Molecules

30 pages, 1138 KB

Open AccessReview

Recent Advances in Ent-Abietane Diterpenes: Natural Sources, Biological Activities and Total Synthesis

by Lu Li, Yongjie Zhu, Haixia Deng, Liqiong Xie, Chang-Bo Zheng, Jian-Neng Yao and Ji Li

Molecules 2026, 31(1), 98; https://doi.org/10.3390/molecules31010098 (registering DOI) - 25 Dec 2025

Ent-abietane diterpenoids constitute a class of terpenes with a C₂₀ carbon skeleton that underlie a wide range of biological activities. Ent-abietane diterpenoids, enantiomeric to the abietane counterparts, represent a family of diterpenoid natural products characterized by their distinct [...] Read more.

Ent-abietane diterpenoids constitute a class of terpenes with a C₂₀ carbon skeleton that underlie a wide range of biological activities. Ent-abietane diterpenoids, enantiomeric to the abietane counterparts, represent a family of diterpenoid natural products characterized by their distinct 6/6/6 tricyclic carbocyclic skeletons with exceptional structural complexity. An increasing number of these ent-abietane diterpenoids have recently been identified, constituting a well-defined group of naturally occurring compounds. This review provides a comprehensive summary of the natural sources, chemical structures, biological profiles and total synthesis of these ent-abietane diterpenoids from 2016 to early 2025. Full article

(This article belongs to the Special Issue Trends of Drug Synthesis in Medicinal Chemistry)

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18 pages, 901 KB

Open AccessArticle

Multifunctional NADES-Based Extracts from Paeonia lactiflora Pall. Flowers for Potential Cosmetic and Pharmaceutical Applications

by Carla Villa, Eleonora Russo, Anna Maria Schito, Francesco Saverio Robustelli della Cuna, Cristina Sottani, Marta Barabino and Debora Caviglia

Molecules 2026, 31(1), 97; https://doi.org/10.3390/molecules31010097 (registering DOI) - 25 Dec 2025

Abstract

Paeonia lactiflora Pall. is a perennial herbaceous plant widely renowned for its floral ornamental appeal, distinctive pleasant scent, and utilization in folk remedies. Roots and barks are traditionally used in Chinese medicine for various properties, including anti-inflammatory, antioxidant, antibacterial, anticancer, cardiovascular, and neuroprotective [...] Read more.

Paeonia lactiflora Pall. is a perennial herbaceous plant widely renowned for its floral ornamental appeal, distinctive pleasant scent, and utilization in folk remedies. Roots and barks are traditionally used in Chinese medicine for various properties, including anti-inflammatory, antioxidant, antibacterial, anticancer, cardiovascular, and neuroprotective effects. Considering the growing interest and demand in the pharmaceutical and cosmetic fields for sustainable and bioactive botanical derivatives, this study aimed to apply NADES (natural deep eutectic solvents) extraction on fresh flowers of Paeonia lactiflora Pall. The purpose was to obtain a natural, multifunctional, and ready-to-use cosmetic ingredient with concurrent antioxidant activity, antimicrobial functionalities, and olfactive properties. The eutectic systems selected in this study were composed of betaine as the hydrogen bond acceptor and glycerol and/or sorbitol as the hydrogen bond donors. These eutectic systems under microwave activation led to a rapid extraction, from peony fresh flowers, of considerable phenolic amounts (from 33.0 to 34.4 mg of gallic acid equivalents per gram of fresh flowers), which confer to the whole NADES-based extract an excellent radical scavenging activity (around 87.5%, compared to Trolox) and a pleasant fragrance, due to the extraction of some characteristic volatile compounds, as confirmed by GC-MS analysis. Antimicrobial assays against different Gram-positive and Gram-negative strains demonstrated good inhibitory activity of the sample against multidrug-resistant Staphylococcus species (MIC ranging from 0.9 to 14.5 mg/mL) and against Enterococcus species (from 28.8 to 57.8 mg/mL). Furthermore, results on different Staphylococcus aureus strains disclosed additional interesting anti-biofilm properties. Preliminary long-term studies (up to 9 months) on these combined properties highlighted the stabilizing effect of NADESs on the active metabolites, confirming their potential as natural and functional ingredients that could be directly incorporated into pharmaceutical and cosmetic formulations, offering enhanced efficacy and improved stability. Full article

(This article belongs to the Special Issue Deep Eutectic Solvents for the Extraction of Bioactive Compounds from Natural Sources)

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15 pages, 3511 KB

Open AccessArticle

Oxygen Bridge Governs OER via Deep Self-Reconstruction in Fe–Co Oxyhydroxides

by Mingyu Liu, Bowen Pei, Hongyu Ba, Wei Ni, Huaheng Zhao, Shuang Chen, Jiamin Zhao and Jinsheng Zhao

Molecules 2026, 31(1), 96; https://doi.org/10.3390/molecules31010096 (registering DOI) - 25 Dec 2025

Abstract

The oxygen evolution reaction (OER) in water splitting involves complex multi-electron–proton transfer processes and represents the rate-determining step limiting overall electrolysis efficiency. Developing non-noble-metal catalysts with high activity and stability is therefore essential. Herein, a heterogeneous synthesis strategy was employed to in situ [...] Read more.

