Molecules

28 pages, 6724 KB

Open AccessArticle

Nitrogen Vacancy Rich Tubular g-C₃N₄ Modified with FePc for Efficient and Reusable Photo-Fenton Degradation of Oxytetracycline

by Xinyi Yang, Yuxin Tang, Fei Qi, Zhihan Xue, Huiying Zhang, Zhaohai Ni, Bo Feng, Ziyang Yue and Guangbo Che

Molecules 2026, 31(18), 3229; https://doi.org/10.3390/molecules31183229 (registering DOI) - 12 Sep 2026

Abstract

Efficient and reusable photo-Fenton catalysts require the rational integration of photocatalytic platforms, effective H₂O₂ activation sites, and practical immobilization strategies. Herein, nitrogen-vacancy-rich tubular g-C₃N₄ (HCNT) was prepared as the photocatalytic platform. Iron (II) phthalocyanine (FePc) was then [...] Read more.

Efficient and reusable photo-Fenton catalysts require the rational integration of photocatalytic platforms, effective H₂O₂ activation sites, and practical immobilization strategies. Herein, nitrogen-vacancy-rich tubular g-C₃N₄ (HCNT) was prepared as the photocatalytic platform. Iron (II) phthalocyanine (FePc) was then loaded onto HCNT to form the FePc/HCNT composite for antibiotic degradation. The FePc/HCNT composite was further immobilized in a poly (vinylidene fluoride) (PVDF) membrane, denoted as FePc/HCNT-PVDF, to facilitate catalyst recovery and reuse. Benefiting from the micrometer-scale tubular morphology, the FePc/HCNT remained exposed on the membrane surface, preserving accessible catalytic interfaces and reducing encapsulation within the polymer matrix. The tubular architecture facilitated reactant transport, while surface nitrogen vacancies enhanced photogenerated-carrier separation and utilization. Component-dependent experiments revealed that FePc served as the primary center for H₂O₂ activation, whereas HCNT functioned as a defect-engineered tubular photocatalytic platform that promoted photogenerated-carrier separation and reactive oxygen species formation. The optimized FePc/HCNT achieved 94% oxytetracycline degradation within 60 min, with an apparent rate constant of 0.04462 min⁻¹, approximately 11 times higher than bulk g-C₃N₄, and exhibited broad-spectrum degradation capability toward various organic pollutants, including rhodamine B, tetracycline, amoxicillin, and ciprofloxacin. The FePc/HCNT-PVDF membrane removed 90% of oxytetracycline within 60 min and maintained stable performance over ten cycles. This work provides insights into the integrated roles of nitrogen vacancy regulation, FePc-mediated H₂O₂ activation, and morphology-assisted membrane immobilization in the development of reusable g-C₃N₄-based photo-Fenton catalysts. Full article

(This article belongs to the Special Issue Design and Application of Nanomaterials for Photocatalytic Degradation)

44 pages, 1320 KB

Open AccessReview

Molecular Docking of Natural Products: Critical Appraisal of Current Methodology and Practical Guidelines

by Almagul S. Makhmutova, Nazigul S. Remetova and Gulnissa K. Kurmantayeva

Molecules 2026, 31(18), 3228; https://doi.org/10.3390/molecules31183228 (registering DOI) - 12 Sep 2026

Abstract

Molecular docking is among the most widely used techniques in structure-based drug discovery and has become integral to natural-product research. Despite substantial advances in computational algorithms and artificial intelligence, the methodological quality of published docking studies on natural compounds remains highly variable, and [...] Read more.

Molecular docking is among the most widely used techniques in structure-based drug discovery and has become integral to natural-product research. Despite substantial advances in computational algorithms and artificial intelligence, the methodological quality of published docking studies on natural compounds remains highly variable, and generally accepted methodological guidelines have yet to be established. This review critically evaluates current approaches to molecular docking of natural compounds, examines the specific features of different natural-product classes and protein targets, and offers practical recommendations for the design and validation of docking studies. The review covers the main stages of molecular docking, contemporary search algorithms and scoring functions, protein and ligand preparation, the fundamental limitations of the method, strategies for result validation, and the emerging role of artificial intelligence in computational molecular modeling. A central component is a systematic methodological audit of publications within a prespecified 2025 coverage window, identified by Scopus and PubMed searches executed in August 2026. The audit assessed methodological reporting completeness only and was not intended as a systematic review of biological or pharmacological findings. The audit comprised GPT-assisted structured coding of 1127 publications, detailed full-text assessment of a random sample of 80 studies drawn entirely from the same corpus, and independent human validation of 20 randomly selected Stage 2 publications. In the 80-publication full-text sample, redocking was reported in 7.5% of publications, a qualifying redocking RMSD below 2 Å in 6.2%, positive controls in 87.5%, molecular dynamics in 41.2%, MM/PBSA or MM/GBSA in 12.5%, interaction analysis in 98.8%, and ADMET assessment in 35.0%. Agreement between Stage 1 and Stage 2 was 98.3% across 525 paired criterion decisions. Independent human assessment of the 20-publication validation subsample agreed with Stage 2 in 135 of 140 criterion decisions (96.4%); the five discrepancies all involved AI-coded indeterminate/non-confirmed labels (Unconfirmed or N/A) that the human reviewer classified as No. On the basis of these findings, we propose a practical workflow aimed at improving the reproducibility and methodological rigor of molecular docking studies of natural compounds. A complementary targeted case-enriched validation of redocking and redocking-RMSD classification included 19 publications and two human reviewers. The reviewers reached identical classifications in all 38 criterion decisions; their consensus agreed with Stage 2 in 31 of 38 decisions (81.6%), with seven revisions across four publications. Because this sample was deliberately enriched for informative and ambiguous cases, it was used to examine classification boundaries rather than to estimate prevalence. Because PubMed retrieval was restricted to free full text and the Scopus search used restricted bibliographic fields, these reporting-completeness and validation frequencies primarily characterize an accessibility-enriched corpus and may not fully generalize to subscription-only or otherwise less-accessible journals. By combining a critical appraisal of current methods with a quantitative assessment of published studies and practical recommendations for standardizing the molecular docking of natural compounds, this review offers guidance for researchers in computer-aided drug design. Full article

