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Molecules

Molecules is a leading international, peer-reviewed, open access journal of chemistry published semimonthly online by MDPI. The International Society of Nucleosides, Nucleotides & Nucleic Acids (IS3NA), Spanish Society of Medicinal Chemistry (SEQT) and International Society of Heterocyclic Chemistry (ISHC) are affiliated with Molecules and their members receive discounts on the article processing charges.

Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
High Visibility: indexed within Scopus, SCIE (Web of Science), PubMed, MEDLINE, PMC, Reaxys, CaPlus / SciFinder, MarinLit, AGRIS, and other databases.
Journal Rank: JCR - Q2 (Biochemistry and Molecular Biology) / CiteScore - Q1 (Organic Chemistry)
Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 15.1 days after submission; acceptance to publication is undertaken in 2.6 days (median values for papers published in this journal in the second half of 2025).
Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Sections: published in 25 topical sections.
Testimonials: See what our editors and authors say about Molecules.
Companion journal: Foundations.
Journal Cluster of Chemical Reactions and Catalysis: Catalysts, Chemistry, Electrochem, Inorganics, Molecules, Organics, Oxygen, Photochem, Reactions, Sustainable Chemistry.

Impact Factor: 4.6 (2024); 5-Year Impact Factor: 5.0 (2024)

Imprint Information Journal Flyer Open Access ISSN: 1420-3049

Latest Articles

49 pages, 2568 KB

Open AccessReview

Procyanidins: Structural Properties, Production Methods, and Modern Applications

by Aleksandr Yu. Zakharov, Dmitriy Berillo, Annie Ng, Damir S. Aidarkhanov, Anna V. Tukesheva, Kamila M. Temirkulova, Ainur Tanybayeva, Zulkhair A. Mansurov, Mannix P. Balanay and Vladimir V. Pavlenko

Molecules 2026, 31(2), 223; https://doi.org/10.3390/molecules31020223 (registering DOI) - 8 Jan 2026

Procyanidins, a class of substances widely distributed in nature, have attracted the attention of the scientific community due to their bioactive properties, especially with regard to human health. This review is based on an extensive examination of peer-reviewed literature, patents, and clinical trial [...] Read more.

Procyanidins, a class of substances widely distributed in nature, have attracted the attention of the scientific community due to their bioactive properties, especially with regard to human health. This review is based on an extensive examination of peer-reviewed literature, patents, and clinical trial reports published between 2005 and 2025. From an initial pool of more than 300 documents, 283 studies were selected according to criteria of scientific rigor, methodological clarity, and relevance to the research objectives. A literature search was performed using PubMed, PubChem, Google Scholar, Scopus and ResearchGate employing keywords such as Procyanidins, chemical structure, extraction, and health effects. This article provides a comprehensive overview of current methods for obtaining these compounds, which include both natural sources and synthetic approaches. It provides a concise summary of the molecular structure of procyanidins and emphasizes the importance of understanding their conformational features for predicting biological activity. The challenges of establishing correlations between the structural features of procyanidins and their properties are described. In addition, this article explores the many potential applications of these compounds, spanning both biochemistry and the field of design and synthesis of novel materials. This review provides a comprehensive evaluation of Procyanidins, focusing on their geometrical conformation analysis through advanced NMR spectroscopy techniques including homonuclear correlation (COSY, TOCSY), heteronuclear one-bond (HSQC, HMQC), multiple-bond (HMBC) experiments, and through-space correlation (NOESY) in conjunction with various extraction methodologies. Full article

(This article belongs to the Special Issue Flavonoids’ and Other Polyphenols’ Pharmacological Activities for Phytopharmaceutical and Medicinal Applications, 2nd Edition)

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11 pages, 870 KB

Open AccessArticle

The Modification of Nitrogen to Modulate Perovskite for the Application of p-Type Transparent Conductive Oxides

by Yunting Liang, Kaihua Li, Haixu Chen, Yinling Wang, Shasha Zheng and Liuyang Bai

Molecules 2026, 31(2), 222; https://doi.org/10.3390/molecules31020222 (registering DOI) - 8 Jan 2026

Due to the strong electronegativity of oxygen ions, the valence band maximum (VBM) that is derived from the O 2p orbital leads to strong localization, as well as further heavy hole mass and low hole mobility, which makes it extremely difficult to obtain [...] Read more.

Due to the strong electronegativity of oxygen ions, the valence band maximum (VBM) that is derived from the O 2p orbital leads to strong localization, as well as further heavy hole mass and low hole mobility, which makes it extremely difficult to obtain high-conductivity p-type transparent conductive materials. Herein, we propose the strategy of multiple anions through the introduction of weaker electronegative nitrogen, in consideration of the delocalization on VBM, as well as the stability of octahedral anion cages. As such, first-principles calculations in the framework of density functional theory (DFT) are used for this work. Crystal structure prediction software USPEX (version 2023.0) was adopted to investigate the N-O appropriate ratio in CaTiO_3−xN_x (0 ≤ x ≤ 1) to balance the high transmission of light and highly favorable dispersion at the VBM. Furthermore, the p-type TCO performance of CaTiO_3-xN_x was evaluated based on the hole effective mass, hole mobility, and conductivity. The effectiveness of modulating p-type TCO through N-O multiple anions was also evaluated through defect formation energy and ionization energy. Ultimately, the construction of a CaTiO_3-xN_x/Si heterojunction and band alignment were considered for practical application. This approach attempts to boost the diversity of p-type perovskite-based TCOs and opens a new perspective for engineering and innovative material design for sustainable TCOs demand. Full article