The oxygen evolution reaction (OER) in water splitting involves complex multi-electron–proton transfer processes and represents the rate-determining step limiting overall electrolysis efficiency. Developing non-noble-metal catalysts with high activity and stability is therefore essential. Herein, a heterogeneous synthesis strategy was employed to in situ construct an iron-rich layered sulfate precursor (Fe_0.42Co_0.58-SO₄/NF) on nickel foam, which underwent deep self-reconstruction in alkaline electrolyte to form nanoflower-like Fe_0.42Co_0.58OOH/NF. The optimized catalyst maintained its iron-rich composition and hierarchical structure, delivering outstanding OER performance with an overpotential of 220 mV at 10 mA·cm⁻², a Tafel slope of 31.9 mV·dec⁻¹, and stability exceeding 12 h at 600 mA·cm⁻². Synchrotron analyses revealed dynamic transitions between mono-μ-O and di-μ-O Fe–M (M = Fe, Co) oxygen bridges during reconstruction, which enhanced both structural robustness and active-site density. The Fe-rich environment promoted the formation of Fe³⁺–O–Fe³⁺ units that synergized with Co⁴⁺ species to activate the lattice oxygen mechanism (LOM), thereby accelerating OER kinetics. This work elucidates the key role of oxygen-bridge geometry in optimizing catalytic activity and durability, providing valuable insights into the rational design of Fe–Co-based non-noble-metal catalysts with high iron content for efficient water oxidation. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Electrocatalysis)

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17 pages, 1956 KB

Open AccessReview

Cork By-Products as Bioactive Ingredients: From Waste Valorization to Pharmaceutical Prototypes

by Nuno Miguel Silva, Ana Colette Maurício, Ruben Fernandes and Ana Novo Barros

Molecules 2026, 31(1), 95; https://doi.org/10.3390/molecules31010095 (registering DOI) - 25 Dec 2025

Abstract

The pharmaceutical sector has evolved toward innovation-driven and sustainability-oriented development, driven by increasing regulatory pressure and global health challenges. In this context, cork (Quercus suber L.) has emerged as a promising bio-based resource due to its renewable nature, near-zero-waste processing chain, and [...] Read more.

The pharmaceutical sector has evolved toward innovation-driven and sustainability-oriented development, driven by increasing regulatory pressure and global health challenges. In this context, cork (Quercus suber L.) has emerged as a promising bio-based resource due to its renewable nature, near-zero-waste processing chain, and growing evidence of biological activity. Cork by-products are rich in phenolic compounds, triterpenes, lignin derivatives, and other secondary metabolites exhibiting antioxidant, anti-inflammatory, and anti-aging properties, with relevance for pharmaceutical and dermocosmetic applications. These bioactivities are associated with the modulation of oxidative stress, inhibition of pro-inflammatory signaling pathways, and support of skin barrier function. This review provides an updated and focused overview of the chemical composition, bioactive potential, and valorization pathways of cork by-products, with particular emphasis on their translation into pharmaceutical and dermocosmetic formulations. Key challenges related to extraction standardization, bioavailability, safety, and clinical validation are critically discussed, highlighting future directions for the sustainable development of cork-derived bioactive ingredients within circular bioeconomy frameworks. Full article

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

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15 pages, 1882 KB

Open AccessArticle

The Influence of the Capping Step During Solid-Phase Phosphoramidite Synthesis of Oligonucleotides on Synthetic Errors in Oligonucleotides

by Kristina I. Yakovleva, Ivan M. Pereverzev, Andrey A. Kechin, Ulyana A. Boyarskikh, Maxim L. Filipenko, Georgiy Y. Shevelev, Yuliya V. Sherstyuk and Ilya S. Dovydenko

Molecules 2026, 31(1), 94; https://doi.org/10.3390/molecules31010094 (registering DOI) - 25 Dec 2025

Abstract

Errors in de novo synthesized DNA can originate from the oligonucleotides used during assembly. Oligonucleotides may contain substitutions, deletions, and insertions resulting from either incomplete reactions at individual steps of the phosphoramidite synthetic cycle or various side reactions. In this study, we quantitatively [...] Read more.

Errors in de novo synthesized DNA can originate from the oligonucleotides used during assembly. Oligonucleotides may contain substitutions, deletions, and insertions resulting from either incomplete reactions at individual steps of the phosphoramidite synthetic cycle or various side reactions. In this study, we quantitatively assessed errors in both gene constructs assembled from synthetic oligonucleotides by Sanger sequencing and in synthetic oligonucleotides by NGS. Our data demonstrate that side reactions involving carboxylic acid anhydrides during the capping step of oligonucleotide synthesis lead to the modification of guanine residues. This guanine modification subsequently results in the accumulation of G to A substitutions in the final gene constructs. We show that the error rate can be reduced by replacing the standard acetic anhydride-based capping mixture with anhydrides of carboxylic acids weaker than acetic acid. Furthermore, a more significant reduction in errors is achievable by using capping reagents based on phosphoramidite chemistry. Full article

(This article belongs to the Special Issue 10th Anniversary of the Bioorganic Chemistry Section of Molecules)