(This article belongs to the Special Issue Computational Approaches for Drug and Protein Design)

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14 pages, 8593 KB

Open AccessArticle

SDS-Assisted Morphology Regulation of NiMoO₄ for Efficient Alkaline Water Oxidation

by Mrunal Bhosale, Pritam J. Morankar, Sahil S. Magdum, Aditya A. Patil and Chan-Wook Jeon

Molecules 2026, 31(18), 3227; https://doi.org/10.3390/molecules31183227 (registering DOI) - 12 Sep 2026

Abstract

Oxygen evolution reaction (OER) remains the primary kinetic bottleneck in alkaline water electrolysis, necessitating the development of efficient, economically viable, and earth-abundant electrocatalysts. Herein, a facile sodium dodecyl sulfate (SDS)-assisted hydrothermal strategy is employed to synthesize nanostructured NiMoO₄ electrocatalysts with tailored morphology [...] Read more.

Oxygen evolution reaction (OER) remains the primary kinetic bottleneck in alkaline water electrolysis, necessitating the development of efficient, economically viable, and earth-abundant electrocatalysts. Herein, a facile sodium dodecyl sulfate (SDS)-assisted hydrothermal strategy is employed to synthesize nanostructured NiMoO₄ electrocatalysts with tailored morphology and enhanced electrocatalytic activity. Acting as a soft-template and structure-directing agent, SDS regulates the nucleation and growth of NiMoO₄, resulting in a porous and interconnected nanostructure with abundant exposed active sites. The optimized NiMoO₄-SDS-2 electrode exhibits outstanding OER performance, requiring an overpotential of only 428.5 mV to achieve a current density of 100 mA cm⁻², together with a Tafel slope of 62.4 mV dec⁻¹, demonstrating accelerated reaction kinetics. Electrochemical impedance spectroscopy and double-layer capacitance analyses reveal enhanced charge-transfer capability and a larger electrochemically active surface area, while long-term durability tests confirm excellent operational stability under alkaline conditions. The enhanced catalytic performance is associated with SDS-induced morphology regulation, improved active-site accessibility, and favorable interfacial charge-transfer characteristics. This work demonstrates that surfactant-assisted soft-templating is an effective strategy for engineering high-performance NiMoO₄-based electrocatalysts and provides valuable insights into the rational design of advanced transition metal oxide catalysts for efficient and durable alkaline water oxidation. Full article

(This article belongs to the Special Issue Advancements in Electrochemistry and Corrosion Protection)

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19 pages, 1596 KB

Open AccessArticle

4-Hydroxy-3-Methyl-2-Alkenylquinoline Disrupts Temporospatial Control of Flagellar Assembly and Induces Transcriptomic Remodeling in Bacillus subtilis Consistent with a Short-Circuiting of the Spo0A Phosphorelay

by McKinley D. Williams and Leif Smith

Molecules 2026, 31(18), 3226; https://doi.org/10.3390/molecules31183226 (registering DOI) - 12 Sep 2026

Abstract

4-hydroxy-3-methyl-2-alkenylquinolines (HMAQs) belong to an emerging sub-class of naturally synthesized alkaloids with several prominent biological properties. HMAQ-7 is a novel variant recently identified in Burkholderia contaminans MS14 which was previously shown to impede normal cellular behaviors in Bacillus subtilis, including multiple colonization [...] Read more.

4-hydroxy-3-methyl-2-alkenylquinolines (HMAQs) belong to an emerging sub-class of naturally synthesized alkaloids with several prominent biological properties. HMAQ-7 is a novel variant recently identified in Burkholderia contaminans MS14 which was previously shown to impede normal cellular behaviors in Bacillus subtilis, including multiple colonization phenotypes such as motility, pellicle formation, and sporulation. While the list of biological and chemical characteristics among HMAQ’s and related molecules is extensive, the mechanistic basis of these responses has been far more elusive. Using a combination of RNA-seq and bioinformatics, we have determined that several of the physiological defects induced by HMAQ-7 are strongly correlated with alterations in systems related to phospho-transduction. Specifically, HMAQ-7 augments gene expression in elements associated with late stationary phase growth, including those involved in phosphate assimilation and regulation of the spo0A phosphorelay. We also note that HMAQ-7 promotes dysregulated transcription of flagellar assembly genes which would normally be downregulated during late stationary phase. This study constitutes one of the first extensive investigations into an HMAQ’s mode of action, providing vital insight into the ecological dynamics between B. contaminans and B. subtilis. Full article

(This article belongs to the Special Issue Natural and Synthetic Alkaloids in Drug Discovery)

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25 pages, 2945 KB

Open AccessArticle

Design, Synthesis, and Antiproliferative Evaluation of C3/C12-Modified Panaxadiol Derivatives Against Gastric Cancer Cells: Integrated Transcriptomic and Metabolomic Analyses

by Yueru Zhang, Hongqing Xie, Chenggang Shan, Jinlong Han, Fangzhou Zhao, Xianchang Wang, Yinan Qi, Xiaoyang Li, Jianhua Zhang, Feng Zhang and Yun Zhou

Molecules 2026, 31(18), 3225; https://doi.org/10.3390/molecules31183225 (registering DOI) - 12 Sep 2026

Abstract

Panaxadiol (PD) is a bioactive dammarane triterpenoid with limited antiproliferative potency, and systematic optimization of its C3 and C12 positions remains underexplored. Here, a stepwise, site-differentiated strategy was established by combining selective C3 esterification with late-stage C12 diversification through a chloroacetyl–piperazine linker, affording [...] Read more.

