Molecules

12 pages, 1977 KiB

Open AccessArticle

Multi-Detection Size Exclusion Chromatography as an Advanced Tool for Monitoring Enzyme–Antibody Conjugation Reaction and Quality Control of a Final Product

by Adela Štimac, Tihana Kurtović and Beata Halassy

Molecules 2023, 28(11), 4567; https://doi.org/10.3390/molecules28114567 - 5 Jun 2023

Viewed by 2169

Abstract

The multi-detection size exclusion chromatography (SEC) has been recognized as an advanced analytical technique for the characterization of macromolecules and process control, as well as the manufacturing and formulation of biotechnology products. It reveals reproducible molecular characterization data, such as molecular weight and [...] Read more.

The multi-detection size exclusion chromatography (SEC) has been recognized as an advanced analytical technique for the characterization of macromolecules and process control, as well as the manufacturing and formulation of biotechnology products. It reveals reproducible molecular characterization data, such as molecular weight and its distribution, and the size, shape, and composition of the sample peaks. The aim of this work was to investigate the potential and suitability of the multi-detection SEC as a tool for surveillance over the molecular processes during the conjugation reaction between the antibody (IgG) and horseradish peroxidase (HRP), and demonstrate the plausibility of its application in the quality control of the final product, the IgG-HRP conjugate. Guinea pig anti-Vero IgG-HRP conjugate was prepared using a modified periodate oxidation method, based on periodate oxidation of the carbohydrate side chains of HRP, followed by the formation of Schiff bases between the activated HRP and amino groups of the IgG. The quantitative molecular characterization data of the starting samples, intermediates, and final product were obtained by multi-detection SEC. Titration of the prepared conjugate was performed by the ELISA and its optimal working dilution was determined. This methodology proved to be a promising and powerful technology for the IgG-HRP conjugate process control and development, as well as for the quality control of the final product, as verified by the analysis of several commercially available reagents. Full article

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

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16 pages, 3786 KiB

Open AccessArticle

Novel Mn⁴⁺-Activated K₂Nb_1−xMo_xF₇ (0 ≤ x ≤ 0.15) Solid Solution Red Phosphors with Superior Moisture Resistance and Good Thermal Stability

by Yuhan Gao, Lei Feng, Linglin Wang, Jun Zheng, Feiyao Ren, Siyu Liu, Zhanglei Ning, Ting Zhou, Xiaochun Wu, Xin Lai and Daojiang Gao

Molecules 2023, 28(11), 4566; https://doi.org/10.3390/molecules28114566 - 5 Jun 2023

Cited by 9 | Viewed by 1627

Abstract

Nowadays, Mn⁴⁺-activated fluoride red phosphors with excellent luminescence properties have triggered tremendous attentions for enhancing the performance of white light-emitting diodes (WLEDs). Nonetheless, the poor moisture resistance of these phosphors impedes their commercialization. Herein, we proposed the dual strategies of “solid [...] Read more.

Nowadays, Mn⁴⁺-activated fluoride red phosphors with excellent luminescence properties have triggered tremendous attentions for enhancing the performance of white light-emitting diodes (WLEDs). Nonetheless, the poor moisture resistance of these phosphors impedes their commercialization. Herein, we proposed the dual strategies of “solid solution design” and “charge compensation” to design K₂Nb_1−xMo_xF₇ novel fluoride solid solution system, and synthesized the Mn⁴⁺-activated K₂Nb_1−xMo_xF₇ (0 ≤ x ≤ 0.15, x represents the mol % of Mo⁶⁺ in the initial solution) red phosphors via co-precipitation method. The doping of Mo⁶⁺ not only significantly improve the moisture resistance of the K₂NbF₇: Mn⁴⁺ phosphor without any passivation and surface coating, but also effectively enhance the luminescence properties and thermal stability. In particular, the obtained K₂Nb_1−xMo_xF₇: Mn⁴⁺ (x = 0.05) phosphor possesses the quantum yield of 47.22% and retains 69.95% of its initial emission intensity at 353 K. Notably, the normalized intensity of the red emission peak (627 nm) for the K₂Nb_1−xMo_xF₇: Mn⁴⁺ (x = 0.05) phosphor is 86.37% of its initial intensity after immersion for 1440 min, prominently higher than that of the K₂NbF₇: Mn⁴⁺ phosphor. Moreover, a high-performance WLED with high CRI of 88 and low CCT of 3979 K is fabricated by combining blue chip (InGaN), yellow phosphor (Y₃Al₅O₁₂: Ce³⁺) and the K₂Nb_1−xMo_xF₇: Mn⁴⁺ (x = 0.05) red phosphor. Our findings convincingly demonstrate that the K₂Nb_1−xMo_xF₇: Mn⁴⁺ phosphors have a good practical application in WLEDs. Full article

(This article belongs to the Collection Green Energy and Environmental Materials)

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10 pages, 11078 KiB

Open AccessArticle

Wheat Roll Enhanced by Buckwheat Hull, a New Functional Food: Focus on the Retention of Bioactive Compounds

by Małgorzata Wronkowska, Natalia Bączek, Joanna Honke, Joanna Topolska, Wiesław Wiczkowski and Henryk Zieliński

Molecules 2023, 28(11), 4565; https://doi.org/10.3390/molecules28114565 - 5 Jun 2023

Cited by 2 | Viewed by 1529

Abstract

Wheat roll enhanced by buckwheat hull was used as a model for determining the retention of bioactive compounds during technological steps. The research included analysis of the formation of Maillard reaction products (MRPs) and retention of bioactive compounds such as tocopherols, glutathione, or [...] Read more.

