Molecules

12 pages, 5260 KB

Open AccessCommunication

Green and Ultrafast Preparation of TiO₂ Aerogel Assisted by Mechanical Ball Milling

by Nai Liu, Jingyi Chen, Dongzhi Zhu, Kao Chen and Qingge Feng

Molecules 2026, 31(15), 2690; https://doi.org/10.3390/molecules31152690 (registering DOI) - 2 Aug 2026

TiO₂ aerogel is a uniquely promising photocatalyst that has been widely applied in water environment remediation. Despite continuous advances in its synthesis methods, bottlenecks such as long preparation cycles, large organic solvent consumption, and high production costs still restrict its large-scale application. [...] Read more.

TiO₂ aerogel is a uniquely promising photocatalyst that has been widely applied in water environment remediation. Despite continuous advances in its synthesis methods, bottlenecks such as long preparation cycles, large organic solvent consumption, and high production costs still restrict its large-scale application. This work presents a mechanical force-assisted (MFA) strategy for green and ultrafast TiO₂ aerogel preparation, with process intensification as its core innovation. The total preparation time is reduced by 60%, and n-hexane consumption is decreased by 25%. BET, XRD and TEM characterizations confirm that the MFA-derived TiO₂ aerogel maintains physicochemical properties comparable to the conventional sample, and its photocatalytic reaction rate constant for tetracycline hydrochloride degradation is approximately twice that of the original sample. Full article

(This article belongs to the Section Inorganic Chemistry)

► Show Figures

Figure 1

35 pages, 1473 KB

Open AccessArticle

Synthesis and Characterization of New Functionalized Pyrimidine (Hetero)Cyclic Molecular Hybrids as Chiral Heterocyclic Amino Acid Derivatives

by Paulina Voznikaitė, Greta Račkauskienė, Miglė Dagilienė, Vilija Kederienė, Frank A. Sløk and Algirdas Šačkus

Molecules 2026, 31(15), 2689; https://doi.org/10.3390/molecules31152689 (registering DOI) - 2 Aug 2026

Abstract

Heterocyclic unnatural amino acids and their biheterocyclic derivatives represent invaluable structural scaffolds in modern medicinal chemistry and peptidomimetics due to their ability to induce conformational constraints and modulate pharmacokinetic profiles. While saturated nitrogen heterocycles and monocycle heteroaromatic systems are well-established pharmacophores, research on [...] Read more.

Heterocyclic unnatural amino acids and their biheterocyclic derivatives represent invaluable structural scaffolds in modern medicinal chemistry and peptidomimetics due to their ability to induce conformational constraints and modulate pharmacokinetic profiles. While saturated nitrogen heterocycles and monocycle heteroaromatic systems are well-established pharmacophores, research on linear biheterocyclic amino acid frameworks remains significantly underrepresented in the literature. Addressing this structural gap, this study aims to synthesize and characterize a novel series of functionalized pyrimidine (hetero)cyclic molecular hybrids acting as chiral heterocyclic amino acid derivatives. The target pyrimidine-5-carboxylates and pyrimidine-4-carboxylic acid derivatives were prepared from β-dicarbonyl compounds and their corresponding enamine analogues via cyclocondensation approaches. Particular attention was paid to reaction optimization, substrate scope exploration, and stereochemical integrity preservation, utilizing chiral HPLC analysis to evaluate enantiomeric retention. Pyrimidine-5-carboxylates prepared from β-enamino keto esters retained high enantiomeric excess (90.2–100% ee), whereas cyclization of β-diketones under strongly basic conditions at elevated temperature resulted in complete racemization (ee < 1%). Modification of the synthetic route and application of milder cyclization conditions partially suppressed racemization, affording pyrimidine derivatives with 61.8–65.5% ee. These findings suggest that substrate structure influences stereochemical integrity during pyrimidine synthesis. Full article

(This article belongs to the Special Issue Advances in Heterocyclic Synthesis, 2nd Edition)

► Show Figures

Figure 1

34 pages, 3078 KB

Open AccessArticle

Development, Electrochemical Characterization, and Statistical Optimization of a Low-Cost Membraneless Tubular Flow-By Alkaline Electrolyzer for Green Hydrogen Production

by Bruno Augusto Cabral Roque, Hugo Morais Meira, Valdemir Alexandre dos Santos, Mohand Benachour and Leonie Asfora Sarubbo

Molecules 2026, 31(15), 2688; https://doi.org/10.3390/molecules31152688 (registering DOI) - 2 Aug 2026

Abstract

Hydrogen production by alkaline water electrolysis is a promising pathway for sustainable energy systems; however, conventional electrolyzers rely on membranes or diaphragms that increase cost, electrical resistance, and maintenance requirements. This study reports the development and experimental evaluation of a low-cost, membrane-less, flow-by [...] Read more.

