Molecules

22 pages, 421 KiB

Open AccessReview

A Review of Bioactive Compounds and Antioxidant Activity Properties of Piper Species

by Nono Carsono, Sefren Geiner Tumilaar, Dikdik Kurnia, Diding Latipudin and Mieke Hermiawati Satari

Molecules 2022, 27(19), 6774; https://doi.org/10.3390/molecules27196774 - 10 Oct 2022

Cited by 11 | Viewed by 3212

Abstract

Antioxidants are compounds that are able to inhibit the negative effects that come from free radicals. The phenomenon of imbalanced antioxidant production and the accumulation of free radicals in cells and tissues can cause oxidative stress. Excessive free radicals that enter the body [...] Read more.

Antioxidants are compounds that are able to inhibit the negative effects that come from free radicals. The phenomenon of imbalanced antioxidant production and the accumulation of free radicals in cells and tissues can cause oxidative stress. Excessive free radicals that enter the body cannot be warded off by endogenous antioxidant compounds so that the required antioxidant compounds can come from the outside, which helps in the performance of endogenous antioxidants. Antioxidants that come from outside consist of synthetic and natural antioxidants; however, synthetic antioxidants are not an option because they have toxic and carcinogenic effects. Therefore, the use of natural ingredients is an alternative method that is needed to create a new natural antioxidant compound. Piper species are being considered as possible medicinal plants for the development of new sources of antioxidants. Several studies have been carried out starting from the extract levels, fractions, and compounds of the Piper species, which showed good antioxidant activity. Currently, some of these plants are being used as ingredients in traditional medicines to treat allergies, toothaches, and coughs. This review examines the distribution, botanical data, pharmacology, especially antioxidant activity, and the compounds contained in five Piper species, namely Piper amalago L., Piper betle L., Piper hispidum Sw., Piper longum L., and Piper umbellatum L. Full article

(This article belongs to the Special Issue Advances in Natural Products and Their Biological Activities)

29 pages, 1828 KiB

Open AccessFeature PaperReview

The Enteric Glia and Its Modulation by the Endocannabinoid System, a New Target for Cannabinoid-Based Nutraceuticals?

by Laura López-Gómez, Agata Szymaszkiewicz, Marta Zielińska and Raquel Abalo

Molecules 2022, 27(19), 6773; https://doi.org/10.3390/molecules27196773 - 10 Oct 2022

Cited by 5 | Viewed by 3582

Abstract

The enteric nervous system (ENS) is a part of the autonomic nervous system that intrinsically innervates the gastrointestinal (GI) tract. Whereas enteric neurons have been deeply studied, the enteric glial cells (EGCs) have received less attention. However, these are immune-competent cells that contribute [...] Read more.

The enteric nervous system (ENS) is a part of the autonomic nervous system that intrinsically innervates the gastrointestinal (GI) tract. Whereas enteric neurons have been deeply studied, the enteric glial cells (EGCs) have received less attention. However, these are immune-competent cells that contribute to the maintenance of the GI tract homeostasis through supporting epithelial integrity, providing neuroprotection, and influencing the GI motor function and sensation. The endogenous cannabinoid system (ECS) includes endogenous classical cannabinoids (anandamide, 2-arachidonoylglycerol), cannabinoid-like ligands (oleoylethanolamide (OEA) and palmitoylethanolamide (PEA)), enzymes involved in their metabolism (FAAH, MAGL, COX-2) and classical (CB1 and CB2) and non-classical (TRPV1, GPR55, PPAR) receptors. The ECS participates in many processes crucial for the proper functioning of the GI tract, in which the EGCs are involved. Thus, the modulation of the EGCs through the ECS might be beneficial to treat some dysfunctions of the GI tract. This review explores the role of EGCs and ECS on the GI tract functions and dysfunctions, and the current knowledge about how EGCs may be modulated by the ECS components, as possible new targets for cannabinoids and cannabinoid-like molecules, particularly those with potential nutraceutical use. Full article

(This article belongs to the Special Issue Nutraceuticals in Immune Function II)

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20 pages, 1141 KiB

Open AccessArticle

On Some Topological Indices Defined via the Modified Sombor Matrix

by Xuewu Zuo, Bilal Ahmad Rather, Muhammad Imran and Akbar Ali

Molecules 2022, 27(19), 6772; https://doi.org/10.3390/molecules27196772 - 10 Oct 2022

Cited by 3 | Viewed by 1979

Abstract

Let G be a simple graph with the vertex set

V = {v_{1}, \dots, v_{n}}

and denote by

d_{v_{i}}

the degree of the vertex

v_{i}

. The modified Sombor index of G is the [...] Read more.

Let G be a simple graph with the vertex set

V = {v_{1}, \dots, v_{n}}

and denote by

d_{v_{i}}

the degree of the vertex

v_{i}

. The modified Sombor index of G is the addition of the numbers

{(d_{v_{i}}^{2} + d_{v_{j}}^{2})}^{- 1 / 2}

over all of the edges

v_{i} v_{j}

of G. The modified Sombor matrix

A_{M S} (G)

of G is the n by n matrix such that its

(i, j)

-entry is equal to

{(d_{v_{i}}^{2} + d_{v_{j}}^{2})}^{- 1 / 2}

when

v_{i}

and

v_{j}

are adjacent and 0 otherwise. The modified Sombor spectral radius of G is the largest number among all of the eigenvalues of

A_{M S} (G)

. The sum of the absolute eigenvalues of

A_{M S} (G)

is known as the modified Sombor energy of G. Two graphs with the same modified Sombor energy are referred to as modified Sombor equienergetic graphs. In this article, several bounds for the modified Sombor index, the modified Sombor spectral radius, and the modified Sombor energy are found, and the corresponding extremal graphs are characterized. By using computer programs (Mathematica and AutographiX), it is found that there exists only one pair of the modified Sombor equienergetic chemical graphs of an order of at most seven. It is proven that the modified Sombor energy of every regular, complete multipartite graph is

\sqrt{2}

; this result gives a large class of the modified Sombor equienergetic graphs. The (linear, logarithmic, and quadratic) regression analyses of the modified Sombor index and the modified Sombor energy together with their classical versions are also performed for the boiling points of the chemical graphs of an order of at most seven. Full article

(This article belongs to the Special Issue Study of Molecules in the Light of Spectral Graph Theory)

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12 pages, 3821 KiB

Open AccessCommunication

Fabrication of Orange Fluorescent Boron-Doped Graphene Quantum Dots for Al³⁺ Ion Detection

by Weitao Li, Luoman Zhang, Ningjia Jiang, Yongqian Chen, Jie Gao, Jihang Zhang, Baoshuo Yang and Jialin Liu

Molecules 2022, 27(19), 6771; https://doi.org/10.3390/molecules27196771 - 10 Oct 2022

Cited by 7 | Viewed by 2286

Abstract

Aluminum is a kind of metal that we often encounter. It can also be absorbed by the human body invisibly and will affect our bodies to a certain extent, e.g., by causing symptoms associated with Alzheimer’s disease. Therefore, the detection of aluminum is [...] Read more.