Wheat roll enhanced by buckwheat hull was used as a model for determining the retention of bioactive compounds during technological steps. The research included analysis of the formation of Maillard reaction products (MRPs) and retention of bioactive compounds such as tocopherols, glutathione, or antioxidant capacity. About a 30% decrease in the content of available lysine in the roll was observed compared to the value obtained for fermented dough. Free FIC, FAST index, and browning index were highest for the final products. The increase of analyzed tocopherols (α-, β-,γ-, and δ-T) was noticed during the technological steps, with the highest values found for the roll with 3% of buckwheat hull. A significant reduction in GSH and GSSG content occurred during the baking process. The observed increase in the value of the antioxidant capacity after the baking process may be the result of the formation of new antioxidant compounds. Full article

(This article belongs to the Special Issue Advances in Functional Foods)

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46 pages, 16773 KiB

Open AccessReview

1,3-Butadiynamides the Ethynylogous Ynamides: Synthesis, Properties and Applications in Heterocyclic Chemistry

by Illia Lenko, Carole Alayrac, Igor Bożek and Bernhard Witulski

Molecules 2023, 28(11), 4564; https://doi.org/10.3390/molecules28114564 - 5 Jun 2023

Cited by 3 | Viewed by 2514

Abstract

1,3-butadiynamides—the ethynylogous variants of ynamides—receive considerable attention as precursors of complex molecular scaffolds for organic and heterocyclic chemistry. The synthetic potential of these C4-building blocks reveals itself in sophisticated transition-metal catalyzed annulation reactions and in metal-free or silver-mediated HDDA (Hexa-dehydro-Diels–Alder) cycloadditions. 1,3-Butadiynamides also [...] Read more.

1,3-butadiynamides—the ethynylogous variants of ynamides—receive considerable attention as precursors of complex molecular scaffolds for organic and heterocyclic chemistry. The synthetic potential of these C4-building blocks reveals itself in sophisticated transition-metal catalyzed annulation reactions and in metal-free or silver-mediated HDDA (Hexa-dehydro-Diels–Alder) cycloadditions. 1,3-Butadiynamides also gain significance as optoelectronic materials and in less explored views on their unique helical twisted frontier molecular orbitals (Hel-FMOs). The present account summarizes different methodologies for the synthesis of 1,3-butadiynamides followed by the description of their molecular structure and electronic properties. Finally, the surprisingly rich chemistry of 1,3-butadiynamides as versatile C4-building blocks in heterocyclic chemistry is reviewed by compiling their exciting reactivity, specificity and opportunities for organic synthesis. Besides chemical transformations and use in synthesis, a focus is set on the mechanistic understanding of the chemistry of 1,3-butadiynamides—suggesting that 1,3-butadiynamides are not just simple alkynes. These ethynylogous variants of ynamides have their own molecular character and chemical reactivity and reflect a new class of remarkably useful compounds. Full article

(This article belongs to the Special Issue Recent Developments in the Synthesis and Functionalization of Nitrogen Heterocycles)

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13 pages, 484 KiB

Open AccessArticle

Spectroscopic Constants and Anharmonic Vibrational Frequencies of C(O)OC, c-C₂O₂ and Their Silicon-Containing Analogues

by Olivia A. Harwick and Ryan C. Fortenberry

Molecules 2023, 28(11), 4563; https://doi.org/10.3390/molecules28114563 - 5 Jun 2023

Viewed by 2313

Abstract

Comets are likely to contain various carbon oxide molecules potentially including C(O)OC and c-C

_{2}

O

_{2}

on their surfaces and comae, as well as their silicon-substituted analogues possibly playing a role in the formation of interstellar dust grains. In this work, high-level [...] Read more.