Panaxadiol (PD) is a bioactive dammarane triterpenoid with limited antiproliferative potency, and systematic optimization of its C3 and C12 positions remains underexplored. Here, a stepwise, site-differentiated strategy was established by combining selective C3 esterification with late-stage C12 diversification through a chloroacetyl–piperazine linker, affording 23 PD derivatives and enabling complementary C3/C12 structure–activity analysis. Antiproliferative screening in AGS gastric cancer cells identified compounds 6, 11, and 17 as the most active analogues, with IC₅₀ values of 8.41, 5.08, and 6.78 μM, respectively, all outperforming 5-fluorouracil under identical conditions. Compound 6 provided a relatively favorable balance between low-micromolar activity and preservation of non-malignant GES-1 cells within a defined concentration range and was therefore selected for mechanistic investigation. Transcriptomic profiling identified 298 differentially expressed genes associated with cellular stress, cytokine signaling, epithelial growth regulation, and extracellular remodeling, whereas metabolomic analysis revealed marked perturbation of glycerophospholipid, choline, polyunsaturated fatty acid, and glutathione metabolism. Integrated analysis highlighted membrane-lipid remodeling, redox dysregulation, and ferroptosis-related processes as central features of the response. These findings establish a modular platform for PD optimization and identify compound 6 as a promising lead for further anti-gastric cancer development. Full article

31 pages, 2695 KB

Open AccessReview

Reprogramming Photodynamic Therapy with BODIPY Photosensitizers: From Local Phototoxicity Toward Precision Photodynamic Oncology

by Lina Deng, Yimiao Zhou and Zuowei Xiao

Molecules 2026, 31(18), 3223; https://doi.org/10.3390/molecules31183223 (registering DOI) - 12 Sep 2026

Abstract

Photodynamic therapy (PDT) offers spatially confined, repeatable and mechanistically orthogonal tumor control, yet its broader clinical impact remains limited by inadequate light access, oxygen dependence and incomplete biological selectivity. Boron–dipyrromethene (BODIPY) dyes provide an unusually programmable platform for addressing these constraints. Although native [...] Read more.

Photodynamic therapy (PDT) offers spatially confined, repeatable and mechanistically orthogonal tumor control, yet its broader clinical impact remains limited by inadequate light access, oxygen dependence and incomplete biological selectivity. Boron–dipyrromethene (BODIPY) dyes provide an unusually programmable platform for addressing these constraints. Although native BODIPYs are fluorescence-biased and inefficient triplet photosensitizers, their absorption, intersystem crossing, reactive oxygen species identity, aggregation, targeting and activation can be independently engineered through modular scaffold modification. In this Review, we present BODIPY as a programmable photochemical chassis for precision-oriented PDT. We first define the structure–photophysics–function relationships that convert BODIPY fluorophores into red- or near-infrared-responsive, type I- or type II-tunable and formulation-compatible photosensitizers. We then introduce a tumor-context-adaptive framework that integrates light-delivery routes, oxygen economy, multiscale targeting, organelle vulnerability and microenvironment-locked activation. Finally, we examine how BODIPY PDT can extend beyond direct cytotoxicity to vascular remodeling, immunogenic cell death, the potential to support in situ vaccination and rational combination therapy, while proposing translational go/no-go criteria for clinically credible candidates. We argue that progress will depend less on molecular complexity than on indication-first co-design of BODIPY chemistry, tumor biology and deployable light hardware. Full article

(This article belongs to the Special Issue The Development of Photosensitizers and Photodynamic Medicine)

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24 pages, 2925 KB

Open AccessArticle

Coumarin Compounds with 6- or 7-(4-Aminobutynyloxy) Substituent: Synthesis, In Vitro Cytotoxicity and In Silico DNA Binding Studies

by Anarkul S. Kishkentayeva, Mohammad S. Hamad, Victor A. Savelyev, Zhasmin A. Boyaubayeva, Andrey I. Khlebnikov, Andrey G. Pokrovsky, Yurii V. Gatilov, Almagul S. Makhmutova and Elvira E. Shults

Molecules 2026, 31(18), 3222; https://doi.org/10.3390/molecules31183222 (registering DOI) - 12 Sep 2026

Abstract

Coumarin compounds are of great interest in drug development research. Various substituents on the coumarin core significantly influence its biological activity. Although a number of coumarins with specific biological properties have already been identified, the ongoing challenge lies in the design and synthesis [...] Read more.

Coumarin compounds are of great interest in drug development research. Various substituents on the coumarin core significantly influence its biological activity. Although a number of coumarins with specific biological properties have already been identified, the ongoing challenge lies in the design and synthesis of novel derivatives with high specificity for pharmacological targets. In this work, 6-(4-aminobut-2-ynyloxy)- and 7-(4-aminobut-2-ynyloxy)-substituted coumarin derivatives were designed and synthesized. As a method for the synthesis of 6- or 7-substituted coumarins (yields 26–98%), a copper-catalyzed one-pot three-component reaction (A³ coupling) of 6- or 7-(prop-2-ynyloxy)coumarins with formaldehyde and secondary amines was studied. In vitro biological testing (MTT assay) results showed that the new coumarins exhibit pronounced cytotoxicity against human cervical cancer (C33 A and CaSki) and breast cancer (MCF-7) cell lines, with activity being dependent on the substituent at the nitrogen atom in the side chain. The most active compounds inhibited tumor cell growth, with GI₅₀ values of 4.3–9.4 μM (SI = 9.1–19.8). All new compounds demonstrated low cytotoxicity against the non-malignant epithelial VERO cells (GI50 > 86 μM). To understand the observed SAR trends, molecular modeling of the interaction between the new coumarin derivatives and DNA G-quadruplex binding sites was performed. Full article