Aluminum is a kind of metal that we often encounter. It can also be absorbed by the human body invisibly and will affect our bodies to a certain extent, e.g., by causing symptoms associated with Alzheimer’s disease. Therefore, the detection of aluminum is particularly important. The methods to detect metal ions include precipitation methods and electrochemical methods, which are cumbersome and costly. Fluorescence detection is a fast and sensitive method with a low cost and non-toxicity. Traditional fluorescent nanomaterials have a high cost, high toxicity, and cause harm to the human body. Graphene quantum dots are a new type of fluorescent nanomaterials with a low cost and non-toxicity that can compensate for the defects of traditional fluorescent nanomaterials. In this paper, c-GQDs and o-GQDs with good performance were prepared by a bottom-up hydrothermal method using o-phenylenediamine as a precursor and citric acid or boric acid as modulators. They have very good optical properties: o-GQDs exhibit orange fluorescence under UV irradiation, while c-GQDs exhibits cyan fluorescence. Then, different metal ions were used for ion detection, and it was found that Al³⁺ had a good quenching effect on the fluorescence of the o-GQDs. The reason for this phenomenon may be related to the strong binding of Al³⁺ ions to the N and O functional groups of the o-GQDs and the rapid chelation kinetics. During the chelation process, the separation of o-GQDs’ photoexcited electron hole pairs leads to their rapid electron transfer to Al³⁺, in turn leading to the occurrence of a fluorescence-quenching phenomenon. In addition, there was a good linear relationship between the concentration of the Al³⁺ ions and the fluorescence intensity, and the correlation coefficient of the linear regression equation was 0.9937. This illustrates the potential for the wide application of GQDs in sensing systems, while also demonstrating that Al³⁺ sensors can be used to detect Al³⁺ ions. Full article

(This article belongs to the Special Issue Functional Carbon Quantum Dots: Synthesis and Applications)

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12 pages, 4145 KiB

Open AccessArticle

Synthesis and Characterization of Novel Hydrazone Derivatives of Isonicotinic Hydrazide and Their Evaluation for Antibacterial and Cytotoxic Potential

by Muhammad Abdullah Shah, Ala Uddin, Muhammad Raza Shah, Imdad Ali, Riaz Ullah, Peer Abdul Hannan and Hidayat Hussain

Molecules 2022, 27(19), 6770; https://doi.org/10.3390/molecules27196770 - 10 Oct 2022

Cited by 12 | Viewed by 2426

Abstract

Hydrazones are active compounds having an azomethine –NHN=CH group and are widely studied owing to their ease of preparation and diverse pharmacological benefits. Novel isonicotinic hydrazone derivatives of vanillin aldehyde and salicyl aldehyde were synthesized that had azomethine linkages and were characterized by [...] Read more.

Hydrazones are active compounds having an azomethine –NHN=CH group and are widely studied owing to their ease of preparation and diverse pharmacological benefits. Novel isonicotinic hydrazone derivatives of vanillin aldehyde and salicyl aldehyde were synthesized that had azomethine linkages and were characterized by UV–Visible, FTIR, EI-MS, 1H-NMR and 13C-NMR spectroscopy. The compounds were screened for their antibacterial activity against Staphylococcus aureus, Bacillus subtilus, and Escherichia coli using disc diffusion and minimum inhibitory concentration (MIC) methods. For cytotoxicity, a brine shrimp lethality test was performed to calculate the lethal concentration (LC50). The results demonstrated appreciable antibacterial activities against the applied strains, amongst which the compounds coded NH3 and NH5 showed maximum inhibition and MIC responses. In terms of cytotoxic activity, the maximum effect was observed in compound NH5 and NH6 treatments with minimum survival percentages of 36.10 ± 3.45 and 32.44 ± 2.0, respectively. These hydrazones could be potential candidates in antitumorigenic therapy against various human cancer cells. Full article

(This article belongs to the Special Issue The Chemistry of Imines)

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17 pages, 5783 KiB

Open AccessArticle

Syntheses of New Multisubstituted 1-Acyloxyindole Compounds

by Ye Eun Kim, Yoo Jin Lim, Chorong Kim, Yu Ra Jeong, Hyunsung Cho and Sang Hyup Lee

Molecules 2022, 27(19), 6769; https://doi.org/10.3390/molecules27196769 - 10 Oct 2022

Cited by 2 | Viewed by 1391

Abstract

The syntheses of novel 1-acyloxyindole compounds 1 and the investigations on reaction pathways are presented. Nitro ketoester substrate 2, obtained in a two-step synthetic process, underwent reduction, intramolecular addition, nucleophilic 1,5-addition, and acylation to afford 1-acyloxyindoles 1 in one pot. Based on [...] Read more.

The syntheses of novel 1-acyloxyindole compounds 1 and the investigations on reaction pathways are presented. Nitro ketoester substrate 2, obtained in a two-step synthetic process, underwent reduction, intramolecular addition, nucleophilic 1,5-addition, and acylation to afford 1-acyloxyindoles 1 in one pot. Based on the systematic studies, we established the optimized reaction conditions for 1 focusing on the final acylation step of the intermediate 1-hydroxyindole 8. With the optimized conditions, we succeeded in synthesizing 21 examples of new 1-acyloxyindole derivatives 1 in modest yields (Y = 24 − 35%). Among the 1-acyloxyindole compounds, 1-acetoxyindole compounds 1x were generally unstable, and their yields were relatively lower than the other 1-acyloxyindoles. We expect that a bulkier alkyl or aromatic group on R² could stabilize the 1-acyloxyindole compounds. Significantly, one-pot reactions of a four-step sequence successfully generated compounds 1 that are all new and might be difficult to be synthesized otherwise. Full article

(This article belongs to the Special Issue Recent Advances in Indole Derivatives in Medicinal and Synthetic Organic Chemistry)

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25 pages, 4413 KiB

Open AccessArticle

Luminescent Carbon Dots from Wet Olive Pomace: Structural Insights, Photophysical Properties and Cytotoxicity

by Diogo A. Sousa, Luís F. V. Ferreira, Alexander A. Fedorov, Ana M. B. do Rego, Ana M. Ferraria, Adriana B. Cruz, Mário N. Berberan-Santos and José V. Prata

Molecules 2022, 27(19), 6768; https://doi.org/10.3390/molecules27196768 - 10 Oct 2022

Cited by 7 | Viewed by 2144

Abstract

Carbon nanomaterials endowed with significant luminescence have been synthesized for the first time from an abundant, highly localized waste, the wet pomace (WP), a semi-solid by-product of industrial olive oil production. Synthetic efforts were undertaken to outshine the photoluminescence (PL) of carbon nanoparticles [...] Read more.

Carbon nanomaterials endowed with significant luminescence have been synthesized for the first time from an abundant, highly localized waste, the wet pomace (WP), a semi-solid by-product of industrial olive oil production. Synthetic efforts were undertaken to outshine the photoluminescence (PL) of carbon nanoparticles through a systematic search of the best reaction conditions to convert the waste biomass, mainly consisting in holocellulose, lignin and proteins, into carbon dots (CDs) by hydrothermal carbonization processes. Blue-emitting CDs with high fluorescence quantum yields were obtained. Using a comprehensive set of spectroscopic tools (FTIR, Raman, XPS, and ¹H/¹³C NMR) in combination with steady-state and time-resolved fluorescence spectroscopy, a rational depiction of WP-CDs structures and their PL properties was reached. WP-CDs show the up-conversion of PL capabilities and negligible cytotoxicity against two mammalian cell lines (L929 and HeLa). Both properties are excellent indicators for their prospective application in biological imaging, biosensing, and dynamic therapies driven by light. Full article

(This article belongs to the Special Issue Exclusive Feature Papers in Physical Chemistry)

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19 pages, 3589 KiB

Open AccessReview

Layer-by-Layer Self-Assembly Coating for Multi-Functionalized Fabrics: A Scientometric Analysis in CiteSpace (2005–2021)

by Ying Pan, Li Fu, Jia Du, Dong Zhang, Ting Lü, Yan Zhang and Hongting Zhao

Molecules 2022, 27(19), 6767; https://doi.org/10.3390/molecules27196767 - 10 Oct 2022

Cited by 2 | Viewed by 2067

Abstract

Surface-engineered coatings have been increasingly applied to functionalize fabrics due to the ease of deposition of the coatings and their effectiveness in endowing the fabric with abundant properties. Among the surface modification methods, layer-by-layer (LbL) self-assembly has emerged as an important approach for [...] Read more.

