Journal Description

Molecules

Molecules is the leading international, peer-reviewed, open access journal of chemistry. Molecules is published semimonthly online by MDPI. The International Society of Nucleosides, Nucleotides & Nucleic Acids (IS3NA), the Spanish Society of Medicinal Chemistry (SEQT) and the International Society of Heterocyclic Chemistry (ISHC) are affiliated with Molecules and their members receive a discount 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 (Chemistry, Multidisciplinary) / CiteScore - Q1 (Chemistry (miscellaneous))
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 2.8 days (median values for papers published in this journal in the first half of 2024).
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 26 topical sections.
Testimonials: See what our editors and authors say about Molecules.
Companion journal: Foundations.

Impact Factor: 4.2 (2023); 5-Year Impact Factor: 4.6 (2023)

Imprint Information Journal Flyer Open Access ISSN: 1420-3049

Latest Articles

26 pages, 1059 KiB

Open AccessReview

Review of the Integrated Approaches for Monitoring and Treating Parabens in Water Matrices

by Denga Ramutshatsha-Makhwedzha and Tshimangadzo S. Munonde

Molecules 2024, 29(23), 5533; https://doi.org/10.3390/molecules29235533 - 22 Nov 2024

Abstract

Due to their antibacterial and antifungal properties, parabens are commonly used as biocides and preservatives in food, cosmetics, and pharmaceuticals. Parabens have been reported to exist in various water matrices at low concentrations, which renders the need for sample preparation before their quantification using analytical techniques. Thus, sample preparation methods such as solid-phase extraction (SPE), rotating-disk sorptive extraction (RDSE), and vortex-assisted dispersive liquid–liquid extraction (VA-DLLE) that are commonly used for parabens extraction and preconcentration have been discussed. As a result of sample preparation methods, analytical techniques now detect parabens at trace levels ranging from µg/L to ng/L. These compounds have been detected in water, air, soil, and human tissues. While the full impact of parabens on human health and ecosystems is still being debated in the scientific community, it is widely recognized that parabens can act as endocrine disruptors. Furthermore, some studies have suggested that parabens may have carcinogenic effects. The presence of parabens in the environment is primarily due to wastewater discharges, which result in widespread contamination and their concentrations increased during the COVID-19 pandemic waves. Neglecting the presence of parabens in water exposes humans to these compounds through contaminated food and drinking water. Although there are reviews that focus on the occurrence, fate, and behavior of parabens in the environment, they frequently overlook critical aspects such as removal methods, policy development, and regulatory frameworks. Addressing this gap, the effective treatment of parabens in water relies on combined approaches that address both cost and operational challenges. Membrane filtration methods, such as nanofiltration (NF) and reverse osmosis (RO), demonstrate high efficacy but are hindered by maintenance and energy costs due to extensive fouling. Innovations in anti-fouling and energy efficiency, coupled with pre-treatment methods like adsorption, help mitigate these costs and enhance scalability. Furthermore, combining adsorption with advanced oxidation processes (AOPs) or biological treatments significantly improves economic and energy efficiency. Integrating systems like O₃/UV with activated carbon, along with byproduct recovery strategies, further advances circular economy goals by minimizing waste and resource use. This review provides a thorough overview of paraben monitoring in wastewater, current treatment techniques, and the regulatory policies that govern their presence. Furthermore, it provides perspectives that are critical for future scientific investigations and shaping policies aimed at mitigating the risks of parabens in drinking water. Full article

16 pages, 1271 KiB

Open AccessArticle

The Biochar Derived from Pecan Shells for the Removal of Congo Red: The Effects of Temperature and Heating Rate

by Wanqiang Xu, Bo Cai, Xujie Zhang, Yating Zhang, Yongjian Zhang and Hehuan Peng

Molecules 2024, 29(23), 5532; https://doi.org/10.3390/molecules29235532 - 22 Nov 2024