(This article belongs to the Special Issue Organic Synthesis and Medicinal Chemistry, Two Inseparable Partners: Recent Advances in Heterocyclic Chemistry, 2nd Edition)

30 pages, 5979 KB

Open AccessArticle

Rational Design of Putative Dual-Target Opioid-Dopaminergic Casomorphin–Ranatensin Hybrid Peptides: Computational Modeling and Preliminary Antiproliferative Evaluation

by Krystian Małek, Adrian Górski, Łukasz Szeleszczuk, Anna K. Laskowska, Zuzanna Markowska, Sebastian Granica, Anna Pogorzelska, Piotr Koch, Natalia Pielaszkiewicz, Jagoda Michniewicz, Wojciech Kamysz, Małgorzata Milczarek, Karol Sikora and Patrycja Kleczkowska

Molecules 2026, 31(18), 3221; https://doi.org/10.3390/molecules31183221 (registering DOI) - 12 Sep 2026

Abstract

Despite advances in oncology, cancer remains a leading cause of mortality worldwide, and both μ-opioid receptor (MOR) and dopamine D2 receptor (D2R) signaling have been implicated in the regulation of tumor proliferation, survival, and progression, positioning them as attractive targets for multifunctional anticancer [...] Read more.

Despite advances in oncology, cancer remains a leading cause of mortality worldwide, and both μ-opioid receptor (MOR) and dopamine D2 receptor (D2R) signaling have been implicated in the regulation of tumor proliferation, survival, and progression, positioning them as attractive targets for multifunctional anticancer strategies. In the present study, a series of novel casomorphin–ranatensin hybrid peptides were designed, synthesized, and evaluated as putative dual-target anticancer agents combining MOR and D2R pharmacophores. Among the evaluated analogues, KAZO_5.2 and KAZO_7.2 reduced viability of HCT116 colorectal cancer cells in a dose- and time-dependent manner, with a modest selectivity ratio compared to non-tumorigenic MCF 10A cells. Both compounds showed favorable docking scores toward MOR and D2R, while single 100 ns molecular dynamics trajectories showed that the peptides remained associated with their respective receptor models over the simulated timescale. Partial reversal of the viability-reducing effect by naloxone suggested involvement of opioid-sensitive pathways, while only low baseline MOR expression was detected in HCT116 cells under our experimental conditions, consistent with a possible contribution of additional receptor-mediated mechanisms to the observed activity. Neither compound induced pronounced apoptosis or cell cycle arrest, suggesting cytostatic rather than cytotoxic effects. Both peptides exhibited negligible hemolytic activity and high proteolytic stability in human plasma, with intact peptides remaining predominant after 24 h of incubation at 37 °C. These findings identify casomorphin–ranatensin hybrids as a promising scaffold for dual-target anticancer peptide development, warranting further structural optimization and mechanistic investigation. Full article

(This article belongs to the Special Issue Synthesis, Modification, and Bioactive Evaluation of Peptides and Their Analogs)

23 pages, 1687 KB

Open AccessArticle

UV/Chlorine Treatment of Sulfamethoxazole: Removal, Transformation Products, Ecotoxicity, and Environmental Fate

by Waldemar Studziński, Alicja Gackowska, Edyta Kudlek and Maciej Przybyłek

Molecules 2026, 31(18), 3220; https://doi.org/10.3390/molecules31183220 (registering DOI) - 12 Sep 2026

Abstract

UV/NaOCl and UV/H₂O₂/NaOCl treatments of sulfamethoxazole (SMX) were compared across several reagent ratios using pseudo-first-order kinetics, LC-DAD/LC-MS screening of transformation products (TPs), multi-trophic bioassays, and quantitative structure–activity relationship (QSAR)-based toxicity and fate screening. Increasing the NaOCl proportion from an [...] Read more.

UV/NaOCl and UV/H₂O₂/NaOCl treatments of sulfamethoxazole (SMX) were compared across several reagent ratios using pseudo-first-order kinetics, LC-DAD/LC-MS screening of transformation products (TPs), multi-trophic bioassays, and quantitative structure–activity relationship (QSAR)-based toxicity and fate screening. Increasing the NaOCl proportion from an SMX:NaOCl molar ratio of 1:1 to 1:10 increased the pseudo-first-order rate constant from 0.215 to 0.818 min⁻¹, but faster SMX removal did not correspond to a more favorable post-treatment bioassay profile. The 1:1 and 1:2 UV/NaOCl systems achieved substantial SMX removal within 10 min and gave the lowest responses among the treated systems in the Microtox^®, Daphtox F^®, and Lemna sp. assays. Higher NaOCl loadings and the mixed-oxidant systems produced stronger post-treatment bioassay responses and larger signals for ECOSAR-prioritized chlorinated aromatics and coupling products. Fate screening further distinguished more persistent, strongly sorbing products from TPs with lower sorption or greater predicted transport potential. The tested reagent ratios therefore revealed a trade-off between removal kinetics and the biological and environmental profile of the resulting mixtures. Full article

(This article belongs to the Special Issue Advances in Remediation Methods of Pharmaceutical Pollutants in Water)

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15 pages, 14950 KB

Open AccessArticle

Tetracyclines Removal from Aquaculture Effluents by Waste Mussel Shells After Thermal Modification

by Hongmei Hu, Tongtong Zhang, Meiying Ye, Zhenhua Li, Tiejun Li and Yuanming Guo

Molecules 2026, 31(18), 3219; https://doi.org/10.3390/molecules31183219 (registering DOI) - 12 Sep 2026

Abstract

As a class of low-cost and broad-spectrum antibiotics in wide aquaculture use, residues of tetracyclines (TCs) are imperiling aquatic organisms and public health worldwide, leading to a high demand for TC removal from the aquaculture environment. In addition, considerable consumption of thick-shell mussels [...] Read more.