Comets are likely to contain various carbon oxide molecules potentially including C(O)OC and c-C

_{2}

O

_{2}

on their surfaces and comae, as well as their silicon-substituted analogues possibly playing a role in the formation of interstellar dust grains. In this work, high-level quantum chemical data are provided to support such potential future astrophysical detection through the generation of predicted rovibrational data. Laboratory-based chemistry would also benefit from such aforementioned computational benchmarking considering these molecules’ historic computational and experimental elusiveness. Coupled-cluster singles, doubles, and perturbative triples, the F12b formalism, and the cc-pCVTZ-F12 basis set garner the rapid, yet highly trusted F12-TcCR level of theory leveraged presently. This current work points to all four molecules’ strong IR activity, coupled with large intensities, thus suggesting the potential for JWST detection. Although Si(O)OSi possesses a permanent dipole moment significantly larger than those of the other molecules of present interest, the significant abundance of the potential precursor carbon monoxide suggests that the dicarbon dioxide molecules may yet be observable in the microwave region of the electromagnetic spectrum. Thus, this present work details the likely existence and detectability of these four cyclic molecules, providing updated implications compared to previous work performed both experimentally and computationally. Full article

(This article belongs to the Special Issue Spectroscopic and Theoretical Methods to Investigate Interstellar Medium)

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16 pages, 3423 KiB

Open AccessReview

Progress in the Mechanism of the Effect of Fe₃O₄ Nanomaterials on Ferroptosis in Tumor Cells

by Yaxuan Wang, Xiao Wu, Xiaoying Bao and Xianbo Mou

Molecules 2023, 28(11), 4562; https://doi.org/10.3390/molecules28114562 - 5 Jun 2023

Cited by 6 | Viewed by 2509

Abstract

Ferroptosis is a new form of iron-dependent programmed cell death discovered in recent years, which is caused by the accumulation of lipid peroxidation (LPO) and reactive oxygen species (ROS). Recent studies have shown that cellular ferroptosis is closely related to tumor progression, and [...] Read more.

Ferroptosis is a new form of iron-dependent programmed cell death discovered in recent years, which is caused by the accumulation of lipid peroxidation (LPO) and reactive oxygen species (ROS). Recent studies have shown that cellular ferroptosis is closely related to tumor progression, and the induction of ferroptosis is a new means to inhibit tumor growth. Biocompatible Fe₃O₄ nanoparticles (Fe₃O₄-NPs), rich in Fe²⁺ and Fe³⁺, act as a supplier of iron ions, which not only promote ROS production but also participate in iron metabolism, thus affecting cellular ferroptosis. In addition, Fe₃O₄-NPs combine with other techniques such as photodynamic therapy (PDT); heat stress and sonodynamic therapy (SDT) can further induce cellular ferroptosis effects, which then enhance the antitumor effects. In this paper, we present the research progress and the mechanism of Fe₃O₄-NPs to induce ferroptosis in tumor cells from the perspective of related genes and chemotherapeutic drugs, as well as PDT, heat stress, and SDT techniques. Full article

(This article belongs to the Special Issue Functional Nanomaterials and Their Applications in Analysis, Sensing, and Catalysis)

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11 pages, 3452 KiB

Open AccessArticle

Chemical Composition of Essential Oil of Cymbopogon schoenanthus (L.) Spreng from Burkina Faso, and Effects against Prostate and Cervical Cancer Cell Lines

by Bagora Bayala, Laetizia Liz Coulibaly, Florencia Djigma, Julio Bunay, Albert Yonli, Lassina Traore, Silvère Baron, Gilles Figueredo, Jacques Simpore and Jean-Marc A. Lobaccaro

Molecules 2023, 28(11), 4561; https://doi.org/10.3390/molecules28114561 - 5 Jun 2023

Cited by 2 | Viewed by 2188

Abstract

The aim of this research was to evaluate the essential oil of Cymbopogon schoenanthus (L.) Spreng. (C. schoenanthus) from Burkina Faso in terms of cytotoxic activity against LNCaP cells, derived from prostate cancer, and HeLa cells, derived from cervical cancer. Antioxidant activities [...] Read more.

The aim of this research was to evaluate the essential oil of Cymbopogon schoenanthus (L.) Spreng. (C. schoenanthus) from Burkina Faso in terms of cytotoxic activity against LNCaP cells, derived from prostate cancer, and HeLa cells, derived from cervical cancer. Antioxidant activities were evaluated in vitro. Essential oil (EO) was extracted by hydrodistillation and analyzed by GC/FID and GC/MS. Thirty-seven compounds were identified, the major compounds being piperitone (49.9%), δ-2-carene (24.02%), elemol (5.79%) and limonene (4.31%). EO exhibited a poor antioxidant activity, as shown by the inhibition of DPPH radicals (IC₅₀ = 1730 ± 80 µg/mL) and ABTS^+. (IC₅₀ = 2890 ± 26.9 µg/mL). Conversely, EO decreased the proliferation of LNCaP and HeLa cells with respective IC50 values of 135.53 ± 5.27 µg/mL and 146.17 ± 11 µg/mL. EO also prevented LNCaP cell migration and led to the arrest of their cell cycle in the G2/M phase. Altogether, this work points out for the first time that EO of C. schoenanthus from Burkina Faso could be an effective natural anticancer agent. Full article

(This article belongs to the Special Issue Phytochemicals: Extraction, Bioactivities and Applications)

