electronic origins of activation energy barriers in chemical reactions. We employed ab initio VB calculations to investigate the hydrogen abstraction (H-abstraction) barrier in cytochrome P450 enzymes (P450s), using a simplified model in which an oriented external electric field (OEEF) was applied to efficiently capture the electronic effects of the equatorial porphyrin and proximal thiolate ligands on the iron(IV)–oxo unit in compound I (Cpd I). Methane (CH₄) was used as the model substrate. The VB-calculated barrier height, evaluated with this simplified model, qualitatively reproduced the barrier predicted by density functional theory (DFT) calculations using a more complete active-site model. Additionally, by examining the weights and diagonal elements of the Hamiltonian matrix for different VB structures along the reaction coordinate, we identified key VB structures—including covalent and ionic configurations representing the C–H and O–H bonds—that contribute significantly to the electronic origin of the barrier height. The mixing of these distinct VB structures leads to resonance stabilization, which is maximized at the transition state. Full article

(This article belongs to the Special Issue Fundamental Concepts and Recent Developments in Chemical Bonding)

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9 pages, 584 KiB

Open AccessCommunication

Green Synthesis of Trifluoromethanesulfonyl Fluoride as an Eco-Friendly Alternative to SF₆ Gas Insulation and Analysis of Its Acute Inhalation Toxicity

by Shile Wang, Li Dong, Ruichao Peng and Hongding Tang

Molecules 2025, 30(10), 2241; https://doi.org/10.3390/molecules30102241 - 21 May 2025

Viewed by 69

Abstract

This study demonstrates an eco-friendly synthesis of trifluoromethanesulfonyl fluoride (TFSF) as a sustainable SF₆ alternative. Optimized halogen exchange reactions using CF₃SO₂Cl/KF (3:1 ratio) with crown ether catalysis at low temperatures achieved 65% TFSF yield (97.9% purity). Scale-up trials [...] Read more.

This study demonstrates an eco-friendly synthesis of trifluoromethanesulfonyl fluoride (TFSF) as a sustainable SF₆ alternative. Optimized halogen exchange reactions using CF₃SO₂Cl/KF (3:1 ratio) with crown ether catalysis at low temperatures achieved 65% TFSF yield (97.9% purity). Scale-up trials in pressurized reactors showed >50% conversion and >90% selectivity. Acute inhalation tests (OECD standards) on Sprague-Dawley rats revealed transient toxicity at 20,000 ppm (4 h exposure), with survival rates >66% and LC₅₀ exceeding 22,600 ppm—significantly safer than SF₆. These findings confirm TFSF’s technical viability and low toxicity, positioning it as a practical insulating medium to curb SF₆ emissions. The methodology highlights precision halogen exchange control and systematic safety validation, offering actionable solutions for industrial adoption. Full article

(This article belongs to the Special Issue 5th Anniversary of Applied Chemistry Section)

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15 pages, 1001 KiB

Open AccessArticle

Biological Activity Evaluation Against Fusarium oxysporum, Fusarium circinatum, and Meloidogyne incognita of Bioactives-Enriched Extracts of Ruta graveolens L.

by Lorena Reyes-Vaquero, Elena Ibáñez, Soledad Sanz-Alférez, Gloria Nombela, Alma Angélica Del Villar-Martínez and Mónica Bueno

Molecules 2025, 30(10), 2240; https://doi.org/10.3390/molecules30102240 - 21 May 2025

Viewed by 181

Abstract

Ruta graveolens L. has been described as possessing antifungal and nematicidal activity. Among the bioactive compounds present in this plant, alkaloids and furanocoumarins have attracted considerable attention. The aim of this study was to evaluate the in vitro biological activity of extracts from [...] Read more.

Ruta graveolens L. has been described as possessing antifungal and nematicidal activity. Among the bioactive compounds present in this plant, alkaloids and furanocoumarins have attracted considerable attention. The aim of this study was to evaluate the in vitro biological activity of extracts from rue enriched in bioactive compounds against Fusarium oxysporum, F. circinatum, and Meloidogyne incognita, and to correlate the chemical profile of the extracts with their biological activities. Six extracts with contrasting chemical profiles, obtained by pressurized liquid extraction and supercritical fluid extraction using green solvents, were selected for biological evaluation. The highest F. oxysporum growth inhibition was achieved with the extracts enriched in fatty acids and furanocoumarins at concentrations of 4, 8, and 16 mg/mL, while for F. circinatum, the highest growth inhibition was obtained using the extract enriched in terpenes at 16 mg/mL; moreover, the six extracts evaluated caused mortality in M. incognita. Therefore, enriched extracts of R. graveolens might be considered as an alternative for pathogen control on economically important crops such as potatoes, tomatoes, and onions, among others. Correlations between biological activities and chemical compositions suggest the importance of fatty acids against F. oxysporum, fatty acids and terpenes against F. circinatum, and alkaloids, coumarins, and furanocoumarins for M. incognita. Full article

(This article belongs to the Special Issue Natural Products: Extraction, Analysis and Biological Activities)

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19 pages, 814 KiB

Open AccessArticle

The Effect of Bromine and Iodine on the Plant Growth, Phytochemical Composition and Antioxidant Capacity of Dandelion (Taraxacum officinale F.H. Wiggers Coll.) Plants

by Iwona Ledwożyw-Smoleń, Sylwester Smoleń, Marta Liszka-Skoczylas, Joanna Pitala and Łukasz Skoczylas

Molecules 2025, 30(10), 2239; https://doi.org/10.3390/molecules30102239 - 21 May 2025

Viewed by 82

Abstract

Iodine is a crucial microelement for humans, and iodine deficiencies may be reduced through the consumption of iodine-enriched plants. The possible effects of exogenous bromine regarding plant growth, iodine biofortification efficiency, and the chemical composition of cultivated plants have not been previously evaluated. [...] Read more.