Abstract

Organic pollutants, especially dyes, are seriously hazardous to the aquatic system and humans due to their toxicity, and carcinogenic or mutagenic properties. In this study, a biochar prepared from agricultural waste (pecan shells) via pyrolysis was applied to remove the dye pollutant Congo Red from wastewater to avoid a negative effect to the ecosystem. This study also investigated the effect of preparation conditions (temperature and heating rate) on the physicochemical properties and the adsorption performance of biochars. The physicochemical properties of the biochar were characterized using scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The adsorption performance of the biochar was evaluated for Congo Red removal. The results showed that biochar prepared at 800 °C with a heating rate of 20 °C/min (PSC-800-20) exhibited a higher specific surface area of 450.23 m²/g and a higher adsorption capacity for Congo Red (130.48 mg/g). Furthermore, adsorption experiments indicated that the pseudo-second-order and Langmuir models fitted well with the adsorption kinetics and isotherms of the biochar derived from pecan shells, respectively. Additionally, the PSC-800-20 biochar demonstrated a stable adsorption capacity over multiple cycles, suggesting its potential for regeneration and reuse in wastewater treatment applications. Therefore, the biochar derived from agricultural waste presents a promising and sustainable solution for the removal of toxic dye pollutants from wastewater. Full article

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26 pages, 822 KiB

Open AccessReview

Behavior of Silver Species in Soil: Ag Nanoparticles vs. Ionic Ag

by Joanna Kyziol-Komosinska, Agnieszka Dzieniszewska and Justyna Czupioł

Molecules 2024, 29(23), 5531; https://doi.org/10.3390/molecules29235531 - 22 Nov 2024

Abstract

Silver nanoparticles are one of the most commonly used forms of silver (Ag) in nanotechnology applications due to their antibacterial properties and electrical and thermal resistance. The increasing production and use of products containing nanoparticles has led to their release into and contamination of soil and water. This review summarizes the literature on the fate, behavior (adsorption/desorption, precipitation/oxidative dissolution, transformation), and transport/mobility of Ag forms in soils (Ag⁺ ions and Ag nanoparticles—AgNPs). The behavior of Ag⁺/AgNPs in soil is a complex process. It depends on many factors, including the characteristics of the Ag forms (ions, nanoparticle size, ligand type used for coating, surface charge, initial Ag concentration), the soil properties (organic matter and clay mineral content, textural properties, point of zero charge, cation exchange capacity, surface functional groups), and the solute properties (pH–Eh, ionic strength, cation type, oxygen content). The binding of Ag⁺ and AgNPs is significantly positively correlated with Al/Fe/Mn oxide and SOM content and depends on the surface charge of the minerals and CEC, which controls adsorption processes. Very important parameters to consider are the pH and Eh of the solution, which determine the durability of the ligands, the aggregation rate and the oxidation process of AgNPs, as well as the presence of sulfide and chloride and the Cl/Ag ratio, which determine the stability/mobility of Ag. Since AgNPs can be oxidized to Ag⁺ ions during their life cycle, it is necessary to consider the behavior of both forms of Ag in soils. Understanding the transport and behavior of Ag in soil is essential for the environmental risk assessment and management of wastes containing Ag. Full article

19 pages, 380 KiB

Open AccessArticle

Extraction of Bioactive Compounds and Influence of Storage Conditions of Raw Material Chamaenerion angustifolium (L.) Holub Using Different Strategies

by Domantas Armonavičius, Mantas Stankevičius and Audrius Maruška

Molecules 2024, 29(23), 5530; https://doi.org/10.3390/molecules29235530 - 22 Nov 2024

Abstract

The study evaluates different preparation methods for identifying the best strategy for extracting biologically active compounds from raw Chamaenerion angustifolium (L.) Holub plant material. The methodologies include direct aqueous methanol extraction with a combination of natural aerobic and anaerobic fermentation for 24–72 h, followed by 35 °C and 60 °C drying. Furthermore, the study also focuses on determining the different temperature storage conditions on the stability of biologically active compounds. UV-VIS spectroscopy was used to quantitatively evaluate the total content of phenolic compounds, flavonoids, and radical scavenging activity. For qualitative analysis, chromatographic separation with electrochemical detection (ED) of extracted compounds, a gradient high-performance liquid chromatography (HPLC) system was used. Study results indicate that 48 h natural aerobic fermentation followed by 35 °C drying and 75% (v/v) aqueous methanol extraction yielded the maximum amount of biologically active compounds in Chamaenerion angustifolium (L.) Holub leaves, blossom, and stem samples. Freezing samples in liquid nitrogen had the lowest impact on the total content of phenolic compounds, flavonoids, and radical scavenging activity. HPLC-ED system results identified chlorogenic acid, oenothein B, trans-p-Coumaric acid, ellagic acid, and rutin in Chamaenerion angustifolium (L.) Holub leave samples. Full article

