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 14.6 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- 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 journals for Molecules include: Foundations and Photochem.
Impact Factor:
4.6 (2022);
5-Year Impact Factor:
4.9 (2022)
Latest Articles
Preparative Fractionation of Brazilian Red Propolis Extract Using Step-Gradient Counter-Current Chromatography
Molecules 2024, 29(12), 2757; https://doi.org/10.3390/molecules29122757 (registering DOI) - 9 Jun 2024
Abstract
Propolis is a resinous bee product with a very complex composition, which is dependent upon the plant sources that bees visit. Due to the promising antimicrobial activities of red Brazilian propolis, it is paramount to identify the compounds responsible for it, which, in
[...] Read more.
Propolis is a resinous bee product with a very complex composition, which is dependent upon the plant sources that bees visit. Due to the promising antimicrobial activities of red Brazilian propolis, it is paramount to identify the compounds responsible for it, which, in most of the cases, are not commercially available. The aim of this study was to develop a quick and clean preparative-scale methodology for preparing fractions of red propolis directly from a complex crude ethanol extract by combining the extractive capacity of counter-current chromatography (CCC) with preparative HPLC. The CCC method development included step gradient elution for the removal of waxes (which can bind to and block HPLC columns), sample injection in a single solvent to improve stationary phase stability, and a change in the mobile phase flow pattern, resulting in the loading of 2.5 g of the Brazilian red propolis crude extract on a 912.5 mL Midi CCC column. Three compounds were subsequently isolated from the concentrated fractions by preparative HPLC and identified by NMR and high-resolution MS: red pigment, retusapurpurin A; the isoflavan 3(R)-7-O-methylvestitol; and the prenylated benzophenone isomers xanthochymol/isoxanthochymol. These compounds are markers of red propolis that contribute to its therapeutic properties, and the amount isolated allows for further biological activities testing and for their use as chromatographic standards.
Full article
(This article belongs to the Special Issue Countercurrent Chromatography (CCC/CPC) as Versatile Separation ‘Tool-Box’ in the Field of Natural Product Recovery)
Open AccessArticle
Spectral Assignment in the [3 + 2] Cycloadditions of Methyl (2E)-3-(acridin-4-yl)-prop-2-enoate and 4-[(E)-2-Phenylethenyl]acridin with Unstable Nitrile N-Oxides
by
Lucia Ungvarská Maľučká and Mária Vilková
Molecules 2024, 29(12), 2756; https://doi.org/10.3390/molecules29122756 (registering DOI) - 9 Jun 2024
Abstract
The investigation of cycloaddition reactions involving acridine-based dipolarophiles revealed distinct regioselectivity patterns influenced mainly by the electronic factor. Specifically, the reactions of methyl-(2E)-3-(acridin-4-yl)-prop-2-enoate and 4-[(1E)-2-phenylethenyl]acridine with unstable benzonitrile N-oxides were studied. For methyl-(2E)-3-(acridin-4-yl)-prop-2-enoate, the formation of two
[...] Read more.
The investigation of cycloaddition reactions involving acridine-based dipolarophiles revealed distinct regioselectivity patterns influenced mainly by the electronic factor. Specifically, the reactions of methyl-(2E)-3-(acridin-4-yl)-prop-2-enoate and 4-[(1E)-2-phenylethenyl]acridine with unstable benzonitrile N-oxides were studied. For methyl-(2E)-3-(acridin-4-yl)-prop-2-enoate, the formation of two regioisomers favoured the 5-(acridin-4-yl)-4,5-dihydro-1,2-oxazole-4-carboxylates, with remarkable exclusivity in the case of 4-methoxybenzonitrile oxide. Conversely, 4-[(1E)-2-phenylethenyl]acridine displayed reversed regioselectivity, favouring products 4-[3-(substituted phenyl)-5-phenyl-4,5-dihydro-1,2-oxazol-4-yl]acridine. Subsequent hydrolysis of isolated methyl 5-(acridin-4-yl)-3-phenyl-4,5-dihydro-1,2-oxazole-4-carboxylates resulted in the production of carboxylic acids, with nearly complete conversion. During NMR measurements of carboxylic acids in CDCl3, decarboxylation was observed, indicating the formation of a new prochiral carbon centre C-4, further confirmed by a noticeable colour change. Overall, this investigation provides valuable insights into regioselectivity in cycloaddition reactions and subsequent transformations, suggesting potential applications across diverse scientific domains.
Full article
(This article belongs to the Special Issue New Insights into Nuclear Magnetic Resonance (NMR) Spectroscopy)
Open AccessArticle
A Benzothiadiazole-Based Zn(II) Metal–Organic Framework with Visual Turn-on Sensing for Anthrax Biomarker and Theoretical Calculation
by
Jing Ru, Yi-Xuan Shi, Qing-Yun Yang, Teng Li, Hai-Ying Wang, Fan Cao, Qiang Guo and Yan-Lan Wang
Molecules 2024, 29(12), 2755; https://doi.org/10.3390/molecules29122755 (registering DOI) - 9 Jun 2024
Abstract
2,6-pyridine dicarboxylic acid (DPA) is an exceptional biomarker of notorious anthrax spores. Therefore, the rapid, sensitive, and selective quantitative detection of DPA is extremely significant and urgent. This paper reports a Zn(II) metal–organic framework with the formula of {[Zn6(NDA)6(DPBT)
[...] Read more.