Iodine is a crucial microelement for humans, and iodine deficiencies may be reduced through the consumption of iodine-enriched plants. The possible effects of exogenous bromine regarding plant growth, iodine biofortification efficiency, and the chemical composition of cultivated plants have not been previously evaluated. A two-year pot cultivation of dandelion was conducted, applying KBr and KIO₃ in the following combinations: (1) Control, (2) 10 µM I, (3) 50 µM I, (4) 10 µM Br, (5) 50 µM Br, (6) 10 µM I + 10 µM Br, and (7) 50 µM I + 50 µM Br. An increased plant biomass indicated the low toxicity of the tested doses of I and Br for dandelion. However, a slightly increased antioxidant capacity in the leaves and roots and higher proline content in the leaves may suggest a potential stress effect of iodine and/or bromine accumulation for plants. The Br:I ratios observed in biofortified leaves and roots indicate the need to monitor bromine levels in soils or substrates used for plant cultivation in order to reduce the risk of excessive Br contents in iodine-enriched plants. Full article

(This article belongs to the Special Issue Phytochemical Profiling, Bioactivity, Biotechnology Studies and Practical Applications of Medicinal and Cosmetic Plants)

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25 pages, 1807 KiB

Open AccessReview

Porphyrin-Based Sorbents for the Enrichment and Removal of Metal Ions

by Krystyna Pyrzynska and Krzysztof Kilian

Molecules 2025, 30(10), 2238; https://doi.org/10.3390/molecules30102238 - 21 May 2025

Viewed by 119

Abstract

Porphyrins and their derivatives are excellent materials with specific physical and photochemical properties in medical, chemical, and technological applications. In chemistry, their properties are applied to create new functional materials with specific characteristics, such as porphyrin-based sorbents combined with porous organic polymers, silica, [...] Read more.

Porphyrins and their derivatives are excellent materials with specific physical and photochemical properties in medical, chemical, and technological applications. In chemistry, their properties are applied to create new functional materials with specific characteristics, such as porphyrin-based sorbents combined with porous organic polymers, silica, carbon nanostructures, or metal–organic frameworks. This review covers the applications of porphyrins and metalloporphyrins in preparing and using sorbents for metal ion enrichment and their separation. Uncommon applications that utilize specific properties of porphyrins, such as light-enhanced processes and redox properties for selective sorption and photocatalytic conversion of metal ions, are also discussed. These applications suggest new fields of use, such as the removal or recycling of metals from electronic waste or the selective elimination of heavy metals from the environment. Full article

(This article belongs to the Special Issue Porphyrin-Based Compounds: Synthesis and Application, 2nd Edition)

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19 pages, 3568 KiB

Open AccessArticle

Efficiently Degrading RhB Using Bimetallic Co₃O₄/ZnO Oxides: Ultra-Fast and Persistent Activation of Permonosulfate

by Bai Sun, Rui Liu, Fengshou Zhao, Shengnan He, Yun Wang, Xiangxiang Wang, Hao Huang, Mingjian Yi and Shuguang Zhu

Molecules 2025, 30(10), 2237; https://doi.org/10.3390/molecules30102237 - 21 May 2025

Viewed by 55

Abstract

To address the issues of poor Co²⁺ regeneration and limited interfacial electron transfer in heterogeneous catalytic systems, this study proposes the synthesis of highly efficient and stable Co₃O₄/ZnO composites through the pyrolysis–oxidation reaction of Co/Zn MOFs for the [...] Read more.

To address the issues of poor Co²⁺ regeneration and limited interfacial electron transfer in heterogeneous catalytic systems, this study proposes the synthesis of highly efficient and stable Co₃O₄/ZnO composites through the pyrolysis–oxidation reaction of Co/Zn MOFs for the degradation of rhodamine B (RhB) using activated peroxymonosulfate (PMS). The results confirmed that the catalyst exhibited a high electron transfer capacity, and the synergistic effect between the bimetals enhanced the reversible redox cycle of Co³⁺/Co²⁺. Under optimal conditions, complete removal of RhB was achieved in just 6 min using the Co₃O₄/ZnO composite, which demonstrated excellent stability after five cycles. Furthermore, the catalyst exhibited a high degradation efficiency in real water samples with a total organic carbon (TOC) removal rate of approximately 65% after 60 min. The electrochemical measurements, identification of active species, and X-ray photoelectron spectroscopy (XPS) analysis revealed that non-radicals (¹O₂ and direct charge transfer) played a major role in the degradation of RhB. Finally, the potential mechanisms and degradation pathways for RhB degradation using this catalyst were systematically investigated. This study opens new avenues for the development of efficient and stable PMS catalysts, and provides insights into the preparation of other emerging metal oxides. Full article