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19 pages, 1678 KiB

Open AccessArticle

Evaluation of Quinazolin-2,4-Dione Derivatives as Promising Antibacterial Agents: Synthesis, In Vitro, In Silico ADMET and Molecular Docking Approaches

by Aboubakr H. Abdelmonsef, Mohamed El-Naggar, Amal O. A. Ibrahim, Asmaa S. Abdelgeliel, Ihsan A. Shehadi, Ahmed M. Mosallam and Ahmed Khodairy

Molecules 2024, 29(23), 5529; https://doi.org/10.3390/molecules29235529 - 22 Nov 2024

Abstract

Abstract: A series of new quinazolin-2,4-dione derivatives incorporating amide/eight-membered nitrogen-heterocycles 2a–c, in addition, acylthiourea/amide/dithiolan-4-one and/or phenylthiazolidin-4-one 3a–d and 4a–d. The starting compound 1 was prepared by reaction of 4-(2,4-dioxo-1,4-dihydro-2H-quinazolin-3-yl)-benzoyl chloride with ammonium thiocyanate and cyanoacetic acid hydrazide. The reaction of 1 with strong electrophiles, namely, o-aminophenol, o-amino thiophenol, and/or o-phenylene diamine, resulted in corresponding quinazolin-2,4-dione derivatives incorporating eight-membered nitrogen-heterocycles 2a–d. Compounds 3a–d and 4a–d were synthesized in good-to-excellent yield through a one-pot multi-component reaction (MCR) of 1 with carbon disulfide and/or phenyl isocyanate under mild alkaline conditions, followed by ethyl chloroacetate, ethyl iodide, methyl iodide, and/or concentrated HCl, respectively. The obtained products were physicochemically characterized by melting points, elemental analysis, and spectroscopic techniques, such as FT-IR, ¹H-NMR, ¹³C-NMR, and MS. The antibacterial efficacy of the obtained eleven molecules was examined in vitro against two Gram-positive bacterial strains (Staphylococcus aureus and Staphylococcus haemolyticus). Furthermore, Computer-Aided Drug Design (CADD) was performed on the synthesized derivatives, standard drug (Methotrexate), and reported antibacterial drug with the target enzymes of bacterial strains (S. aureus and S. haemolyticus) to explain their binding mode of actions. Notably, our findings highlight compounds 2b and 2c as showing both the best antibacterial activity and docking scores against the targets. Finally, according to ADMET predictions, compounds 2b and 2c possessed acceptable pharmacokinetics properties and drug-likeness properties. Full article

(This article belongs to the Section Organic Chemistry)

23 pages, 2873 KiB

Open AccessArticle

Effect of Different Colours of Light on Chosen Aspects of Metabolism of Radish Sprouts with Phosphoromic Approach

by Anna Kafka, Jacek Lipok, Beata Żyszka-Haberecht and Dorota Wieczorek

Molecules 2024, 29(23), 5528; https://doi.org/10.3390/molecules29235528 - 22 Nov 2024

Abstract

Among various environmental factors, light is a crucial parameter necessary for the germination of some seeds. Seed germination is an important phase in the plant life cycle, when metabolic activity is resumed and reserves are mobilized to support initial plant development. Although all nutrients are extremely important for proper physiological and biochemical development of plants, phosphorus (P) seems to play a special role, as it is an essential component of all important structural and functional substances which compose the cells of plants. We believe that transformations of the forms of phosphorus accompanying metabolic activity of germinating seeds determine the efficiency of this process, and thus the seedling’s metabolic status. Therefore, we decided to study the changes in the major phosphorus-containing substances in radish sprouts during the first phase of growth. The effect of different colours of light on the quality parameters in radish, as a model plant, during germination, was evaluated. Contents of Pi, adenylates, antioxidants, pigments, phytase activity, and ³¹P NMR phosphorus profile were investigated. Based on the results of our study, we may propose the phosphoromic approach as an important metabolic parameter determining the physiological status of the plant. Full article

(This article belongs to the Section Applied Chemistry)

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18 pages, 5118 KiB

Open AccessArticle

Thermooxidation of Four Sartans: Kinetic Analysis Based on Thermo-Gravimetric Data

by Adriana Ledeţi, Bianca Baul, Amalia Ridichie, Denisa Ivan, Titus Vlase, Carmen Tomoroga, Anca Dragomirescu, Gabriela Vlase, Răzvan Adrian Bertici, Dana Emilia Man and Ionuţ Ledeţi

Molecules 2024, 29(23), 5527; https://doi.org/10.3390/molecules29235527 - 22 Nov 2024