2,6-pyridine dicarboxylic acid (DPA) is an exceptional biomarker of notorious anthrax spores. Therefore, the rapid, sensitive, and selective quantitative detection of DPA is extremely significant and urgent. This paper reports a Zn(II) metal–organic framework with the formula of {[Zn6(NDA)6(DPBT)3] 2H2O·3DMF}n (MOF-1), which consists of 2,6-naphthalenedicarboxylic acid (2,6-NDA), 4,7-di(4-pyridyl)-2,1,3-benzothiadiazole (DPBT), and Zn(II) ions. Structural analysis indicated that MOF-1 is a three-dimensional (3D) network which crystallized in the monoclinic system with the C2/c space group, revealing high pH, solvent, and thermal stability. Luminescence sensing studies demonstrated that MOF-1 had the potential to be a highly selective, sensitive, and recyclable fluorescence sensor for the identification of DPA. Furthermore, fluorescent test paper was made to detect DPA promptly with color changes. The enhancement mechanism was established by the hydrogen-bonding interaction and photoinduced electron transfer transition between MOF-1 and DPA molecules.
Full article
(This article belongs to the Special Issue Metal Organic Frameworks (MOFs) for Sensing Applications)
Open AccessArticle
The Influence of Clustered DNA Damage Containing Iz/Oz and OXOdG on the Charge Transfer through the Double Helix: A Theoretical Study
by
Bolesław T. Karwowski
Molecules 2024, 29(12), 2754; https://doi.org/10.3390/molecules29122754 (registering DOI) - 9 Jun 2024
Abstract
The genome—the source of life and platform of evolution—is continuously exposed to harmful factors, both extra- and intra-cellular. Their activity causes different types of DNA damage, with approximately 80 different types of lesions having been identified so far. In this paper, the influence
[...] Read more.
The genome—the source of life and platform of evolution—is continuously exposed to harmful factors, both extra- and intra-cellular. Their activity causes different types of DNA damage, with approximately 80 different types of lesions having been identified so far. In this paper, the influence of a clustered DNA damage site containing imidazolone (Iz) or oxazolone (Oz) and 7,8-dihydro-8-oxo-2′-deoxyguanosine (OXOdG) on the charge transfer through the double helix as well as their electronic properties were investigated. To this end, the structures of oligo-Iz, d[A1Iz2A3OXOG4A5]*d[T5C4T3C2T1], and oligo-Oz, d[A1Oz2A3OXOG4A5]*d[T5C4T3C2T1], were optimized at the M06-2X/6-D95**//M06-2X/sto-3G level of theory in the aqueous phase using the ONIOM methodology; all the discussed energies were obtained at the M06-2X/6-31++G** level of theory. The non-equilibrated and equilibrated solvent–solute interactions were taken into consideration. The following results were found: A) In all the discussed cases, OXOdG showed a higher predisposition to radical cation formation, and B) the excess electron migration toward Iz and Oz was preferred. However, in the case of oligo-Oz, the electron transfer from Oz2 to complementary C4 was noted during vertical to adiabatic anion relaxation, while for oligo-Iz, it was settled exclusively on the Iz2 moiety. The above was reflected in the charge transfer rate constant, vertical/adiabatic ionization potential, and electron affinity energy values, as well as the charge and spin distribution. It can be postulated that imidazolone moiety formation within the CDL ds-oligo structure and its conversion to oxazolone can significantly influence the charge migration process, depending on the C2 carbon hybridization sp2 or sp3. The above can confuse the single DNA damage recognition and removal processes, cause an increase in mutagenesis, and harm the effectiveness of anticancer therapy.
Full article
Open AccessArticle
Effect of Calcination Atmosphere on the Performance of Cu/Al2O3 Catalyst for the Selective Hydrogenation of Furfural to Furfuryl Alcohol
by
Yongzhen Gao, Wenjing Yi, Jingyi Yang, Kai Jiang, Tao Yang, Zhihan Li, Meng Zhang, Zhongyi Liu and Benlai Wu
Molecules 2024, 29(12), 2753; https://doi.org/10.3390/molecules29122753 (registering DOI) - 9 Jun 2024
Abstract
The selective hydrogenation of the biomass platform molecule furfural (FAL) to produce furfuryl alcohol (FA) is of great significance to alleviate the energy crisis. Cu-based catalysts are the most commonly used catalysts, and their catalytic performance can be optimized by changing the preparation
[...] Read more.
The selective hydrogenation of the biomass platform molecule furfural (FAL) to produce furfuryl alcohol (FA) is of great significance to alleviate the energy crisis. Cu-based catalysts are the most commonly used catalysts, and their catalytic performance can be optimized by changing the preparation method. This paper emphasized the effect of calcination atmosphere on the performance of a Cu/Al2O3 catalyst for the selective hydrogenation of FAL. The precursor of the Cu/Al2O3 catalyst prepared by the ammonia evaporation method was treated with different calcination atmospheres (N2 and air). On the basis of the combined results from the characterizations using in situ XRD, TEM, N2O titration, H2-TPR and XPS, the Cu/Al2O3 catalyst calcined in the N2 atmosphere was more favorable for the dispersion and reduction of Cu species and the reduction process could produce more Cu+ and Cu0 species, which facilitated the selective hydrogenation of FAL to FA. The experimental results showed that the N2 calcination atmosphere improved the FAL conversion and FA selectivity, and the FAL conversion was further increased after reduction. Cu/Al2O3-N2-R exhibited the outstanding performance, with a high yield of 99.9% of FA after 2 h at 120 °C and an H2 pressure of 1 MPa. This work provides a simple, efficient and economic method to improve the C=O hydrogenation performance of Cu-based catalysts.
Full article
(This article belongs to the Special Issue New Strategies for Metal Catalysis in Heterogeneous System)
►▼
Show Figures
Figure 1
Open AccessArticle
Efficient Preparation of Biodiesel Using Sulfonated Camellia oleifera Shell Biochar as a Catalyst
by
Zhimin Yang, Yu Wang, Xichang Wu, Wenxuan Quan, Qi Chen and Anping Wang
Molecules 2024, 29(12), 2752; https://doi.org/10.3390/molecules29122752 (registering DOI) - 9 Jun 2024
Abstract
Abstract: This study prepared sulfonated Camellia oleifera shell biochar using Camellia oleifera shell agricultural waste as a carbon source, and evaluated its performance as a catalyst for preparing biodiesel. The biochar obtained from carbonizing Camellia oleifera shells at 500 °C for 2
[...] Read more.