(This article belongs to the Section Nanochemistry)

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17 pages, 2002 KiB

Open AccessCommunication

Towards a Rational Design of Biosensors: Engineering Covalently Grafted Interfacial Adlayers as a Testbed Platform for Electrochemical Detection of Epinephrine

by Xiaoli Chang, Yuan Fang and Oleksandr Ivasenko

Molecules 2025, 30(10), 2236; https://doi.org/10.3390/molecules30102236 - 21 May 2025

Viewed by 62

Abstract

The performance of electrochemical (bio)sensors is fundamentally determined by the precise engineering of interfacial layers that govern (bio)analyte–surface interactions. However, elucidating structure–function relationships remains challenging due to the complex architecture of modern sensors and the irregular nanoscale morphology of many high-performance materials. In [...] Read more.

The performance of electrochemical (bio)sensors is fundamentally determined by the precise engineering of interfacial layers that govern (bio)analyte–surface interactions. However, elucidating structure–function relationships remains challenging due to the complex architecture of modern sensors and the irregular nanoscale morphology of many high-performance materials. In this study, we present a strategy for designing custom functional interfaces as well-defined platforms for probing interfacial processes. Focusing on epinephrine (EP) detection as an important representative of catecholamines, we compare the interfacial behavior of two carboxy-functionalized electrodes—grafted with either para-aminobenzoic acid (PAB) or 3,4,5-tricarboxybenzenediazonium (ATA)—against atomically flat highly oriented pyrolytic graphite (HOPG) as a control. While both modifiers introduce carboxyl groups, PAB forms disordered multilayers that inhibit surface responsiveness, whereas ATA yields an ultrathin monolayer with accessible COOH groups. Electrochemical analysis reveals that ATA-HOPG significantly enhances EP detection at sub-micromolar levels, facilitated by electrostatic interactions between surface-bound COO⁻ and protonated EP and its redox products. These results demonstrate that nanoscale control of diazonium grafting is crucial for optimizing bioanalyte recognition. More broadly, this work highlights how molecular-level surface engineering on high-quality carbon substrates can serve as a test-bed platform for the rational design of advanced electrochemical sensing interfaces. Full article

(This article belongs to the Special Issue Physicochemical Research on Material Surfaces)

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15 pages, 1322 KiB

Open AccessArticle

Viscosity of Polycaprolactone Microplastic Dispersions and Nonlinear Kinetic Models of Plastic Fragmentation

by Vincenzo Villani and Pier Luigi Gentili

Molecules 2025, 30(10), 2235; https://doi.org/10.3390/molecules30102235 - 21 May 2025

Viewed by 49

Abstract

Viscosimetric experiments and microscopy measurements on microdispersions of polycaprolactone (PCL) plastics showed an unexpected exponential decrease in viscosity over the first 3 months and a plateau for a further 4 months of observations. This behavior is due to the release of nanoplastics from [...] Read more.

Viscosimetric experiments and microscopy measurements on microdispersions of polycaprolactone (PCL) plastics showed an unexpected exponential decrease in viscosity over the first 3 months and a plateau for a further 4 months of observations. This behavior is due to the release of nanoplastics from semicrystalline particles that reduce the viscosity of the dispersion, and leave stable and fine crystalline microplastics ranging in size from 30 to 180 μm. The development of nonlinear kinetic models for the fragmentation process from macro- to meso-, micro-, and nanoplastics reveals complex behavior that we call a cracking–leaching mechanism. The autocatalytic mechanical cracking of macroplastics larger than 5 mm is followed by a logistic-type mechanical cracking of mesoplastics between 5 and 1 mm. Therefore, microplastics smaller than 1 mm experience the leaching diffusion modeled via nonlinear coupled kinetic differential equations: semicrystalline microplastics quickly release nanoplastics from the amorphous fraction, followed by fine and stable crystalline microplastics. This proposed mechanism explains the size distribution of floating plastic debris in the oceans, with an unexpected gap of microplastics. Considering the outcome, a general reflection is made on the critical issues that currently appear unsolvable regarding plastic pollution. Full article

(This article belongs to the Section Macromolecular Chemistry)

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17 pages, 1505 KiB

Open AccessArticle

De Novo Terpenes Emitted from Juvenile Leaves of Eucalyptus globulus Labill. subsp. globulus

by Anthony J. Winters, Charles H. Hocart, Jörg-Peter Schnitzler, Ina Zimmer, Mark A. Adams, Heinz Rennenberg, Jürgen Kreuzwieser and Claudia Keitel

Molecules 2025, 30(10), 2234; https://doi.org/10.3390/molecules30102234 - 21 May 2025

Viewed by 86

Abstract

The contributions of de novo synthesis to terpene emissions from Eucalyptus globulus subsp. globulus were determined by fumigating branchlets with ¹³CO₂ in a gas exchange system. Of more than thirty-four terpenes emitted by this species, only four, i.e., isoprene, iso-valeraldehyde, cis [...] Read more.