Surface-engineered coatings have been increasingly applied to functionalize fabrics due to the ease of deposition of the coatings and their effectiveness in endowing the fabric with abundant properties. Among the surface modification methods, layer-by-layer (LbL) self-assembly has emerged as an important approach for creating multifunctional surfaces on fabrics. In this review, bibliometric analysis with the visualization analysis of LbL self-assembly coatings on fabrics was performed on publications extracted from the Web of Science (WOS) from 2005 to 2021 based on the CiteSpace software. The analysis results showed that research on LbL self-assembly coatings on fabrics has attracted much attention, and this technique has plentiful and flexible applications. Moreover, research on the LbL self-assembly method in the field of functionalization of fabrics has been summarized, which include flame retardant fabric, antibacterial fabric, ultraviolet resistant fabric, hydrophobic fabric and electromagnetic shielding fabric. It was found that the functionalization of the fabric has been changing from singularity to diversification. Based on the review, several future research directions can be proposed. The weatherability, comfort, cost and environmental friendliness should be considered when the multifunctional coatings are designed. Full article

(This article belongs to the Special Issue Recent Advances in Flame Retardant Polymeric Materials)

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14 pages, 2859 KiB

Open AccessArticle

Exploring 2-Tetradecanoylimino-3-aryl-4-methyl-1,3-thiazolines Derivatives as Alkaline Phosphatase Inhibitors: Biochemical Evaluation and Computational Analysis

by Aftab Ahmed, Sajid-ur Rehman, Syeda Abida Ejaz, Aamer Saeed, Rabail Ujan, Pervaiz Ali Channar, Khalida Mahar, Reshma Sahito, Sarah M. Albogami, Qamar Abbas, Mohammed Alorabi, Michel De Waard and Gaber El-Saber Batiha

Molecules 2022, 27(19), 6766; https://doi.org/10.3390/molecules27196766 - 10 Oct 2022

Cited by 1 | Viewed by 1391

Abstract

The current study focused on the laboratory approach in conjunction with computational methods for the synthesis and bioactivity assessment of unique 2-tetradecanoylimino-3-aryl-4-methyl-1,3-thiazolines (2a–2k). Processes included cyclizing 1-aroyl-3-arylthioureas with propan-2-one in the presence of trimethylamine and bromine. By using spectroscopic [...] Read more.

The current study focused on the laboratory approach in conjunction with computational methods for the synthesis and bioactivity assessment of unique 2-tetradecanoylimino-3-aryl-4-methyl-1,3-thiazolines (2a–2k). Processes included cyclizing 1-aroyl-3-arylthioureas with propan-2-one in the presence of trimethylamine and bromine. By using spectroscopic techniques and elemental analyses, structures were elucidated. To assess the electronic properties, density functional theory (DFT) calculations were made, while binding interactions of synthesized derivatives were studied by the molecular docking tool. Promising results were found during the evaluation of bioactivity of synthesized compounds against alkaline phosphatase. The drug likeliness score, an indicator used for any chemical entity posing as a drug, was within acceptable limits. The data suggested that most of the derivatives were potent inhibitors of alkaline phosphatase, which in turn may act as lead molecules to synthesize derivatives having desired pharmacological profiles for the treatment of specific diseases associated with abnormal levels of ALPs. Full article

(This article belongs to the Special Issue Spectroscopic, Thermodynamic and Molecular Docking Studies on Molecular Mechanisms of Drug Binding to Proteins II)

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9 pages, 2923 KiB

Open AccessArticle

Uranium Isotope (U-232) Removal from Waters by Biochar Fibers: An Adsorption Study in the Sub-Picomolar Concentration Range

by Maria Philippou, Ioannis Pashalidis and Charis R. Theocharis

Molecules 2022, 27(19), 6765; https://doi.org/10.3390/molecules27196765 - 10 Oct 2022

Cited by 4 | Viewed by 1155

Abstract

The adsorption of the U-232 radionuclide by biochar fibers in the sub-picomolar concentration range has been investigated in laboratory aqueous solutions and seawater samples. The adsorption efficiency (K_d values and % relative removal) of untreated and oxidized biochar samples towards U-232 [...] Read more.

The adsorption of the U-232 radionuclide by biochar fibers in the sub-picomolar concentration range has been investigated in laboratory aqueous solutions and seawater samples. The adsorption efficiency (K_d values and % relative removal) of untreated and oxidized biochar samples towards U-232 has been investigated as a function of pH, adsorbent mass, ionic strength and temperature by means of batch-type experiments. According to the experimental data, the solution pH determines to a large degree the adsorption efficiency, and adsorbent mass and surface oxidation lead to significantly higher K_d values. The ionic strength and temperature effect indicate that the adsorption is based on the formation of inner-sphere complexes, and is an endothermic and entropy-driven process (ΔH° and ΔS° > 0), respectively. Regarding the sorption kinetics, the diffusion of U-232 from the solution to the biochar surface seems to be the rate-determining step. The application of biochar-based adsorbents to treat radioactively (U-232) contaminated waters reveals that these materials are very effective adsorbents, even in the sub-picomolar concentration range. Full article

(This article belongs to the Special Issue Wastewater Treatments Based on Adsorption, Catalysis, Biodegradation, and Beyond)

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14 pages, 3462 KiB

Open AccessArticle

Solvation of Large Polycyclic Aromatic Hydrocarbons in Helium: Cationic and Anionic Hexabenzocoronene

by Miriam Kappe, Florent Calvo, Johannes Schöntag, Holger F. Bettinger, Serge Krasnokutski, Martin Kuhn, Elisabeth Gruber, Fabio Zappa, Paul Scheier and Olof Echt

Molecules 2022, 27(19), 6764; https://doi.org/10.3390/molecules27196764 - 10 Oct 2022

Viewed by 1323

Abstract

The adsorption of helium on charged hexabenzocoronene (Hbc, C₄₂H₁₈), a planar polycyclic aromatic hydrocarbon (PAH) molecule of D_6h symmetry, was investigated by a combination of high-resolution mass spectrometry and classical and quantum computational methods. The ion abundance [...] Read more.

The adsorption of helium on charged hexabenzocoronene (Hbc, C₄₂H₁₈), a planar polycyclic aromatic hydrocarbon (PAH) molecule of D_6h symmetry, was investigated by a combination of high-resolution mass spectrometry and classical and quantum computational methods. The ion abundance of He_nHbc⁺ complexes versus size n features prominent local anomalies at n = 14, 38, 68, 82, and a weak one at 26, indicating that for these “magic” sizes, the helium evaporation energies are relatively large. Surprisingly, the mass spectra of anionic He_nHbc⁻ complexes feature a different set of anomalies, namely at n = 14, 26, 60, and 62, suggesting that the preferred arrangement of the adsorbate atoms depends on the charge of the substrate. The results of our quantum calculations show that the adsorbate layer grows by successive filling of concentric rings that surround the central benzene ring, which is occupied by one helium atom each on either side of the substrate. The helium atoms are fairly localized in filled rings and they approximately preserve the D_6h symmetry of the substrate, but helium atoms in partially filled rings are rather delocalized. The first three rings contain six atoms each; they account for magic numbers at n = 14, 26, and 38. The size of the first ring shrinks as atoms are filled into the second ring, and the position of atoms in the second ring changes from hollow sites to bridge sites as atoms are filled into the third ring. Beyond n = 38, however, the arrangement of helium atoms in the first three rings remains essentially frozen. Presumably, another ring is filled at n = 68 for cations and n = 62 for anions. The calculated structures and energies do not account for the difference between charge states, although they agree with the measurements for the cations and show that the first solvation shell of Hbc^± is complete at n = 68. Beyond that size, the adsorbate layer becomes three-dimensional, and the circular arrangement of helium changes to hexagonal. Full article

(This article belongs to the Section Physical Chemistry)

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40 pages, 4430 KiB

Open AccessReview

Thiazolidin-2,4-Dione Scaffold: An Insight into Recent Advances as Antimicrobial, Antioxidant, and Hypoglycemic Agents

by Harsh Kumar, Navidha Aggarwal, Minakshi Gupta Marwaha, Aakash Deep, Hitesh Chopra, Mohammed M. Matin, Arpita Roy, Talha Bin Emran, Yugal Kishore Mohanta, Ramzan Ahmed, Tapan Kumar Mohanta, Muthupandian Saravanan, Rakesh Kumar Marwaha and Ahmed Al-Harrasi

Molecules 2022, 27(19), 6763; https://doi.org/10.3390/molecules27196763 - 10 Oct 2022

Cited by 14 | Viewed by 2768

Abstract

Heterocyclic compounds containing nitrogen and sulfur, especially those in the thiazole family, have generated special interest in terms of their synthetic chemistry, which is attributable to their ubiquitous existence in pharmacologically dynamic natural products and also as overwhelmingly powerful agrochemicals and pharmaceuticals. The [...] Read more.