Abstract: This study prepared sulfonated Camellia oleifera shell biochar using Camellia oleifera shell agricultural waste as a carbon source, and evaluated its performance as a catalyst for preparing biodiesel. The biochar obtained from carbonizing Camellia oleifera shells at 500 °C for 2 h serves as the carbon skeleton, and then the biochar is sulfonated with chlorosulfonic acid. The sulfonic acid groups are mainly grafted onto the surface of Camellia oleifera shell biochar through covalent bonding to obtain sulfonic acid type biochar catalysts. The catalysts were characterized by Scanning Electron Microscope (SEM), X-ray diffraction (XRD), Nitrogen adsorption-desorption Brunel-Emmett-Taylor Theory (BET), and Fourier-transform infrared spectroscopy (FT-IR). The acid density of the sulfonated Camellia oleifera fruit shell biochar catalyst is 2.86 mmol/g, and the specific surface area is 2.67 m2/g, indicating high catalytic activity. The optimal reaction conditions are 4 wt% catalyst with a 6:1 alcohol to oil ratio. After esterification at 70 °C for 2 h, the yield of biodiesel was 91.4%. Under the optimal reaction conditions, after four repeated uses of the catalyst, the yield of biodiesel still reached 90%. Therefore, sulfonated Camellia oleifera shell biochar is a low-cost, green, non-homogeneous catalyst with great potential for biodiesel production by esterification reaction in future development.
Full article
(This article belongs to the Special Issue Advances in Biomass Chemicals: Transformation and Valorization)
Open AccessArticle
Influence of Novel Microcapsulates of Bee Products on Gut Microbiota Modulation and Their Prebiotic and Pro-Adhesive Properties
by
Gabriela Kowalska, Justyna Rosicka-Kaczmarek, Karolina Miśkiewicz, Adriana Nowak, Ilona Motyl, Joanna Oracz, Anna Brzozowska, Aleksandra Grzegorczyk and Zuzanna Świniarska
Molecules 2024, 29(12), 2751; https://doi.org/10.3390/molecules29122751 (registering DOI) - 9 Jun 2024
Abstract
With the aim to obtain controlled-release systems and to preserve the antioxidant, immunomodulatory, and prebiotic activity of the bioactive compounds, microencapsulation of both honeydew honey and royal jelly into biopolymeric microparticles based on rye bran heteropolysaccharides (HPS) was successfully performed. Honeydew honey and
[...] Read more.
With the aim to obtain controlled-release systems and to preserve the antioxidant, immunomodulatory, and prebiotic activity of the bioactive compounds, microencapsulation of both honeydew honey and royal jelly into biopolymeric microparticles based on rye bran heteropolysaccharides (HPS) was successfully performed. Honeydew honey and royal jelly microcapsules were prepared by spray-drying method and were characterized in terms of morphology and biological properties. Due to the resistance of the obtained encapsulates to the acidic pH in the stomach and digestive enzymes, the microcapsules showed prebiotic properties positively influencing both the growth, retardation of the dying phase, and the pro-adhesive properties of probiotic bacteria, i.e., Bifidobacterium spp. and lactic acid bacteria. Moreover, as a result of fermentation of the microcapsules of bee products in the lumen of the large intestine, an increased synthesis of short-chain fatty acids, i.e., butyric acid, was found on average by 39.2% in relation to the SCFA concentrations obtained as a result of fermentation of native bee products, thus opening new perspectives for the exploitation of honeydew honey and royal jelly loaded microcapsules for nutraceutical applications.
Full article
(This article belongs to the Special Issue Recent Advances in Micro- and Nanoencapsulation of Bioactive Compounds 2.0)
►▼
Show Figures
Figure 1
Open AccessArticle
Enhanced CH4/N2 Separation Efficiency of UiO-66-Br2 through Hybridization with Mesoporous Silica
by
Hu Wang, Ziao Zong, Yadong Zhou, Chaochuang Yin, Yizhu Lei, Renshu Wang, Yuheng Deng and Tingting Wu
Molecules 2024, 29(12), 2750; https://doi.org/10.3390/molecules29122750 (registering DOI) - 9 Jun 2024
Abstract
Efficient separation of CH4 from N2 is essential for the purification of methane from nitrogen. In order to address this problem, composite materials consisting of rod-shaped SBA-15-based UiO-66-Br2 were synthesized for the purpose of separating a CH4/N2
[...] Read more.
Efficient separation of CH4 from N2 is essential for the purification of methane from nitrogen. In order to address this problem, composite materials consisting of rod-shaped SBA-15-based UiO-66-Br2 were synthesized for the purpose of separating a CH4/N2 mixture. The materials were characterized via PXRD, N2 adsorption–desorption, SEM, TEM, FT-IR, and TGA. The adsorption isotherms of CH4 and N2 under standard pressure conditions for the composites were determined and subsequently compared. The study revealed that the composites were formed through the growth of MOF nanocrystals on the surfaces of the SBA-15 matrix. The enhancements in surface area and adsorption capacity of hybrid materials were attributed to the structural modifications resulting from the interactions between surface silanol groups and metal centers. The selectivity of the composites towards a gas mixture of CH4 and N2 was assessed utilizing the Langmuir adsorption equation. The results of the analysis revealed that the U6B2S5/SBA-15 sample exhibited the greatest selectivity for CH4/N2 adsorption compared to the other samples, with an adsorption selectivity parameter (S) of 20.06. Additional research is necessary to enhance the enrichment of methane from CH4/N2 mixtures using SBA-15-based metal-organic framework materials.