Hydrogen production by alkaline water electrolysis is a promising pathway for sustainable energy systems; however, conventional electrolyzers rely on membranes or diaphragms that increase cost, electrical resistance, and maintenance requirements. This study reports the development and experimental evaluation of a low-cost, membrane-less, flow-by tubular alkaline electrolyzer integrated with a dedicated gas–liquid separation and volumetric gas-measurement system. The electrolyzer was designed, constructed, experimentally validated, and electrochemically characterized using polarization curves. The effects of KOH concentration (0.50–2.00 mol L⁻¹), electrolyte flow rate (1.00–4.00 L min⁻¹), and applied voltage (2.20–3.20 V) on hydrogen production were investigated through a full factorial 3³ experimental design combined with analysis of variance, response surface methodology, and numerical optimization using the desirability function. The applied voltage was identified as the dominant operating variable, followed by KOH concentration and electrolyte flow rate, while significant interactions involving voltage were also observed. The quadratic regression model showed excellent predictive performance (R² = 0.9614), and within the investigated operating domain, the highest hydrogen production rate was obtained at 2.00 mol L⁻¹ KOH, 1.00 L min⁻¹ electrolyte flow rate, and 3.20 V, resulting in an experimental hydrogen production rate of 0.4395 mL s⁻¹. These findings demonstrate the potential of the proposed membrane-less flow-by electrolyzer as a simplified, low-cost, and experimentally validated platform for investigating and optimizing membrane-less alkaline water electrolysis under the evaluated operating conditions. Full article

12 pages, 1380 KB

Open AccessArticle

Phytosteryl Esters Encapsulated in Liposomes as Bioactive Additives in Mayonnaise

by Magdalena Rudzińska, Joanna Igielska-Kalwat, Anna Grygier, Aleksander Siger and Anna Misiak

Molecules 2026, 31(15), 2687; https://doi.org/10.3390/molecules31152687 (registering DOI) - 2 Aug 2026

Abstract

Background: Phytosterols are natural compounds that provide health benefits by lowering LDL cholesterol levels, but they are susceptible to thermo-oxidative degradation during food storage and processing. Encapsulating them in liposomes could increase their stability and bioavailability. The aim of this study was [...] Read more.

Background: Phytosterols are natural compounds that provide health benefits by lowering LDL cholesterol levels, but they are susceptible to thermo-oxidative degradation during food storage and processing. Encapsulating them in liposomes could increase their stability and bioavailability. The aim of this study was to examine the stability of phytosterols encapsulated in liposomes during heating of mayonnaise at temperatures simulating storage and frying conditions. Methods: Mayonnaise containing 2, 4, 6, and 8% liposomes encapsulating stigmasterol oleate was prepared and heated at 60 °C for 8 h and at 180 °C for 30, 60, 90, and 120 min. The fat content, percentage composition of fatty acids and levels of oleic acid and stigmasterol were determined in each tested mayonnaise. Results: The fat content of mayonnaise with liposomes heated at 60 °C for 8 h was 97–98%. During heating at 180 °C for 60 min, it reached 100%, and after 120 min, it decreased to 75%. The oleic acid content of liposome-enriched mayonnaise remained stable during heating. The greatest loss of stigmasterol was observed in the control sample without liposomes, in which the sterol content decreased 79%. After heating mayonnaise with liposomes, the decrease in stigmasterol ranged from 3 to 25% at 60 °C for 8 h and from 90% to 100% at 180 °C for 90 and 120 min. Conclusions: Enriching mayonnaise with phytosterol esters encapsulated in liposomes can effectively improve the thermal-oxidative stability of plant sterols during short-term heating, but does not protect the product from the loss of these sterols during prolonged, intense heating. Full article

(This article belongs to the Special Issue Functional Foods Enriched with Natural Bioactive Compounds)

► Show Figures

Figure 1

39 pages, 28686 KB

Open AccessArticle

Investigations of the Molecular Nature of Low-Molecular-Mass Copper(II) Ion Complexes in Human Saliva: Physiological and Toxicological Significance

by Kayleigh Hunwin, Oliver Megram, Georgina Page, Wyman Chan, Nazmin Juma, Rachel Armitage, Olivia Steel, Katie Jane Hewitt and Martin Grootveld

Molecules 2026, 31(15), 2686; https://doi.org/10.3390/molecules31152686 (registering DOI) - 1 Aug 2026

Abstract

Copper is an essential trace element that plays critical roles in enzymatic processes and cellular metabolism. However, excessive exposure to its ions can lead to toxicity through oxidative stress mechanisms. Therefore, the chemical ‘speciation’ of copper(II) ions (Cu(II)) in biological fluids such as [...] Read more.

Copper is an essential trace element that plays critical roles in enzymatic processes and cellular metabolism. However, excessive exposure to its ions can lead to toxicity through oxidative stress mechanisms. Therefore, the chemical ‘speciation’ of copper(II) ions (Cu(II)) in biological fluids such as saliva is of critical importance. However, currently this phenomenon remains poorly understood, despite its importance for our understanding of bioavailability, toxicity, and sensory perception. Therefore, this study employed ¹H nuclear magnetic resonance (NMR) spectroscopy, Fourier-transform infrared attenuated total reflectance (FTIR-ATR) spectroscopy, and scanning electron microscopy (SEM) to investigate the molecular nature and complexation characteristics of low-molecular-mass Cu(II) complexes formed in human whole mouth salivary supernatant (WMSS) samples. Findings obtained revealed that Cu(II) ions form distinct complexes with salivary biomolecules, particularly amino acids such as histidine and glutamine, aromatic metabolites, proteins, and further small organic biomolecules, e.g., carboxylic acid anions. These results provide new insights into copper speciation in the oral cavity, with implications for dietary Cu(II) ion availability, metallic taste perception, and potential toxicological risks associated with elevated oral exposure levels. Full article