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23 pages, 2775 KiB

Open AccessArticle

Structural and Spectroscopic Study of New Copper(II) and Zinc(II) Complexes of Coumarin Oxyacetate Ligands and Determination of Their Antimicrobial Activity

by Muhammad Mujahid, Natasha Trendafilova, Georgina Rosair, Kevin Kavanagh, Maureen Walsh, Bernadette S. Creaven and Ivelina Georgieva

Molecules 2023, 28(11), 4560; https://doi.org/10.3390/molecules28114560 - 5 Jun 2023

Cited by 5 | Viewed by 2120

Abstract

Tackling antimicrobial resistance is of increasing concern in a post-pandemic world where overuse of antibiotics has increased the threat of another pandemic caused by antimicrobial-resistant pathogens. Derivatives of coumarins, a naturally occurring bioactive compound, and its metal complexes have proven therapeutic potential as [...] Read more.

Tackling antimicrobial resistance is of increasing concern in a post-pandemic world where overuse of antibiotics has increased the threat of another pandemic caused by antimicrobial-resistant pathogens. Derivatives of coumarins, a naturally occurring bioactive compound, and its metal complexes have proven therapeutic potential as antimicrobial agents and in this study a series of copper(II) and zinc(II) complexes of coumarin oxyacetate ligands were synthesised and characterised by spectroscopic techniques (IR, ¹H, ¹³C NMR, UV-Vis) and by X-ray crystallography for two of the zinc complexes. The experimental spectroscopic data were then interpreted on the basis of molecular structure modelling and subsequent spectra simulation using the density functional theory method to identify the coordination mode in solution for the metal ions in the complexes. Interestingly, the solid-state coordination environment of the zinc complexes is in good agreement with the simulated solution state, which has not been the case in our previous studies of these ligands when coordinated to silver(I). Previous studies had indicated excellent antimicrobial activity for Ag(I) analogues of these ligands and related copper and zinc complexes of coumarin-derived ligands, but in this study none of the complexes displayed antimicrobial activity against the clinically relevant methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Candida albicans. Full article

(This article belongs to the Special Issue Applications of Metal Complexes)

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10 pages, 1178 KiB

Open AccessArticle

Antioxidant Activities of Essential Oils and Their Major Components in Scavenging Free Radicals, Inhibiting Lipid Oxidation and Reducing Cellular Oxidative Stress

by Xiaohua Chen, Shufeng Shang, Fei Yan, Hai Jiang, Guanjie Zhao, Shan Tian, Rui Chen, Dejing Chen and Yafeng Dang

Molecules 2023, 28(11), 4559; https://doi.org/10.3390/molecules28114559 - 5 Jun 2023

Cited by 32 | Viewed by 5217

Abstract

Antioxidant activities of five essential oils (cinnamon, thyme, clove, lavender and peppermint oils) and their major components (eugenol, thymol, linalool, and menthol) were evaluated on scavenging DPPH (2,2-diphenyl-1 picrylhydrazyl) free radicals, inhibiting polyunsaturated fatty acid oxidation in fish oil emulsion (FOE), and reducing [...] Read more.

Antioxidant activities of five essential oils (cinnamon, thyme, clove, lavender and peppermint oils) and their major components (eugenol, thymol, linalool, and menthol) were evaluated on scavenging DPPH (2,2-diphenyl-1 picrylhydrazyl) free radicals, inhibiting polyunsaturated fatty acid oxidation in fish oil emulsion (FOE), and reducing oxidative stress in human red blood cells (RBC). The essential oils from cinnamon, thyme, clove and their main components, eugenol and thymol, exhibited the highest antioxidant activity in the FOE and RBC systems. It was found that the antioxidant activity of essential oils was positively correlated to the content of eugenol and thymol, while lavender and peppermint oils and their main components, linalool and menthol, had very low antioxidant activity. Compared with scavenging DPPH free radical activity, the antioxidant activity in FOE and RBC systems could better reflect the actual antioxidant potential of essential oil in preventing lipid oxidation and reducing oxidative stress in biological system. Full article

(This article belongs to the Special Issue Key Role of Natural Bioactive Compounds in Health and Diseases)

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12 pages, 3800 KiB

Open AccessArticle

Characterization of Dissolved Organic Matter Released from Aged Biochar: A Comparative Study of Two Feedstocks and Multiple Aging Approaches

by Yan Yue, Leqi Xu, Guitong Li, Xiang Gao and Hongfang Ma

Molecules 2023, 28(11), 4558; https://doi.org/10.3390/molecules28114558 - 5 Jun 2023

Cited by 6 | Viewed by 1629

Abstract

Dissolved organic matter (DOM) plays important roles in environmental ecosystems. While many studies have explored the characteristics of aged biochar, limited information is available about the properties of DOM derived from aged biochar. In this study, biochar obtained from maize stalk and soybean [...] Read more.