The contributions of de novo synthesis to terpene emissions from Eucalyptus globulus subsp. globulus were determined by fumigating branchlets with ¹³CO₂ in a gas exchange system. Of more than thirty-four terpenes emitted by this species, only four, i.e., isoprene, iso-valeraldehyde, cis-ocimene, and trans-caryophyllene, incorporated ¹³C into the terpene carbon skeleton during the ~5–6 h experiment. ¹³C incorporation into isoprene and iso-valeraldehyde reached a maximum of ca. 82% of the carbon skeleton, similar to cis-ocimene, with a maximum of 77% ¹³C incorporation after ~2.5 h exposure to ¹³CO₂. Only ca. 20% of carbon was labelled in trans-caryophyllene after 5–6 h. the incorporation of ¹³C was observed only in compounds emitted from leaves, and was not detected in either individual oil glands or in bulk leaf tissue. The results suggest the de novo synthesis of some terpenes (isoprene, cis-ocimene, trans-caryophyllene, and iso-valeraldehyde) and their emission is independent of emissions of terpenes stored in oil glands. Full article

(This article belongs to the Section Chemical Biology)

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12 pages, 1447 KiB

Open AccessArticle

Analysis of Volatile Compounds with Odor Characteristics in Dianhong, Chuanhong, and Keemunhong Based on SPME-GC×GC-MS

by Sinuo Li, Qi Meng, Chunli Huang, Peihan Zhou, Sirui Yao, Yamin Guo and Xiaojun Wang

Molecules 2025, 30(10), 2233; https://doi.org/10.3390/molecules30102233 - 21 May 2025

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Abstract

China is the place of origin and main producer of black tea worldwide, with Dianhong (DH), Chuanhong (CH), and Keemunhong (KH) being the famous Chinese black teas. The contents of various odor components in black teas differ with their origins. However, the effects [...] Read more.

China is the place of origin and main producer of black tea worldwide, with Dianhong (DH), Chuanhong (CH), and Keemunhong (KH) being the famous Chinese black teas. The contents of various odor components in black teas differ with their origins. However, the effects of these differences on the presentation of distinctive odor characteristics in various products remain unclear. We aimed to elucidate the odor characteristics and odor compounds of these three black teas; to this end, we performed a sensory evaluation and multivariate statistical analysis based on comprehensive two-dimensional gas chromatography–mass spectrometry (GC×GC-MS) results. The sensory evaluation revealed that the odor characteristics of DH were floral and fruity, whereas sweet and herbal-like odors were more intense in CH and QH. A total of 119 volatile compounds were detected, with alcohols, aldehydes, and esters being the main volatile compounds. Among them, 41 volatile compounds were identified with an odor activity value (OAV) of >1, and 24 of them were selected through principal component analysis, hierarchical cluster analysis, and orthogonal partial least squares discriminant analysis as marker substances to distinguish the three teas; thus, 24 volatile compounds are important odor compounds of DH, CH, and QH. Full article

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12 pages, 4682 KiB

Open AccessArticle

Immobilized Copper Complexes on Coal-Bearing Kaolin for Catalyzing Allylic Ester Synthesis via C(sp³)–H Bond Activation

by Chun-Ling Zhang, Dao Su, Habuer Wang, Tegshi Muschin, Yun Wu, Yong-Sheng Bao and Huai-Yong Zhu

Molecules 2025, 30(10), 2232; https://doi.org/10.3390/molecules30102232 - 21 May 2025

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Abstract

Copper complexes have attracted significant interest for catalyzing oxidative dehydrogenative carboxylation of alkanes to form esters. Here, we report a heterogeneous catalyst, in which copper complexes are immobilized on coal-bearing kaolin for the synthesis of allylic esters via C(sp³)-H bond [...] Read more.

Copper complexes have attracted significant interest for catalyzing oxidative dehydrogenative carboxylation of alkanes to form esters. Here, we report a heterogeneous catalyst, in which copper complexes are immobilized on coal-bearing kaolin for the synthesis of allylic esters via C(sp³)-H bond activation through cross-dehydrogenation coupling reactions between cyclic alkanes and aromatic carboxylic acids. Systematic optimization of reaction conditions—including catalyst loading, copper content, oxidant, temperature, and reaction time—resulted in a high yield of 71% of allylic ester, comparable to homogeneous transition metal catalysts. The catalyst is easily recoverable via centrifugation and retains its activity over five consecutive reuse cycles. This system demonstrates broad substrate compatibility with various aromatic carboxylic acids and cyclic alkanes. Beyond offering an efficient and reusable catalytic route for allylic ester synthesis, this work highlights the potential of coal-bearing kaolin as a sustainable support material for transition metal catalysis and provides an environmentally benign method for activating inert C(sp³)–H bonds. Full article

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23 pages, 1251 KiB

Open AccessArticle

Impact of Geographical Origin on the Contents of Inorganic Elements and Bioactive Compounds in Polygonum perfoliatum L.

by Yanping Zhang, Liyuan Zhao, Xinsheng Wang, Chenxi Zhang, Haichao Zuo and Di Gao

Molecules 2025, 30(10), 2231; https://doi.org/10.3390/molecules30102231 - 21 May 2025

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Abstract

This study investigated the correlation between thirteen inorganic elements, five key bioactive compounds, and environmental factors in Polygonum perfoliatum L. from fifteen different origins. Analyses were conducted using techniques such as ultrasound-assisted extraction, HPLC, ICP-AES, PCA, and HCA. The results indicate that the [...] Read more.