Abstract

Angiotensin II receptor antagonists are tetrazole derivatives used in the treatment of high blood pressure, and are also indicated for the treatment of heart failure (NYHA class II-IV). They are used alone or in combination with other classes of antihypertensives or diuretics for the effective management of high blood pressure. In this study, we aim to evaluate the thermal stability and degradation kinetics for the principal compounds used in therapy from this class, namely telmisartan, valsartan, olmesartan medoxomil, and losartan potassium. To obtain the thermoanalytical data for the kinetic investigations, the TG and DTG curves were registered at five different heating rates (β = 2, 4, 6, 8, and 10 °C min⁻¹). The kinetic methods used were a preliminary ASTM E698 method and two isoconversional methods: Flynn–Wall–Ozawa and Friedman. For each molecule, the results showed complex decomposition processes consisting of complex reaction sequences. Full article

(This article belongs to the Special Issue Advances in Pharmaceutical Analytical Technologies)

29 pages, 2199 KiB

Open AccessArticle

Development of Naphthalene-Derivative Bis-QACs as Potent Antimicrobials: Unraveling Structure–Activity Relationship and Microbiological Properties

by Nikita A. Frolov, Mary A. Seferyan, Elena V. Detusheva, Elizabeth Son, Ilya G. Kolmakov, Alena S. Kartseva, Victoria V. Firstova, Anatoly N. Vereshchagin and Michail N. Elinson

Molecules 2024, 29(23), 5526; https://doi.org/10.3390/molecules29235526 - 22 Nov 2024

Abstract

While the pandemic is behind us, the world community faces a global threat of bacterial resistance outbreak. One of the key ways to combat the spread of multi-resistant bacteria is infection prevention and control tactics using modern antiseptic and disinfectant compositions. Herein, we continue the path to unravel the structure–activity relationship (SAR) of potent pyridine-derived biocide class bis-quaternary ammonium compounds (QACs). In this study, twenty dihydroxynaphthalene-derivative bis-QACs were subjected to extensive microbiological analysis on planktonic cells and biofilms of the ESKAPE microorganisms. Among them, hit compounds were superior in their bacteriostatic and bactericidal action to commercial mono-QACs and were comparable to the best bis-QAC antiseptic on the market. SAR analysis indicated that the linker conformation does not significantly affect the activity, though structure symmetry and especially lipophilicity had an influence on antibacterial performance. Furthermore, we delve deeper in investigation of the antimicrobial potential of bis-QACs and conducted a variety of assays, including time–kill kinetics, bacterial resistance formation, cell morphology, and cytotoxicity. Studies showed promising results for compounds 5d and 6d, indicating 2 to 3-fold less cytotoxicity and hemotoxicity compared to commercial QACs. Moreover, SEM imaging revealed that bis-QACs can cause severe membrane damage to S. aureus and P. aeruginosa strains, confirming great potential of novel compounds as antiseptic and disinfectant. Full article

35 pages, 989 KiB

Open AccessReview

Diversity of Microglia-Derived Molecules with Neurotrophic Properties That Support Neurons in the Central Nervous System and Other Tissues

by Kennedy R. Wiens, Naved Wasti, Omar Orlando Ulloa and Andis Klegeris

Molecules 2024, 29(23), 5525; https://doi.org/10.3390/molecules29235525 - 22 Nov 2024

Abstract

Microglia, the brain immune cells, support neurons by producing several established neurotrophic molecules including glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF). Modern analytical techniques have identified numerous phenotypic states of microglia, each associated with the secretion of a diverse set of substances, which likely include not only canonical neurotrophic factors but also other less-studied molecules that can interact with neurons and provide trophic support. In this review, we consider the following eight such candidate cytokines: oncostatin M (OSM), leukemia inhibitory factor (LIF), activin A, colony-stimulating factor (CSF)-1, interleukin (IL)-34, growth/differentiation factor (GDF)-15, fibroblast growth factor (FGF)-2, and insulin-like growth factor (IGF)-2. The available literature provides sufficient evidence demonstrating murine cells produce these cytokines and that they exhibit neurotrophic activity in at least one neuronal model. Several distinct types of neurotrophic activity are identified that only partially overlap among the cytokines considered, reflecting either their distinct intrinsic properties or lack of comprehensive studies covering the full spectrum of neurotrophic effects. The scarcity of human-specific studies is another significant knowledge gap revealed by this review. Further studies on these potential microglia-derived neurotrophic factors are warranted since they may be used as targeted treatments for diverse neurological disorders. Full article