Full article
(This article belongs to the Special Issue Zeolite: A Strategic Materials for Sustainable Chemistry and Future Energy)
►▼
Show Figures
Figure 1
Open AccessArticle
Aggregation Behavior and Application Properties of Novel Glycosylamide Quaternary Ammonium Salts in Aqueous Solution
by
Yunkai Wang, Zeyu Chen, Erzhuang Zhang, Lifei Zhi, Martino Di Serio, Guoyong Wang, Yan Wang, Xiaoming Li, Xudong Liu and Ying Huang
Molecules 2024, 29(12), 2749; https://doi.org/10.3390/molecules29122749 (registering DOI) - 9 Jun 2024
Abstract
Amidation of lactobionic acid with N,N-dimethylaminopropyltriamine was conducted to obtain N-(3′-dimethylaminopropyl)-lactamido-3-aminopropane (DDLPD), which was quaternized with bromoalkanes of different carbon chain lengths to synthesize double-stranded lactosylamide quaternary ammonium salt N-[N′[3-(lactosylamide)]propyl-N′-alkyl] propyl-N,N-dimethyl-N-alkylammonium bromide (CnDDLPB, n = 8, 10, 12, 14, 16). The
[...] Read more.
Amidation of lactobionic acid with N,N-dimethylaminopropyltriamine was conducted to obtain N-(3′-dimethylaminopropyl)-lactamido-3-aminopropane (DDLPD), which was quaternized with bromoalkanes of different carbon chain lengths to synthesize double-stranded lactosylamide quaternary ammonium salt N-[N′[3-(lactosylamide)]propyl-N′-alkyl] propyl-N,N-dimethyl-N-alkylammonium bromide (CnDDLPB, n = 8, 10, 12, 14, 16). The surface activity and the adsorption and aggregation behaviors of the surfactants were investigated via equilibrium surface tension, dynamic light scattering, and cryo-electron microscopy measurements in an aqueous solution. The application properties of the products in terms of wettability, emulsification, foam properties, antistatic, salt resistance, and bacteriostatic properties were tested. CnDDLPB exhibited a low equilibrium surface tension of 27.82 mN/m. With an increase in the carbon chain length, the critical micellar concentration of CnDDLPBD decreased. Cryo-electron microscopy revealed that all products except C8DDLPB formed stable monolayer, multi-layer, and multi-compartmental vesicle structures in an aqueous solution. C14DDLPB has the best emulsification performance on soybean oil, with a time of 16.6 min; C14DDLPB has good wetting and spreading properties on polytetrafluoroethylene (PTFE) when the length of carbon chain is from 8 to 14, and the contact angle can be lowered to 33°~40°; CnDDLPB has low foam, which is typical of low-foaming products; C8DDLPB and C10DDLPB both show good antistatic properties. C8DDLPB and C14DDLPB have good salt resistance, and C12DDLPB has the best antimicrobial property, with the inhibition rate of 99.29% and 95.28% for E. coli and Gluconococcus aureus, respectively, at a concentration of 350 ppm.
Full article
(This article belongs to the Special Issue Amphiphilic Molecules, Interfaces and Colloids)
►▼
Show Figures
Figure 1
Open AccessReview
An Overview of the Synthesis of 3,4-Fused Pyrrolocoumarins of Biological Interest
by
Eleni Kapidou and Konstantinos E. Litinas
Molecules 2024, 29(12), 2748; https://doi.org/10.3390/molecules29122748 (registering DOI) - 9 Jun 2024
Abstract
3,4-Fused pyrrolocoumarins, synthetically prepared or naturally occurring, possess interesting biological properties. In this review, the synthetic strategies for the synthesis of the title compounds are presented along with their biological activities. Two routes are followed for that synthesis. In one, the pyrrole ring
[...] Read more.
3,4-Fused pyrrolocoumarins, synthetically prepared or naturally occurring, possess interesting biological properties. In this review, the synthetic strategies for the synthesis of the title compounds are presented along with their biological activities. Two routes are followed for that synthesis. In one, the pyrrole ring is formed from coumarin derivatives, such as aminocoumarins or other coumarins. In the other approach, the pyranone moiety is built from an existing pyrrole derivative or through the simultaneous formation of coumarin and pyrrole frameworks. The above syntheses are achieved via 1,3-dipolar cycloaddition reactions, Michael reaction, aza-Claisen rearrangement reactions, multi-component reactions (MCR), as well as metal-catalyzed reactions. Pyrrolocoumarins present cytotoxic, antifungal, antibacterial, α-glucosidase inhibition, antioxidant, lipoxygenase (LOX) inhibition, and fluorescent activities, as well as benzodiazepine receptor ability.
Full article
(This article belongs to the Special Issue Organic Synthesis and Application of Bioactive Molecules)
Open AccessReview
Modulating the Gut Microbiota and Metabolites with Traditional Chinese Medicines: An Emerging Therapy for Type 2 Diabetes Mellitus and Its Complications
by
Peiyan Jiang, Zhenghan Di, Wenting Huang and Lan Xie
Molecules 2024, 29(12), 2747; https://doi.org/10.3390/molecules29122747 (registering DOI) - 9 Jun 2024
Abstract
Currently, an estimated 537 million individuals are affected by type 2 diabetes mellitus (T2DM), the occurrence of which is invariably associated with complications. Glucose-lowering therapy remains the main treatment for alleviating T2DM. However, conventional antidiabetic agents are fraught with numerous adverse effects, notably
[...] Read more.