As a class of low-cost and broad-spectrum antibiotics in wide aquaculture use, residues of tetracyclines (TCs) are imperiling aquatic organisms and public health worldwide, leading to a high demand for TC removal from the aquaculture environment. In addition, considerable consumption of thick-shell mussels generates massive mussel shell waste, and their treatment has been an economic and environmental issue. Herein, a low-cost and high-efficiency mussel shells-based material was successfully prepared for TC removal by thermal modification of shell waste of Mytilus coruscus. Morphological and structural characterizations revealed the phase transformation of calcium carbonate to calcium oxide. The shell-based material calcined at 1050 °C (MC1050) yielded a Langmuir-fitted maximum removal capacity (q_m) of 68.0 mg/g towards oxytetracycline (OTC). Thermodynamic calculations indicate that OTC removal by MC1050 is a spontaneous and endothermic process. OTC removal by MC1050 is likely achieved via multiple co-existing pathways, where Ca-OTC co-precipitation driven by CaO-phase hydration and resultant high-pH conditions dominates, accompanied by auxiliary surface-interaction contributions. Furthermore, MC1050 achieves removal efficiencies exceeding 96% for the ten target TCs spiked at 20 μg/L in real-world freshwater and marine aquaculture effluent matrices. Overall, the developed shell-based material shows promising performance for wastewater treatment and facilitates the resource utilization of waste mussel shells. Full article

(This article belongs to the Special Issue Functional Materials and Chemical Technologies for Sustainable Water Treatment)

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34 pages, 33860 KB

Open AccessArticle

Enhanced CO₂ Methanation over Solution-Combustion Synthesized Ni/Kaolin Catalysts: The Effect of Fe and La Promotion

by Agnieszka Szymaszek-Wawryca, Szymon Hanf, Michał Szymaszek, Konrad Świerczek, Dorota Duraczyńska, Mateusz Marzec and Monika Motak

Molecules 2026, 31(18), 3218; https://doi.org/10.3390/molecules31183218 - 11 Sep 2026

Abstract

Ni-based catalysts supported on kaolin were synthesized via solution combustion synthesis and promoted with Fe and/or La to investigate their catalytic performance in CO₂ methanation. Catalytic tests showed that Fe significantly improved CO₂ conversion from approximately 52% for Ni-catalyst to 83% [...] Read more.

Ni-based catalysts supported on kaolin were synthesized via solution combustion synthesis and promoted with Fe and/or La to investigate their catalytic performance in CO₂ methanation. Catalytic tests showed that Fe significantly improved CO₂ conversion from approximately 52% for Ni-catalyst to 83% for Ni2.5Fe_SCS at 300 °C. However, the promotional effect of Fe showed only a weak dependence on its loading, with Ni modification already being achieved at the lowest Fe content. Among all investigated catalysts, the La-promoted sample exhibited the highest CO₂ conversion (85% at 300 °C), owing to the formation of highly dispersed Ni⁰ crystallites, enhanced surface basicity, and strong metal–support interactions. These interactions also effectively suppressed particle sintering during prolonged stability tests. In contrast, simultaneous promotion with Fe and La did not provide additional catalytic enhancement, indicating that the effects of both promoters were not simply additive. Full article

(This article belongs to the Special Issue Zeolites and Mesoporous Materials: Properties and Applications, 3rd Edition)

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18 pages, 2493 KB

Open AccessArticle

Luminescence Enhancement of an Indium(III) Complex Through Introducing an Electron-Donating Group in (1H-Pyrazol-1-yl)pyridazine

by Evgeniia Sergeevna Sedykh, Nikita Vasilievich Naletov, Veronika Igorevna Komlyagina, Yulia Sergeevna Spiridonova, Elvira Ilgizovna Musina, Marianna Ivanovna Rakhmanova, Nikolay Filippovich Romashev, Katerina Aleksandrovna Vinogradova, Marat Damirovich Nafikov, Alexey Yuryevich Vorob’ev, Iakov Sergeevich Fomenko and Artem Leonidovich Gushchin

Molecules 2026, 31(18), 3217; https://doi.org/10.3390/molecules31183217 - 11 Sep 2026

Abstract

New deep-blue-emitting materials are crucial for Organic Light-Emitting Diode (OLED) technology, as iridium-based blue emitters often suffer from degradation and inadequate colour purity. Indium(III) complexes offer an alternative, since the d¹⁰ configuration of In³⁺ precludes metal-centred transitions, and emission arises from [...] Read more.

New deep-blue-emitting materials are crucial for Organic Light-Emitting Diode (OLED) technology, as iridium-based blue emitters often suffer from degradation and inadequate colour purity. Indium(III) complexes offer an alternative, since the d¹⁰ configuration of In³⁺ precludes metal-centred transitions, and emission arises from ligand-centred states via the chelation-enhanced fluorescence (CHEF) effect. We previously reported complexes 1 ([In(L^H)(H₂O)Cl₃]) and 2 ([In(L^Me)₂Cl₂][InCl₄]), which exhibited excitation-dependent emission, and the electronic transitions were assigned as ILCT for 1 and mixed ILCT/LL’CT for 2. Herein, we present a new complex, complex 3, i.e., [In(L^Morph)₂Cl₂][InCl₄], where L^Morph contains electron-donating morpholine substituents, in contrast to the acceptor chloride group in L^H and L^Me. Complex 3 was characterised by elemental CHN analysis, infrared spectroscopy (IR), nuclear magnetic resonance spectroscopy (NMR), ultraviolet–visible spectroscopy (UV-Vis), single-crystal X-ray diffraction analysis (SC-XRD), and photoluminescence. The ionic structure of 3 is analogous to 2, with a cis-octahedral [In(L^Morph)₂Cl₂]⁺ cation and tetrahedral [InCl₄]⁻ anion. The UV-Vis spectrum of 3 shows a significant bathochromic shift relative to 1 and 2 which is attributable to the morpholine group. TD-DFT calculations were employed to assign the electronic transitions. The introduction of a morpholino group into the pyridazine ring resulted in significant changes to the solid-state photoluminescence properties of the indium complex: (i) the emission maximum shifted to the red region (CIE 1931 coordinates: 0.1725, 0.2487), (ii) the lifetime increased by an order of magnitude, and (iii) the quantum yield rose to 15%. This work highlights that substituent variation on the pyrazolyl–pyridazine scaffold provides a versatile route to tune the structural and photophysical properties of indium(III) complexes. Full article