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16 pages, 1159 KB

Open AccessReview

Molecular Imaging Advances in Endometriosis: The Promise of Radiopharmaceuticals

by Rebecca Napolitano, Giorgia Speltri, Petra Martini, Francesca Porto, Lorenza Marvelli, Alessandro Niorettini, Licia Uccelli, Luca Urso, Luca Filippi, Hatice Uslu, Burak Canitez, Hamza Alperen Kösem and Alessandra Boschi

Molecules 2026, 31(1), 93; https://doi.org/10.3390/molecules31010093 (registering DOI) - 25 Dec 2025

Abstract

Endometriosis is a highly prevalent, chronic gynecological disorder characterized by the ectopic presence of endometrial-like tissue, driving significant morbidity and chronic pelvic pain. Pathologically, it is increasingly recognized as a fibro-inflammatory condition involving extensive tissue remodeling and fibrosis. Current conventional imaging modalities, including [...] Read more.

Endometriosis is a highly prevalent, chronic gynecological disorder characterized by the ectopic presence of endometrial-like tissue, driving significant morbidity and chronic pelvic pain. Pathologically, it is increasingly recognized as a fibro-inflammatory condition involving extensive tissue remodeling and fibrosis. Current conventional imaging modalities, including ultrasound and MRI, are primarily morphological, while standard molecular imaging using Positron Emission Tomography (PET) tracers has shown limited diagnostic utility. [¹⁸F]Fluorodeoxyglucose (FDG) suffers from high physiological uptake in pelvic organs and inconsistent detection of lesions. Receptor-based tracers like [⁶⁸Ga]Ga-DOTATATE have demonstrated uncertain efficacy. In contrast, radiopharmaceuticals targeting the Fibroblast Activation Protein (FAP) offer a promising molecular approach. FAP is specifically overexpressed by activated fibroblasts present in the stroma of endometriotic lesions, correlating significantly with tissue fibrosis (collagen content) and local immune infiltration (e.g., CD68 macrophages). This comprehensive review analyzes the landscape of radiopharmaceuticals for endometriosis imaging, contrasting the specific limitations of traditional metabolic and receptor agents with the molecular rationale and emerging evidence supporting the use of FAP Inhibitors (FAPI), positioning them as crucial, non-invasive tools for the future diagnosis and management of this challenging disease. Full article

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15 pages, 7295 KB

Open AccessArticle

Atomistic Insights into the Molecular Interactions of Rod and Cluster Shaped CdS for Photocatalytic Water Splitting

by Aliya Assilbekova, Irina Irgibaeva, Mirat Karibayev, Ayaulym Amankeldiyeva, Sergei Piskunov, Nurlan Almas, Galiya Baisalova and Anuar Aldongarov

Molecules 2026, 31(1), 92; https://doi.org/10.3390/molecules31010092 (registering DOI) - 25 Dec 2025

Abstract

Understanding the atomic-level behavior of photocatalysts under hydrated conditions is essential for improving hydrogen production efficiency. In this work, density functional theory calculations and classical all-atom molecular dynamics simulations were performed to investigate the intra- and intermolecular interactions of rod- and cluster-shaped cadmium [...] Read more.

Understanding the atomic-level behavior of photocatalysts under hydrated conditions is essential for improving hydrogen production efficiency. In this work, density functional theory calculations and classical all-atom molecular dynamics simulations were performed to investigate the intra- and intermolecular interactions of rod- and cluster-shaped cadmium sulfide in the presence of implicit and explicit water, respectively. The density functional theory optimized geometries, reduced density gradient, noncovalent interaction, critical point, and molecular electrostatic potential maps were examined using the LC-ωPBE functional with the LANL2DZ basis set and the IEFPCM implicit solvation model, while explicit hydration was modeled via classical all-atom molecular dynamics simulations by obtaining molecular snapshots and radial distribution functions. Density functional theory results revealed that rod-shaped cadmium sulfide exhibits stronger directional bonding and higher electronic localization compared to cluster-shaped cadmium sulfide, while classical all-atom molecular dynamics simulations showed that water molecules preferentially interact with surface S atoms of cadmium sulfide sites. This atomistic insight clarifies how morphology and hydration jointly modulate cadmium sulfide electronic structure and reactivity, providing guidance for the rational design of efficient cadmium sulfide-based photocatalysts for solar-driven water splitting. Full article

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15 pages, 7052 KB

Open AccessArticle

Molecular Dynamics Simulation of Texture Contact Friction Between Crystalline Silicon Layers for Application in Micro-Nano System Devices

by Jinping Zhang, Minghui Tan, Shan Yuan, Fei Wang, Yu Jia and Xiaolei Wang

Molecules 2026, 31(1), 91; https://doi.org/10.3390/molecules31010091 (registering DOI) - 25 Dec 2025

Abstract

Silicon is commonly used in micro/nano-electromechanical system (MEMS/NEMS) devices. Because detailed information about the friction interface in these systems is lacking, the relationship between texture shape and friction remains unclear. In this study, molecular dynamics simulations were performed to investigate the dry-friction tribological [...] Read more.