22 pages, 10960 KB

Open AccessArticle

Huisgen Cycloaddition of Azidoazulenes: Synthesis, Structural and Optical Properties of 2- and 6-(1,2,3-Triazol-1-yl)azulenes

by Taku Shoji, Miku Yoshida, Masayuki Iwabuchi, Mitsuki Furuhata, Shigeki Mori, Tetsuo Okujima, Ikumi Uchiyama, Ryuta Sekiguchi and Shunji Ito

Molecules 2026, 31(2), 221; https://doi.org/10.3390/molecules31020221 - 8 Jan 2026

We developed an efficient and modular route to 2- and 6-(1,2,3-triazol-1-yl)azulenes to expand the synthetic accessibility and functional scope of azulene-based π-systems with stimulus-responsive photophysics. Readily accessible 2- and 6-azidoazulenes, prepared in excellent yields via S_NAr reactions of haloazulenes, were subjected [...] Read more.

We developed an efficient and modular route to 2- and 6-(1,2,3-triazol-1-yl)azulenes to expand the synthetic accessibility and functional scope of azulene-based π-systems with stimulus-responsive photophysics. Readily accessible 2- and 6-azidoazulenes, prepared in excellent yields via S_NAr reactions of haloazulenes, were subjected to Cu(I)-catalyzed Huisgen [3 + 2] cycloaddition with a broad range of terminal alkynes to afford the corresponding triazolylazulenes in good to high yields, followed by acid-mediated decarboxylation and Staudinger reduction to enable further diversification to 2-azulenyltriazoles and a 6-aminoazulene derivative. Single-crystal X-ray diffraction analysis revealed substitution-position-dependent torsional arrangements and variations in π-conjugation between the azulene and triazole units. Photophysical characterization by UV/Vis absorption and fluorescence spectroscopy showed pronounced halochromism under acidic conditions, and selected derivatives displayed substantially enhanced fluorescence quantum yields. Overall, these results establish the azulene–1,2,3-triazole motif as a versatile building block for designing optoelectronic π-systems with acid-responsive emission properties. Full article

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

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33 pages, 1180 KB

Open AccessArticle

Seasonal Variation in Wild Rosmarinus officinalis L.: Phytochemicals and Their Multifunctional Potential Against Metabolic Disorders

by Khaled Kherraz, Khalil Guelifet, Mokhtar Benmohamed, Luca Rastrelli, Latifa Khattabi, Afaf Khadra Bendrihem, Abderrazek Ferhat, Mohamed Amine Ferhat, Khaled Aggoun, Duygu Aygünes Jafari, Barbara Sawicka, Lilya Harchaoui, Wafa Zahnit, Azzeddine Zeraib and Mohammed Messaoudi

Molecules 2026, 31(2), 220; https://doi.org/10.3390/molecules31020220 - 8 Jan 2026

This investigation explored how seasonal variation affects the phytochemical composition and biological potential of Rosmarinus officinalis L., a widely used aromatic and medicinal plant. Aerial parts collected during spring, summer, autumn, and winter were extracted with ethanol and analyzed using LC-ESI-MS/MS, while total [...] Read more.

This investigation explored how seasonal variation affects the phytochemical composition and biological potential of Rosmarinus officinalis L., a widely used aromatic and medicinal plant. Aerial parts collected during spring, summer, autumn, and winter were extracted with ethanol and analyzed using LC-ESI-MS/MS, while total phenolic (TPC) and flavonoid (TFC) contents were determined spectrophotometrically. The extracts were evaluated for antioxidant, anti-inflammatory, enzyme inhibitory, analgesic, antimicrobial, cytotoxic, and photoprotective properties. Major constituents identified in all seasons included luteolin, kaempferol, rutin, and biochanin A. The autumn extract contained the highest phenolic (353.21 ± 4.05 µg GAE/mg) and flavonoid (190.11 ± 5.65 µg QE/mg) levels. Antioxidant assays revealed that the autumn extract had the strongest DPPH radical scavenging activity (IC₅₀ = 24.72 ± 0.16 µg/mL), while the spring extract exhibited the greatest reducing power (A_0.5 = 7.62 ± 0.30 µg/mL). The winter extract demonstrated superior anti-inflammatory activity (IC₅₀ = 28.60 ± 2.84 µg/mL), exceeding the reference drug diclofenac. Only the spring extract inhibited urease (IC₅₀ = 62.26 ± 0.58 µg/mL) and moderately inhibited α-amylase. All seasonal extracts showed notable photoprotective potential, with SPF values between 25.18 and 32.46, well above the recommended minimum. The spring extract also presented strong analgesic activity and no acute toxicity up to 2000 mg/kg. Antimicrobial effects were weak, limited to slight inhibition of Staphylococcus aureus, while moderate cytotoxicity was observed against MCF-7 and MDA-MB-231 breast cancer cells. Overall, seasonal variation significantly influenced the chemical profile and bioactivities of R. officinalis, with autumn and spring identified as the most suitable harvesting periods for pharmaceutical and cosmetic applications. Full article