Currently, an estimated 537 million individuals are affected by type 2 diabetes mellitus (T2DM), the occurrence of which is invariably associated with complications. Glucose-lowering therapy remains the main treatment for alleviating T2DM. However, conventional antidiabetic agents are fraught with numerous adverse effects, notably elevations in blood pressure and lipid levels. Recently, the use of traditional Chinese medicines (TCMs) and their constituents has emerged as a preferred management strategy aimed at curtailing the progression of diabetes and its associated complications with fewer adverse effects. Increasing evidence indicates that gut microbiome disturbances are involved in the development of T2DM and its complications. This regulation depends on various metabolites produced by gut microbes and their interactions with host organs. TCMs’ interventions have demonstrated the ability to modulate the intestinal bacterial microbiota, thereby restoring host homeostasis and ameliorating metabolic disorders. This review delves into the alterations in the gut microbiota and metabolites in T2DM patients and how TCMs treatment regulates the gut microbiota, facilitating the management of T2DM and its complications. Additionally, we also discuss prospective avenues for research on natural products to advance diabetes therapy.
Full article
(This article belongs to the Special Issue Antidiabetic Natural Products)
Open AccessArticle
First-Principles Investigation of Phosphorus-Doped Graphitic Carbon Nitride as Anchoring Material for the Lithium-Sulfur Battery
by
Yuehui Chen, Fengxia Liu, Shuang Wei, Yingkai Xia, Xiaodong Li, Shengnan Liu, Xu Zhang, Shuwei Tang, Ding Shen, Wei Dong and Shaobin Yang
Molecules 2024, 29(12), 2746; https://doi.org/10.3390/molecules29122746 (registering DOI) - 9 Jun 2024
Abstract
The utilization of lithium–sulfur battery is hindered by various challenges, including the “shuttle effect”, limited sulfur utilization, and the sluggish conversion kinetics of lithium polysulfides (LiPSs). In the present work, a theoretical design for the viability of graphitic carbon nitride (g-C3N
[...] Read more.
The utilization of lithium–sulfur battery is hindered by various challenges, including the “shuttle effect”, limited sulfur utilization, and the sluggish conversion kinetics of lithium polysulfides (LiPSs). In the present work, a theoretical design for the viability of graphitic carbon nitride (g-C3N4) and phosphorus-doping graphitic carbon nitride substrates (P-g-C3N4) as promising host materials in a Li-S battery was conducted utilizing first-principles calculations. The PDOS shows that when the P atom is introduced, the 2p of the N atom is affected by the 2p orbital of the P atom, which increases the energy band of phosphorus-doping substrates. The energy bands of PC and Pi are 0.12 eV and 0.20 eV, respectively. When the lithium polysulfides are adsorbed on four substrates, the overall adsorption energy of PC is 48–77% higher than that of graphitic carbon nitride, in which the charge transfer of long-chain lithium polysulfides increase by more than 1.5-fold. It is found that there are powerful Li-N bonds between lithium polysulfides and P-g-C3N4 substrates. Compared with the graphitic carbon nitride monolayer, the anchoring effect of the LiPSs@P-g-C3N4 substrate is enhanced, which is beneficial for inhibiting the shuttle of high-order lithium polysulfides. Furthermore, the catalytic performance of the P-g-C3N4 substrate is assessed in terms of the S8 reduction pathway and the decomposition of Li2S; the decomposition energy barrier of the P-g-C3N4 substrate decrease by 10% to 18%. The calculated results show that P-g-C3N4 can promote the reduction of S8 molecules and Li-S bond cleavage within Li2S, thus improving the utilization of sulfur-active substances and the ability of rapid reaction kinetics. Therefore, the P-g-C3N4 substrates are a promising high-performance lithium-sulfur battery anchoring material.
Full article
(This article belongs to the Special Issue 2D Nanosheets and Their Nanohybrids)
►▼
Show Figures
Figure 1
Open AccessArticle
Dynamic Interplay between Microbiota Shifts and Differential Metabolites during Dairy Processing and Storage
by
Yinan Zhang, Peng Yu and Fei Tao
Molecules 2024, 29(12), 2745; https://doi.org/10.3390/molecules29122745 (registering DOI) - 9 Jun 2024
Abstract
Due to the intricate complexity of the original microbiota, residual heat-resistant enzymes, and chemical components, identifying the essential factors that affect dairy quality using traditional methods is challenging. In this study, raw milk, pasteurized milk, and ultra-heat-treated (UHT) milk samples were collectively analyzed
[...] Read more.
Due to the intricate complexity of the original microbiota, residual heat-resistant enzymes, and chemical components, identifying the essential factors that affect dairy quality using traditional methods is challenging. In this study, raw milk, pasteurized milk, and ultra-heat-treated (UHT) milk samples were collectively analyzed using metagenomic next-generation sequencing (mNGS), high-throughput liquid chromatography-mass spectrometry (LC-MS), and gas chromatography–mass spectrometry (GC-MS). The results revealed that raw milk and its corresponding heated dairy products exhibited different trends in terms of microbiota shifts and metabolite changes during storage. Via the analysis of differences in microbiota and correlation analysis of the microorganisms present in differential metabolites in refrigerated pasteurized milk, the top three differential microorganisms with increased abundance, Microbacterium (p < 0.01), unclassified Actinomycetia class (p < 0.05), and Micrococcus are (p < 0.01), were detected; these were highly correlated with certain metabolites in pasteurized milk (r > 0.8). This indicated that these genera were the main proliferating microorganisms and were the primary genera involved in the metabolism of pasteurized milk during refrigeration-based storage. Microorganisms with decreased abundance were classified into two categories based on correlation analysis with certain metabolites. It was speculated that the heat-resistant enzyme system of a group of microorganisms with high correlation (r > 0.8), such as Pseudomonas and Acinetobacter, was the main factor causing milk spoilage and that the group with lower correlation (r < 0.3) had a lower impact on the storage process of pasteurized dairy products. By comparing the metabolic pathway results based on metagenomic and metabolite annotation, it was proposed that protein degradation may be associated with microbial growth, whereas lipid degradation may be linked to raw milk’s initial heat-resistant enzymes. By leveraging the synergy of metagenomics and metabolomics, the interacting factors determining the quality evolution of dairy products were systematically investigated, providing a novel perspective for controlling dairy processing and storage effectively.