Silicon is commonly used in micro/nano-electromechanical system (MEMS/NEMS) devices. Because detailed information about the friction interface in these systems is lacking, the relationship between texture shape and friction remains unclear. In this study, molecular dynamics simulations were performed to investigate the dry-friction tribological behavior of crystalline silicon, focusing on the effects of surface roughness, normal load, and sliding speed. The results show that between normal loads of 4 GPa and 8 GPa, the average frictional force exhibits significant nonlinear behavior under a sliding speed of 0.2 Å/ps. The approximate steady value of the friction coefficient is 0.39, which is in good agreement with the experimental result of 0.37. Under a normal load of 5 GPa, the friction force increases linearly from 110 nN at 0.05 Å/ps to 311 nN at 2 Å/ps. In addition, in systems with sinusoidal surface roughness, the amplitude has a greater effect on the frictional properties than the period. Among the four rough surfaces studied, A10T32 exhibits the lowest friction force and friction coefficient. This provides theoretical support for the further design of MEMS/NEMS devices with long operational lifetimes. Full article

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17 pages, 811 KB

Open AccessArticle

Targeted Determination of Residual Sex Hormones in Cosmetics Using Magnetic Solid-Phase Extraction with Isotope-Labeled Internal Standards by UHPLC-MS/MS

by Yalei Dong, Shuyan Sun, Yasen Qiao, Chunhui Yu, Haiyan Wang and Lei Sun

Molecules 2026, 31(1), 90; https://doi.org/10.3390/molecules31010090 (registering DOI) - 25 Dec 2025

Abstract

As rapidly developing consumer products, cosmetics confront challenges regarding safety, especially hazardous ingredients, like sex hormones. Prolonged exposure to trace sex hormones in cosmetics can inflict immeasurable damage to human health. To accurately detect the trace amounts of sex hormones in cosmetics, a [...] Read more.

As rapidly developing consumer products, cosmetics confront challenges regarding safety, especially hazardous ingredients, like sex hormones. Prolonged exposure to trace sex hormones in cosmetics can inflict immeasurable damage to human health. To accurately detect the trace amounts of sex hormones in cosmetics, a reliable method was developed and validated using ultra-high performance liquid chromatography–mass spectrometry (UHPLC-MS/MS) with magnetic solid-phase extraction (MSPE) and isotope-labeled internal standards (IL-ISs). The conditions of sample pretreatment, chromatography, and mass parameters were systemically investigated. In the MSPE procedure, the commercial Fe₃O₄@HLB magnetic material was employed for sample pretreatment, which was beneficial for operation, as well as sample purification and analyte enrichment. The utilization of IL-ISs compensated for potential matrix effects and losses during sample preparation, thereby improving precision and accuracy. Based on the proposed MSPE technology, UHPLC-MS/MS can address the qualitative and quantitative analysis needs for target analytes in complex cosmetic matrices. At three fortification levels, recoveries were in the range of 71.7–116.2%, with a relative standard deviation (RSD) ranging from 1.6% to 8.3%. Furthermore, based on the method proposed here, a total of 116 batches of cosmetics were analyzed, and trace progestins and estrogens were discovered in 10 samples. The MSPE method, coupled with UHPLC-MS/MS using IL-ISs, was convenient, efficient, and feasible for detecting trace amounts of sex hormones in cosmetics. The method scored 0.66 (out of 1) on the AGREE metric, confirming its green profile. Based on the detected concentrations, a preliminary safety evaluation was performed to assess the potential health risks of residual progesterone in hair loss prevention cosmetics by calculating the margin of safety (MoS). Full article

(This article belongs to the Section Analytical Chemistry)

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20 pages, 5523 KB

Open AccessArticle

Synthesis and Magnetic and Optical Properties of Novel Fe@ZSM-5 Composites

by Irina A. Zvereva, Denis A. Pankratov, Elena G. Zemstova, Vladimir K. Kudymov, Azamat Samadov, Sergey A. Kurnosenko, Sergey O. Kirichenko, Marina G. Shelyapina and Vitalii Petranovskii

Molecules 2026, 31(1), 89; https://doi.org/10.3390/molecules31010089 (registering DOI) - 25 Dec 2025

Abstract

Alkaline treatment in 0.2 and 0.4 M NaOH solutions successfully generated controlled mesoporosity into ZSM-5 (Zeolite Socony Mobil-5) zeolite, resulting in average mesopore diameters of approximately 15 and 25 nm, respectively, while preserving the crystalline structure of the zeolite framework. Parent ZSM-5 and [...] Read more.

Alkaline treatment in 0.2 and 0.4 M NaOH solutions successfully generated controlled mesoporosity into ZSM-5 (Zeolite Socony Mobil-5) zeolite, resulting in average mesopore diameters of approximately 15 and 25 nm, respectively, while preserving the crystalline structure of the zeolite framework. Parent ZSM-5 and its mesoporous derivatives obtained by desilication were used to prepare (Fe species)@(zeolite matrix) composites. The synthesis was carried out by co-precipitating Fe²⁺/Fe³⁺ ions onto both parent and desilicated ZSM-5 matrices under oxygen-free conditions. Comprehensive characterization by X-ray diffraction, scanning electron microscopy, N₂ adsorption, vibrating-sample magnetometry, ⁵⁷Fe Mössbauer spectroscopy, and diffuse reflectance UV–Vis spectroscopy revealed that the degree of introduced mesoporosity dramatically influences the size, dispersion, phase composition, and oxidation state of the iron-containing nanospecies. On purely microporous ZSM-5, relatively large (~15 nm) partially oxidized magnetite nanoparticles are formed predominantly on the external surface, exhibiting superparamagnetism at room temperature (Mₛ = 11 emu/g) and a band gap of 2.12 eV. Increasing mesoporosity leads to progressively smaller and more highly dispersed iron(III) oxo/hydroxo clusters with significantly lower blocking temperatures and reduced magnetization (down to 0.7 emu/g for Fe@ZSM-5_0.4). All composites display strong visible-light absorption confirming their potential as magnetically separable visible-light-driven photocatalysts for environmental remediation. Full article