(This article belongs to the Special Issue Phytochemicals as Valuable Tools for Fighting Metabolic Disorders)

17 pages, 7091 KB

Open AccessReview

Recent Advances in Erinacine A: Preparation, Biological Activities, and Biosynthetic Pathway

by Jingyuan Wang, Huan Liu, Chunlei Wang and Chengwei Liu

Molecules 2026, 31(2), 219; https://doi.org/10.3390/molecules31020219 - 8 Jan 2026

Erinacine A, a cyathane diterpenoid derived from the medicinal and edible fungus Hericium erinaceus, is increasingly recognized for its potent neurotrophic and neuroprotective properties. It demonstrates significant therapeutic promise for neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease, primarily by stimulating the [...] Read more.

Erinacine A, a cyathane diterpenoid derived from the medicinal and edible fungus Hericium erinaceus, is increasingly recognized for its potent neurotrophic and neuroprotective properties. It demonstrates significant therapeutic promise for neurodegenerative disorders, such as Alzheimer’s and Parkinson’s disease, primarily by stimulating the synthesis of nerve growth factor (NGF). However, the clinical applicability of erinacine A is currently restricted by its low yield from natural sources and high production costs. This challenge has spurred significant research focused on optimizing its production. This review provides a comprehensive overview of the current advancements in the fermentation-based preparation of erinacine A, including both liquid and solid-state cultivation techniques. Furthermore, we summarize its diverse biological activities, spanning neuroprotection, anticancer, and anti-inflammatory effects, and detail the recent discoveries elucidating its complex biosynthetic pathway. This consolidated overview offers insights into strategies for enhancing its production and supports its ongoing development as a therapeutic agent. Full article

(This article belongs to the Special Issue Bioactive Compounds and Small Molecules with Neuroprotective and Anti-Inflammatory Functions)

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17 pages, 3319 KB

Open AccessArticle

Study of Structural, Vibrational, and Molecular Docking Properties of (1S,9aR)-1-({4-[4-(Benzyloxy)-3-methoxyphenyl]-1H-1,2,3-triazol-1-yl}methyl)octahydro-2H-quinolizine

by Dastan Turdybekov, Zhangeldy Nurmaganbetov, Almagul Makhmutova, Dmitry Baev, Yury Gatilov, Dmitrii Pankin, Mikhail Smirnov, Pernesh Bekisheva and Kymbat Kopbalina

Molecules 2026, 31(2), 218; https://doi.org/10.3390/molecules31020218 - 8 Jan 2026

A promising direction for the creation of new biologically active derivatives of the alkaloid lupinine is the synthesis of “hybrid molecules” that combine a fragment of the alkaloid and the pharmacophore of 1,2,3-triazole in their structure. From a biological perspective, this work presents [...] Read more.

A promising direction for the creation of new biologically active derivatives of the alkaloid lupinine is the synthesis of “hybrid molecules” that combine a fragment of the alkaloid and the pharmacophore of 1,2,3-triazole in their structure. From a biological perspective, this work presents the first X-ray diffraction study of a single crystal of (1S,9aR)-1-({4-[4-(Benzyloxy)-3-methoxyphenyl]-1H-1,2,3-triazol-1-yl}methyl)octahydro-2H-quinolizine, a new, recently synthesized 1,2,3-triazole derivative of lupinine. A comparison of theoretically predicted and experimentally observed structural parameters was carried out. The FTIR spectroscopy study and vibrational properties calculations allowed us to interpret the FTIR absorption spectrum and localize specific vibrational modes in quinolizidine, 1,2,3-triazole, and benzene rings. Such information can be fruitful for further characterization of the synthesis process and products. The molecular docking of the compound was performed. It was shown that the studied molecules are capable of interacting with the Mpro binding site via non-covalent and hydrophobic interactions with subsites S3 (Met165, Glu166, Leu167, Pro168) and S5 (Gln189, Thr190, Gln192), which ensure the stabilization of the Mpro substrate. Blocking of the active site of the enzyme in the region of the oxyanion hole does not occur, but stable stacking interactions with the π-system of one of the catalytic amino acids, His41, are observed. Full article

(This article belongs to the Section Molecular Structure)

19 pages, 5577 KB

Open AccessArticle

Active Packaging Films from PBAT/PLA with Rosmarinus officinalis L. Extract: Antioxidant, UV-Shielding, and Compostable Properties

by Xiaoyan He, Lisheng Tang and Ran Huang

Molecules 2026, 31(2), 217; https://doi.org/10.3390/molecules31020217 - 8 Jan 2026

With the growing demand for eco-friendly food packaging, poly(butylene adipate-co-terephthalate) (PBAT)/polylactic acid (PLA) composite films have emerged as promising biodegradable alternatives, but their inherent limitations (e.g., poor antioxidant capacity, weak UV stability, and insufficient antimicrobial activity) hinder practical applications. This study aimed to [...] Read more.