Heterocyclic compounds containing nitrogen and sulfur, especially those in the thiazole family, have generated special interest in terms of their synthetic chemistry, which is attributable to their ubiquitous existence in pharmacologically dynamic natural products and also as overwhelmingly powerful agrochemicals and pharmaceuticals. The thiazolidin-2,4-dione (TZD) moiety plays a central role in the biological functioning of several essential molecules. The availability of substitutions at the third and fifth positions of the Thiazolidin-2,4-dione (TZD) scaffold makes it a highly utilized and versatile moiety that exhibits a wide range of biological activities. TZD analogues exhibit their hypoglycemic activity by improving insulin resistance through PPAR-γ receptor activation, their antimicrobial action by inhibiting cytoplasmic Mur ligases, and their antioxidant action by scavenging reactive oxygen species (ROS). In this manuscript, an effort has been made to review the research on TZD derivatives as potential antimicrobial, antioxidant, and antihyperglycemic agents from the period from 2010 to the present date, along with their molecular mechanisms and the information on patents granted to TZD analogues. Full article

(This article belongs to the Special Issue Five and Six-Membered Heterocyclic Compounds and Their Therapeutic Potential)

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18 pages, 2472 KiB

Open AccessArticle

Molecular Analysis of the Melanogenesis Inhibitory Effect of Saponins-Rich Fraction of Argania spinosa Leaves Extract

by Myra O. Villareal, Thanyanan Chaochaiphat, Rachida Makbal, Chemseddoha Gadhi and Hiroko Isoda

Molecules 2022, 27(19), 6762; https://doi.org/10.3390/molecules27196762 - 10 Oct 2022

Cited by 1 | Viewed by 1868

Abstract

Plant saponins are abundant and diverse natural products with a great potential for use in drug-discovery research. Here, we evaluated extracts of saponins-rich fractions of argan leaves and argan oil extraction byproducts (shell, pulp, press cake) for their effect on melanogenesis. Results show [...] Read more.

Plant saponins are abundant and diverse natural products with a great potential for use in drug-discovery research. Here, we evaluated extracts of saponins-rich fractions of argan leaves and argan oil extraction byproducts (shell, pulp, press cake) for their effect on melanogenesis. Results show that from among the samples tested, only the saponins-rich fraction from leaves (ALS) inhibited melanin production in B16 murine melanoma (B16) cells. The mechanism of the melanogenesis inhibition was elucidated by determining the protein and mRNA expression of melanogenesis-associated enzymes tyrosinase (TYR), tyrosinase-related protein 1 (TRP1), and dopachrome tautomerase (DCT), and microphthalmia-associated transcription factor (MITF), and performing DNA microarray analysis. Results showed that 10 µg/mL ALS significantly inhibited melanogenesis in B16 cells and human epidermal melanocytes by 59% and 48%, respectively, without cytotoxicity. The effect of ALS on melanogenesis can be attributed to the decrease in TYR, TRP1, and MITF expression at the protein and mRNA levels. MITF inhibition naturally led to the downregulation of the expression of Tyr and Trp1 genes. Results of the DNA microarray analysis revealed the effect on melanogenesis-associated cAMP and Wnt signaling pathways’ genes. The results of this study suggest that ALS may be used in cosmeceuticals preparations for hyperpigmentation treatment. Full article

(This article belongs to the Special Issue Bioactive Plant Extracts for Pharmaceutical, Nutraceutical and Cosmetic Applications)

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9 pages, 965 KiB

Open AccessArticle

Simultaneous Quantification of Opioids in Blood and Urine by Gas Chromatography-Mass Spectrometer with Modified Dispersive Solid-Phase Extraction Technique

by Sara Yasien, Ejaz Ali, Mohsin Javed, Muhammad Muntazir Iqbal, Shahid Iqbal, Hamad Alrbyawi, Samar O. Aljazzar, Eslam B. Elkaeed, Ayed A. Dera, Rami Adel Pashameah, Eman Alzahrani and Abd-ElAziem Farouk

Molecules 2022, 27(19), 6761; https://doi.org/10.3390/molecules27196761 - 10 Oct 2022

Cited by 1 | Viewed by 2219

Abstract

Common methodologies such as liquid-liquid extraction and solid-phase extraction are applied for the extraction of opioids from biological specimens i.e., blood and urine. Techniques including LC-MS/LC-MSMS, GC-MS, etc. are used for qualitative or quantitative determination of opioids. The goal of the present work [...] Read more.

Common methodologies such as liquid-liquid extraction and solid-phase extraction are applied for the extraction of opioids from biological specimens i.e., blood and urine. Techniques including LC-MS/LC-MSMS, GC-MS, etc. are used for qualitative or quantitative determination of opioids. The goal of the present work is to design a green, economic, rugged, and simple extraction technique for famous opioids in human blood and urine and their simultaneous quantification by GC-MS equipped with an inert plus electron impact (EI) ionization source at SIM mode to produce reproducible and efficient results. Morphine, codeine, 6-acetylmorphine, nalbuphine, tramadol and dextromethorphan were selected as target opioids. Anhydrous Epsom salt was applied for dSPE of opioids from blood and urine into acetonitrile extraction solvent with the addition of sodium phosphate buffer (pH 6) and n-hexane was added to remove non-polar interfering species from samples. BSTFA was used as a derivatizing agent for GC-MS. Following method validation, the LOD/LLOQ and ULOQ were determined for morphine, codeine, nal-buphine, tramadol, and dextromethorphan at 10 ng/mL and 1500 ng/mL, respectively, while the LOD/LLOQ and ULOQ were determined for 6-acetylmorphine at 5 ng/mL and 150 ng/mL, respectively. This method was applied to real blood and urine samples of opioid abusers and the results were found to be reproducible with true quantification. Full article

(This article belongs to the Special Issue Development of Chromatographic and Other Analytical Technologies for Pharmaceutical Drugs)

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17 pages, 2660 KiB

Open AccessArticle

Exploratory Quality Control Study for Polygonum multiflorum Thunb. Using Dinuclear Anthraquinones with Potential Hepatotoxicity

by Huiyu Gao, Jianbo Yang, Xueting Wang, Yunfei Song, Xianlong Cheng, Feng Wei, Ying Wang, Donglin Gu, Hua Sun and Shuangcheng Ma

Molecules 2022, 27(19), 6760; https://doi.org/10.3390/molecules27196760 - 10 Oct 2022

Cited by 4 | Viewed by 1394

Abstract

In recent years, the hepatotoxicity of Polygoni Multiflora Radix (PMR) has attracted increased research interest. Some studies suggest that anthraquinone may be the main hepatotoxic component. Most of the relevant studies have focused on the mononuclear anthraquinone component rather than binuclear anthraquinones. The [...] Read more.