(This article belongs to the Special Issue Metal Complexes: From Synthesis to Applications)

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24 pages, 1779 KB

Open AccessArticle

Study on the Quality Component Differences Among Tea Cultivars in Northern Guizhou

by Manman Gao, Kai Zhang, Huan Wang and Heng Sun

Molecules 2026, 31(18), 3216; https://doi.org/10.3390/molecules31183216 - 11 Sep 2026

Abstract

To elucidate how quality is reshaped in introduced tea varieties under Guizhou’s unique ecological conditions and to identify quality advantages and flavor differences between exotic and local germplasm resources, this study investigated the quality characteristics of tea plant germplasm from different geographic origins [...] Read more.

To elucidate how quality is reshaped in introduced tea varieties under Guizhou’s unique ecological conditions and to identify quality advantages and flavor differences between exotic and local germplasm resources, this study investigated the quality characteristics of tea plant germplasm from different geographic origins under Guizhou’s ecological conditions. Quality components and volatile aroma compounds were analyzed in four introduced cultivars (CC4H, SLX, SMCY, HJC1) and two local cultivars (QM601, GZSC). Sensory evaluation indicated that CC4H, SMCY, and HJC1 were more suitable for manufacturing premium green tea in the local area. GC-MS identified 147 volatile compounds, with alcohols present at the highest concentrations (1090.69–1499.18 μg/kg). SMCY had the highest total alcohol content. rOAV analysis confirmed that benzaldehyde, (E)-β-damascone, β-ionone, and 1-octene-3-one are the key contributors to the aroma profile. Among the introduced cultivars, SMCY stands out for its floral and aromatic compounds; SLX is notably rich in floral and fruity aldehydes and esters; CC4H has a distinct roasted sweetness, and HJC1 offers the best freshness. The local variety QM601 exhibits synergistic accumulation of tea polyphenols and fruity terpenes, while GZSC maintains its traditional advantage in the balance of phenolic and amino compounds. These findings provide a theoretical basis for the differentiated deployment of tea cultivars in Guizhou’s tea-growing regions. Full article

(This article belongs to the Section Food Chemistry)

20 pages, 3333 KB

Open AccessArticle

The Assembly of Alginate–Chitosan–Xanthine Hydrogel and Halomonas Improves Soil Quality of Protected Crop Growth Under Saline–Alkali Stress

by Rou Liu, Zirun Zhao, Guangbo Feng, Jiawen Yu, Xiaoxiang Zhou, Zijia Zhao, Danni Wang, Mingchun Li and Qilin Yu

Molecules 2026, 31(18), 3215; https://doi.org/10.3390/molecules31183215 - 11 Sep 2026

Abstract

Soil saline–alkali stress has become a great risk, leading to significant decline in crop yields, especially in protected agriculture that is frequently threatened by excessive chemical fertilization. There is an urgent need to develop friendly strategies for improving the quality of saline–alkali soil. [...] Read more.

Soil saline–alkali stress has become a great risk, leading to significant decline in crop yields, especially in protected agriculture that is frequently threatened by excessive chemical fertilization. There is an urgent need to develop friendly strategies for improving the quality of saline–alkali soil. Microbial inoculants are promising agents in attenuating soil stress, but their colonization ability in the crop rhizosphere is often limited. To improve the efficiency of microbial inoculants, this study constructed the assembly of a salt-tolerant bacterium Halomonas (Homs) and a hydrogel composed of sodium alginate, chitosan and xanthine with the assistance of artificial Homs-binding protein (Schx). The effect of this Homs + Schx assembly on the growth of crops and the rhizosphere microecology under saline–alkali stress was systematically evaluated by pot experiments. The results indicate that the application of Homs + Schx enhanced the Shannon index of the rhizosphere bacterial community and increased the relative abundance of key bacterial genera related to biofilm formation and nitrogen cycling (e.g., Curvibacter and Nitrospira). Furthermore, Homs + Schx enhanced the activity of soil urease, peroxidase, and sucrase, reducing the sodium ion content, increasing the potassium ion content, and effectively lowering the soil pH and salt contents. Physiologically, this treatment induced a root osmotic regulatory response, resulting in an increase in the proline contents and a decrease in malondialdehyde contents. Consequently, Homs-Schx promoted the growth of tomatoes and wheat in saline–alkali soil. This study provides new ideas for enhancing the rhizosphere colonization of plant growth-promoting bacteria, regulating the structure of microbial communities, and enhancing crop stress tolerance with the aid of green material strategies. Full article

(This article belongs to the Special Issue Molecular Mechanisms of Rhizosphere Microbe–Plant Interactions: Chemical Signaling, Metabolite Exchange and Synergistic Networks)

13 pages, 6027 KB

Open AccessArticle

Different Alkali Carbonates on the Microstructure and Photoluminescence Properties of SrWO₄:Tb³⁺ Phosphors

by Faxue Ma, Xiangju Wu, Jingwei Hu, Ruoyang Li, Dingcheng Yang, Weiwei Shi, Xueqing Zhu, Yongguo Cao and Aiyun Jiang

Molecules 2026, 31(18), 3214; https://doi.org/10.3390/molecules31183214 - 11 Sep 2026

Abstract

In this research, terbium-doped strontium tungsten oxide samples were synthesized using the solid-state synthesis method. It was found through X-ray powder diffraction (XRD) that the samples belong to the tetragonal crystal system and have the space group I4₁/a. The SEM-EDS images [...] Read more.