With the growing demand for eco-friendly food packaging, poly(butylene adipate-co-terephthalate) (PBAT)/polylactic acid (PLA) composite films have emerged as promising biodegradable alternatives, but their inherent limitations (e.g., poor antioxidant capacity, weak UV stability, and insufficient antimicrobial activity) hinder practical applications. This study aimed to address these drawbacks by incorporating Rosmarinus officinalis L. extract (RM) as a natural multifunctional additive. PBAT/PLA/RM blend films with RM concentrations of 0.1%, 0.3%, 0.5%, and 1% were fabricated via melt extrusion and blown film processing. Key characterizations were conducted to evaluate thermal stability, mechanical properties, morphology, antioxidant activity, UV-shielding performance, antimicrobial efficacy, and biodegradability. The results showed that RM significantly enhanced the antioxidant capacity of the films, with the highest DPPH radical scavenging activity achieved at 0.3% RM. UV-blocking performance improved incrementally with increasing RM concentration, and films containing ≥0.5% RM filtered over 90% of UVA and UVB radiation. All composite films met biodegradability standards, with over 90% degradation observed after 240 days of composting, though RM prolonged the initial degradation stage by inhibiting early microbial activity. However, the antimicrobial effect of RM was limited, and concentrations exceeding 1% caused film stickiness, impeding processing. This work demonstrates that RM is a viable natural additive for functionalizing PBAT/PLA films, offering enhanced antioxidant and UV-shielding properties while maintaining biodegradability, thus providing a promising solution for sustainable food packaging. Full article

(This article belongs to the Special Issue Biobased Functional Materials for Sustainable Food Packaging and Preservation)

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1 pages, 130 KB

Open AccessCorrection

Correction: Dhiman et al. Rare Earth Doped ZnO Nanoparticles as Spintronics and Photo Catalyst for Degradation of Pollutants. Molecules 2023, 28, 2838

by Pooja Dhiman, Garima Rana, Amit Kumar, Elmuez A. Dawi and Gaurav Sharma

Molecules 2026, 31(2), 216; https://doi.org/10.3390/molecules31020216 - 8 Jan 2026

In the original publication [...] Full article

5 pages, 163 KB

Open AccessEditorial

Two-Dimensional Materials: From Synthesis to Applications, 2nd Edition

by Sake Wang, Nguyen Tuan Hung and Minglei Sun

Molecules 2026, 31(2), 215; https://doi.org/10.3390/molecules31020215 - 8 Jan 2026

Two-dimensional materials continue to redefine modern materials science by offering a unique combination of atomic-scale thickness, tunable electronic structures, and highly accessible surfaces [...] Full article

(This article belongs to the Section Materials Chemistry)

14 pages, 4071 KB

Open AccessArticle

From Functional Food to Therapeutic Prospect: Mechanistic Study of Gypenoside XVII in HeLa Cells

by Sayed Sajid Hussain, Muhammad Maisam, Shoaib Younas, Feng Wang and Weijie Li

Molecules 2026, 31(2), 214; https://doi.org/10.3390/molecules31020214 - 8 Jan 2026

Cervical cancer remains a prominent cause of cancer-related mortality among women worldwide because of chronic infection with high-risk human papillomavirus (HPV) and disparate access to prevention and treatment. The current research evaluates the anticancer activity of Gypenoside XVII, a bioactive saponin of Gynostemma [...] Read more.

Cervical cancer remains a prominent cause of cancer-related mortality among women worldwide because of chronic infection with high-risk human papillomavirus (HPV) and disparate access to prevention and treatment. The current research evaluates the anticancer activity of Gypenoside XVII, a bioactive saponin of Gynostemma pentaphyllum, in HeLa cells as a model of cervical cancer. MTT, Annexin V-PI, and Hoechst 33342 assays showed dose-dependent growth inhibition with typical apoptotic morphology. Flow cytometry revealed G₀/G₁ cell-cycle arrest, while pathway interrogation revealed participation of mitochondrial and death-receptor cascades, in agreement with caspase-9 and caspase-8 activation, respectively. Collectively, these findings position Gypenoside XVII as a natural-product bioactive with potential both as an anticancer lead and as a functional-food ingredient, deserving of further preclinical development. Full article

(This article belongs to the Section Natural Products Chemistry)

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18 pages, 2502 KB

Open AccessArticle

Synthesis and Photocatalytic Evaluation of CoPc/g-C₃N₄ and CuPc/g-C₃N₄ Catalysts for Efficient Degradation of Chlorinated Phenols

by Cagla Akkol, Yasemin Caglar and Ece Tugba Saka

Molecules 2026, 31(2), 213; https://doi.org/10.3390/molecules31020213 - 8 Jan 2026

The oxidation of chlorophenolic compounds is essential for converting these persistent and toxic pollutants into less harmful products, thereby reducing their environmental and health impacts. In this study, a p-coumaric acid ester derivative was employed as the starting material to synthesize the corresponding [...] Read more.