(This article belongs to the Special Issue NMR and MRI in Materials Analysis: Opportunities and Challenges)

► Show Figures

Figure 1

11 pages, 343 KB

Open AccessArticle

Lanthanide Content and Adulteration Testing of Greek Honeydew and Nectar Honey

by Eleni C. Mazarakioti, Vassilios K. Karabagias, Sofia Karabournioti, Dimitrios G. Lazaridis, Anastasios Zotos, Angelos Patakas, Athanasios Ladavos and Ioannis K. Karabagias

Molecules 2026, 31(15), 2685; https://doi.org/10.3390/molecules31152685 (registering DOI) - 1 Aug 2026

Abstract

Given the scarce data in the literature regarding the lanthanide content of Greek monofloral honey, Sc (Scandium), Y (Yttrium), La (Lanthanum), Ce (Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium), Eu (Europium), Gd (Gadolinium), Tb (Terbium), Dy (Dysprosium), Ho (Holmium), Er (Erbium), Tm (Thulium), [...] Read more.

Given the scarce data in the literature regarding the lanthanide content of Greek monofloral honey, Sc (Scandium), Y (Yttrium), La (Lanthanum), Ce (Cerium), Pr (Praseodymium), Nd (Neodymium), Sm (Samarium), Eu (Europium), Gd (Gadolinium), Tb (Terbium), Dy (Dysprosium), Ho (Holmium), Er (Erbium), Tm (Thulium), Yb (Ytterbium), Lu (Lutetium) and Th (Thorium) were determined in honeydew and nectar honey, using inductively coupled plasma mass spectrometry (ICP-MS). Results showed that, in general, honeydew honey had a higher lanthanide content than nectar honey, even though the determined values were below the limit of quantification. Preliminary reference values in this case for pine honey were Ce (26.82 ± 21.49 ng/L) and La (15.25 ± 11.82 ng/L). Adulteration testing was also performed using elemental analysis coupled to isotope ratio mass spectrometry (EA-IRMS), where no adulteration with cheap sugars was detected. Factor analysis identified the principal lanthanides related to honey botanical origin, basically Ce, and the k-NN algorithm classified the samples, achieving a training classification rate of 81.8% and a hold-out classification rate of 76.5%. Even in low amounts, lanthanides may contribute to the botanical origin identification of monofloral honey. Full article

(This article belongs to the Collection Qualitative and Quantitative Analysis of Bioactive Natural Products)

► Show Figures

Figure 1

34 pages, 5265 KB

Open AccessArticle

Synthesis and Organocatalytic Activity of Imidazolidinone Organocatalysts

by Nejc Petek, Luka Ciber, Amalija Golobič, Andrej Mihevc, Franc Požgan, Jurij Svete, Bogdan Štefane and Uroš Grošelj

Molecules 2026, 31(15), 2684; https://doi.org/10.3390/molecules31152684 (registering DOI) - 31 Jul 2026

Abstract

A series of cis-5-arylmethyl-2-alkyl-3-methylimidazolidin-4-ones, prepared from arylmethyl-substituted α-amino acids, and a series of trans- and cis-2-(fluoromethyl)-2,3-dimethylimidazolidin-4-ones, derived from L-valine and L-leucine, were synthesized and fully characterized. Their catalytic activity was evaluated in the addition of 1-methylindole to cinnamaldehyde. Using the [...] Read more.

A series of cis-5-arylmethyl-2-alkyl-3-methylimidazolidin-4-ones, prepared from arylmethyl-substituted α-amino acids, and a series of trans- and cis-2-(fluoromethyl)-2,3-dimethylimidazolidin-4-ones, derived from L-valine and L-leucine, were synthesized and fully characterized. Their catalytic activity was evaluated in the addition of 1-methylindole to cinnamaldehyde. Using the cis-5-arylmethyl-2-alkyl-3-methylimidazolidin-4-one catalysts, enantioselectivities of up to 78% ee (S) were achieved. Notably, with the L-valine-derived cis-imidazolidinone organocatalyst, the highest reversal of stereoselectivity to date (92% ee, (R) at –43 °C) was observed. Full article

(This article belongs to the Special Issue Recent Advances in Asymmetric Synthesis: From Reagents to Reactions)

► Show Figures

Graphical abstract

21 pages, 2754 KB

Open AccessArticle

The Effect of Hybrid Convective–Infrared–Ultrasonic Drying on Selected Properties of Kale and Nutritional Value of Kale Bars

by Hanna Kowalska, Agnieszka Salamon, Jadwiga Wolska-Wilk, Małgorzata Chobot, Mariola Kozłowska, Klaudia Wieczorek, Agata Marzec and Jolanta Kowalska

Molecules 2026, 31(15), 2683; https://doi.org/10.3390/molecules31152683 (registering DOI) - 31 Jul 2026

Abstract

The study aimed to determine the content of biocompounds and the nutrient composition of dried kale (with/without blanching) and bars containing it (fresh/dried). Kale leaves and bars were dried using convection (CD), convection–infrared–ultrasonic (HD), and freeze-drying (FD) methods to obtain potential snacks. The [...] Read more.