This study investigated the correlation between thirteen inorganic elements, five key bioactive compounds, and environmental factors in Polygonum perfoliatum L. from fifteen different origins. Analyses were conducted using techniques such as ultrasound-assisted extraction, HPLC, ICP-AES, PCA, and HCA. The results indicate that the geographical origin significantly influences the contents of inorganic elements and bioactive compounds in Polygonum perfoliatum L., and a certain correlation exists among elements, compounds, and environmental factors. This research provides a theoretical foundation for the development and utilization of Polygonum perfoliatum L. Full article

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15 pages, 4689 KiB

Open AccessArticle

Hyaluronic Acid Interactions with Pork Myofibrillar Proteins in Emulsion Gel-Type Systems

by Marzena Zając, Lei Zhou, Magdalena Mika, Ziyi Yang, Jingyu Wang, Ye Tao and Wangang Zhang

Molecules 2025, 30(10), 2230; https://doi.org/10.3390/molecules30102230 - 20 May 2025

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Abstract

Health benefits associated with hyaluronic acid, along with its properties such as water-binding capacity and antimicrobial activity, suggest that incorporating it into meat systems could provide a basis for formulating functional meat products. This study aimed to evaluate the properties of myofibrillar protein [...] Read more.

Health benefits associated with hyaluronic acid, along with its properties such as water-binding capacity and antimicrobial activity, suggest that incorporating it into meat systems could provide a basis for formulating functional meat products. This study aimed to evaluate the properties of myofibrillar protein gels and emulsions with varying concentrations of hyaluronic acid. The results indicate that increasing the hyaluronic acid concentration (0.008% to 0.04%) does not significantly affect the cooking loss, while a concentration of 0.08% enhances cooking loss. This, in turn, increased gel hardness, while the water-holding capacity remains unaffected. Cryo-scanning electron microscopy (Cryo-SEM) images revealed a partial disruption of the gel structure, with rising hyaluronic concentrations. In pork myofibrillar protein emulsions, smaller droplets and higher stability were observed after HA incorporation. Samples containing hyaluronic acid were more viscous and exhibited shear-thinning properties. Overall, the hyaluronic acid used in this study improved emulsion properties, whereas the gel structure was compromised. Full article

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

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15 pages, 2265 KiB

Open AccessArticle

Synthesis and Photoluminescent Properties of Dy³⁺-Doped and Dy³⁺/Eu³⁺ Co-Doped 50ZnO:40B₂O₃:5WO₃:Nb₂O₅ Glass

by Margarita Milanova, Aneliya Yordanova, Lyubomir Aleksandrov, Reni Iordanova and Petia Petrova

Molecules 2025, 30(10), 2229; https://doi.org/10.3390/molecules30102229 - 20 May 2025

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Abstract

Dy³⁺ single-doped and Dy³⁺/Eu³⁺ co-doped ZnO:B₂O₃:WO₃:Nb₂O₅ glass was successfully synthesized using the melt quenching method. The amorphous character of the prepared samples was confirmed by X-ray diffraction (XRD). The glass [...] Read more.

Dy³⁺ single-doped and Dy³⁺/Eu³⁺ co-doped ZnO:B₂O₃:WO₃:Nb₂O₅ glass was successfully synthesized using the melt quenching method. The amorphous character of the prepared samples was confirmed by X-ray diffraction (XRD). The glass transition and crystallization temperatures were examined by differential scanning calorimetry (DSC). Raman spectroscopy was applied to investigate the glass microstructure. Physical properties like the density, molar volume, oxygen molar volume and oxygen packing density of the glass were also determined. The photoluminescence excitation (PLE) and emission (PL) spectra of the resultant glass types were measured. The obtained Dy³⁺ single-doped glass was characterized by strong luminescence at 482 and 574 nm, corresponding to the ⁴F_9/2 → ⁶H_15/2 (blue) and ⁴F_9/2 → ⁶H_13/2 (yellow) transitions, respectively, and weak luminescence at 663 nm and 753 nm due to the ⁴F_9/2 → ⁶H_11/2 (red) and ⁴F_9/2 → ⁶H_9/2 + ⁶F_11/2 (red) transitions. The luminescence results indicate that energy transfer from the Dy³⁺ to Eu³⁺ ions occurs in the proposed glass system. The emitted light from the Dy³⁺ single-doped glass was found to be yellow-orange. The Dy³⁺/Eu³⁺ co-doped samples emitted darker orange light. The obtained results show that the investigated types of glass have the potential to be used as orange light-emitting materials. Full article

(This article belongs to the Section Materials Chemistry)

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18 pages, 4068 KiB

Open AccessReview

Functional Approaches to Discover New Compounds via Enzymatic Modification: Predicted Data Mining Approach and Biotransformation-Guided Purification

by Te-Sheng Chang

Molecules 2025, 30(10), 2228; https://doi.org/10.3390/molecules30102228 - 20 May 2025

Viewed by 139

Abstract

In the field of biotechnology, natural compounds isolated from medicinal plants are highly valued; however, their discovery, purification, biofunctional characterization, and biochemical validation have historically involved time-consuming and laborious processes. Two innovative approaches have emerged to more efficiently discover new bioactive substances: the [...] Read more.