(This article belongs to the Section Medicinal Chemistry)

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18 pages, 2202 KiB

Open AccessArticle

Osmotic Dehydration of Japanese Quince (Chaenomeles japonica) Fruits in Erythritol Solutions: Impact of Processing Conditions on the Kinetic Parameters and on Physicochemical and Antioxidant Properties of the Fruits

by Angelika Wojtyś, Sławomir Pietrzyk, Sylwia Bogacz and Robert Witkowicz

Molecules 2024, 29(23), 5524; https://doi.org/10.3390/molecules29235524 - 22 Nov 2024

Abstract

The present work aimed to evaluate the effectiveness of erythritol as an osmotic agent in the osmotic dehydration (OD) process of Japanese quince fruits and to assess its effects on their physicochemical and antioxidant properties. The efficiency of the OD process was determined by examining its kinetics and comparing the results to those from a sucrose solution. In selected osmotically dehydrated fruits, the following parameters were determined: dry matter content, total acidity, pH, sugar profile, color parameters, total phenolic and flavonoid content, antioxidant activity (DPPH and ABTS assays), and vitamin C content. Moreover, principal component analysis (PCA) was also performed. Generally, the OD process using a 40% erythritol solution demonstrated the most efficient kinetics among all osmotic agents tested; however, fruits dehydrated in this solution also showed the most significant changes in physicochemical and antioxidant properties compared to fresh fruits. Remarkably, Japanese quince fruits dehydrated in a 30% erythritol solution exhibited higher levels of total phenolic, flavonoid, vitamin C, and antioxidant activity than those treated with a 50% sucrose solution, despite displaying similar dehydration kinetics. The use of erythritol solutions also led to a decrease in sugar content. In turn, PCA analysis confirmed a correlation between pH values and the L* color parameter, with the highest L* value observed in fruits dehydrated with the sucrose solution. Thus, erythritol may be utilized as a low-calorie alternative to sucrose as an osmotic agent while simultaneously minimizing the loss of antioxidant compounds. Full article

(This article belongs to the Section Food Chemistry)

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3 pages, 179 KiB

Open AccessEditorial

Organosulfur and Organoselenium Chemistry

by Ming Wang

Molecules 2024, 29(23), 5523; https://doi.org/10.3390/molecules29235523 - 22 Nov 2024

Abstract

Organosulfur- and organoselenium-containing compounds play a crucial role in organic synthesis [...] Full article

(This article belongs to the Special Issue Organosulfur and Organoselenium Chemistry)

16 pages, 4694 KiB

Open AccessArticle

Effects of Ethylene Propylene Diene Monomer (EPDM)-Based Polar Macromolecular Compatibilizers on the Low-Temperature Properties of Fluoroelastomer/EPDM Rubber Blends

by Gen Liu, Faxin Du, Zhangjun Yao, Guangzhao Li, Wen Kuang, Chongyu Zhu, Yi Liu, Honglin Chen, Fumei Wang, Ce Zhou, Xueli Wei, Wenyan Wang and Rui Han

Molecules 2024, 29(23), 5522; https://doi.org/10.3390/molecules29235522 - 22 Nov 2024

Abstract

Integrating rubber with superior low-temperature capabilities, such as ethylene propylene diene monomer (EPDM), is a strategic approach to bolster the low-temperature performance of fluoroelastomer (FKM). However, FKM and EPDM are thermodynamically incompatible. This work synthetized three EPDM-based polar macromolecular compatibilizers, epoxidized EPDM (EPDM-EP), 2,2-trifluoroethylamine-grafted epoxidized EPDM (EPDM-TF), and 2,4-difluorobenzylamine-grafted epoxidized EPDM (EPDM-DF), to enhance the compatibility between FKM and EPDM. These compatibilizers were subsequently incorporated into FKM/EPDM rubber blends. The results revealed that the glass transition temperature (T_g) of FKM/EPDM decreased by 1.3 °C, 2.68 °C, and 2.78 °C, respectively, upon the addition of 10 phr of EPDM-EP, EPDM-TF, or EPDM-DF. Moreover, the T_g of the two phases converged. The tensile strength, elongation at break, and tear strength of the FKM/EPDM rubber blends were also enhanced by the inclusion of these compatibilizers. Notably, EPDM-TF and EPDM-DF exhibited remarkable compatibilization effects due to an increase in polarity. This research not only sheds light on the potential for developing new compatibilizers but also paves the way for innovative applications of FKM and its derivatives. Full article