(This article belongs to the Special Issue Synthesis and Application of Multifunctional Nanocomposites)

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29 pages, 3159 KB

Open AccessArticle

Energy-Dependent Effects of Pulsed Electric Field (PEF) Treatment on the Quality Attributes, Bioactive Compounds, and Microstructure of Red Bell Pepper

by Katarzyna Rybak, Aleksandra Skarżyńska, Szymon Ossowski, Magdalena Dadan, Katarzyna Pobiega and Małgorzata Nowacka

Molecules 2026, 31(1), 88; https://doi.org/10.3390/molecules31010088 (registering DOI) - 25 Dec 2025

Abstract

This study evaluated the energy-dependent effects of pulsed electric field (PEF) treatment on the physicochemical properties, bioactive compounds, antioxidant activity, and microstructure of red bell pepper (Capsicum annuum L.). Red bell pepper tissue was treated at specific energy inputs ranging from 1 [...] Read more.

This study evaluated the energy-dependent effects of pulsed electric field (PEF) treatment on the physicochemical properties, bioactive compounds, antioxidant activity, and microstructure of red bell pepper (Capsicum annuum L.). Red bell pepper tissue was treated at specific energy inputs ranging from 1 to 10 kJ/kg and compared with a fresh (untreated sample). The cell disintegration index (CDI) increased progressively with PEF energy, confirming enhanced membrane permeabilization and structural disruption. Structural analyses (SEM and micro-CT) confirmed the formation of pores and interconnected channels, particularly at moderate and high energies. PEF treatment caused a decrease in total polyphenols and flavonoids, whereas vitamin C and total carotenoid contents increased at intermediate energies. Antioxidant activity (ABTS, DPPH, FRAP) declined overall but remained at comparable levels for mild PEF exposure. A significant reduction in firmness was observed (from 17% to 27% compared with the untreated control), and color changes were dependent on the energy input, while microstructural degradation intensified as the energy level approached 10 kJ/kg. PEF treatment improved microbial stability, resulting in a measurable reduction in total viable counts and yeast and mold counts, particularly at higher energy inputs. FTIR, TGA, and NMR data confirmed molecular alterations without degradation of major components. Multivariate analysis (dendrogram, PCA) distinguished four characteristic response groups: fresh, low-energy (1–2 kJ/kg), moderate-energy (4–5 kJ/kg), and high-energy (10 kJ/kg). PEF treatment selectively modified red bell pepper tissue, enhancing permeabilization and carotenoid/vitamin C release while preserving visual quality at mild–moderate energies. These results demonstrate the potential of PEF as a nonthermal technique for tailoring the structural and functional properties of plant-based products. Full article

(This article belongs to the Special Issue Anti-inflammatory and Antioxidant Activities of Bioactive Compounds in Plants)

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22 pages, 631 KB

Open AccessArticle

Multifaceted Evaluation of Paliurus spina-christi Mill. Plant, Seeds, and Oils: Hydrogen Cyanide, Phytochemical, Bioactive, and Antimicrobial Insights from Türkiye Ecotypes

by Rabiya Safiye Çelebi and Erman Duman

Molecules 2026, 31(1), 87; https://doi.org/10.3390/molecules31010087 (registering DOI) - 25 Dec 2025

Abstract

This investigation comparatively examined the toxicological, chemical, phytochemical, and antimicrobial characteristics of Paliurus spina-christi Mill. seeds and their oils collected over two consecutive years from four distinct locations in Türkiye. In the seeds, HCN levels ranged from 1.11 to 1.43 g/kg and total [...] Read more.

This investigation comparatively examined the toxicological, chemical, phytochemical, and antimicrobial characteristics of Paliurus spina-christi Mill. seeds and their oils collected over two consecutive years from four distinct locations in Türkiye. In the seeds, HCN levels ranged from 1.11 to 1.43 g/kg and total phenolics from 6.84 to 15.48 mg GAE/g, while quinic, gallic, protocatechlic, and tannic acids, along with cosmosiin, were identified as the main phenolics in the phenolic profile. In the seed oils, α-tocopherol content ranged from 2178.5 to 2528.4 mg/kg, total phenolics from 96.99 to 118.87 mg GAE/g, and antioxidant activity from 0.147 to 0.150 mg TE/g. β-Sitosterol predominated among sterols (61.51–66.51%). Macrominerals P, S, K, and Ca and microminerals Si, Pt, Pd, Ge, and Sn were present in notable amounts. An antimicrobial activity test revealed the bacteriostatic effects of the seed oils. In conclusion, this study elucidates the toxicological, chemical, phytochemical, and antimicrobial attributes of P. spina-christi seeds and oils, showing that the proportions of the identified bioactive components varied according to harvest year and location. Based on this data, it is recommended that further research is conducted in the future regarding the potential use of P. spina-christi seeds/seed oil for human nutrition, in terms of standardization, bioavailability, and clinical validation. Full article