The study aimed to determine the content of biocompounds and the nutrient composition of dried kale (with/without blanching) and bars containing it (fresh/dried). Kale leaves and bars were dried using convection (CD), convection–infrared–ultrasonic (HD), and freeze-drying (FD) methods to obtain potential snacks. The bar recipe consisted of 20% fresh kale (plus 30% water) or 10% dried kale (plus 40% water), 20% dried dates, 10% coconut flour, 10% flaxseed, and 10% hemp protein. Dried blanched kale contained from 524 to 618 mg of GAE/100 g d.m., which was 6.8–12.4% more than in unblanched kale, but about four times less in the bars. Similarly, blanched kale had a higher content of chlorophyll A + B and carotenoids. Both of these groups of compounds in blanched kale dried using the HD method were comparable to or slightly higher than in the raw material (approx. 932 and 174 mg/100 g d.m. of chlorophyll A + B and carotenoids, respectively), while in the bars their content was low, 34–64 and 7.6–13.2 mg/100 g d.m., respectively. The caloric content of the bars ranged from 325 to 348 kcal/100 g (1356 to 1452 kJ/100 g of product). Dried kale has proven to be a valuable snack due to its antioxidant content. In turn, the bars were rich in nutrients such as protein (approx. 14.4%), fat (approx. 9.3%), minerals (approx. 4.0%), carbohydrates (approx. 35.2%), and especially fiber (approx. 27.3%), which allows them to be classified as “high-fiber” products. Full article

(This article belongs to the Special Issue Advances in Physicochemical Properties of Innovative Food Products During Processing)

► Show Figures

Figure 1

24 pages, 17615 KB

Open AccessArticle

Synthesis and Antitumor Mechanism of Emodin-Derived Transition Metal Complexes

by Yumin Pan, Ying Rui, Biqun Zou, Xiaoteng Jing, Ruijie He, Jianyi Liang and Fangyao Li

Molecules 2026, 31(15), 2682; https://doi.org/10.3390/molecules31152682 (registering DOI) - 31 Jul 2026

Abstract

In this study, emodin was used as the starting material to synthesize two novel ligands, L1 and L2, containing bipyridine or phenanthroline moieties. Seven metal complexes (1–7) were obtained through coordination with Co, Rh, Ru, and Pt ions. Their structures [...] Read more.

In this study, emodin was used as the starting material to synthesize two novel ligands, L1 and L2, containing bipyridine or phenanthroline moieties. Seven metal complexes (1–7) were obtained through coordination with Co, Rh, Ru, and Pt ions. Their structures were confirmed via NMR, HRMS, UV–Vis, IR, HPLC and SC-XRD analyses. The MTT assay showed that L1 and complex 2 selectively inhibited HepG-2 cells, with IC₅₀ values of 8.77 μM and 6.10 μM, respectively. Both compounds exhibited stronger activity than cisplatin (9.05 μM) and low toxicity toward normal 293T cells. Mechanistic studies demonstrated that they induced G2/M phase arrest by regulating Cyclin B1 and P21 expression, which was accompanied by ROS and Ca²⁺ accumulation, mitochondrial membrane potential disruption, and activation of the Caspase-9/3 cascade. Complex 2 showed superior antitumor activity to L1, and this finding was further supported by molecular docking analysis. In sum, Rh(III) complex 2 was identified as a selective and mechanistically defined anti-hepatocellular carcinoma lead compound, providing a potential strategy for the development of natural product-based metal anticancer agents. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Anticancer Activities of Metal Complexes)

► Show Figures

Figure 1

9 pages, 260 KB

Open AccessArticle

Phosphodiesterase Type 5 Inhibitors as Chemical Hazards in Honey and Honey-Based Products

by Joanna Wojtacka

Molecules 2026, 31(15), 2681; https://doi.org/10.3390/molecules31152681 - 31 Jul 2026

Abstract

The processing of bee products has recently become more frequent due to the rapidly growing market and demand for healthy, natural, and functional food. Therefore, bee products, and above all honey, while maintaining the reputation of healthy and natural foods, become carriers of [...] Read more.

The processing of bee products has recently become more frequent due to the rapidly growing market and demand for healthy, natural, and functional food. Therefore, bee products, and above all honey, while maintaining the reputation of healthy and natural foods, become carriers of various additives. Their consumption without proper control, or not declaring their presence in the composition, may pose a significant hazard to human health and life. This study was based on data mining with the use of all accessible RASFF records. They were formatted to analyze all chemical hazards that have occurred in bee honey and have been noted by EU countries to support swift reaction by food safety authorities since 2014. Within 10 food categories presenting 13,295 records, 93 records applied to bee products, including 79 records that referred to honey, 65% (n = 51) of which related to chemical hazards. PDE-5 inhibitors, i.e., sildenafil and tadalafil, were identified 14 times during the last 6 years and were the second most numerous group of hazards in honey and honey-based products after VMPs. The periodically published results of market sample tests and the continuing trend of RASFF notifications of these compounds in honey and honey-based products may suggest an iceberg phenomenon that requires frequent and thorough inspections. Full article

(This article belongs to the Special Issue Bee Products: Physicochemical Properties, Bioactivities, and Health Benefits)

► Show Figures

Graphical abstract

17 pages, 815 KB

Open AccessArticle

Sequence-Controlled Synthesis of Heteroaryl-Substituted Decahydroacridine-1,8-diones: Comparative Evaluation of Preformed Enaminone and Multicomponent Routes

by Gökhan Özokan

Molecules 2026, 31(15), 2680; https://doi.org/10.3390/molecules31152680 - 31 Jul 2026

Abstract

Six 9-thienyl-10-aryl-substituted 3,3,6,6-tetramethyl-decahydroacridine-1,8-diones (5a–f) were prepared by two acid-mediated routes that used the same solvent, temperature, and reaction time. In the sequential route, preformed 5,5-dimethyl-3-(arylamino)cyclohex-2-enones were reacted with a heteroaryl aldehyde and dimedone; in the corresponding one-pot route, the [...] Read more.