(This article belongs to the Section Macromolecular Chemistry)

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15 pages, 4411 KiB

Open AccessArticle

Spectroscopic and Quantum Chemical Evidence of Amine–CO₂ and Alcohol–CO₂ Interactions: Confirming an Intriguing Affinity of CO₂ to Monoethanolamine (MEA)

by Sahar Hafizi Yazdabadi, Dmytro Mihrin, Karen Louise Feilberg and René Wugt Larsen

Molecules 2024, 29(23), 5521; https://doi.org/10.3390/molecules29235521 - 22 Nov 2024

Abstract

A recent broadband rotational spectroscopic investigation of the cross-association mechanisms of CO₂ with monoethanolamine (MEA) in molecular beams [F. Xie et al., Angew. Chem. Int. Ed., 2023, 62, e202218539] revealed an intriguing affinity of CO₂ to the hydroxy group. These findings have triggered the present systematic vibrational spectroscopic exploration of weakly bound amine··CO₂ and alcohol··CO₂ van der Waals cluster molecules embedded in inert “quantum” matrices of neon at 4.2 K complemented by high-level quantum chemical conformational analyses. The non-covalent interactions formed between the amino and hydroxy groups and the electron-deficient carbon atom of CO₂ are demonstrated to lift the degeneracy of the doubly degenerate intramolecular CO₂-bending fundamental significantly with characteristic observed spectral splittings for the amine··CO₂ (≈35–45 cm⁻¹) and alcohol··CO₂ (≈20–25 cm⁻¹) interactions, respectively, despite the almost identically predicted total association energies (≈12–14 kJ·mol⁻¹) for these van der Waals contacts, as revealed by benchmark Domain-based Local Pair Natural Orbital Coupled Cluster DLPNO-CCSD(T) theory. These high-level theoretical predictions reveal significantly higher “geometry preparation energies” for the amine··CO₂ systems leading to a more severe distortion of the CO₂ linearity upon complexation in agreement with the infrared spectroscopic findings. The systematic combined spectroscopic and quantum chemical evidences for cross-association between CO₂ and amines/alcohols in the present work unambiguously confirm an intriguing binding preference of CO₂ to the hydroxy group of the important carbon capture agent MEA, with an accurate vibrational zero-point energy corrected association energy (D₀) of 13.5 kJ·mol⁻¹ at the benchmark DLPNO-CCSD(T)/aug-cc-pV5Z level of theory. Full article

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

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16 pages, 1275 KiB

Open AccessReview

Silver Nanoparticles as a Potent Nanopesticide: Toxic Effects and Action Mechanisms on Pest Insects of Agricultural Importance—A Review

by Daniel Martínez-Cisterna, Olga Rubilar, Gonzalo Tortella, Lingyun Chen, Manuel Chacón-Fuentes, Marcelo Lizama, Pablo Parra and Leonardo Bardehle

Molecules 2024, 29(23), 5520; https://doi.org/10.3390/molecules29235520 - 22 Nov 2024

Abstract

Nanotechnology has been a promising plant protection discipline in recent years, attributed to the unique physicochemical properties exhibited at the nanoscale. In this context, silver nanoparticles (AgNPs) have been effective in various applications, including medical, industrial, and agronomic, and during the last few years, the control of insect pests has raised great interest. The present review mainly provides updated information about the use of AgNPs elaborated by different synthesis methods, such as biological (plants, microorganisms), physical, and chemical, and their effect against various insect species of agricultural importance belonging to the order Diptera, Coleoptera, Lepidoptera, and Hemiptera. The physiological and toxic effects of applying AgNPs are reported and characterized by developmental problems, mortality, weight reduction, interference with enzymatic activity, and anomalies in the life cycle. Moreover, in the final section, the action mechanisms through which AgNPs act on insects are also discussed, highlighting mechanisms such as alteration of transmembrane permeability, interruption of DNA replication, alteration of protein synthesis, and production of reactive oxygen species (ROS). Full article

(This article belongs to the Special Issue Natural Products as Insecticidal Agents)

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19 pages, 1632 KiB

Open AccessArticle

New Conjugates of Vancomycin with Cell-Penetrating Peptides—Synthesis, Antimicrobial Activity, Cytotoxicity, and BBB Permeability Studies

by Jarosław Ruczyński, Katarzyna Prochera, Natalia Kaźmierczak, Katarzyna Kosznik-Kwaśnicka, Lidia Piechowicz, Piotr Mucha and Piotr Rekowski