In recent years, the hepatotoxicity of Polygoni Multiflora Radix (PMR) has attracted increased research interest. Some studies suggest that anthraquinone may be the main hepatotoxic component. Most of the relevant studies have focused on the mononuclear anthraquinone component rather than binuclear anthraquinones. The hepatotoxicity of dinuclear anthraquinone (dianthrone) was investigated in a cell-based model. Next, a method for the determination of six free and total dianthonones in PMR and PMR Praeparata (PMRP) was established using ultra-high-performance liquid chromatography triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS), which was then used to analyze the collected samples. The data show that four binuclear anthraquinone compounds were hepatotoxic and may be potential toxicity indicators for the safety evaluation of PMR and PMRP. Herein, we provide a theoretical basis for the improvement of PMRP quality standards. Full article

(This article belongs to the Special Issue Application of Analytical Methods in Food, Drug, and Natural Products Research)

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46 pages, 4986 KiB

Open AccessReview

Aspergillus ochraceus: Metabolites, Bioactivities, Biosynthesis, and Biotechnological Potential

by Rawan H. Hareeri, Mohammed M. Aldurdunji, Hossam M. Abdallah, Ali A. Alqarni, Shaimaa G. A. Mohamed, Gamal A. Mohamed and Sabrin R. M. Ibrahim

Molecules 2022, 27(19), 6759; https://doi.org/10.3390/molecules27196759 - 10 Oct 2022

Cited by 11 | Viewed by 2424

Abstract

Fungus continues to attract great attention as a promising pool of biometabolites. Aspergillus ochraceus Wilh (Aspergillaceae) has established its capacity to biosynthesize a myriad of metabolites belonging to different chemical classes, such as isocoumarins, pyrazines, sterols, indole alkaloids, diketopiperazines, polyketides, peptides, quinones, polyketides, [...] Read more.

Fungus continues to attract great attention as a promising pool of biometabolites. Aspergillus ochraceus Wilh (Aspergillaceae) has established its capacity to biosynthesize a myriad of metabolites belonging to different chemical classes, such as isocoumarins, pyrazines, sterols, indole alkaloids, diketopiperazines, polyketides, peptides, quinones, polyketides, and sesquiterpenoids, revealing various bioactivities that are antimicrobial, cytotoxic, antiviral, anti-inflammatory, insecticidal, and neuroprotective. Additionally, A. ochraceus produces a variety of enzymes that could have variable industrial and biotechnological applications. From 1965 until June 2022, 165 metabolites were reported from A. ochraceus isolated from different sources. In this review, the formerly separated metabolites from A. ochraceus, including their bioactivities and biosynthesis, in addition, the industrial and biotechnological potential of A. ochraceus are highlighted. Full article

(This article belongs to the Special Issue Structural Analysis and Biological Evaluation of Compounds from Fungi)

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24 pages, 10881 KiB

Open AccessArticle

Synthesis and SAR Analysis of Novel 4-Hydroxytamoxifen Analogues Based on Their Cytotoxic Activity and Electron-Donor Character

by Cintia Duró, Tamás Jernei, Krisztina J. Szekeres, Győző G. Láng, Rita Oláh-Szabó, Szilvia Bősze, Ildikó Szabó, Ferenc Hudecz and Antal Csámpai

Molecules 2022, 27(19), 6758; https://doi.org/10.3390/molecules27196758 - 10 Oct 2022

Cited by 2 | Viewed by 2020

Abstract

Utilizing McMurry reactions of 4,4′-dihydroxybenzophenone with appropriate carbonyl compounds, a series of 4-Hydroxytamoxifen analogues were synthesized. Their cytotoxic activity was evaluated in vitro on four human malignant cell lines (MCF-7, MDA-MB 231, A2058, HT-29). It was found that some of these novel Tamoxifen [...] Read more.

Utilizing McMurry reactions of 4,4′-dihydroxybenzophenone with appropriate carbonyl compounds, a series of 4-Hydroxytamoxifen analogues were synthesized. Their cytotoxic activity was evaluated in vitro on four human malignant cell lines (MCF-7, MDA-MB 231, A2058, HT-29). It was found that some of these novel Tamoxifen analogues show marked cytotoxicity in a dose-dependent manner. The relative ROS-generating capability of the synthetized analogues was evaluated by cyclic voltammetry (CV) and DFT modeling studies. The results of cell-viability assays, CV measurements and DFT calculations suggest that the cytotoxicity of the majority of the novel compounds is mainly elicited by their interactions with cellular targets including estrogen receptors rather than triggered by redox processes. However, three novel compounds could be involved in ROS-production and subsequent formation of quinone-methide preventing proliferation and disrupting the redox balance of the treated cells. Among the cell lines studied, HT-29 proved to be the most susceptible to the treatment with compounds having ROS-generating potency. Full article

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11 pages, 1226 KiB

Open AccessArticle

Dammarane-Type Triterpenoid from the Stem Bark of Aglaia elliptica (Meliaceae) and Its Cytotoxic Activities

by Kindi Farabi, Desi Harneti, Darwati, Tri Mayanti, Nurlelasari, Rani Maharani, Aprilia Permata Sari, Tati Herlina, Ace Tatang Hidayat, Unang Supratman, Sofa Fajriah, Mohamad Nurul Azmi and Yoshihito Shiono

Molecules 2022, 27(19), 6757; https://doi.org/10.3390/molecules27196757 - 10 Oct 2022

Cited by 3 | Viewed by 1925

Abstract

Two new dammarane-type triterpenoid fatty acid ester derivatives, 3β-oleate-20S-hydroxydammar-24-en (1) and 3β-oleate-20S,24S-epoxy-25-hydroxydammarane (2) with a known dammarane-type triterpenoid compound, such as 20S-hydroxydammar-24-en-3-on (3), were isolated from the stem bark [...] Read more.

Two new dammarane-type triterpenoid fatty acid ester derivatives, 3β-oleate-20S-hydroxydammar-24-en (1) and 3β-oleate-20S,24S-epoxy-25-hydroxydammarane (2) with a known dammarane-type triterpenoid compound, such as 20S-hydroxydammar-24-en-3-on (3), were isolated from the stem bark of Aglaiaelliptica (C.DC.) Blume. The chemical structures were determined by spectroscopic methods, including FTIR, NMR (one and two-dimensional), and HRESITOF-MS analysis, as well as chemical derivatization and comparison with previous literature. Furthermore, the synthetic analog resulting from transesterification of 1 and 2 also obtained 3β,20S-dihydroxy-dammar-24-en (4) and 20S,24S-epoxy-3β,25-dihydroxydammarane (5), respectively. The cytotoxic effect of all isolated and synthetic analog compounds was evaluated using PrestoBlue reagent against MCF-7 breast cancer cell and B16-F10 melanoma cell lines. The 20S-hydroxydammar-24-en-3-on (3) showed the strongest activity against MCF-7 breast cancer and B16-F10 melanoma cell, indicating that the ketone group at C-3 in 3 plays an essential role in the cytotoxicity of dammarane-type triterpenoid. On the other hand, compounds 1 and 2 had very weak cytotoxic activity against the two cell lines, indicating the presence of fatty acid, significantly decreasing cytotoxic activity. This showed the significance of the discovery to investigate the essential structural feature in dammarane-type triterpenoid, specifically for the future development of anticancer drugs. Full article

(This article belongs to the Special Issue Extraction, Analysis and Biological Activity Studies of Compounds from Natural Products)

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11 pages, 4826 KiB

Open AccessArticle

Cold Sintering of Li_6.4La₃Zr_1.4Ta_0.6O₁₂/PEO Composite Solid Electrolytes

by Binlang He, Shenglin Kang, Xuetong Zhao, Jiexin Zhang, Xilin Wang, Yang Yang, Lijun Yang and Ruijin Liao

Molecules 2022, 27(19), 6756; https://doi.org/10.3390/molecules27196756 - 10 Oct 2022

Cited by 2 | Viewed by 2327

Abstract

Ceramic/polymer composite solid electrolytes integrate the high ionic conductivity of in ceramics and the flexibility of organic polymers. In practice, ceramic/polymer composite solid electrolytes are generally made into thin films rather than sintered into bulk due to processing temperature limitations. In this work, [...] Read more.