In the field of biotechnology, natural compounds isolated from medicinal plants are highly valued; however, their discovery, purification, biofunctional characterization, and biochemical validation have historically involved time-consuming and laborious processes. Two innovative approaches have emerged to more efficiently discover new bioactive substances: the predicted data mining approach (PDMA) and biotransformation-guided purification (BGP). The PDMA is a computational method that predicts biotransformation potential, identifying potential substrates for specific enzymes from numerous candidate compounds to generate new compounds. BGP combines enzymatic biotransformation with traditional purification techniques to directly identify and isolate biotransformed products from crude extract fractions. This review examines recent research employing BGP or the PDMA for novel compound discovery. This research demonstrates that both approaches effectively allow for the discovery of novel bioactive molecules from natural sources, the enhancement of the bioactivity and solubility of existing compounds, and the development of alternatives to traditional methods. These findings highlight the potential of integrating traditional medicinal knowledge with modern enzymatic and computational tools to advance drug discovery and development. Full article

(This article belongs to the Special Issue Recent Advances in Natural Compounds Research: Chemistry, Biology and Biotechnology)

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13 pages, 1830 KiB

Open AccessArticle

Experimental Investigation of the Stability of Au_nCl_n+m⁻ (n = 1–5; m = 1, 3, 5, 7) Clusters by Laser Desorption/Ionization Mass Spectrometry

by Filip Veljković, Xianglei Kong, Stevan Dimitrijević, Marija Janković, Bojan Janković, Vladimir Dodevski and Suzana Veličković

Molecules 2025, 30(10), 2227; https://doi.org/10.3390/molecules30102227 - 20 May 2025

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Abstract

The stability of gold chloride clusters is an important topic in catalysis and nanomaterials, but experimental data are missing. Here, fourteen different clusters were obtained simultaneously using laser desorption/ionization mass spectrometry and were identified as Au_nCl_n+m⁻ (n = 1–5; [...] Read more.

The stability of gold chloride clusters is an important topic in catalysis and nanomaterials, but experimental data are missing. Here, fourteen different clusters were obtained simultaneously using laser desorption/ionization mass spectrometry and were identified as Au_nCl_n+m⁻ (n = 1–5; m = 1, 3, 5, 7) or AuCl_n+1⁻, Au₂Cl_2n+1⁻, Au₃Cl_2n+2⁻, Au₄Cl_2n+1⁻ and Au₅Cl_2n+2⁻. Consequently, the effects of laser intensity on their stability were evaluated, considering differences in the AuCl unit or the number of Cl atoms. For the Au_nCl_n+1⁻ and Au_nCl_n+3⁻ groups, the relative intensity of the clusters decreased with each additional AuCl unit as the laser intensity increased. Au_nCl_n+5⁻ clusters showed a different trend in relative intensities: Au₃Cl₈⁻ > Au₂Cl₇⁻ > Au₄Cl₉⁻ > Au₅Cl₁₀⁻. The mononuclear AuCl₄⁻ showed the highest stability, which is consistent with their “superhalogen” character. In the Au₂Cl_2n+1⁻ clusters, Au₂Cl₅⁻ with Au (III)–Au(I) interaction was more stable at lower laser intensities, while Au₂Cl₃ with Au(I)–Au(I) bonds became more dominant at higher intensities. Among the Au₃Cl_2n+2⁻, Au₄Cl_2n+1⁻ clusters, those with purely “aurophilic” interactions became increasingly stable with increasing laser intensity. These results emphasize the importance of bond type and cluster size for the stability of gold chloride clusters at different laser intensities. Full article

(This article belongs to the Section Physical Chemistry)

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18 pages, 3975 KiB

Open AccessArticle

Effect of Chitooligosaccharides on TLR2/NF-κB Signaling in LPS-Stimulated RAW 264.7 Macrophages

by Mengting Zhao, Shurong Pang, Yiqing Gao, Ting Li and Hongrui Jiang

Molecules 2025, 30(10), 2226; https://doi.org/10.3390/molecules30102226 - 20 May 2025

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Abstract

Chitooligosaccharides (COSs), degraded products of chitosan or chitin, are attracting growing interest owing to their low degree of polymerization (DP), high solubility, and prominent anti-inflammatory activity. However, the correlation between their structure and anti-inflammatory activities still needs to be explored. In this study, [...] Read more.