Molecules 2024, 29(23), 5519; https://doi.org/10.3390/molecules29235519 - 22 Nov 2024

Abstract

Vancomycin (Van) is a glycopeptide antibiotic commonly used as a last resort for treating life-threatening infections caused by multidrug-resistant bacterial strains, such as Staphylococcus aureus and Enterococcus spp. However, its effectiveness is currently limited due to the rapidly increasing number of drug-resistant clinical strains and its inherent cytotoxicity and poor penetration into cells and specific regions of the body, such as the brain. One of the most promising strategies to enhance its efficacy appears to be the covalent attachment of cell-penetrating peptides (CPPs) to the Van structure. In this study, a series of vancomycin conjugates with CPPs—such as TP10, Tat (47–57), PTD4, and Arg₉—were designed and synthesized. These conjugates were tested for antimicrobial activity against four reference strains (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa) and two clinical drug-resistant strains: methicillin-resistant S. aureus and vancomycin-resistant E. faecium. In addition, cytotoxicity tests (using a human fibroblast cell line) and blood–brain barrier (BBB) permeability tests (using a parallel artificial membrane permeability assay—PAMPA-BBB assay) were conducted for selected compounds. Our research demonstrated that conjugation of Van with CPPs, particularly with Tat (47–57), Arg₉, or TP10, significantly enhances its antimicrobial activity against Gram-positive bacteria such as S. aureus and Enterococcus spp., reduces its cytotoxicity, and improves its access to brain tissues. We conclude that these findings provide a strong foundation for the design of novel antimicrobial agents effective in treating infections caused by drug-resistant staphylococcal and enterococcal strains, while also being capable of crossing the BBB. Full article

(This article belongs to the Special Issue Chemical Biology of Antimicrobial Resistance, 2nd Edition)

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13 pages, 3291 KiB

Open AccessArticle

Using the Theozyme Model to Study the Dynamical Mechanism of the Post-Transition State Bifurcation Reaction by NgnD Enzyme

by Yaning Hou, Jingyun Chen, Weizhe Liu, Gaohua Zhu, Qianying Yang and Xin Wang

Molecules 2024, 29(23), 5518; https://doi.org/10.3390/molecules29235518 - 22 Nov 2024

Abstract

Post-transition state bifurcation (PTSB) is a fundamental process in which a single transition state leads to multiple products. This phenomenon is important in both biological and chemical contexts and offers valuable insights into reaction mechanisms and their applications. The theozyme model, which focuses on key residues within enzymes, offers a computationally efficient method for studying these processes while preserving the enzyme’s catalytic properties. This approach enhances our understanding of how enzymes stabilize and direct the transition state, thereby influencing product distribution and selectivity. In this study, we investigate the dynamics and regulatory mechanisms of the PTSB reaction catalyzed by the enzyme NgnD. The enzyme NgnD facilitates a cycloaddition reaction that produces both [6 + 4] and [4 + 2] adducts, with a preference for the [6 + 4] adduct. By analyzing the potential energy surface, bond length distribution, and interactions between the theozyme and the ambimodal transition state, we elucidate the role of the enzyme’s active site residues in determining product selectivity. We illustrate how these key residues contribute to the formation of different adducts, providing insights from various perspectives. Using theozyme models, we propose how the four most influential active residues collectively might control the direction of adduct formation through their cumulative effects. Full article

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7 pages, 220 KiB

Open AccessBrief Report

An Environmentally Compatible and Less Costly (Greener) Microwave Digestion Method of Bone Samples Using Dilute Nitric Acid for Analysis by ICP-MS

by Derek D. Bussan, Forrest H. Nielsen, Chris Douvris, Brett Kelzenberg, Allison Grimestad and Jay J. Cao

Molecules 2024, 29(23), 5517; https://doi.org/10.3390/molecules29235517 - 22 Nov 2024

Abstract

An environmentally compatible and less costly (greener) analytical method for the digestion of bone meal samples using microwave-assisted dilute nitric acid (HNO₃) was developed and optimized. The method, employing a mixture of 1 mL concentrated HNO₃ and 4 mL of deionized water, offered a comparable performance to the conventional method using 5 mL of concentrated HNO₃. The accuracy of the method was validated by using certified reference material NIST 1486 (Bone Meal); percentage recoveries were within ±15% for all eight certified elements. Statistical analysis revealed no significant differences (p > 0.05) in percentage recoveries between the green and conventional methods for all elements except calcium. The greenness of the developed method was evaluated by using the analytical Eco-Scale, achieving a score of 87, categorizing it as an “excellent green analysis” method. This research highlights the potential for adopting greener practices in trace element analysis that reduce the environmental impact and safety risks associated with concentrated acids. Full article