Full article
(This article belongs to the Special Issue Recent Insights on the Molecular Basis Food Quality and Security Analysis)
►▼
Show Figures
Figure 1
Open AccessArticle
Infrared Spectroscopy of Neutral and Cationic Benzonitrile–Methanol Binary Clusters in Supersonic Jets
by
Xianming Xiong and Yongjun Hu
Molecules 2024, 29(12), 2744; https://doi.org/10.3390/molecules29122744 (registering DOI) - 8 Jun 2024
Abstract
The formation of nitrogen-containing organic interstellar molecules is of great importance to reveal chemical processes and the origin of life on Earth. Benzonitrile (BN) is one of the simplest nitrogen-containing aromatic molecules in the interstellar medium (ISM) that has been detected in recent
[...] Read more.
The formation of nitrogen-containing organic interstellar molecules is of great importance to reveal chemical processes and the origin of life on Earth. Benzonitrile (BN) is one of the simplest nitrogen-containing aromatic molecules in the interstellar medium (ISM) that has been detected in recent years. Methanol (CH3OH) exists widely in interstellar space with high reactivity. Herein, we measured the infrared (IR) spectra of neutral and cationic BN–CH3OH clusters by vacuum ultraviolet (VUV) photoionization combined with time-of-flight mass spectrometry. Combining IR spectra with the density functional theory calculations, we reveal that the BN–CH3OH intends to form a cyclic H-bonded structure in neutral clusters. However, after the ionization of BN–CH3OH clusters, proton-shared N···H···O and N···H···C structures are confirmed to form between BN and CH3OH, with the minor coexistence of H-bond and O-π structures. The formation of the proton-shared structure expands our knowledge of the evolution of the life-related nitrogen-containing molecules in the universe and provides a possible pathway to the further study of biorelevant aromatic organic macromolecules.
Full article
(This article belongs to the Section Physical Chemistry)
Open AccessArticle
Cobalt(III)–Macrocyclic Scaffolds with Anti-Cancer Stem Cell Activity
by
Jiaxin Fang, Philipp Gerschel, Kuldip Singh, Ulf-Peter Apfel and Kogularamanan Suntharalingam
Molecules 2024, 29(12), 2743; https://doi.org/10.3390/molecules29122743 (registering DOI) - 8 Jun 2024
Abstract
Cobalt(III) compounds with tetradentate ligands have been widely employed to deliver cytotoxic and imaging agents into cells. A large body of work has focused on using cobalt(III)–cyclam scaffolds for this purpose. Here, we investigate the cytotoxic properties of cobalt(III) complexes containing 14-membered macrocycles
[...] Read more.
Cobalt(III) compounds with tetradentate ligands have been widely employed to deliver cytotoxic and imaging agents into cells. A large body of work has focused on using cobalt(III)–cyclam scaffolds for this purpose. Here, we investigate the cytotoxic properties of cobalt(III) complexes containing 14-membered macrocycles related to cyclam. A breast cancer stem cell (CSC) in vitro model was used to gauge efficacy. Specifically, [Co(1,4,7,11-tetraazacyclotetradecane)Cl2]+ (1) and [Co(1-oxa-4,8,12-triazacyclotetradecane)Cl2]+ (2) were synthesised and characterised, and their breast CSC activity was determined. The cobalt(III) complexes 1 and 2 displayed micromolar potency towards bulk breast cancer cells and breast CSCs grown in monolayers. Notably, 1 and 2 displayed selective potency towards breast CSCs over bulk breast cancer cells (up to 4.5-fold), which was similar to salinomycin (an established breast CSC-selective agent). The cobalt(III) complexes 1 and 2 were also able to inhibit mammosphere formation at low micromolar doses (with respect to size and number). The mammopshere inhibitory effect of 2 was similar to that of salinomycin. Our studies show that cobalt(III) complexes with 1,4,7,11-tetraazacyclotetradecane and 1-oxa-4,8,12-triazacyclotetradecane macrocycles could be useful starting points for the development of new cobalt-based delivery systems that can transport cytotoxic and imaging agents into breast CSCs.
Full article
(This article belongs to the Special Issue Exclusive Feature Papers in Inorganic Chemistry 2.0)
►▼
Show Figures
Figure 1
Open AccessArticle
Health-Related Composition and Bioactivity of an Agave Sap/Prickly Pear Juice Beverage
by
Luisa Fernanda Duque-Buitrago, Iraham Enrique Solórzano-Lugo, Marcela González-Vázquez, Cristian Jiménez-Martínez, María Antonia Hernández-Aguirre, Perla Osorio-Díaz, Georgina Calderón-Domínguez, Verónica Loera-Castañeda and Rosalva Mora-Escobedo
Molecules 2024, 29(12), 2742; https://doi.org/10.3390/molecules29122742 (registering DOI) - 8 Jun 2024
Abstract
In this study, a beverage made from a combination of Agave sap (AS) and prickly pear juice (PPJ) was analyzed for its nutrients and bioactive and potentially health-promoting compounds. The beverage was evaluated for its ability to act as an antioxidant, regulate glycemic
[...] Read more.