In this research, terbium-doped strontium tungsten oxide samples were synthesized using the solid-state synthesis method. It was found through X-ray powder diffraction (XRD) that the samples belong to the tetragonal crystal system and have the space group I4₁/a. The SEM-EDS images indicate that the Na, K, W, and Tb atoms are uniformly distributed throughout the samples. Photoluminescence (PL) measurements were applied for sample characterization. All of them exhibited green emission with the highest peak at 545 nm attributable to the ⁵D₄ → ⁷F₅ transition. The highest emission intensity was observed in the Sr_0.996Tb_0.004WO₄ sample, while higher doping levels resulted in a decrease in the PL intensities due to concentration quenching. Samples with additional alkali metal ions for charge compensation were also prepared, and their PL properties were measured; the enhancement of co-doping alkali metal (A⁺ = Li⁺, Na⁺, K⁺) on the green luminescence is demonstrated thoroughly. Doping with 0.5 mol% Na⁺ ions yielded a 9.14-fold increase in peak intensity of 545 nm, a 8.02-fold enhancement in operational lifespan, and a 88.82% improvement in quantum yield. These results indicate that Sr_0.991Tb_0.004Na_0.005WO₄ materials have potential application as green phosphors in LEDs. Full article

(This article belongs to the Topic New Advances in Luminescent Materials)

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31 pages, 978 KB

Open AccessArticle

Sequential Enzymatic Bioprocessing of Protein-Rich Unhairing–Liming and Lime-Fleshing Tannery Wastewater for the Production of Amino Acid-Based Plant Biostimulants

by Henoc Pérez-Aguilar, Víctor M. Serrano-Martínez, Carlos Ruzafa-Silvestre, Alberto Vico and María Dolores Romero-Sánchez

Molecules 2026, 31(18), 3213; https://doi.org/10.3390/molecules31183213 - 11 Sep 2026

Abstract

The recovery of bioactive compounds from industrial wastewaters is a key strategy for improving resource efficiency and reducing the environmental impact of high-load effluents. In this work, two protein-rich tannery wastewater streams with different origins and compositions, unhairing–liming wastewater and lime-fleshing wastewater, were [...] Read more.

The recovery of bioactive compounds from industrial wastewaters is a key strategy for improving resource efficiency and reducing the environmental impact of high-load effluents. In this work, two protein-rich tannery wastewater streams with different origins and compositions, unhairing–liming wastewater and lime-fleshing wastewater, were comparatively evaluated as secondary raw materials for the production of amino acid-based protein hydrolysates with potential biostimulant activity. Both streams were characterised in terms of physicochemical composition, mineral content and amino acid profile, and subsequently subjected to a comparative sequential enzymatic hydrolysis approach using endo- and exo-proteolytic enzymes. Alcalase, followed by Pancreatin, was selected as the most effective enzymatic system for both streams, although different optimal enzyme loadings were required depending on the wastewater composition. For unhairing–liming wastewater, the optimal conditions were 1.5% Alcalase and 1.0% Pancreatin, yielding 70.76 ± 1.95% hydrolysate, 80.87 ± 1.98% protein recovery and 11.42 ± 1.03% free amino acids. For lime-fleshing wastewater, 0.7% Alcalase and 1.0% Pancreatin provided 98.42 ± 1.97% yield, 92.19 ± 1.92% protein recovery and 16.97 ± 0.98% free amino acids. The two hydrolysates showed differentiated amino acid profiles, reflecting the keratin- and collagen-derived nature of the original streams. Germination assays indicated a growth-stimulating effect of the hydrolysates, increasing seed growth by up to 20.7% for the unhairing–liming wastewater hydrolysate at 0.10% (w/v) and by up to 27.1% for the lime-fleshing wastewater hydrolysate at 0.07% (w/v). These results demonstrate that enzymatic hydrolysis can be an effective and environmentally friendly route for converting tannery wastewaters into value-added bio-based products for agricultural applications, while also highlighting the industrial relevance of adapting the enzymatic process to the origin, composition and protein accessibility of each wastewater stream. Full article

(This article belongs to the Special Issue Environmentally Friendly Technologies for Waste Processing and Recovery)

57 pages, 5280 KB

Open AccessArticle

Process Intensification Sonocatalytic Degradation of Malachite Green Wastewater over Hydrothermally Engineered M-ZLT@Co₃O₄ Nanocatalyst: Structure–Activity Relationships, Radical-Mediated Mechanism and Degradation Pathways

by Murat Kıranşan

Molecules 2026, 31(18), 3212; https://doi.org/10.3390/molecules31183212 - 11 Sep 2026

Abstract

This study reports the sonocatalytic degradation of malachite green (MG) in media using synthesized Co₃O₄ nanoparticles and a CTAB-modified zeolite supported Co₃O₄ hybrid nanocatalyst (M-ZLT@Co₃O₄). The catalysts were characterized by XRD, FT-IR, SEM-EDX, [...] Read more.