The oxidation of chlorophenolic compounds is essential for converting these persistent and toxic pollutants into less harmful products, thereby reducing their environmental and health impacts. In this study, a p-coumaric acid ester derivative was employed as the starting material to synthesize the corresponding phthalonitrile precursor (EnCA-CN), followed by the preparation of non-peripherally substituted Co(II) and Cu(II) phthalocyanine complexes (EnCA-Copc and EnCA-CuPc). These complexes were subsequently characterized using a range of spectroscopic techniques and designed to engage in π–π interactions with graphitic carbon nitride to form efficient photocatalytic materials. The structures of the two effective catalysts were characterized by FT-IR, SEM, and XRD analyses, after which their photocatalytic performance and recyclability in the degradation of 2-chlorophenol, 2,3-dichlorophenol, and 2,3,6-trimethylphenol were evaluated. The optimum catalyst loading for the MPc/g-C₃N₄ composites was determined to be 0.5 g/L, yielding the highest photocatalytic efficiency. The EnCA-CoPc/g-C₃N₄ catalyst achieved 90.8% product selectivity and 82.6% conversion in the oxidation of 2-chlorophenol, whereas the EnCA-CuPc/g-C₃N₄ catalyst exhibited approximately 80.0% pollutant removal. The degradation efficiencies followed the order 2-CP > 2,3-DCP > 2,3,6-TCP, with benzoquinone derivatives identified as the major oxidation products. In recyclability tests, both catalysts retained more than 50% of their activity after five cycles; EnCA-CoPc/g-C₃N₄ maintained 68% conversion in the 5th cycle, while EnCA-CuPc/g-C₃N₄ retained 60% conversion in the 4th cycle. Full article

(This article belongs to the Special Issue Advances in Porphyrinoid-Based Functional Materials)

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16 pages, 2558 KB

Open AccessArticle

Psychedelic Drugs Rediscovered—In Silico Study of Potential Fetal Exposure to Analogues of Psychedelic Drugs During Pregnancy

by Anna W. Sobańska, Andrzej M. Sobański and Elżbieta Brzezińska

Molecules 2026, 31(2), 212; https://doi.org/10.3390/molecules31020212 - 8 Jan 2026

A total of 250 known and novel compounds—ketamine and serotonergic psychedelics or their analogues—designed to target depression, addictions and/or other mental or neurological disorders and developed as “recreational” (illegal) drugs from three chemical families, ergolines, tryptamines and phenylethylamines, were investigated in the context [...] Read more.

A total of 250 known and novel compounds—ketamine and serotonergic psychedelics or their analogues—designed to target depression, addictions and/or other mental or neurological disorders and developed as “recreational” (illegal) drugs from three chemical families, ergolines, tryptamines and phenylethylamines, were investigated in the context of their ability to cross the human placenta. Using a novel multivariate model involving compounds’ drug-likeness (according to Lipinski’s Ro5), caco-2 membrane permeability, fraction unbound to plasma proteins, steady-state volume of distribution and the total count of heteroatoms (non-carbon atoms with hydrogens included), it was established that the majority of studied compounds are likely to cross the placenta easily, most probably by the passive diffusion mechanism. Atomic contributions of structural elements of studied compounds were investigated using the Morgan fingerprinting algorithm and it was postulated that the fragments promoting transport of compounds across the placenta are carbonyl, hydroxyl, nitro- and phosphoryloxy groups—rigid polycyclic structures, bulky alkyl/aryl groups and halogen atoms restrict the trans-placental passage. All studied compounds are expected to be relatively easily obtained by synthetic routes, which makes them an interesting target for manufacturers of illegal drugs and warrants the need to pursue pharmacological studies of these compounds in silico. Full article

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24 pages, 7995 KB

Open AccessArticle

Study on Degradation of Sulfamethoxazole in Water by Activated Persulfate of Molybdenite Supported on Biochar

by Xuemei Li, Jian Wang, Xinglin Chen, Shengnan Li and Hai Lu

Molecules 2026, 31(2), 211; https://doi.org/10.3390/molecules31020211 - 7 Jan 2026

In this study, the advanced oxidation system of peroxymonosulfate (PMS) was activated by molybdenite supported on biochar (Molybdenite@BC), and the degradation efficiency, influencing factors and degradation mechanism of sulfamethoxazole (SMX) were explored through experiments. Molybdenite@BC, a composite material used in the study, was [...] Read more.