17 pages, 3095 KiB

Open AccessArticle

Toxicological Analysis of the Arylnaphthalene Lignan Justicidin B Using a Caenorhabditis elegans Model

by Barbara Sciandrone, Roméo Arago Dougué Kentsop, Roberta Pensotti, Gianluca Ottolina, Iride Mascheretti, Monica Mattana and Maria Elena Regonesi

Molecules 2024, 29(23), 5516; https://doi.org/10.3390/molecules29235516 - 22 Nov 2024

Abstract

The screening of plant-derived compounds with anti-cancer properties is a promising strategy to meet the growing need for new, safe and effective anti-cancer drugs. Justicidin B is a plants secondary metabolite that displays anti-cancer properties in several tumor cells. Therefore, it represents a good candidate. We used the 3R-compliant organism Caenorhabditis elegans to evaluate the safety of justicidin B produced by in vitro-grown adventitious roots of Linum lewisii. We showed that a dose of 100 µg/mL justicidin B does not affect worm vitality in either short-term or chronic administration; in contrast, the 200 µg/mL dose induces a lifespan reduction, but only in short-term daily treatment. We attributed this effect to its accumulation in lipofuscin granules in the pharynx as observed through confocal analysis. HPLC analysis confirmed the higher accumulation justicidin B with a 200 µg/mL dose but also revealed the presence of metabolic derivatives that could be responsible for the toxicity. We also demonstrated that the 100 µg/mL dose does not affect worm fertility or development. Our results highlight the safety of justicidin B, supporting its employment in cancer therapy, and encourage the use of a C. elegans model as an appropriate tool to assess compounds’ toxicity before moving to more complex organisms. Full article

(This article belongs to the Special Issue Research Progress and Application of Natural Compounds—2nd Edition)

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5 pages, 204 KiB

Open AccessEditorial

Nano-Functional Materials for Sensor Applications

by Aiwu Wang and Li Fu

Molecules 2024, 29(23), 5515; https://doi.org/10.3390/molecules29235515 - 22 Nov 2024

Abstract

The rapid development of nanotechnology and materials science has led to remarkable advances in sensor applications across various fields [...] Full article

(This article belongs to the Special Issue Nano-Functional Materials for Sensor Applications)

17 pages, 4157 KiB

Open AccessArticle

Laccase Production Optimization from Recombinant E. coli BL21 Codon Plus Containing Novel Laccase Gene from Bacillus megaterium for Removal of Wastewater Textile Dye

by Zannara Mustafa, Ikram ul Haq, Ali Nawaz, Abdulrahman H. Alessa, Muhammad Nauman Aftab, Ahmad A. Alsaigh and Aziz ur Rehman

Molecules 2024, 29(23), 5514; https://doi.org/10.3390/molecules29235514 - 22 Nov 2024

Abstract

The aim of the present research was the efficient degradation of industrial textile wastewater dyes using a very active cloned laccase enzyme. For this purpose, potent laccase-producing bacteria were isolated from soil samples collected from wastewater-replenished textile sites in Punjab, Pakistan. The laccase gene from locally isolated strain LI-81, identified as Bacillus megaterium, was cloned into vector pET21a, which was further transformed into E. coli BL21 codon plus. The optimized conditions for the increased production of laccase include fermentation in a 2% glucose, 5% yeast extract and 250 mg/L CuSO₄ medium with pH 7.5; inoculation with 5% inoculum; induction with 0.1 mM IPTG at 0.5 O.D.; and incubation for 36 h at 37 °C. The crude enzyme produced was employed for the removal of commercially used textile dyes. The dyes were quickly precipitated under optimized reaction conditions. Rose bengal, brilliant green, brilliant blue G, Coomassie brilliant blue R and methylene blue were precipitated at rates of 10.69, 54.47, 84.04, 78.99 and 7.40%, respectively. The FTIR and UV–Vis spectroscopic analyses of dyes before and after confirmed the chemical changes brought about by the cloned laccase that led to the dye removal. Full article

(This article belongs to the Section Chemical Biology)

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