This study reports the sonocatalytic degradation of malachite green (MG) in media using synthesized Co₃O₄ nanoparticles and a CTAB-modified zeolite supported Co₃O₄ hybrid nanocatalyst (M-ZLT@Co₃O₄). The catalysts were characterized by XRD, FT-IR, SEM-EDX, TEM, XRF, N₂ adsorption–desorption, BET, and BJH analyses, verifying crystalline Co₃O₄ formation, successful immobilization on the modified zeolite support, porous architecture, morphology and elemental distribution. Under optimized conditions of 1 g L⁻¹ catalyst dosage, 20 mg L⁻¹ MG concentration, natural pH, and 300 W L⁻¹ ultrasonic power, M-ZLT@Co₃O₄ achieved 99.31% ± 0.45% degradation within 120 min. Decreasing the MG concentration to 5 mg L⁻¹ increased the efficiency to 99.96% ± 0.64%, confirming high activity at low pollutant loading. The degradation followed pseudo-first-order kinetics, with k_app values of 0.0042–0.0595 min⁻¹ depending on catalyst dosage, 0.0046–0.0667 min⁻¹ for initial MG concentration, and 0.0117–0.0620 min⁻¹ under pH conditions. Water matrix inhibition followed distilled water (99.31%) > tap water (96.08%) > river water (88.84%) > lake water (86.90%), whereas higher ultrasonic power increased degradation from 91.98% at 200 W L⁻¹ to 99.90% at 500 W L⁻¹. Dye degradation followed MG (99.31%) > CR (95.78%) > BY2 (92.15%) > MV (90.24%) > AO7 (85.62%) > RB19 (82.49%). Comparative tests demonstrated performance for US/M-ZLT@Co₃O₄ (99.31%) compared with US/Co₃O₄ nanoparticles (78.48%), US/ZLT (72.86%), and US/MG alone (35.71%). The best activity was obtained at 0.8–2 g L⁻¹ catalyst dosage and 5–20 mg L⁻¹ MG concentration, while reusability tests showed a decrease from 99.31% to 78.82% after six cycles, indicating promising stability. Full article

(This article belongs to the Special Issue Advanced Oxidation Processes for Organic Wastewater Treatment: Recent Advances and Future Prospects)

13 pages, 1022 KB

Open AccessArticle

Spectrophotometric Studies of a Fluorescent Naphthalenediimide PET and ICT pH Indicator and DNA Intercalator

by Alex D. Johnson, Mario Valentino, Gary J. Hunter and David C. Magri

Molecules 2026, 31(18), 3211; https://doi.org/10.3390/molecules31183211 - 11 Sep 2026

Abstract

Three naphthalenedimides (NDIs) were studied by UV-visible absorbance, fluorescence and circular dichroism spectroscopy in aqueous methanolic solution as DNA intercalators. Distinct solution colours are observed for the compounds under room lighting and upon irradiation with 365 nm UV light. The tetra-substituted dimethylaminoethylene NDI [...] Read more.

Three naphthalenedimides (NDIs) were studied by UV-visible absorbance, fluorescence and circular dichroism spectroscopy in aqueous methanolic solution as DNA intercalators. Distinct solution colours are observed for the compounds under room lighting and upon irradiation with 365 nm UV light. The tetra-substituted dimethylaminoethylene NDI is designed as a fluorescent pH indicator with a ‘fluorophore–spacer–receptor’ construct based on a photoinduced electron transfer (PET) mechanism. This NDI derivative exhibits a significant change in the ellipticity with calf-thymus DNA. Fluorescence DNA titrations further revealed strong binding towards DNA, resulting in pronounced emission quenching. Incubation of MCF-7 cells reveals localisation of the fluorescent probe in the nucleus, specifically in the nucleoli. Full article

(This article belongs to the Special Issue Advances in Supramolecular Systems for Biomolecular Recognition)

16 pages, 1969 KB

Open AccessArticle

Synergistic Catalysis over MoS₂/CuS in Ultrasound-Assisted Peroxymonosulfate System: Performance and Mechanism for Degradation of Multiple Organic Contaminants

by Chu Dai, Jie Li, Chuanhui Wang, Hongyan Qi and Chen Tian

Molecules 2026, 31(18), 3210; https://doi.org/10.3390/molecules31183210 - 11 Sep 2026

Abstract

Aquatic antibiotic pollution represented by ofloxacin (OFX) causes serious ecological hazards and endangers public health due to the high persistence and bioaccumulation of antibiotic residues. Conventional water treatment techniques are insufficient for OFX elimination, limited by low removal efficiency, high energy consumption, and [...] Read more.

Aquatic antibiotic pollution represented by ofloxacin (OFX) causes serious ecological hazards and endangers public health due to the high persistence and bioaccumulation of antibiotic residues. Conventional water treatment techniques are insufficient for OFX elimination, limited by low removal efficiency, high energy consumption, and poor operational stability. Herein, a novel MoS₂/CuS heterojunction composite was fabricated via a hydrothermal method and applied to an ultrasound-driven piezocatalysis-coupled peroxymonosulfate (PMS) advanced oxidation system for OFX wastewater remediation. The introduction of CuS effectively remedies the inherent shortcomings of pristine MoS₂, including insufficient active sites and rapid photogenerated carrier recombination. The constructed heterojunction induces a strong interfacial built-in electric field, which significantly accelerates the migration of piezoelectric charges. The synergistic photo-piezoelectric effect further promotes continuous PMS activation and facilitates the massive generation of reactive oxygen species (ROS). The influences of key operating parameters and common water inorganic anions on OFX degradation performance were systematically investigated. Radical trapping experiments confirmed the synergistic mechanism between piezocatalysis and PMS activation during the catalytic reaction. The optimized MoS₂/CuS heterojunction exhibits remarkable OFX degradation efficiency and excellent cyclic stability. This work provides a feasible strategy for the rational design and fabrication of high-efficiency piezocatalysts and offers a promising technical route for the remediation of refractory antibiotic wastewater via piezocatalysis-coupled PMS advanced oxidation. Full article

(This article belongs to the Special Issue A New Perspective on the Determination and Removal of Pollutants in the Environment, 2nd Edition)

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