Dissolved organic matter (DOM) plays important roles in environmental ecosystems. While many studies have explored the characteristics of aged biochar, limited information is available about the properties of DOM derived from aged biochar. In this study, biochar obtained from maize stalk and soybean straw were aged using farmland or vegetable-soil solution, as well as soil solution containing hydrogen peroxide (H₂O₂). Chemical composition of the extracted DOM from the aged biochar was analyzed via excitation–emission matrix coupled with fluorescence regional integration (FRI) and parallel factor analysis (PARAFAC). Obtained results showed that biochar aged with H₂O₂-enriched soil solution had higher water-soluble organic carbon, ranging from 147.26–734.13% higher than the controls. FRI analysis revealed fulvic and humic-like organics as the key components, with a considerable increase of 57.48–235.96% in the humic-like component, especially in soybean-straw-aged biochar. PARAFAC identified four humic-like substance components. Concurrently, the aromaticity and humification of the aged-biochar-derived DOM increased, while the molecular weight decreased. These findings suggest that DOM derived from aged biochar, with a high content of humic-like organics, might impact the mobility and toxicity of pollutants in soil. Full article

(This article belongs to the Collection Recycling of Biomass Resources: Biofuels and Biochemicals)

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4 pages, 209 KiB

Open AccessEditorial

Special Issue: Research and Application of Food By-Products

by Renata Różyło

Molecules 2023, 28(11), 4557; https://doi.org/10.3390/molecules28114557 - 5 Jun 2023

Viewed by 1117

Abstract

Recently, there has been an increase in interest in reusing food processing by-products [...] Full article

(This article belongs to the Special Issue Research and Application of Food By-Products)

1 pages, 505 KiB

Open AccessCorrection

Correction: Grancharov et al. Flexible Polymer–Organic Solar Cells Based on P3HT:PCBM Bulk Heterojunction Active Layer Constructed under Environmental Conditions. Molecules 2021, 26, 6890

by Georgy Grancharov, Mariya-Desislava Atanasova, Radostina Kalinova, Rositsa Gergova, Georgi Popkirov, Christosko Dikov and Marushka Sendova-Vassileva

Molecules 2023, 28(11), 4556; https://doi.org/10.3390/molecules28114556 - 5 Jun 2023

Viewed by 887

Abstract

The authors would like to correct a mistake in Figure 3 as published in the original publication [...] Full article

(This article belongs to the Special Issue Advances in Photonic Materials)

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16 pages, 4911 KiB

Open AccessArticle

Terroir Influence on Polyphenol Metabolism from Grape Canes: A Spatial Metabolomic Study at Parcel Scale

by Kévin Billet, Sébastien Salvador-Blanes, Thomas Dugé De Bernonville, Guillaume Delanoue, Florent Hinschberger, Audrey Oudin, Vincent Courdavault, Olivier Pichon, Sébastien Besseau, Samuel Leturcq, Nathalie Giglioli-Guivarc’h and Arnaud Lanoue

Molecules 2023, 28(11), 4555; https://doi.org/10.3390/molecules28114555 - 5 Jun 2023

Cited by 4 | Viewed by 1656

Abstract

The composition of bioactive polyphenols from grape canes, an important viticultural byproduct, was shown to be varietal-dependent; however, the influence of soil-related terroir factors remains unexplored. Using spatial metabolomics and correlation-based networks, we investigated how continuous changes in soil features and topography may [...] Read more.

The composition of bioactive polyphenols from grape canes, an important viticultural byproduct, was shown to be varietal-dependent; however, the influence of soil-related terroir factors remains unexplored. Using spatial metabolomics and correlation-based networks, we investigated how continuous changes in soil features and topography may impact the polyphenol composition in grape canes. Soil properties, topography, and grape cane extracts were analyzed at georeferenced points over 3 consecutive years, followed by UPLC-DAD-MS-based metabolomic analysis targeting 42 metabolites. Principal component analyses on intra-vintage metabolomic data presented a good reproducibility in relation to geographic coordinates. A correlation-driven approach was used to explore the combined influence of soil and topographic variables on metabolomic responses. As a result, a metabolic cluster including flavonoids was correlated with elevation and curvature. Spatial metabolomics driven by correlation-based networks represents a powerful approach to spatialize field-omics data and may serve as new field-phenotyping tool in precision agriculture. Full article

(This article belongs to the Section Natural Products Chemistry)

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16 pages, 2220 KiB

Open AccessArticle

Mentha longifolia Essential Oil and Pulegone in Edible Coatings of Alginate and Chitosan: Effects on Pathogenic Bacteria in Lactic Cheese

by Fatemeh Shahdadi, Maliheh Faryabi, Haroon Khan, Ali Salehi Sardoei, Bahman Fazeli-Nasab, Bey Hing Goh, Khang Wen Goh and Ching Siang Tan

Molecules 2023, 28(11), 4554; https://doi.org/10.3390/molecules28114554 - 5 Jun 2023

Cited by 5 | Viewed by 1877

Abstract

Mentha longifolia is a valuable medicinal and aromatic plant that belongs to Lamiaceae family. This study looked at the antibacterial effects of M. longifolia essential oil and pulegone in edible coatings made of chitosan and alginate on the growth of Staphylococcus aureus, [...] Read more.