Ceramic/polymer composite solid electrolytes integrate the high ionic conductivity of in ceramics and the flexibility of organic polymers. In practice, ceramic/polymer composite solid electrolytes are generally made into thin films rather than sintered into bulk due to processing temperature limitations. In this work, Li_6.4La₃Zr_1.4Ta_0.6O₁₂ (LLZTO)/polyethylene-oxide (PEO) electrolyte containing bis(trifluoromethanesulfonyl)imide (LiTFSI) as the lithium salt was successfully fabricated into bulk pellets via the cold sintering process (CSP). Using CSP, above 80% dense composite electrolyte pellets were obtained, and a high Li-ion conductivity of 2.4 × 10⁻⁴ S cm^–1 was achieved at room temperature. This work focuses on the conductivity contributions and microstructural development within the CSP process of composite solid electrolytes. Cold sintering provides an approach for bridging the gap in processing temperatures of ceramics and polymers, thereby enabling high-performance composites for electrochemical systems. Full article

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15 pages, 6832 KiB

Open AccessArticle

Highly Sensitive, Robust, and Recyclable TiO₂/AgNP Substrate for SERS Detection

by Hsing-Yu Wu, Hung-Chun Lin, Yung-Hsien Liu, Kai-Lin Chen, Yu-Hsun Wang, Yung-Shin Sun and Jin-Cherng Hsu

Molecules 2022, 27(19), 6755; https://doi.org/10.3390/molecules27196755 - 10 Oct 2022

Cited by 10 | Viewed by 2301

Abstract

Label-free biosensors provide an important platform for detecting chemical and biological substances without needing extra labeling agents. Unlike surface-based techniques such as surface plasmon resonance (SPR), interference, and ellipsometry, surface-enhanced Raman spectroscopy (SERS) possesses the advantage of monitoring analytes both on surfaces and [...] Read more.

Label-free biosensors provide an important platform for detecting chemical and biological substances without needing extra labeling agents. Unlike surface-based techniques such as surface plasmon resonance (SPR), interference, and ellipsometry, surface-enhanced Raman spectroscopy (SERS) possesses the advantage of monitoring analytes both on surfaces and in solutions. Increasing the SERS enhancement is crucial to preparing high-quality substrates without quickly losing their stability, sensitivity, and repeatability. However, fabrication methods based on wet chemistry, nanoimprint lithography, spark discharge, and laser ablation have drawbacks of waste of time, complicated processes, or nonreproducibility in surface topography. This study reports the preparation of recyclable TiO₂/Ag nanoparticle (AgNP) substrates by using simple arc ion plating and direct-current (dc) magnetron sputtering technologies. The deposited anatase-phased TiO₂ ensured the photocatalytic degradation of analytes. By measuring the Raman spectra of rhodamine 6G (R6G) in titrated concentrations, a limit of detection (LOD) of 10⁻⁸ M and a SERS enhancement factor (EF) of 1.01 × 10⁹ were attained. Self-cleaning was performed via UV irradiation, and recyclability was achieved after at least five cycles of detection and degradation. The proposed TiO₂/AgNP substrates have the potential to serve as eco-friendly SERS enhancers for label-free detection of various chemical and biological substances. Full article

(This article belongs to the Special Issue Past Present and Future of Raman Spectroscopy)

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13 pages, 5373 KiB

Open AccessArticle

Determination of Residual Diisocyanates and Related Diamines in Biodegradable Mulch Films Using N-Ethoxycarbonylation Derivatization and GC-MS

by Kai Cai, Yechun Lin, Yunfei Ma, Zhixiao Yang, Lei Yu, Jie Zhang, Dongqing Xu, Rong Zeng and Weichang Gao

Molecules 2022, 27(19), 6754; https://doi.org/10.3390/molecules27196754 - 10 Oct 2022

Cited by 3 | Viewed by 1734

Abstract

Diisocyanates are highly reactive compounds with two functional isocyanate groups. The exposure of diisocyanates is associated with severely adverse health effects, such as asthma, inflammation in the respiratory tract, and cancer. The hydrolysis product from diisocyanates to related diamines is also a potential [...] Read more.

Diisocyanates are highly reactive compounds with two functional isocyanate groups. The exposure of diisocyanates is associated with severely adverse health effects, such as asthma, inflammation in the respiratory tract, and cancer. The hydrolysis product from diisocyanates to related diamines is also a potential carcinogen. Here, we developed an effective, accurate, and precise method for simultaneous determination of residual diisocyanates and related diamines in biodegradable mulch films, based on N-ethoxycarbonylation derivatization and gas chromatography-mass spectrometry. The method development included the optimization of ultrasonic hydrolysis and extraction, screening of N-ethoxycarbonylation conditions with ethyl chloroformate, evaluation of the diamines degradation, and analysis of the fragmentation mechanisms. Under the optimum experimental conditions, good linearity was observed with R² > 0.999. The extraction recoveries were found in the range of 93.9–101.2% with repeatabilities and reproducibilities in 0.89–8.12% and 2.12–10.56%, respectively. The limits of detection ranged from 0.0025 to 0.057 µg/mL. The developed method was applied to commercial polybutylene adipate co-terephthalate (PBAT) biodegradable mulch film samples for analysis of the diverse residual diisocyanates and related diamine additives. The components varied greatly among the sample from different origin. Overall, this study provides a reliable method for assessing safety in biodegradable mulch films. Full article

(This article belongs to the Section Analytical Chemistry)

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15 pages, 4610 KiB

Open AccessArticle

Promoting Efficacy and Environmental Safety of Pesticide Synergists via Non-Ionic Gemini Surfactants with Short Fluorocarbon Chains

by Ruiguo Wang, Xinxin Xu, Xiaodi Shi, Junjie Kou, Hongjian Song, Yuxiu Liu, Jingjing Zhang and Qingmin Wang

Molecules 2022, 27(19), 6753; https://doi.org/10.3390/molecules27196753 - 10 Oct 2022

Cited by 3 | Viewed by 1613

Abstract

Improving the utilization rate of pesticides is key to achieve a reduction and synergism, and adding appropriate surfactant to pesticide preparation is an effective way to improve pesticide utilization. Fluorinated surfactants have excellent surface activity, thermal and chemical stability, but long-chain linear perfluoroalkyl [...] Read more.

Improving the utilization rate of pesticides is key to achieve a reduction and synergism, and adding appropriate surfactant to pesticide preparation is an effective way to improve pesticide utilization. Fluorinated surfactants have excellent surface activity, thermal and chemical stability, but long-chain linear perfluoroalkyl derivatives are highly toxic, obvious persistence and high bioaccumulation in the environment. Therefore, new strategies for designing fluorinated surfactants which combine excellent surface activity and environmental safety would be useful. In this study, four non-ionic gemini surfactants with short fluorocarbon chains were synthesized. The surface activities of the resulting surfactants were assessed on the basis of equilibrium surface tension, dynamic surface tension, and contact angle. Compared with their monomeric counterparts, the gemini surfactants had markedly lower critical micelle concentrations and higher diffusivities, as well as better wetting abilities. We selected a single-chain surfactant and a gemini surfactant with good surface activities as synergists for the glyphosate water agent. Both surfactants clearly improved the efficacy of the herbicide, but the gemini surfactant had a significantly greater effect than the single-chain surfactant. An acute toxicity test indicated that the gemini surfactant showed slight toxicity to rats. Full article

(This article belongs to the Special Issue Gemini Surfactants for Medical and Non-medical Applications)

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16 pages, 2541 KiB

Open AccessArticle

Effect of Laser-Induced Optical Breakdown on the Structure of Bsa Molecules in Aqueous Solutions: An Optical Study

by Egor I. Nagaev, Ilya V. Baimler, Alexey S. Baryshev, Maxim E. Astashev and Sergey V. Gudkov

Molecules 2022, 27(19), 6752; https://doi.org/10.3390/molecules27196752 - 10 Oct 2022

Cited by 9 | Viewed by 1790

Abstract

The influence of laser radiation of a typical surgical laser on the physicochemical properties of the Bovine Serum Albumin (BSA) protein was studied. It was established that the physicochemical characteristics of optical breakdown weakly depend on the concentration of protein molecules. At the [...] Read more.