In this study, a beverage made from a combination of Agave sap (AS) and prickly pear juice (PPJ) was analyzed for its nutrients and bioactive and potentially health-promoting compounds. The beverage was evaluated for its ability to act as an antioxidant, regulate glycemic properties, and undergo gut bacterial fermentation in vitro. The major mono- and oligosaccharides present in the beverage were galacturonic acid (217.74 ± 13.46 mg/100 mL), rhamnose (227.00 ± 1.58 mg/100 mL), and fructose (158.16 ± 8.86 mg/mL). The main phenolic compounds identified were protocatechuic acid (440.31 ± 3.06 mg/100 mL) and catechin (359.72 ± 7.56 mg/100 mL). It was observed that the beverage had a low glycemic index (<40) and could inhibit digestive carbohydrases. The combination of ingredients also helped to reduce gas production during AS fermentation from 56.77 cm3 to 15.67 cm3. The major SCFAs produced during fermentation were butyrate, acetate, and propionate, with valerate being produced only during the late fermentation of the AS. This beverage is rich in bioactive compounds, such as polyphenols and dietary fiber, which will bring health benefits when consumed.
Full article
(This article belongs to the Special Issue Metabolites of Biofunctional Interest from Plant Sources)
Open AccessArticle
Supercritical Carbon Dioxide Extraction of Coumarins from the Aerial Parts of Pterocaulon polystachyum
by
Júlia M. Scopel, Bruna Medeiros-Neves, Helder Ferreira Teixeira, Nathalya T. Brazil, Sérgio A. L. Bordignon, Fernando Mendonça Diz, Fernanda Bueno Morrone, Rafael N. Almeida, Eduardo Cassel, Gilsane L. von Poser and Rubem M. F. Vargas
Molecules 2024, 29(12), 2741; https://doi.org/10.3390/molecules29122741 (registering DOI) - 8 Jun 2024
Abstract
Pterocaulon polystachyum is a species of pharmacological interest for providing volatile and non-volatile extracts with antifungal and amebicidal properties. The biological activities of non-volatile extracts may be related to the presence of coumarins, a promising group of secondary metabolites. In the present study,
[...] Read more.
Pterocaulon polystachyum is a species of pharmacological interest for providing volatile and non-volatile extracts with antifungal and amebicidal properties. The biological activities of non-volatile extracts may be related to the presence of coumarins, a promising group of secondary metabolites. In the present study, leaves and inflorescences previously used for the extraction of essential oils instead of being disposed of were subjected to extraction with supercritical CO2 after pretreatment with microwaves. An experimental design was followed to seek the best extraction condition with the objective function being the maximum total extract. Pressure and temperature were statistically significant factors, and the optimal extraction condition was 240 bar, 60 °C, and pretreatment at 30 °C. The applied mathematical models showed good adherence to the experimental data. The extracts obtained by supercritical CO2 were analyzed and the presence of coumarins was confirmed. The extract investigated for cytotoxicity against bladder tumor cells (T24) exhibited significant reduction in cell viability at concentrations between 6 and 12 μg/mL. The introduction of green technology, supercritical extraction, in the exploration of P. polystachyum as a source of coumarins represents a paradigm shift with regard to previous studies carried out with this species, which used organic solvents. Furthermore, the concept of circular bioeconomy was applied, i.e., the raw material used was the residue of a steam-distillation process. Therefore, the approach used here is in line with the sustainable exploitation of native plants to obtain extracts rich in coumarins with cytotoxic potential against cancer cells.
Full article
(This article belongs to the Special Issue Advances in Natural Products and Their Biological Activities)
►▼
Show Figures
Graphical abstract
Open AccessArticle
Enhancement of the Electric-Force Response of Carbon Black/Silicone Rubber Composites by Silane Coupling Agents
by
Yanfang Zhao, Yang Yang, Bangwei Wan, Tianyu Ding and Xun Sha
Molecules 2024, 29(12), 2740; https://doi.org/10.3390/molecules29122740 (registering DOI) - 8 Jun 2024
Abstract
►▼
Show Figures
Flexible strain sensors have a wide range of applications in the field of health monitoring of seismic isolation bearings. However, the nonmonotonic response with shoulder peaks limits their application in practical engineering. Here we eliminate the shoulder peak phenomenon during the resistive-strain response
[...] Read more.
Flexible strain sensors have a wide range of applications in the field of health monitoring of seismic isolation bearings. However, the nonmonotonic response with shoulder peaks limits their application in practical engineering. Here we eliminate the shoulder peak phenomenon during the resistive-strain response by adjusting the dispersion of conductive nanofillers. In this paper, carbon black (CB)/methyl vinyl silicone rubber (VMQ) composites were modified by adding a silane coupling agent (KH550). The results show that the addition of KH550 eliminates the shoulder peak phenomenon in the resistive response signal of the composites. The reason for the disappearance of the shoulder peak phenomenon was explained, and at the same time, the mechanical properties of the composites were enhanced, the percolation threshold was reduced, and they had excellent strain-sensing properties. It also exhibited excellent stability and repeatability during 18,000 cycles of loading–unloading. The resistance-strain response mechanism was explained by the tunneling effect theoretical model analysis. It was shown that the sensor has a promising application in the health monitoring of seismic isolation bearings.
Full article
Figure 1
Open AccessArticle
Interlayer Interactions and Macroscopic Property Calculations of Squaric-Acid-Linked Zwitterionic Covalent Organic Frameworks: Structures, Photocatalytic Carrier Transport, and a DFT Study
by
Gaojie Yan and Xiaojie Zhang
Molecules 2024, 29(12), 2739; https://doi.org/10.3390/molecules29122739 (registering DOI) - 8 Jun 2024
Abstract
►▼
Show Figures
Squaric-acid-linked zwitterionic covalent organic frameworks (Z-COFs), assembled through interlayer interactions, are emerging as potential materials in the field of photocatalysis. However, the study of their interlayer interactions has been largely overlooked. To address this, this work systematically calculated interlayer interactions via density functional
[...] Read more.