Mentha longifolia is a valuable medicinal and aromatic plant that belongs to Lamiaceae family. This study looked at the antibacterial effects of M. longifolia essential oil and pulegone in edible coatings made of chitosan and alginate on the growth of Staphylococcus aureus, Listeria monocytogenes, and Escherichia coli in cheese. For this purpose, first fresh mint plant was collected from the cold region of Jiroft in Kerman province. Plant samples were dried in the shade at ambient temperature, and essential oil was prepared using Clevenger. The essential oil was analyzed by gas chromatography using mass spectrometric (GC/MS) detection. The major composition of M. longifolia oil was pulegone (26.07%), piperitone oxide (19.72%), and piperitone (11.88%). The results showed that adding M. longifolia essential oils and pulegone to edible coatings significantly reduced the growth of bacteria during storage. The bacterial population decreased by increasing the concentration of chitosan, M. longifolia, and pulegone in edible coatings. When the effects of pulegone and M. longifolia essential oils on bacteria were compared, it was found that pulegone had a stronger effect on bacterial population reduction. Coating treatments showed more antibacterial activity on E. coli than other bacteria. In general, the results of this research showed that alginate and chitosan coatings along with M. longifolia essential oil and its active ingredient pulegone had antibacterial effects against S. aureus, L. monocytogenes, and E. coli in cheese. Full article

(This article belongs to the Special Issue Bioactives and Functional Ingredients in Foods II)

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20 pages, 338 KiB

Open AccessArticle

Study of Brewer’s Spent Grain Environmentally Friendly Processing Ways

by Konstantin V. Kobelev, Irina N. Gribkova, Larisa N. Kharlamova, Armen V. Danilyan, Maxim A. Zakharov, Irina V. Lazareva, Valery I. Kozlov and Olga A. Borisenko

Molecules 2023, 28(11), 4553; https://doi.org/10.3390/molecules28114553 - 5 Jun 2023

Cited by 1 | Viewed by 1458

Abstract

Background: This article is devoted to the study of the effect of electrochemically activated water (catholyte with pH 9.3) on organic compounds of the plant matrix of brewer’s spent grain in order to extract various compounds from it. Methods: Brewer’s spent grain was [...] Read more.

Background: This article is devoted to the study of the effect of electrochemically activated water (catholyte with pH 9.3) on organic compounds of the plant matrix of brewer’s spent grain in order to extract various compounds from it. Methods: Brewer’s spent grain was obtained from barley malt at a pilot plant by mashing the malt followed by filtration and washing of the grain in water and storing it at (0 ± 2) °C in craft bags. For the organic compound quantitative determination, instrumental methods of analysis (HPLC) were used, and the results were subjected to mathematical analysis. Results: The study results showed that at atmospheric pressure, the alkaline properties of the catholyte showed better results compared to aqueous extraction with respect to β-glucan, sugars, nitrogenous and phenolic compounds, and 120 min was the best period for extraction at 50 °C. The excess pressure conditions used (0.5 ÷ 1 atm) revealed an increase in the accumulation of non-starch polysaccharide and nitrogenous compounds, while the level of sugars, furan and phenolic compounds decreased with increasing treatment duration. The waste grain extract ultrasonic treatment used revealed the effectiveness of catholyte in relation to the extraction of β-glucan and nitrogenous fractions; however, sugars and phenolic compounds did not significantly accumulate. The correlation method made it possible to reveal the regularities in the formation of furan compounds under the conditions of extraction with the catholyte: Syringic acid had the greatest effect on the formation of 5-OH-methylfurfural at atmospheric pressure and 50 °C and vanillic acid under conditions of excess pressure. Regarding furfural and 5-methylfurfural, amino acids had a direct effect at excess pressure. It was shown that the content of all furan compounds depends on amino acids with thiol groups and gallic acid; the formation of 5-hydroxymethylfurfural and 5-methylfurfural is influenced by gallic and vanillic acids; the release of furfural and 5-methylfurfural is determined by amino acids and gallic acid; excess pressure conditions promote the formation of furan compounds under the action of gallic and lilac acids. Conclusions: This study showed that a catholyte allows for efficient extraction of carbohydrate, nitrogenous and monophenolic compounds under pressure conditions, while flavonoids require a reduction in extraction time under pressure conditions. Full article

(This article belongs to the Special Issue Development of Analytical Methodologies for Selective Extraction, Separation, Identification, and Purification of Valuable Compounds)

22 pages, 4939 KiB

Open AccessArticle

Pyrene-Containing Polyamines as Fluorescent Receptors for Recognition of PFOA in Aqueous Media

by Yschtar Tecla Simonini Steiner, Giammarco Maria Romano, Lara Massai, Martina Lippi, Paola Paoli, Patrizia Rossi, Matteo Savastano and Andrea Bencini

Molecules 2023, 28(11), 4552; https://doi.org/10.3390/molecules28114552 - 5 Jun 2023

Cited by 3 | Viewed by 1853

Abstract

The globally widespread perfluorooctanoic acid (PFOA) is a concerning environmental contaminant, with a possible toxic long-term effects on the environment and human health The development of sensible, rapid, and low-cost detection systems is a current change in modern environmental chemistry. In this context, [...] Read more.