The influence of laser radiation of a typical surgical laser on the physicochemical properties of the Bovine Serum Albumin (BSA) protein was studied. It was established that the physicochemical characteristics of optical breakdown weakly depend on the concentration of protein molecules. At the same time, the patterns observed for an aqueous solution of BSA irradiated with a laser for different time periods were extremely similar to the classical ones. It was established that after exposure to laser radiation, the optical density of protein solutions increases. At the same time, the intensity of BSA fluorescence due to aromatic amino acid residues decreases insignificantly after exposure to laser radiation. In this case, the position of the excitation and emission maximum does not change, and the shape of the fluorescence spot on 3D maps also does not change significantly. On the Raman spectrum after exposure to laser radiation, a significant decrease in 1570 cm⁻¹ was observed, which indicates the degradation of α-helices and, as a result, partial denaturation of BSA molecules. Partial denaturation did not significantly change the total area of protein molecules, since the refractive index of solutions did not change significantly. However, in BSA solutions, after exposure to laser radiation, the viscosity increased, and the pseudoplasticity of aqueous solutions decreased. In this case, there was no massive damage to the polypeptide chain; on the contrary, when exposed to optical breakdown, intense aggregation was observed, while aggregates with a size of 400 nm or more appeared in the solution. Thus, under the action of optical breakdown induced by laser radiation in a BSA solution, the processes of partial denaturation and aggregation prevail, aromatic amino acid residues are damaged to a lesser extent, and fragmentation of protein molecules is not observed. Full article

(This article belongs to the Special Issue Biophysical Chemistry)

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12 pages, 2023 KiB

Open AccessReview

Conformational Essentials Responsible for Neurotoxicity of Aβ42 Aggregates Revealed by Antibodies against Oligomeric Aβ42

by Chuli Song, Tianyu Zhang and Yingjiu Zhang

Molecules 2022, 27(19), 6751; https://doi.org/10.3390/molecules27196751 - 10 Oct 2022

Cited by 5 | Viewed by 1569

Abstract

Soluble aggregation of amyloid β-peptide 1-42 (Aβ42) and deposition of Aβ42 aggregates are the initial pathological hallmarks of Alzheimer’s disease (AD). The bipolar nature of Aβ42 molecule results in its ability to assemble into distinct oligomers and higher aggregates, which may drive some [...] Read more.

Soluble aggregation of amyloid β-peptide 1-42 (Aβ42) and deposition of Aβ42 aggregates are the initial pathological hallmarks of Alzheimer’s disease (AD). The bipolar nature of Aβ42 molecule results in its ability to assemble into distinct oligomers and higher aggregates, which may drive some of the phenotypic heterogeneity observed in AD. Agents targeting Aβ42 or its aggregates, such as anti-Aβ42 antibodies, can inhibit the aggregation of Aβ42 and toxicity of Aβ42 aggregates to neural cells to a certain extent. However, the epitope specificity of an antibody affects its binding affinity for different Aβ42 species. Different antibodies target different sites on Aβ42 and thus elicit different neuroprotective or cytoprotective effects. In the present review, we summarize significant information reflected by anti-Aβ42 antibodies in different immunotherapies and propose an overview of the structure (conformation)−toxicity relationship of Aβ42 aggregates. This review aimed to provide a reference for the directional design of antibodies against the most pathogenic conformation of Aβ42 aggregates. Full article

(This article belongs to the Special Issue Chemical Agents for Neurodegenerative Diseases)

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11 pages, 3942 KiB

Open AccessArticle

Investigations into the Antifungal, Photocatalytic, and Physicochemical Properties of Sol-Gel-Produced Tin Dioxide Nanoparticles

by Sirajul Haq, Nadia Shahzad, Muhammad Imran Shahzad, Khaled Elmnasri, Manel Ben Ali, Alaa Baazeem, Amor Hedfi and Rimsha Ehsan

Molecules 2022, 27(19), 6750; https://doi.org/10.3390/molecules27196750 - 10 Oct 2022

Cited by 3 | Viewed by 1298

Abstract

Transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and Fourier transform infrared (FTIR) spectroscopy were applied to evaluate the tin dioxide nanoparticles (SnO₂ NPs) amalgamated by the [...] Read more.

Transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), and Fourier transform infrared (FTIR) spectroscopy were applied to evaluate the tin dioxide nanoparticles (SnO₂ NPs) amalgamated by the sol-gel process. XRD was used to examine the tetragonal-shaped crystallite with an average size of 26.95 (±1) nm, whereas the average particle size estimated from the TEM micrograph is 20.59 (±2) nm. A dose-dependent antifun3al activity was performed against two fungal species, and the activity was observed to be increased with an increase in the concentration of SnO₂ NPs. The photocatalytic activity of SnO₂ NPs in aqueous media was tested using Rhodamine 6G (Rh-6G) under solar light illumination. The Rh-6G was degraded at a rate of 0.96 × 10⁻² min for a total of 94.18 percent in 350 min. Full article

(This article belongs to the Special Issue Advances of Metal and Metal Oxide Nanocomposites: Synthesis, Characterization and Biomedical Applications)

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12 pages, 2111 KiB

Open AccessArticle

Sensitive, Selective and Reliable Detection of Fe³⁺ in Lake Water via Carbon Dots-Based Fluorescence Assay

by Zhuang Xiang, Yuxiang Jiang, Chen Cui, Yuanping Luo and Zhili Peng

Molecules 2022, 27(19), 6749; https://doi.org/10.3390/molecules27196749 - 10 Oct 2022

Cited by 11 | Viewed by 1794

Abstract

In this study, C-dots were facilely synthesized via microwave irradiation using citric acid and ethylenediamine as carbon precursors. The fluorescence emissions of the C-dots could be selectively quenched by Fe³⁺, and the degree of quenching was linearly related to the concentrations [...] Read more.

In this study, C-dots were facilely synthesized via microwave irradiation using citric acid and ethylenediamine as carbon precursors. The fluorescence emissions of the C-dots could be selectively quenched by Fe³⁺, and the degree of quenching was linearly related to the concentrations of Fe³⁺ presented. This phenomenon was utilized to develop a sensitive fluorescence assay for Fe³⁺ detection with broad linear range (0–250, 250–1200 μmol/L) and low detection limit (1.68 μmol/L). Most importantly, the assay demonstrated high reliability towards samples in deionized water, tap water and lake water, which should find potential applications for Fe³⁺ monitoring in complicated environments. Full article

(This article belongs to the Special Issue New Trends in Photochemistry in Eurasia)

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12 pages, 4150 KiB

Open AccessArticle

A Density Functional Theory and Microkinetic Study of Acetylene Partial Oxidation on the Perfect and Defective Cu₂O (111) Surface Models

by Ling-Nan Wu, Zhen-Yu Tian and Wu Qin

Molecules 2022, 27(19), 6748; https://doi.org/10.3390/molecules27196748 - 10 Oct 2022

Cited by 1 | Viewed by 1283

Abstract

The catalytic removal of C₂H₂ by Cu₂O was studied by investigating the adsorption and partial oxidation mechanism of C₂H₂ on both perfect (stoichiometric) and Cu_CUS-defective Cu₂O (111) surface models using density [...] Read more.