Six 9-thienyl-10-aryl-substituted 3,3,6,6-tetramethyl-decahydroacridine-1,8-diones (5a–f) were prepared by two acid-mediated routes that used the same solvent, temperature, and reaction time. In the sequential route, preformed 5,5-dimethyl-3-(arylamino)cyclohex-2-enones were reacted with a heteroaryl aldehyde and dimedone; in the corresponding one-pot route, the arylamine, heteroaryl aldehyde, and two equivalents of dimedone were combined directly. The isolated yields of the product-forming second stage were 71–75%, corresponding to calculated overall two-step yields of 58.2–68.6% after accounting for the isolated enaminone-preparation yields. These overall yields remained higher than those of the one-pot procedure (40–47%), although the sequential protocol required an additional reaction, isolation, catalyst charge, and solvent-intensive operation. Structural assignments were based on the available IR, ¹H NMR, ¹³C NMR, and EI-MS data. Tetrahydroacridinone by-products 6a–c were isolated in 13–15% yields and showed diagnostic spectral changes relative to 5a–f, including loss of the C-9 methine resonance and appearance of a strongly deshielded aromatic proton at 9.17–9.21 ppm. Within the limitations of an operational preparative comparison, the product distribution is consistent with a sequence-control interpretation in which preformation of the β-enaminone favors the 1:1:2 aldehyde/amine/dimedone product, whereas simultaneous component activation permits competing Knoevenagel, xanthene-forming, and aromatization pathways. This study provides a practical synthesis of thienyl-substituted decahydroacridine-1,8-diones and a mechanistically cautious explanation for the reduced selectivity of the one-pot process. Full article

(This article belongs to the Special Issue Synthesis and Derivatization of Heterocyclic Compounds)

18 pages, 4457 KB

Open AccessArticle

Theoretical Insights into the Structures and Electronic Properties of Pure Germanium Anionic Ge_n⁻ Clusters and Lanthanum-Doped Neutral and Anionic Germanium LaGe_n^0/− Clusters (n = 10–20)

by Xueyan Dong, Zhefeng Zhang, Chenliang Hao and Jucai Yang

Molecules 2026, 31(15), 2679; https://doi.org/10.3390/molecules31152679 - 31 Jul 2026

Abstract

Doping provides an effective means to tailor the chemical properties of clusters and construct novel functional materials. However, the specific effects of rare-earth doping on the structural evolution and electronic properties of semiconductor clusters remain unclear. To address this, we systematically investigated the [...] Read more.

Doping provides an effective means to tailor the chemical properties of clusters and construct novel functional materials. However, the specific effects of rare-earth doping on the structural evolution and electronic properties of semiconductor clusters remain unclear. To address this, we systematically investigated the structures, growth patterns, electronic properties, and spectroscopic characteristics of Ge_n⁻ and LaGe_n^0/− clusters (n = 10–20) using the ABCluster global search method combined with the mPW2PLYP double-hybrid density functional. Notably, the global minimum (GM) structures of Ge_n⁻ (n = 12–20), confirmed based on calculated energies and measured photoelectron spectroscopy data, differ from previously reported structures. Starting from n = 12, the GM structure of the Ge_n⁻ cluster can be considered as formed by attaching an additional Ge_(n–9) or Ge_(n–10) subcluster to a capped tetragonal antiprism Ge₉ (or dicapped tetragonal antiprism Ge₁₀) subunit. The evolution pattern of LaGe_n (n = 10–19) clusters can be viewed as substitutional structures, in which a La atom substitutes one Ge atom in the Ge_(n+1)⁻ cluster. At n = 20, a cage-like structure is formed. For LaGe_n⁻ (n = 10–19), when n = 10–12 and 18, the structures are linked configurations, where the La atom connects two Ge subclusters. For the remaining clusters, although their global minimum structures tend toward linked configurations, they are fundamentally substitutional in nature. The GM structure of LaGe₂₀⁻ is an encapsulated configuration, with the La atom encapsulated at the center of the Ge cage. The average binding energies, relative stabilities, and HOMO–LUMO energy gaps of the clusters were evaluated. The photoelectron spectra of LaGe_n⁻ (n = 10–20) and the UV–vis absorption spectrum of the LaGe₂₀⁻ cluster were simulated. The results demonstrate that the LaGe₂₀⁻ superatom cluster with high Ih symmetry exhibits favorable optical properties, along with excellent chemical and thermodynamic stability, suggesting its potential as a promising building block for further exploration in optoelectronic-related applications. Full article

(This article belongs to the Section Computational and Theoretical Chemistry)

26 pages, 3586 KB

Open AccessArticle

Zero-Waste Conversion of Juglans regia and Allium sativum Biomass into Porous Carbons for Dye Removal and Recovery from Water

by Nevena Radivojević, Tamara Terzić, Tamara Lazarević-Pašti, Igor Pašti, Nebojša Potkonjak, Aleksa Luković, Jasmina Mušović and Vedran Milanković

Molecules 2026, 31(15), 2678; https://doi.org/10.3390/molecules31152678 - 31 Jul 2026

Abstract

Biomass-derived porous carbons are promising sustainable adsorbents for wastewater treatment. However, most reported materials require chemical activation, while the relationships between biomass precursor, pore structure, adsorption mechanism, and regeneration remain insufficiently understood. In this work, non-activated carbon materials were prepared from Juglans regia [...] Read more.