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32 pages, 18311 KB

Open AccessReview

Magnetic Microrobots for Drug Delivery: A Review of Fabrication Materials, Structure Designs and Drug Delivery Strategies

by Jin Shi, Yanfang Li, Dingran Dong, Junyang Li, Tao Wen, Yue Tang, Qi Zhang, Fei Pan, Liqi Yan, Duanpo Wu and Shaowei Jiang

Molecules 2026, 31(1), 86; https://doi.org/10.3390/molecules31010086 (registering DOI) - 25 Dec 2025

Abstract

Magnetic microrobots have emerged as a promising platform for drug delivery in recent years. By enabling remotely controlled motion and precise navigation under external magnetic fields, these systems offer new solutions to overcome the limitations of traditional drug delivery nanocarriers, such as inadequate [...] Read more.

Magnetic microrobots have emerged as a promising platform for drug delivery in recent years. By enabling remotely controlled motion and precise navigation under external magnetic fields, these systems offer new solutions to overcome the limitations of traditional drug delivery nanocarriers, such as inadequate tissue penetration and heterogeneous biodistribution. Over the past few years, significant advancements have been made in the structural design of magnetic microrobots, as well as in drug loading techniques and stimuli-responsive drug release mechanisms, thereby demonstrating distinct advantages in enhancing therapeutic efficacy and targeting precision. This review provides a comprehensive overview of magnetic drug delivery microrobots, which are categorised into biomimetic structural, bio-templated and advanced material-based types, and introduces their differences in propulsion efficiency and biocompatibility. Additionally, drug loading and release strategies are summarised, including physical adsorption, covalent coupling, encapsulation, and multistimuli-responsive mechanisms such as pH, enzyme activity and thermal triggers. Overall, these advancements highlight the significant potential of magnetic microrobots in targeted drug delivery and emphasise the key challenges in their clinical translation, such as biological safety, large-scale production and precise targeted navigation within complex biological environments. Full article

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39 pages, 4489 KB

Open AccessArticle

High-Resolution ¹H NMR Investigation of the Speciation Status of Nickel(II) and Copper(II) Ions in a Cell Culture Medium: Relevance to Their Toxicological Actions

by Deepinder K. Kalra, Kayleigh Hunwin, Katie Hewitt, Olivia Steel and Martin Grootveld

Molecules 2026, 31(1), 85; https://doi.org/10.3390/molecules31010085 (registering DOI) - 24 Dec 2025

Abstract

Copper and nickel ions play pivotal, albeit distinct, roles as essential trace elements in living systems, and primarily serve as co-factors for a range of enzymes. However, as with all trace metal ions, excessive concentrations can exert adverse toxicological properties. Interestingly, the incorporation [...] Read more.

Copper and nickel ions play pivotal, albeit distinct, roles as essential trace elements in living systems, and primarily serve as co-factors for a range of enzymes. However, as with all trace metal ions, excessive concentrations can exert adverse toxicological properties. Interestingly, the incorporation of these in cell culture media can establish novel chemical interactions, with their speciation status markedly influencing characteristics, including cell maturation, and cellular uptake mechanisms. Thus, the primary objective of this study was to investigate and determine the speciation status (i.e., complexation) of nickel(II) and copper(II) ions by biomolecules present in RPMI 1640 mammalian cell culture medium using virtually non-invasive high-resolution proton NMR analysis, an investigation of much relevance to now routine studies of their toxicological actions towards cultured cells. Samples of the above aqueous culture medium were ¹H NMR-titrated with increasing added concentrations of 71–670 µmol/L Ni(II)(aq.), and 0.71–6.7, 7.1–67 and 71–670 µmol/L Cu(II)(aq.), in duplicate or triplicate. ¹H NMR spectra were acquired on a JEOL ECZ-600 spectrometer at 298 K. Results demonstrated that addition of increasing concentrations of Ni(II) and Cu(II) ions to the culture medium led to the selective broadening of a series of biomolecule resonances, results demonstrating their complexation by these agents. The most important complexants for Ni(II) were histidine > glutamine > acetate ≈ methionine ≈ lysine ≈ threonine ≈ branched-chain amino acids (BCAAs) > asparagine ≈ aspartate > tyrosine ≈ tryptophan, whereas for Cu(II) they were found to be histidine > glutamine > phenylalanine ≈ tyrosine ≈ nearly all remaining aliphatic metabolites (particularly the wealth of amino acids detectable) > 4-hydroxyphenylacetate (trace culture medium contaminant), in these orders. However, Cu(II) had the ability to influence the linewidths of these signals at much lower added levels (≤7 µmol/L) than that of Ni(II), the broadening effects of the latter occurring at concentrations which were approximately 10-fold greater. Virtually all of these added metal ion-induced resonance modifications were, as expected, reversible on addition of equivalent or excess levels of the chelator EDTA. From this study, changes in the co-ordination sphere of metal ions in physiological environments can give rise to marked modifications in their physicochemical properties (e.g., redox potentials, electronic charges, the potential catalytic generation of reactive oxygen species (ROS), and cell membrane passages). Moreover, given that the above metabolites may also function as potent hydroxyl radical (^●OH) scavengers, these findings suggest that generation of this aggressively reactive oxidant directly from Cu(II) and Ni(II) ions in physiologically-relevant complexes may be scavenged in a ‘site-dependent’ manner. This study is of further relevance to trace metal ion research in general since it enhances our understanding of the nature of their interactions with culture medium biomolecules, and therefore provides valuable information regarding their overall chemical and biological activities, and toxicities. Full article