In this study, the advanced oxidation system of peroxymonosulfate (PMS) was activated by molybdenite supported on biochar (Molybdenite@BC), and the degradation efficiency, influencing factors and degradation mechanism of sulfamethoxazole (SMX) were explored through experiments. Molybdenite@BC, a composite material used in the study, was prepared by pyrolysis at high temperature. The optimum pyrolysis temperature was 700 °C, and the mass ratio of molybdenite to biochar (BC) was 1:3. By changing dosage of Molybdenite@BC, pH value, initial concentration of PMS, and the types and concentration of inorganic anions, the effects of various factors on SMX degradation were systematically studied. The optimum reaction conditions of the Molybdenite@BC/PMS process were as follows: Molybdenite@BC dosage was 100 mg/L, PMS concentration was 0.2 mM, pH value was 6.9 ± 0.2, and initial SMX concentration was 6 mg/L. Under these conditions, the degradation rate of SMX was 97.87% after 60 min and 99.06% after 120 min. The material characterization analysis showed that Molybdenite@BC had a porous structure and rich active sites, which was beneficial to the degradation of pollutants. After the composite material was used, the peaks of MoO₂ and MoS₂ became weaker, which indicated that there was some loss of molybdenum from the material structure. Electron paramagnetic resonance (EPR) and radical quenching experiments revealed that Molybdenite@BC effectively catalyzed PMS to generate various reactive oxygen radicals and non-free radicals, including singlet oxygen (¹O₂), hydroxyl radical (^•OH), sulfate radical (SO₄^•−) and superoxide radical (^•O₂⁻). ¹O₂ played a leading role in the degradation of SMX, while ^•OH and SO₄^•− had little influence. The intermediate products of the degradation of SMX in Molybdenite@BC/PMS system were analyzed by liquid chromatography–tandem mass spectrometry (LC–MS). The results showed that there were nine main intermediate products in the process of degradation, and the overall toxicity tended to decrease during the degradation of SMX. The degradation path analysis showed that with the gradual ring opening and bond breaking of SMX, small molecular compounds were generated, which were finally mineralized into H₂O, CO₂, CO₃²⁻, H₂SO₄ and other substances. The research results confirmed that the Molybdenite@BC/PMS process provided a feasible new method for the degradation of SMX in water. Full article

(This article belongs to the Special Issue Functional Nanomaterials and Their Applications in the Environment Remediation)

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14 pages, 1319 KB

Open AccessArticle

Effect of Alkyl Chain Length and Hydroxyl Substitution on the Antioxidant Activity of Gallic Acid Esters

by Qi Chen, Shuaiwei Cui, Wenwen Zhang, Gang Dong, Baoshan Tang, Jinju Ma, Juan Xu, Jun Zhang and Lanxiang Liu

Molecules 2026, 31(2), 210; https://doi.org/10.3390/molecules31020210 - 7 Jan 2026

Gallic acid (GA) exhibits excellent antioxidant properties but suffers from chemical instability due to its carboxyl group, which limits practical application. To address this, we designed and investigated 14 distinct ester derivatives of GA, which were categorized into two major groups based on [...] Read more.

Gallic acid (GA) exhibits excellent antioxidant properties but suffers from chemical instability due to its carboxyl group, which limits practical application. To address this, we designed and investigated 14 distinct ester derivatives of GA, which were categorized into two major groups based on their substituents: chain alkyl and hydroxyl-substituted alkyl groups. Systematic evaluation revealed a striking decline in the DPPH radical scavenging activity of alkyl esters with increasing carbon chain length, from 91.9% for GA-C3 to 55.6% for GA-C30. The hydroxyl-functionalized GA esters GA-EG, GA-GL, and GA-PT maintain high antioxidant activity (>90%) while improving applicability through carboxyl substitution. In the oil system, all derivatives significantly prolong the oxidation induction time, with GA-C3 exhibiting the highest performance by extending the induction time by 2.15 h. Hydroxyl-functionalized esters such as GA-EG, GA-GL, and GA-PT also demonstrated significant efficacy, prolonging oxidation induction by 1.92 to 2.03 h. The results suggest how the structure of GA esters affects their antioxidant behavior, providing a direction for designing antioxidants suitable for specific systems. Full article

(This article belongs to the Topic Natural Bioactive Compounds as a Promising Approach to Mitigating Oxidative Stress)

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24 pages, 13891 KB

Open AccessArticle

Photocatalytic Performance of Zr-Modified TS-1 Zeolites: Structural, Textural and Kinetic Studies

by Hristina Lazarova, Borislav Barbov, Elena Tacheva, Rusi Rusew, Stela Atanasova-Vladimirova and Boris Shivachev

Molecules 2026, 31(2), 209; https://doi.org/10.3390/molecules31020209 - 7 Jan 2026

TS-1 zeolite and a series of Zr-modified samples (TS-1/xZr) were synthesized and systematically characterized to investigate the influence of zirconium incorporation on structural, textural, and photocatalytic properties. The structural and textural properties of the samples were examined by XRD and nitrogen adsorption isotherms. [...] Read more.