Biomass-derived porous carbons are promising sustainable adsorbents for wastewater treatment. However, most reported materials require chemical activation, while the relationships between biomass precursor, pore structure, adsorption mechanism, and regeneration remain insufficiently understood. In this work, non-activated carbon materials were prepared from Juglans regia (JR) and Allium sativum (AS) biomass by pyrolysis at 400 and 900 °C and evaluated for the removal of methylene blue (MB), rhodamine B (RB), crystal violet (CV), and malachite green (MG). Carbonization at 900 °C markedly enhanced porosity, yielding a surface area of 790 m² g⁻¹ for JR900 and 177 m² g⁻¹ for AS900, together with predominantly microporous structures and negatively charged surfaces at neutral pH. The pseudo-second-order model best described adsorption kinetics, while intraparticle diffusion analysis indicated a multistep adsorption process. Equilibrium data were well fitted by both Langmuir and Freundlich isotherm models. JR900 exhibited the highest adsorption capacities for MB (321 mg g⁻¹) and RB (304 mg g⁻¹), whereas AS900 showed superior performance toward MG (278 mg g⁻¹). Stable dynamic filtration, efficient regeneration, and nearly complete dye recovery demonstrate the potential of these non-activated biomass-derived carbons for sustainable dye removal and recovery from water. Full article

(This article belongs to the Special Issue Advances in the Detection and Removal of Organic Residue from Water)

► Show Figures

Graphical abstract

30 pages, 5384 KB

Open AccessArticle

Eco-Friendly Synthesis, Physicochemical Characterization, and In Vitro Biological Evaluation of Plant-Derived Bioactive-Loaded Chitosan Nanoparticles Supported by Molecular Modeling Studies

by Ajwa, Fatma Hussain, Amer Jamil, Bilal Aslam, Piotr Weber, Jacek Nowaczyk and Alicja Nowaczyk

Molecules 2026, 31(15), 2677; https://doi.org/10.3390/molecules31152677 - 31 Jul 2026

Abstract

Silybum marianum (SM) is a rich source of flavonolignans with promising antioxidant and antidiabetic properties; however, its therapeutic application is limited by poor stability and bioavailability. This study combined experimental and computational approaches to develop and evaluate SM-loaded chitosan nanoparticles (CS–SM nanoparticles). Microwave-assisted [...] Read more.

Silybum marianum (SM) is a rich source of flavonolignans with promising antioxidant and antidiabetic properties; however, its therapeutic application is limited by poor stability and bioavailability. This study combined experimental and computational approaches to develop and evaluate SM-loaded chitosan nanoparticles (CS–SM nanoparticles). Microwave-assisted extraction followed by LC-MS/MS profiling identified eleven metabolites, including major flavonolignans characteristic of SM. Nanoparticles prepared by ionic gelation exhibited favorable physicochemical properties, including a particle size of 173–189 nm, a polydispersity index of 0.23, a zeta potential of +41.5 mV, an encapsulation efficiency of 98%, and a drug loading capacity of 50%, indicating the formation of a stable colloidal delivery system. CS–SM nanoparticles showed enhanced antioxidant, anti-inflammatory, and α-amylase inhibitory activities compared with crude extracts. The formulation exhibited an α-amylase IC₅₀ value of approximately 0.40 mg/mL and maintained low hemolytic activity, suggesting favorable preliminary biocompatibility. Molecular docking demonstrated favorable interactions of neosilyhermin A, silibinin, and silyhermin with α-amylase and α-glucosidase active sites. Short-timescale molecular dynamics simulations revealed ligand-dependent behavior within the chitosan–TPP matrix, indicating different release tendencies among the investigated flavonolignans. Overall, the results support CS–SM nanoparticles as a promising platform for the delivery of bioactive phytochemicals with antioxidant and antidiabetic potential. Full article

► Show Figures

Figure 1

27 pages, 492 KB

Open AccessReview

Intravaginal Formulation Strategies for Vaginal Disorders: Optimizing Phytochemical and Biological Preparations—A Review

by Ji Hye Hwang and Eun-Young Nam

Molecules 2026, 31(15), 2676; https://doi.org/10.3390/molecules31152676 - 31 Jul 2026

Abstract

Recurrent vaginal disorders remain a significant clinical challenge despite available antimicrobial and hormonal therapies. Therefore, natural, probiotic, and biological intravaginal preparations have been investigated as locally delivered adjunctive or supportive approaches for infectious, inflammatory, and atrophic vaginal conditions, with growing attention to how [...] Read more.