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20 pages, 861 KB

Open AccessArticle

Photokinetics of Bimolecular Reactions: Analytically Solvable Rate Laws

by Mounir Maafi

Molecules 2026, 31(1), 84; https://doi.org/10.3390/molecules31010084 - 24 Dec 2025

Abstract

Light-induced bimolecular reactions occur in many naturally and artificially (laboratory or industrial) designed processes. The quantification of these reactions is generally performed by kinetics. In particular, the kinetic data of bimolecular photoreactions are often treated by second-order kinetic models. If this situation is [...] Read more.

Light-induced bimolecular reactions occur in many naturally and artificially (laboratory or industrial) designed processes. The quantification of these reactions is generally performed by kinetics. In particular, the kinetic data of bimolecular photoreactions are often treated by second-order kinetic models. If this situation is effectively ubiquitous in practice, it remains that the underlying hypothesis, assuming that photoreactions obey the same kinetics as thermal transformations, is not consistent with the physical photosystem considered. In fact, it has been proven that unimolecular (mono-reactant) photoreactions are effectively modelled by Φ-order kinetics. The latter model is formalised by a logarithmic function bearing an exponential in its argument. Hence, Φ-order kinetics is mathematically different from the thermal reaction models. In the case of the bimolecular photoreactions that are described by different rate laws than those used for the thermal reactions, i.e., involving both radiation intensity and light absorption, there have been no reported solutions in the literature that were based on analytical integration. So much so, no kinetic order has ever been assigned to any bimolecular photoreaction. In the current situation, it is perhaps sensible to proceed, in a first step, by defining among the bimolecular photoreactions those whose rate laws can be solved analytically and establish the corresponding solutions by closed-form integration. Following such a strategy, the present paper unravels the first model equations for the kinetics of bimolecular photoreactions. The findings are part of an effort to standardise photokinetics along the same principles used in thermal kinetics. Full article

(This article belongs to the Section Photochemistry)

11 pages, 2290 KB

Open AccessArticle

4,5-Dihydro-2H-pyridazin-3-ones as a Platform for the Construction of Chiral 4,4-Disubstituted-dihydropyridazin-3-ones

by Paul Joël Henry, Gabriel Burel, William Nzegge, Mario Waser and Jean-François Brière

Molecules 2026, 31(1), 83; https://doi.org/10.3390/molecules31010083 - 24 Dec 2025

Abstract

4,5-Dihydro-2H-pyridazin-3-ones (DHPDOs) are important synthetic as well as naturally occurring heterocycles. We herein report the synthesis of various 4-monofunctionalized 4,5-dihydro-2H-pyridazin-3-ones and their use as starting materials to access 4,4-disubstituted dihydropyridazin-3-ones in an asymmetric fashion. By using chiral ammonium salt [...] Read more.

4,5-Dihydro-2H-pyridazin-3-ones (DHPDOs) are important synthetic as well as naturally occurring heterocycles. We herein report the synthesis of various 4-monofunctionalized 4,5-dihydro-2H-pyridazin-3-ones and their use as starting materials to access 4,4-disubstituted dihydropyridazin-3-ones in an asymmetric fashion. By using chiral ammonium salt phase-transfer catalysts, conjugate additions of these scaffolds to classical acrylate-based Michael acceptors, as well as quinone methides, can be carried out with moderate to good enantioselectivities and in reasonable yields, affording a new pathway to dihydropyridazin-3-one derivatives with an all-carbon stereocenter. Full article

(This article belongs to the Special Issue Feature Papers in Organic Chemistry—Third Edition)

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34 pages, 2080 KB

Open AccessReview

Introduction and Extension of the Unified Theory of Multicenter Bonding: The Role of the Charge-Shift Bonding

by Francisco Javier Manjón, Hussien H. Osman, Álvaro Lobato, Fernando Izquierdo-Ruiz, Enrico Bandiello, Samuel Gallego-Parra, Ángel Vegas, Matteo Savastano and Alfonso Muñoz

Molecules 2026, 31(1), 82; https://doi.org/10.3390/molecules31010082 - 24 Dec 2025

Abstract

Classical chemical bonding is typically categorized into primary, strong interactions, such as covalent, ionic, and metallic bonds, and secondary, weak interactions, such as van der Waals forces, the hydrogen bond, and their likes (halogen bond, chalcogen bond, etc.). However, other not-so-known bonding mechanisms [...] Read more.