Chitooligosaccharides (COSs), degraded products of chitosan or chitin, are attracting growing interest owing to their low degree of polymerization (DP), high solubility, and prominent anti-inflammatory activity. However, the correlation between their structure and anti-inflammatory activities still needs to be explored. In this study, we use LPS-stimulated RAW 264.7 macrophages as an inflammatory model to systematically evaluate COS1–7 for their effects on inflammatory mediators and NF-κB signaling pathways. The results of Griess assay, ELISA, and real-time quantitative PCR show that COSs can inhibit the expression of NO, iNOS, and pro-inflammatory cytokines (IL-6, TNF-α, MCP-1 and IL-1β), thereby attenuating inflammatory signaling. Notably, chitohexaose (COS6) exhibits the most significant anti-inflammatory effect, reducing the mRNA levels of LPS-induced iNOS, IL-6, and IL-1β and the production of IL-6 and TNF-α by more than 50%. Transcriptome, western blotting, and real-time quantitative PCR analysis reveal that COSs can inhibit the activation of the NF-κB signal pathway by down-regulating TLR2 levels. Additionally, molecular docking confirms that COSs retard TLR2/4 dimerization and LPS recognition by TLR4, affecting downstream signaling cascades. In summary, this study provides a valuable insight into the potential anti-inflammatory mechanism of COSs and highlights the possible applications in human health promotion by modulating receptor-mediated signaling pathways. Full article

(This article belongs to the Topic New Insights of Natural Compounds in Antioxidant and Anti-Inflammatory Properties)

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40 pages, 3887 KiB

Open AccessReview

A Comprehensive Review of Catalytic Hydrodeoxygenation of Lignin-Derived Phenolics to Aromatics

by Sitong Dong and Gang Feng

Molecules 2025, 30(10), 2225; https://doi.org/10.3390/molecules30102225 - 20 May 2025

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Abstract

Single-ring aromatic compounds including BTX (benzene, toluene, xylene) serve as essential building blocks for high-performance fuels and specialty chemicals, with extensive applications spanning polymer synthesis, pharmaceutical manufacturing, and aviation fuel formulation. Current industrial production predominantly relies on non-renewable petrochemical feedstocks, posing the dual [...] Read more.

Single-ring aromatic compounds including BTX (benzene, toluene, xylene) serve as essential building blocks for high-performance fuels and specialty chemicals, with extensive applications spanning polymer synthesis, pharmaceutical manufacturing, and aviation fuel formulation. Current industrial production predominantly relies on non-renewable petrochemical feedstocks, posing the dual challenges of resource depletion and environmental sustainability. The catalytic hydrodeoxygenation (HDO) of lignin-derived phenolic substrates emerges as a technologically viable pathway for sustainable aromatic hydrocarbon synthesis, offering critical opportunities for lignin valorization and biorefinery advancement. This article reviews the relevant research on the conversion of lignin-derived phenolic compounds’ HDO to benzene and aromatic hydrocarbons, systematically categorizing and summarizing the different types of catalysts and their reaction mechanisms. Furthermore, we propose a strategic framework addressing current technical bottlenecks, highlighting the necessity for the synergistic development of robust heterogeneous catalysts with tailored active sites and energy-efficient process engineering to achieve scalable biomass conversion systems. Full article

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

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23 pages, 1376 KiB

Open AccessArticle

Microwave Assisted Synthesis of Antioxidant Dihydro-Pyrazole Hybrids as Possible Lipoxygenase Inhibitors

by Stergiani-Chrysovalanti Peitzika, Eirini Tsiampakari and Eleni Pontiki

Molecules 2025, 30(10), 2224; https://doi.org/10.3390/molecules30102224 - 20 May 2025

Viewed by 112

Abstract

Free radicals and inflammation have pivotal role in various degenerative diseases like cancer, rheumatoid arthritis, diabetes, cardiovascular and neurodegenerative disorders. Pyrazoles possess a wide range of biological activities such as antifungal, antituberculosis, antimicrobial, antiviral, anti-inflammatory, anti-convulsant, anticancer etc. In this present study a [...] Read more.

Free radicals and inflammation have pivotal role in various degenerative diseases like cancer, rheumatoid arthritis, diabetes, cardiovascular and neurodegenerative disorders. Pyrazoles possess a wide range of biological activities such as antifungal, antituberculosis, antimicrobial, antiviral, anti-inflammatory, anti-convulsant, anticancer etc. In this present study a series of dibenzalacetones and the corresponding pyrazole hybrids were designed through bioisosterism, synthesized and biologically evaluated to highlight the importance of the extended conjugated system and substitution to the anti-inflammatory and antioxidant activity. The synthesis of dibenzalacetones was achieved via Claisen-Schmidt reaction. The dihydro-pyrazoles were synthesized from the substituted dibenzacetones and phenylhydrazines, hydrazine and semicarbazide under microwave irradiation optimizing reaction conditions. The synthesized compounds were spectroscopically characterized and evaluated for their anti-lipid peroxidation (AAPH) activity, their interaction with the free radical DPPH and the inhibition of soybean LOX. The novel derivatives were studied in terms of their physicochemical properties. Many of the dihydro-pyrazoles showed potent antioxidant properties and significant inhibition of soybean lipoxygenase as a result of their physicochemical features. Compounds 4a and 4b presented the most potent anti-lipid peroxidation abilities (98% and 97%), whereas compounds 2d and 2e have proved to be the most potent lipoxygenase inhibitors with IC₅₀ values 2.5 μM and 0.35 μM. Moreover, docking studies with soybean lipoxygenase highlight the interactions of the novel derivatives with the enzyme. Full article