Recurrent vaginal disorders remain a significant clinical challenge despite available antimicrobial and hormonal therapies. Therefore, natural, probiotic, and biological intravaginal preparations have been investigated as locally delivered adjunctive or supportive approaches for infectious, inflammatory, and atrophic vaginal conditions, with growing attention to how dosage form, mucosal retention, drug release, and patient acceptability influence clinical utility. This structured narrative review of 119 studies across six databases synthesizes clinical evidence for phytochemical-based and biological intravaginal preparations, organized into five formulation categories: creams and gels, suppositories and vaginal tablets, douches and washes, probiotic preparations, and combined phytochemical–biological preparations. Across formulation types, creams and gels were associated with application convenience and local symptom relief, whereas suppositories and vaginal tablets offered longer mucosal contact, dosing precision, and sustained exposure. Herbal intravaginal preparations were the most diverse, encompassing traditional medicine-derived creams, gels, suppositories, tablets, washes, and fumigation-based approaches. Among these, Zataria multiflora- and Sophora flavescens-based formulations were supported by comparatively consistent clinical signals. Probiotic preparations provided an important microbiome-directed model, whereas combined phytochemical–biological preparations remained preliminary. These findings support moving beyond active ingredient selection toward intravaginal formulation optimization. However, heterogeneity in formulations, comparators, outcome measures, and follow-up durations limited direct comparisons across studies. Full article

(This article belongs to the Section Natural Products Chemistry)

► Show Figures

Graphical abstract

38 pages, 1478 KB

Open AccessReview

From Aquatic Pollution to Drinking-Water Exposure: Analytical Challenges in Detecting Nanoplastics in Drinking Water—A PRISMA-Guided Review

by José Roberto Vega-Baudrit, Mary Lopretti and Felipe Orozco

Molecules 2026, 31(15), 2675; https://doi.org/10.3390/molecules31152675 - 31 Jul 2026

Abstract

Nanoplastics (NPs) in drinking water should be interpreted as the downstream analytical endpoint of a broader continuum of aquatic plastic pollution rather than as an isolated problem. Their detection remains analytically immature because environmentally relevant concentrations are low, particle chemistries are heterogeneous, natural [...] Read more.

Nanoplastics (NPs) in drinking water should be interpreted as the downstream analytical endpoint of a broader continuum of aquatic plastic pollution rather than as an isolated problem. Their detection remains analytically immature because environmentally relevant concentrations are low, particle chemistries are heterogeneous, natural colloids and treatment residuals interfere with measurement, and no single method can simultaneously resolve size, morphology, polymer identity, and mass concentration. Unlike occurrence-centered reviews, this PRISMA-guided review treats drinking-water nanoplastics as a metrological and molecular-identification problem in which preprocessing, particle-level confirmation, polymer-specific quantification, and uncertainty reporting must be integrated. A formal search was closed on 11 April 2026 using prespecified query families across publicly accessible scholarly records and backward citation chaining; 33 unique records were screened, 25 full texts were assessed, and 22 studies were included in the qualitative synthesis. Current evidence indicates that conventional FTIR and routine Raman workflows are inadequate for true nanoscale analysis, whereas advanced Raman-based approaches, AFM-IR, optical photothermal infrared spectroscopy, surface-enhanced Raman spectroscopy, and pyrolysis-gas chromatography-mass spectrometry offer complementary strengths but still have major limitations in throughput, particle-level information, or quantification. The main conclusion is that current uncertainty reflects unresolved analytical chemistry and metrological constraints as much as environmental variability. Regulatory progress will depend on orthogonal workflows, contamination-controlled preprocessing, validated reference materials, LOD/LOQ reporting, and interlaboratory harmonization. Full article

(This article belongs to the Special Issue Advances in Microplastics and Nanoplastics Analysis, 2nd Edition)

► Show Figures

Figure 1

51 pages, 23194 KB

Open AccessReview

Progress in the Synthesis of Organoselenium Compounds: Conventional Routes Versus Green Approaches

by Chintankumar Padariya and Anita Kornicka

Molecules 2026, 31(15), 2674; https://doi.org/10.3390/molecules31152674 - 31 Jul 2026

Abstract

Organoselenium chemistry has progressed from the early synthesis of simple selenoorganic molecules in the 20th century to advanced methodologies aligned with the principles of green chemistry. Conventional synthetic approaches, frequently dependent on hazardous reagents and organic solvents, are increasingly being replaced by environmentally [...] Read more.

Organoselenium chemistry has progressed from the early synthesis of simple selenoorganic molecules in the 20th century to advanced methodologies aligned with the principles of green chemistry. Conventional synthetic approaches, frequently dependent on hazardous reagents and organic solvents, are increasingly being replaced by environmentally benign strategies, including solvent-free reactions, aqueous and bio-based solvent systems, microwave-assisted synthesis, and mechanochemical techniques. These sustainable methodologies offer significant advantages, such as enhanced reaction efficiency, higher or comparable yields, reduced waste generation, improved safety, and lower environmental impact. In parallel, evolving regulatory standards and industrial practices are encouraging the adoption of greener synthetic protocols to minimize hazardous waste and support safer pharmaceutical manufacturing. This review systematically categorizes organoselenium compounds, highlighting their synthetic methodologies, structural characteristics, and biological activities. Overall, recent advances emphasize the therapeutic potential of organoselenium compounds and demonstrate the essential role of sustainable synthetic chemistry in the development of future medicinal agents. Full article