The globally widespread perfluorooctanoic acid (PFOA) is a concerning environmental contaminant, with a possible toxic long-term effects on the environment and human health The development of sensible, rapid, and low-cost detection systems is a current change in modern environmental chemistry. In this context, two triamine-based chemosensors, L1 and L2, containing a fluorescent pyrene unit, and their Zn(II) complexes are proposed as fluorescent probes for the detection of PFOA in aqueous media. Binding studies carried out by means of fluorescence and NMR titrations highlight that protonated forms of the receptors can interact with the carboxylate group of PFOA, thanks to salt bridge formation with the ammonium groups of the aliphatic chain. This interaction induces a decrease in the fluorescence emission of pyrene at neutral and slightly acidic pH values. Similarly, emission quenching has also been observed upon coordination of PFOA by the Zn(II) complexes of the receptors. These results evidence that simple polyamine-based molecular receptors can be employed for the optical recognition of harmful pollutant molecules, such as PFOA, in aqueous media. Full article

(This article belongs to the Section Inorganic Chemistry)

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13 pages, 2683 KiB

Open AccessArticle

6-Methylcoumarin Promotes Melanogenesis through the PKA/CREB, MAPK, AKT/PI3K, and GSK3β/β-Catenin Signaling Pathways

by Taejin Kim, Jin-Kyu Kang and Chang-Gu Hyun

Molecules 2023, 28(11), 4551; https://doi.org/10.3390/molecules28114551 - 5 Jun 2023

Cited by 3 | Viewed by 1793

Abstract

We investigated the effects of four coumarin derivatives, namely, 6-methylcoumarin, 7-methylcoumarin, 4-hydroxy-6-methylcoumarin, and 4-hydroxy-7-methylcoumarin, which have similar structures on melanogenesis in a murine melanoma cell line from a C57BL/6J mouse called B16F10. Our results showed that only 6-methylcoumarin significantly increased the melanin synthesis [...] Read more.

We investigated the effects of four coumarin derivatives, namely, 6-methylcoumarin, 7-methylcoumarin, 4-hydroxy-6-methylcoumarin, and 4-hydroxy-7-methylcoumarin, which have similar structures on melanogenesis in a murine melanoma cell line from a C57BL/6J mouse called B16F10. Our results showed that only 6-methylcoumarin significantly increased the melanin synthesis in a concentration-dependent manner. In addition, the tyrosinase, TRP-1, TRP-2, and MITF protein levels were found to significantly increase in response to 6-methylcoumarin in a concentration-dependent manner. To elucidate the molecular mechanism whereby 6-methylcoumarin-induced melanogenesis influences the melanogenesis-related protein expression and melanogenesis-regulating protein activation, we further assessed the B16F10 cells. The inhibition of the ERK, Akt, and CREB phosphorylation, and conversely, the increased p38, JNK, and PKA phosphorylation activated the melanin synthesis via MITF upregulation, which ultimately led to increased melanin synthesis. Accordingly, 6-methylcoumarin increased the p38, JNK, and PKA phosphorylation in the B16F10 cells, whereas it decreased the phosphorylated ERK, Akt, and CREB expressions. In addition, the 6-methylcoumarin activated GSK3β and β-catenin phosphorylation and reduced the β-catenin protein level. These results suggest that 6-methylcoumarin stimulates melanogenesis through the GSK3β/β-catenin signal pathway, thereby affecting the pigmentation process. Finally, we tested the safety of 6-methylcoumarin for topical applications using a primary human skin irritation test on the normal skin of 31 healthy volunteers. We found that 6-methylcoumarin did not cause any adverse effects at concentrations of 125 and 250 μM. Our findings indicate that 6-methylcoumarin may be an effective pigmentation stimulator for use in cosmetics and the medical treatment of photoprotection and hypopigmentation disorders. Full article

(This article belongs to the Special Issue Natural Products for Cosmetic Applications II)

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16 pages, 4997 KiB

Open AccessArticle

Isomerization and Stabilization of Amygdalin from Peach Kernels

by Decai Zhang, Jianfen Ye, Yu Song, Yingying Wei, Shu Jiang, Yi Chen and Xingfeng Shao

Molecules 2023, 28(11), 4550; https://doi.org/10.3390/molecules28114550 - 5 Jun 2023

Cited by 2 | Viewed by 1856

Abstract

In this study, isomerization conditions, cytotoxic activity, and stabilization of amygdalin from peach kernels were analyzed. Temperatures greater than 40 °C and pHs above 9.0 resulted in a quickly increasing isomer ratio (L-amygdalin/D-amygdalin). At acidic pHs, isomerization was significantly inhibited, even [...] Read more.