(This article belongs to the Section Medicinal Chemistry)

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26 pages, 3487 KiB

Open AccessArticle

Effect of Synthetic Peptides Identified in the Bullfrog Skin on Inflammation and Oxidative Stress Control: An In Vitro Analysis

by Silvânia Mól Pelinsari, Patricia da Silva Mattosinhos, Manoela Maciel dos Santos Dias, Rosinéa Aparecida de Paula, Romulo Dias Novaes, Emerson Ferreira Vilela, Giuseppe Valacchi and Reggiani Vilela Gonçalves

Molecules 2025, 30(10), 2223; https://doi.org/10.3390/molecules30102223 - 20 May 2025

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Abstract

(1) Background: This study evaluated the potential of a synthetic peptide (SGHPGAMGPVGPR), identified in the bullfrog (Lithobates catesbeianus) skin, in regulating inflammation and oxidative stress using RAW 264.7 macrophages; (2) Methods: Molecular docking determined its optimal interaction with cyclooxygenase (COX-2) an [...] Read more.

(1) Background: This study evaluated the potential of a synthetic peptide (SGHPGAMGPVGPR), identified in the bullfrog (Lithobates catesbeianus) skin, in regulating inflammation and oxidative stress using RAW 264.7 macrophages; (2) Methods: Molecular docking determined its optimal interaction with cyclooxygenase (COX-2) an enzyme related to the production of prostaglandins, which play a crucial essential role in the inflammatory response. The peptide was commercially synthesized company, and its antioxidant capacity was assessed using DPPH and FRAP assays. Cell viability, nitric oxide (NO) levels, catalase (CAT), superoxide dismutase (SOD) and glutathione s-transferase (GST) activity, interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α) gene expression and cell production were additionally quantified. (3) Results: The peptide SGHPGAMGPVGPR, designated as P1, exhibited remarkable free radical scavenging capacity, antioxidant, and anti-inflammatory activities. No significant difference was observed in SOD and CAT activity in P1-treated macrophages, likely due to downregulation in the Nrf2/HO-1 pathway. Reduced GST activity was observed in these cells, which was potentially associated with TNF-α downregulation; (4) Conclusions: These findings suggest that P1 modulates the antioxidant response through pathways independent of classical antioxidant enzymes. Furthermore, decreased IL-6, COX2, and nuclear factor kappa B (NF-κB) expression was observed, indicating the involvement of a key pathway in the regulation of the OxInflammation process. Full article

(This article belongs to the Special Issue Exploring the Therapeutic Potential of Natural Antioxidants)

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22 pages, 5103 KiB

Open AccessFeature PaperArticle

Exploring Multivalent Architectures for Binding and Stabilization of N-Acetylgalactosamine 6-Sulfatase

by Maria Giulia Davighi, Francesca Clemente, Giampiero D’Adamio, Macarena Martínez-Bailén, Alessio Morano, Andrea Goti, Amelia Morrone, Camilla Matassini and Francesca Cardona

Molecules 2025, 30(10), 2222; https://doi.org/10.3390/molecules30102222 - 20 May 2025

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Abstract

Morquio A syndrome is a lysosomal disorder caused by the deficiency of the lysosomal enzyme N-acetylgalactosamine 6-sulfatase (GALNS, EC 3.1.6.4). Currently, enzyme replacement therapy (ERT) is used to treat Morquio A through the infusion of the recombinant enzyme VIMIZIM^® (elosulfase alfa, [...] Read more.

Morquio A syndrome is a lysosomal disorder caused by the deficiency of the lysosomal enzyme N-acetylgalactosamine 6-sulfatase (GALNS, EC 3.1.6.4). Currently, enzyme replacement therapy (ERT) is used to treat Morquio A through the infusion of the recombinant enzyme VIMIZIM^® (elosulfase alfa, BioMarin). Unfortunately, the recombinant enzyme exhibits low conformational stability in vivo. A promising approach to address this issue is the coadministration of recombinant human GALNS (rhGALNS) with a pharmacological chaperone (PC), a molecule that selectively binds to the misfolded protein, stabilizes its conformation, and assists in the restoration of the impaired function. We report in this work the synthesis of a library of multivalent glycomimetics exploiting the copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) reaction between several dendrimeric scaffolds armed with terminal alkynes and azido ending iminosugars of different structures (pyrrolidines, piperidines, and pyrrolizidines) or simple azido ending carbohydrates as bioactive units. The biological evaluation identified pyrrolidine-based nonavalent dendrimers 1 and 36 as the most promising compounds, able both to bind the native enzyme with IC₅₀ in the micromolar range and to act as enzyme stabilizers toward rhGALNS in a thermal denaturation study, thus identifying promising compounds for a combined PC/ERT therapy. Full article

(This article belongs to the Special Issue Glycomimetics: Design, Synthesis and Bioorganic Applications)

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