Classical chemical bonding is typically categorized into primary, strong interactions, such as covalent, ionic, and metallic bonds, and secondary, weak interactions, such as van der Waals forces, the hydrogen bond, and their likes (halogen bond, chalcogen bond, etc.). However, other not-so-known bonding mechanisms also play a crucial role in chemical systems. Particularly important are the charge-shift bond (CSB) and the multicenter bonds, i.e., the electron-rich multicenter bond (ERMB), also known as hypervalent or three-center-four-electron (3c-4e) bond, and the electron-deficient multicenter bond (EDMB), also known as the three-center-two-electron (3c-2e) bond in molecules and, more recently, as the two-center-one-electron (2c-1e) bond in extended solids. We consider that these latter interactions have not yet received the proper attention of the scientific community, even though multicenter interactions were proposed in the early days of Quantum Mechanics. In this work, we aim at providing: (i) a concise historical overview of the two types of multicenter bonds; (ii) a short introduction to the recently proposed unified theory of multicenter bonding (UTMB), which elucidates the origin and mechanisms of formation of both ERMBs and EDMBs; and (iii) an extension of the UTMB to include CSBs, due to the strong relationship between ERMBs and CSBs. We hope that the integrated perspective of chemical bonding, the heartland of chemistry, offered by the UTMB (beyond traditional and historical assumptions) will help researchers to understand materials properties and will provide a framework allowing the development of advanced materials for enhanced technological applications. Full article

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

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34 pages, 579 KB

Open AccessReview

Albizia amara: A Potential Plant-Derived Surfactant for Cosmetic and Food Applications

by Yalini Sadasivam, Valerie J. Pinfield and Anna Trybala

Molecules 2026, 31(1), 81; https://doi.org/10.3390/molecules31010081 - 24 Dec 2025

Abstract

Surfactants are essential in cosmetic and food formulations but are still dominated by petrochemical-derived anionic systems associated with irritation, aquatic toxicity and sustainability concerns. Plant-derived saponins offer renewable, biodegradable alternatives, yet only a small subset of saponin-producing species has been developed into commercial [...] Read more.

Surfactants are essential in cosmetic and food formulations but are still dominated by petrochemical-derived anionic systems associated with irritation, aquatic toxicity and sustainability concerns. Plant-derived saponins offer renewable, biodegradable alternatives, yet only a small subset of saponin-producing species has been developed into commercial ingredients. The genus Albizia is chemically diverse and widely used in traditional medicine, with several species empirically employed as cleansers. This review examines Albizia amara and related Albizia species as prospective sources of plant-derived surfactants for cosmetic and food applications. We summarise ethnobotanical and phytochemical data with emphasis on saponins, flavonoids and macrocyclic alkaloids, and collate the limited quantitative evidence for surface activity, focusing on foaming behaviour, surface tension reduction and shampoo-type formulations, where A. procera provides the main interfacial benchmark within the genus. Potential roles of A. amara-derived fractions in hair-care products and prospective food systems are discussed alongside current knowledge on toxicity, safety and regulatory constraints. Overall, A. amara emerges as a promising but under-characterised saponin source. Priority areas for future work include robust tensiometric characterisation, surfactant-focused extraction and fractionation, systematic formulation studies, and dedicated safety and sustainability assessments to enable evidence-based evaluation against established plant and synthetic surfactants. Full article

(This article belongs to the Special Issue Foam and Emulsion Systems: Stability, Rheology, and Applications)

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12 pages, 2502 KB

Open AccessArticle

Diurnal and Daily Changes in the Levels of Sesquiterpene Lactone and Other Components in Lettuce Post-Harvest

by Kazuaki Kamata, Hitomi Okada and Yukari Ohta

Molecules 2026, 31(1), 80; https://doi.org/10.3390/molecules31010080 - 24 Dec 2025

Abstract

Lettuce, which contains sesquiterpene lactones that have been associated with anti-inflammatory and sedative properties, also appears to harbor bitter ingredients such as lactucopicrin, often found abundantly in the emulsion released from the cut core. Previous reports suggest that lettuce may gradually increase in [...] Read more.

Lettuce, which contains sesquiterpene lactones that have been associated with anti-inflammatory and sedative properties, also appears to harbor bitter ingredients such as lactucopicrin, often found abundantly in the emulsion released from the cut core. Previous reports suggest that lettuce may gradually increase in bitterness post-harvest, possibly reflecting alterations in the composition of its components during shelf life. Therefore, analyzing changes in the concentrations of these components could contribute to the development of methods for evaluating lettuce freshness. In this study, we examined variations in sugar contents and hydrophilic oxygen radical absorbance capacity values in lettuce leaves, refined an analytical approach for sesquiterpene lactones in the lettuce core, and explored how their levels may differ depending on harvest timing within the same day and across the storage period. High-resolution LC-MS analysis was employed to estimate the levels of key components such as cichorioside B, 11β,13-dihydrolactucin, lactucin, and lactucopicrin. While the emulsion is generally considered to contain substantial amounts of lactucopicrins, relatively little information is available about the components present in the lettuce core. Our current findings indicate that cichorioside B may be a predominant bitter component in the core. Collectively, these results may provide a basis for developing approaches to assess lettuce freshness and monitor compositional changes during storage. Full article

(This article belongs to the Special Issue Natural Bioactive Compounds from Traditional Asian Plants—Second Edition)

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