(This article belongs to the Special Issue Recent Progress in the Field of Sulfur and Selenium Organic Chemistry)

► Show Figures

Graphical abstract

30 pages, 2209 KB

Open AccessArticle

ICP-MS Elemental Profiling and Antioxidant Characterization of Romanian Artisanal Pălincă-Based Beverages Enriched with Honey, Wild Fruits, and Wood Materials

by Petrică Tudor Moțiu, Mariana Florica Bei, Ioana Andra Vlad, Szilárd Bartha, Voichița Timiş-Gânsac, Călin Gheorghe Pășcuț, Laviniu Ioan Nuțu Burescu, Eliza Maria Agud, Eugen Traian Jude, Alexandru Ioan Apahidean, Anamaria Călugăr, Adrian Tunduc and Florin Dumitru Bora

Molecules 2026, 31(15), 2673; https://doi.org/10.3390/molecules31152673 - 31 Jul 2026

Abstract

Traditional Romanian Pălincă is a protected fruit spirit obtained from fermented fruit matrices, whereas honey- and botanical-enriched Pălincă-based beverages require integrated compositional and technological characterization. This study investigated the physicochemical, chromatic, antioxidant, and ICP-MS elemental profiles of experimental beverages prepared from grape- and [...] Read more.

Traditional Romanian Pălincă is a protected fruit spirit obtained from fermented fruit matrices, whereas honey- and botanical-enriched Pălincă-based beverages require integrated compositional and technological characterization. This study investigated the physicochemical, chromatic, antioxidant, and ICP-MS elemental profiles of experimental beverages prepared from grape- and plum-based Pălincă distillates enriched with honey, blackthorn, rosehip, or wood-associated materials under controlled artisanal conditions. Chemometric tools were applied to evaluate ingredient- and process-related differentiation, while target hazard quotient and hazard index calculations were retained as a concise screening-level elemental safety assessment. Honey enrichment produced the strongest compositional changes, mainly reflected by increased soluble solids, conductivity, turbidity, chromatic intensity, and mineral content, together with lower final alcoholic strength. Fruit-macerated and mixed honey-botanical beverages were associated with higher phenolic content and antioxidant activity. ICP-MS profiling highlighted potassium as the dominant macroelement, while Cu, Fe, Zn, and Mn were the main technological trace elements. Potentially toxic elements remained at low concentrations, and the screening-level THQ/HI assessment indicated low non-carcinogenic elemental risk under the applied exposure scenario. Overall, the results show that ICP-MS elemental profiling can support the technological and ingredient-related differentiation of experimental Pălincă-based beverages, while toxicological interpretation should remain limited to elemental exposure screening. Full article

(This article belongs to the Special Issue Chemistry, Bioactivity and Authenticity of Sugar-Rich and Fermented Foods and Beverages)

► Show Figures

Figure 1

16 pages, 255 KB

Open AccessArticle

Changes in the Profile of Phytochemicals During Processing of Durum Pasta Fortified with Broccoli Leaf Powder and Its Effect on Bioactive Properties

by Natalia Drabińska-Fois, Mariana Nogueira, Paulina Nowicka, Maja Jeż, Joanna Honke, Cristina Manis and Anna Michalska-Ciechanowska

Molecules 2026, 31(15), 2672; https://doi.org/10.3390/molecules31152672 - 31 Jul 2026

Abstract

Broccoli processing generates large quantities of leaves that remain underutilized despite being rich in bioactive compounds. Their valorization as a functional ingredient aligns with sustainable food production and offers an opportunity to enhance the nutritional quality of cereal-based foods. This study evaluated the [...] Read more.

Broccoli processing generates large quantities of leaves that remain underutilized despite being rich in bioactive compounds. Their valorization as a functional ingredient aligns with sustainable food production and offers an opportunity to enhance the nutritional quality of cereal-based foods. This study evaluated the impact of broccoli leaf powder (BLP) fortification (2.5 and 5%) on the phytochemical composition and functional properties of durum pasta under three drying regimes. BLP introduced glucosinolates, flavonols, carotenoids, and chlorophylls that were absent in the control samples, and their contents increased proportionally with the fortification level. The drying regime modulated compound stability, with low-temperature drying generally favoring retention, whereas cooking caused up to a 50% loss of glucosinolate, depending on the processing conditions. Functional properties were markedly enhanced by BLP addition. The 5% fortification level showed the greatest improvement, resulting in the highest antioxidant activity, antiglycation potential, and angiotensin-converting enzyme (ACE)-inhibitory activity compared to the control pasta. Antioxidant, antiglycation, and ACE-inhibitory activities increased proportionally with the fortification level, and although drying reduced some activities, the fortified pasta consistently outperformed the control. Among the tested formulations, pasta enriched with 5% BLP showed the most favorable overall functional and bioactive compound profiles. Overall, broccoli leaves represent a valuable by-product for developing nutritionally enriched pasta, and the processing conditions play a key role in shaping the stability and bioactivity of the incorporated compounds. Full article

(This article belongs to the Special Issue Functional Foods Enriched with Natural Bioactive Compounds)

Journal Description

Molecules

Latest Articles

Journal Menu

Journal Browser

Highly Accessed Articles

Latest Books

E-Mail Alert

News

Topics

Conferences

Special Issues

Topical Collections

Further Information

Guidelines

MDPI Initiatives

Follow MDPI