Squaric-acid-linked zwitterionic covalent organic frameworks (Z-COFs), assembled through interlayer interactions, are emerging as potential materials in the field of photocatalysis. However, the study of their interlayer interactions has been largely overlooked. To address this, this work systematically calculated interlayer interactions via density functional theory (DFT) and analyzed the differences in interlayer interactions of different structures of Z-COFs through interlayer slippage, planarity, and an independent gradient model based on the Hirshfeld partition (IGMH). Furthermore, it revealed the relationship between the interactions and the macroscopic photocatalytic carrier transport performance of the material. The results indicated that both preventing interlayer slippage and enhancing planarity can enhance the interlayer interactions of Z-COFs, thereby improving their macroscopic carrier transport performance in photocatalysis.
Full article
Graphical abstract
Open AccessReview
Mitochondrial Dysfunction, Its Oxidative Stress-Induced Pathologies and Redox Bioregulation through Low-Dose Medical Ozone: A Systematic Review
by
Renate Viebahn-Haensler and Olga Sonia León Fernández
Molecules 2024, 29(12), 2738; https://doi.org/10.3390/molecules29122738 (registering DOI) - 8 Jun 2024
Abstract
Our hypothesis that controlled ozone applications interfere with the redox balance of a biological organism (first published in 1998 with a preclinical trial on protecting the liver from CCl4 intoxication) has been verified over the past two decades in reactive oxygen species
[...] Read more.
Our hypothesis that controlled ozone applications interfere with the redox balance of a biological organism (first published in 1998 with a preclinical trial on protecting the liver from CCl4 intoxication) has been verified over the past two decades in reactive oxygen species (ROS)-induced mitochondrial pathologies, such as rheumatoid arthritis, osteoarthritis, aging processes and type 2 diabetes, and in the prevention of intoxications. Low-dose ozone acts as a redox bioregulator: the restoration of the disturbed redox balance is comprehensible in a number of preclinical and clinical studies by a remarkable increase in the antioxidant repair markers, here mainly shown as a glutathione increase and a reduction in oxidative stress markers, mainly malondialdehyde. The mechanism of action is shown, and relevant data are displayed, evaluated and comprehensively discussed: the repair side of the equilibrium increases by 21% up to 140% compared to the non-ozone-treated groups and depending on the indication, the stress markers are simultaneously reduced, and the redox system regains its balance.
Full article
(This article belongs to the Special Issue Featured Review Papers in Bioorganic Chemistry 2024)
►▼
Show Figures
Figure 1
Journal Menu
► ▼ Journal Menu-
- Molecules Home
- Aims & Scope
- Editorial Board
- Reviewer Board
- Topical Advisory Panel
- Instructions for Authors
- Special Issues
- Topics
- Sections & Collections
- Article Processing Charge
- Indexing & Archiving
- Editor’s Choice Articles
- Most Cited & Viewed
- Journal Statistics
- Journal History
- Journal Awards
- Society Collaborations
- Conferences
- Editorial Office
Journal Browser
► ▼ Journal Browser-
arrow_forward_ios
Forthcoming issue
arrow_forward_ios Current issue - Vol. 29 (2024)
- Vol. 28 (2023)
- Vol. 27 (2022)
- Vol. 26 (2021)
- Vol. 25 (2020)
- Vol. 24 (2019)
- Vol. 23 (2018)
- Vol. 22 (2017)
- Vol. 21 (2016)
- Vol. 20 (2015)
- Vol. 19 (2014)
- Vol. 18 (2013)
- Vol. 17 (2012)
- Vol. 16 (2011)
- Vol. 15 (2010)
- Vol. 14 (2009)
- Vol. 13 (2008)
- Vol. 12 (2007)
- Vol. 11 (2006)
- Vol. 10 (2005)
- Vol. 9 (2004)
- Vol. 8 (2003)
- Vol. 7 (2002)
- Vol. 6 (2001)
- Vol. 5 (2000)
- Vol. 4 (1999)
- Vol. 3 (1998)
- Vol. 2 (1997)
- Volumes not published by MDPI
Highly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Topic in
BioChem, Biomedicines, Biomolecules, IJMS, Metabolites, Molecules
Natural Products in Prevention and Therapy of Metabolic Syndrome
Topic Editors: Jianbo Wan, Ligen LinDeadline: 30 June 2024
Topic in
Molecules, Separations, Sustainability, Water, Minerals
Analysis and Separations of Trace Elements in the Environment
Topic Editors: Gene Hall, Begoña GonzálezDeadline: 31 July 2024
Topic in
Analytica, Molecules, Nanomaterials, Polymers, Separations, Chemosensors
Nanomaterials in Green Analytical Chemistry
Topic Editors: George Zachariadis, Rosa Peñalver, Natalia ManousiDeadline: 15 August 2024
Topic in
Analytica, Metabolites, Separations, Toxins, Molecules
Application of Chromatography for Point of Care Diagnosis of Noncommunicable Diseases
Topic Editors: Chiranjit Ghosh, Liqin Chen, Keshava Balakrishna, Chiranjay MukhopadhyayDeadline: 31 August 2024
Conferences
Special Issues
Special Issue in
Molecules
Electrochemical Sensors and Cells for Environmental Applications
Guest Editors: Naoufel Haddour, Yamina Mounia AzriDeadline: 16 June 2024
Special Issue in
Molecules
Nanomaterials for Electrocatalytic Applications
Guest Editor: Paolo BertoncelloDeadline: 30 June 2024
Special Issue in
Molecules
Recent Advances in Food Analysis
Guest Editors: Francisco Javier Arrebola, Jesus Marin Saez, Rosalia Lopez RuizDeadline: 15 July 2024
Special Issue in
Molecules
Advances in Metal Oxide Nanoparticles
Guest Editor: Nadine MillotDeadline: 31 July 2024
Topical Collections
Topical Collection in
Molecules
Ultrasound- and Microwave-Assisted Extraction of Bioactive Compounds
Collection Editors: Stela Jokić, Jelena Vladić
Topical Collection in
Molecules
Novel Approache of Anticancer Therapy
Collection Editor: Isabelle Mus-Veteau