TS-1 zeolite and a series of Zr-modified samples (TS-1/xZr) were synthesized and systematically characterized to investigate the influence of zirconium incorporation on structural, textural, and photocatalytic properties. The structural and textural properties of the samples were examined by XRD and nitrogen adsorption isotherms. Elemental analysis (EDXRF, SEM/EDS) and FTIR confirmed successful incorporation of Zr into the TS-1 framework. Photocatalytic tests under white light irradiation using crystal violet (CV), methylene blue (MB), rhodamine B (RhB) and methyl orange (MO) dyes revealed enhanced degradation efficiency for the Zr-containing samples, particularly TS-1/10Zr. Kinetic modeling using pseudo-first-order (PFO) and pseudo-second-order (PSO) approaches indicated that dye degradation followed mainly PSO kinetics. Reusability studies demonstrated sustained stability and recyclability of the catalysts. The improved photocatalytic performance is attributed to synergistic electronic effects between Ti and Zr species, which enhance charge separation and light absorption. Full article

(This article belongs to the Special Issue 30th Anniversary of Molecules: Recent Advances in Photochemistry)

20 pages, 2922 KB

Open AccessArticle

Theoretical Insight on the Tautomerism and ESIPT Process in Some Hydroxyaryl(hetaryl)idene Azomethine Imines

by Nikoleta Kircheva, Silvia Angelova, Stefan Dobrev and Liudmil Antonov

Molecules 2026, 31(2), 208; https://doi.org/10.3390/molecules31020208 - 7 Jan 2026

The current study aims to model the potential energy surface (PES) of three much less investigated hydroxyaryl(hetaryl)idene azomethine imine derivatives, possessing the same proton crane unit—namely the azomethine imine moiety—but slightly differing in the structure of the proton transfer platform (stator), by applying [...] Read more.

The current study aims to model the potential energy surface (PES) of three much less investigated hydroxyaryl(hetaryl)idene azomethine imine derivatives, possessing the same proton crane unit—namely the azomethine imine moiety—but slightly differing in the structure of the proton transfer platform (stator), by applying the tools of computational chemistry. The obtained calculational results are compared with already reported experimental structural, ¹H NMR, and UV absorption spectra in an attempt to shed light on the observed data, mainly with regard to the efficiency of the excited state intramolecular proton transfer. Full article

(This article belongs to the Special Issue Advances in Computational Spectroscopy, 2nd Edition)

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21 pages, 454 KB

Open AccessArticle

Multivariate Characterization of Essential Oils for Their Antibacterial Activity Against Escherichia coli: A Data-Driven Interpretation of Experimental Results

by Meta Kokalj Ladan, Marsela Supé Vide and Katja Schoss

Molecules 2026, 31(2), 207; https://doi.org/10.3390/molecules31020207 - 7 Jan 2026

The growing problem of antimicrobial resistance emphasizes the urgent need for new and effective natural antimicrobial agents. This study assessed the antibacterial activity of twenty essential oils and one absolute against Escherichia coli and examined the relationship between their chemical composition and biological [...] Read more.

The growing problem of antimicrobial resistance emphasizes the urgent need for new and effective natural antimicrobial agents. This study assessed the antibacterial activity of twenty essential oils and one absolute against Escherichia coli and examined the relationship between their chemical composition and biological activity. The chemical profiles of the samples were determined using gas chromatography–mass spectrometry (GC–MS), and the resulting data were analysed using principal component analysis (PCA), discriminant analysis (DA), and partial least squares (PLS) methods to explore associations between composition and antibacterial activity. The results showed substantial variability among the tested essential oils, with those from Thymus vulgaris, Aniba rosaeodora, Syzygium aromaticum, Pimenta dioica, and the absolute of Evernia prunastri exhibiting the strongest activity. GC–MS analysis identified thymol, eugenol, and methyl atrarate as key bioactive constituents associated with strong antibacterial effects, while linalool, limonene, and α-terpineol were linked to moderate activity. Multivariate analyses provided further insight but were limited by data variability, highlighting compositional diversity rather than clear group separation. Overall, the findings demonstrate that essential oils are a promising source of natural antimicrobial agents and emphasise the importance of linking chemical composition with biological function to understand their potential therapeutic applications. Full article

(This article belongs to the Special Issue Essential Oils: Chemical Composition, Bioactive, and Application)

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24 pages, 7298 KB

Open AccessArticle

Effects of Anionic Groups on Structural and Luminescent Properties of ZnO:Sm³⁺ Phosphors Synthesized via Combustion Method

by Edwin Tumelo Maleho, Machaba Leanyatsa Abraham Letswalo and Buyisiwe M. Sondezi

Molecules 2026, 31(2), 206; https://doi.org/10.3390/molecules31020206 - 7 Jan 2026

BO₃³⁻, PO₄³⁻, and SO₄²⁻ anionic groups were used to study their effects on the structure and luminescence of Sm³⁺-doped ZnO. ZnO, ZnO:Sm³⁺, ZnO, Zn₄B₆O₁₃:Sm³⁺ [...] Read more.