The catalytic removal of C₂H₂ by Cu₂O was studied by investigating the adsorption and partial oxidation mechanism of C₂H₂ on both perfect (stoichiometric) and Cu_CUS-defective Cu₂O (111) surface models using density functional theory calculations. The chemisorption of C₂H₂ on perfect and defective surface models needs to overcome the energy barrier of 0.70 and 0.81 eV at 0 K. The direct decomposition of C₂H₂ on both surface models is energy demanding with the energy barrier of 1.92 and 1.62 eV for the perfect and defective surface models, respectively. The H-abstractions of the chemisorbed C₂H₂ by a series of radicals including H, OH, HO₂, CH₃, O, and O₂ following the Langmuir–Hinshelwood mechanism have been compared. On the perfect Cu₂O (111) surface model, the activity order of the adsorbed radicals toward H-abstraction of C₂H₂ is: OH > O₂ > HO₂ > O > CH₃ > H, while on the defective Cu₂O (111) surface model, the activity follows the sequence: O > OH > O₂ > HO₂ > H > CH₃. The Cu_CUS defect could remarkably facilitate the H-abstraction of C₂H₂ by O₂. The partial oxidation of C₂H₂ on the Cu₂O (111) surface model tends to proceed with the chemisorption process and the following H-abstraction process rather than the direct decomposition process. The reaction of C₂H₂ H-abstraction by O₂ dictates the C₂H₂ overall reaction rate on the perfect Cu₂O (111) surface model and the chemisorption of C₂H₂ is the rate-determining step on the defective Cu₂O (111) surface model. The results of this work could benefit the understanding of the C₂H₂ reaction on the Cu₂O (111) surface and future heterogeneous modeling. Full article

(This article belongs to the Special Issue On-Surface Chemical Reactions)

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15 pages, 4973 KiB

Open AccessArticle

Dextran Fluorescent Probes Containing Sulfadiazine and Rhodamine B Groups

by Bi-Jie Bie, Xiao-Rui Zhao, Jia-Rui Yan, Xi-Jun Ke, Fan Liu and Guo-Ping Yan

Molecules 2022, 27(19), 6747; https://doi.org/10.3390/molecules27196747 - 10 Oct 2022

Cited by 4 | Viewed by 1687

Abstract

Fluorescent imaging has been expanded, as a non-invasive diagnostic modality for cancers, in recent years. Fluorescent probes in the near-infrared window can provide high sensitivity, resolution, and signal-to-noise ratio, without the use of ionizing radiation. Some fluorescent compounds with low molecular weight, such [...] Read more.

Fluorescent imaging has been expanded, as a non-invasive diagnostic modality for cancers, in recent years. Fluorescent probes in the near-infrared window can provide high sensitivity, resolution, and signal-to-noise ratio, without the use of ionizing radiation. Some fluorescent compounds with low molecular weight, such as rhodamine B (RhB) and indocyanine green (ICG), have been used in fluorescent imaging to improve imaging contrast and sensitivity; however, since these probes are excreted from the body quickly, they possess significant restrictions for imaging. To find a potential solution to this, this work investigated the synthesis and properties of novel macromolecular fluorescent compounds. Herein, water-soluble dextran fluorescent compounds (SD-Dextran-RhB) were prepared by the attachment of RhB and sulfadiazine (SD) derivatives to dextran carrier. These fluorescent compounds were then characterized through IR, ¹H NMR, ¹³C NMR, UV, GPC, and other methods. Assays of their cellular uptake and cell cytotoxicity and fluorescent imaging were also performed. Through this study, it was found that SD-Dextran-RhB is sensitive to acidic conditions and possesses low cell cytotoxicities compared to normal 293 cells and HepG2 and HeLa tumor cells. Moreover, SD-Dextran-RhB demonstrated good fluorescent imaging in HepG2 and HeLa cells. Therefore, SD-Dextran-RhB is suitable to be potentially applied as a probe in the fluorescent imaging of tumors. Full article

(This article belongs to the Special Issue Design and Preparation of Organic Fluorescent Materials for Detection and Bio-Imaging)

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16 pages, 22657 KiB

Open AccessArticle

Reversible Sorptive Preconcentration of Noble Metals Followed by FI-ICP-MS Determination

by Yulia A. Maksimova, Alexander S. Dubenskiy, Lyudmila A. Pavlova, Ilya V. Shigapov, Dmitry M. Korshunov, Irina F. Seregina, Vadim A. Davankov and Mikhail A. Bolshov

Molecules 2022, 27(19), 6746; https://doi.org/10.3390/molecules27196746 - 10 Oct 2022

Viewed by 1429

Abstract

In this paper, we propose the combined procedure of noble metal (NM) determination, including fire assay, acid digestion, and reversible dynamic sorptive preconcentration, followed by flow-injection ICP-MS. Reversible preconcentration of all NMs was carried out using micro-column packed new PVBC-VP sorbent and elution [...] Read more.

In this paper, we propose the combined procedure of noble metal (NM) determination, including fire assay, acid digestion, and reversible dynamic sorptive preconcentration, followed by flow-injection ICP-MS. Reversible preconcentration of all NMs was carried out using micro-column packed new PVBC-VP sorbent and elution with a mixture of thiourea, potassium thiocyanate, and HCl, which recovers Pd, Ir, Pt, and Au by 95% and Ru, and Rh by 90%. The proposed procedure was approved using certified reference materials. Full article

(This article belongs to the Special Issue Advances in Detection of Trace Elements by Analytical Spectroscopy)

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12 pages, 1289 KiB

Open AccessArticle

Non-Conventional Time Domain (TD)-NMR Approaches for Food Quality: Case of Gelatin-Based Candies as a Model Food

by Sirvan Sultan Uguz, Baris Ozel, Leonid Grunin, Emin Burcin Ozvural and Mecit H. Oztop

Molecules 2022, 27(19), 6745; https://doi.org/10.3390/molecules27196745 - 10 Oct 2022

Cited by 4 | Viewed by 1622

Abstract

The TD-NMR technique mostly involves the use of T₁ (spin-lattice) and T₂ (spin-spin) relaxation times to explain the changes occurring in food systems. However, these relaxation times are affected by many factors and might not always be the best indicators to [...] Read more.

The TD-NMR technique mostly involves the use of T₁ (spin-lattice) and T₂ (spin-spin) relaxation times to explain the changes occurring in food systems. However, these relaxation times are affected by many factors and might not always be the best indicators to work with in food-related TD-NMR studies. In this study, the non-conventional TD-NMR approaches of Solid Echo (SE)/Magic Sandwich Echo (MSE) and Spin Diffusion in food systems were used for the first time. Soft confectionary gelatin gels were formulated and conventional (T₁) and non-conventional (SE, MSE and Spin Diffusion) TD-NMR experiments were performed. Corn syrups with different glucose/fructose compositions were used to prepare the soft candies. Hardness, °Brix (°Bx), and water activity (a_w) measurements were also conducted complementary to NMR experiments. Relaxation times changed (p < 0.05) with respect to syrup type with no obvious trend. SE/MSE experiments were performed to calculate the crystallinity of the samples. Samples prepared with fructose had the lowest crystallinity values (p < 0.05). Spin Diffusion experiments were performed by using Goldman–Shen pulse sequence and the interface thickness (d) was calculated. Interface thickness values showed a wide range of variation (p < 0.05). Results showed that non-conventional NMR approaches had high potential to be utilized in food systems for quality control purposes. Full article

(This article belongs to the Special Issue Magnetic Resonance and Vibrational Spectroscopy and Imaging in Food Analysis)

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