BO₃³⁻, PO₄³⁻, and SO₄²⁻ anionic groups were used to study their effects on the structure and luminescence of Sm³⁺-doped ZnO. ZnO, ZnO:Sm³⁺, ZnO, Zn₄B₆O₁₃:Sm³⁺, and Zn₂P₂O₇:Sm³⁺ phosphors were successfully synthesized via combustion synthesis. While BO₃³⁻ and PO₄³⁻ ions led to the formation of new crystalline phases, the sulfate precursor decomposed during synthesis, yielding ZnO with only minor surface sulfur traces. The XRD results revealed the formation of wurtzite crystal structures in the ZnO, ZnO:Sm³⁺, and ZnO-SO₄:Sm³⁺ samples, while a complete change of structure was observed after the incorporation of borate (BO₃³⁻) and phosphate (PO₄³⁻) ions into ZnO:Sm³⁺ to Zn₄B₆O₁₃:Sm³⁺ and Zn₂P₂O₇:Sm³⁺, respectively. The structures for borate and phosphate ions were confirmed as cubic (Zn₄B₆O₁₃) and monoclinic (Zn₂P₂O₇) crystal structures, respectively. The morphological studies of ZnO:Sm³⁺ and ZnO-SO₄:Sm³⁺ were characterized by aggregated particles with different shapes and sizes. Zn₄B₆O₁₃ and Zn₂P₂O₇ samples were characterized by having cubic and rough surfaces, respectively. The oxidation state of the Sm ions was confirmed by XPS analysis. The photoluminescence studies revealed a broad-band emission for the ZnO:Sm³⁺ and ZnO-SO₄:Sm³⁺ materials and characteristic Sm³⁺ emissions (from the ⁴G_5/2 level to lower states ⁶H_J (J = 5/2, 7/2, 9/2, and 11/2)) for the Zn₄B₆O₁₃ and Zn₂P₂O₇ samples. Enhanced emissions were observed after the incorporation of anionic group systems. The most intense PL emission was observed from the Zn₄B₆O₁₃ phosphor material. The CIE calculations revealed that the best color purity results were from Zn₄B₆O₁₃, which lay in the orange region with 98% color purity. Full article

(This article belongs to the Special Issue Chemiluminescence and Photoluminescence of Advanced Compounds)

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26 pages, 4324 KB

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Study on Comprehensive Quality Control of Herba Hyssopi Based on Chemical Components and Pharmacological Mechanism Action

by Zhenxia Zhao, Jiangning Peng, Yingfeng Du, Xinyi Yang, Lilan Fan, Cong Li, Amatjan Ayupbek, Hui Li and Yongli Liu

Molecules 2026, 31(2), 205; https://doi.org/10.3390/molecules31020205 - 6 Jan 2026

Herba Hyssopi is a key remedy in Uighur medicine for asthma and cough, frequently used as the monarch or minister herb in prescriptions. However, the lack of effective quality assessment methods complicates the detection of adulteration with common substitutes. In this study, UPLC-LTQ-Orbitrap-MS, [...] Read more.

Herba Hyssopi is a key remedy in Uighur medicine for asthma and cough, frequently used as the monarch or minister herb in prescriptions. However, the lack of effective quality assessment methods complicates the detection of adulteration with common substitutes. In this study, UPLC-LTQ-Orbitrap-MS, network pharmacology, molecular docking, and cell experiments were employed to establish scientific and effective quality control methods to differentiate Hyssopus cuspidatus Boiss from its common adulterants. The results showed that a total of 41 chemical constituents were identified from Herba Hyssopi. Network pharmacology analysis revealed 133 potential target genes associated with its therapeutic actions, among which EGFR, MMP9, TNF, PTGS2, MAPK3, ESR1, and TP53 emerged as key targets. Cellular experiments further demonstrated that diosmin, linarin, and rosmarinic acid significantly suppressed nitric oxide (NO) generation and the release of pro-inflammatory cytokines. Based on these findings, a validated HPLC method was established for the simultaneous quantification of these three bioactive markers, providing a reliable tool for the quality assessment and authentication of Herba Hyssopi. This study offers a scientific basis for improving the standardization and quality control of Herba Hyssopi in traditional medicine applications. Full article

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29 pages, 1719 KB

Open AccessArticle

Fatty Acid and Amino Acid Derivatives in Organocatalyzed Michael Additions

by Aljaž Flis, Helena Brodnik, Nejc Petek, Franc Požgan, Jurij Svete, Bogdan Štefane, Luka Ciber and Uroš Grošelj

Molecules 2026, 31(2), 204; https://doi.org/10.3390/molecules31020204 - 6 Jan 2026

Amino acid derivatives, such as β-keto esters and pyrrolones, were used as nucleophiles in organocatalyzed Michael additions to nitroalkene acceptors, while fatty acid derivatives acted as both nucleophiles (β-keto esters) and electrophiles (nitroalkene acceptors). Bifunctional noncovalent organocatalysts were employed as asymmetric organocatalysts. Twenty [...] Read more.

Amino acid derivatives, such as β-keto esters and pyrrolones, were used as nucleophiles in organocatalyzed Michael additions to nitroalkene acceptors, while fatty acid derivatives acted as both nucleophiles (β-keto esters) and electrophiles (nitroalkene acceptors). Bifunctional noncovalent organocatalysts were employed as asymmetric organocatalysts. Twenty compounds—including fatty acid and amino acid derivatives, as well as fatty acid–amino acid conjugates—were prepared with enantioselectivities of up to 98% ee. All novel products were fully characterized. This research demonstrates the ease of assembling readily available fatty acid and amino acid building blocks under ambient conditions. Full article

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

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