In this study, isomerization conditions, cytotoxic activity, and stabilization of amygdalin from peach kernels were analyzed. Temperatures greater than 40 °C and pHs above 9.0 resulted in a quickly increasing isomer ratio (L-amygdalin/D-amygdalin). At acidic pHs, isomerization was significantly inhibited, even at high temperature. Ethanol inhibited isomerization; the isomer rate decreased with the ethanol concentration increasing. The growth-inhibitory effect on HepG2 cells of D-amygdalin was diminished as the isomer ratio increased, indicating that isomerization reduces the pharmacological activity of D-amygdalin. Extracting amygdalin from peach kernels by ultrasonic power at 432 W and 40 °C in 80% ethanol resulted in a 1.76% yield of amygdalin with a 0.04 isomer ratio. Hydrogel beads prepared by 2% sodium alginate successfully encapsulated the amygdalin, and its encapsulation efficiency and drug loading rate reached 85.93% and 19.21%, respectively. The thermal stability of amygdalin encapsulated in hydrogel beads was significantly improved and reached a slow-release effect in in vitro digestion. This study provides guidance for the processing and storage of amygdalin. Full article

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10 pages, 1791 KiB

Open AccessArticle

Deacylated Derivative of Hericenone C Treated by Lipase Shows Enhanced Neuroprotective Properties Compared to Its Parent Compound

by Sonam Tamrakar, Dongmei Wang, Eri Hiraki, Chunguang Han, Yang Ruan, Ahmed E. Allam, Yhiya Amen, Yoshinori Katakura and Kuniyoshi Shimizu

Molecules 2023, 28(11), 4549; https://doi.org/10.3390/molecules28114549 - 5 Jun 2023

Cited by 2 | Viewed by 2431

Abstract

Hericium erinaceus, a mushroom species commonly known as Yamabushitake in Japan, is known to have a stimulatory effect on neurotrophic factors, such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Hericenone C, a meroterpenoid with palmitic acid as the fatty [...] Read more.

Hericium erinaceus, a mushroom species commonly known as Yamabushitake in Japan, is known to have a stimulatory effect on neurotrophic factors, such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF). Hericenone C, a meroterpenoid with palmitic acid as the fatty acid side chain, is reported to be one such stimulant. However, according to the structure of the compound, the fatty acid side chain seems highly susceptible to lipase decomposition, under in vivo metabolic conditions. To study this phenomenon, hericenone C from the ethanol extract of the fruiting body was subjected to lipase enzyme treatment and observed for changes in the chemical structure. The compound formed after the lipase enzyme digestion was isolated and identified using LC-QTOF-MS combined with ¹H-NMR analysis. It was found to be a derivative of hericenone C without its fatty acid side chain and was named deacylhericenone. Interestingly, a comparative investigation of the neuroprotective properties of hericenone C and deacylhericenone showed that the BDNF mRNA expression in human astrocytoma cells (1321N1) and the protection against H₂O_2-induced oxidative stress was considerably higher in the case of deacylhericenone. These findings suggest that the stronger bioactive form of the hericenone C compound is in fact deacylhericenone. Full article

(This article belongs to the Special Issue Natural Products That Might Change Society)

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24 pages, 4240 KiB

Open AccessArticle

Antioxidant, Anti-Inflammatory, and Anti-Cancer Properties of Amygdalin Extracted from Three Cassava Varieties Cultivated in Benin

by Halfane Lehmane, Arnaud N. Kohonou, Atchadé Pascal Tchogou, Radiate Ba, Durand Dah-Nouvlessounon, Oscar Didagbé, Haziz Sina, Maximin Senou, Adolphe Adjanohoun and Lamine Baba-Moussa

Molecules 2023, 28(11), 4548; https://doi.org/10.3390/molecules28114548 - 5 Jun 2023

Cited by 5 | Viewed by 2546

Abstract

Given that cancer is a disease that is rampant in the world and especially in Africa, where the population has enormous difficulty treating it, plants are a safer and less expensive alternative. Cassava is a plant species valued in Benin because of its [...] Read more.

Given that cancer is a disease that is rampant in the world and especially in Africa, where the population has enormous difficulty treating it, plants are a safer and less expensive alternative. Cassava is a plant species valued in Benin because of its numerous medicinal and nutritional virtues. This study evaluated the biological activities of amygdalin from the organs of three cassava varieties most commonly produced in Benin (BEN, RB, and MJ). HPLC analysis was used to quantify amygdalin in cassava organs and derivatives. Phytochemical screening was performed to determine secondary metabolite groups. DPPH and FRAP methods were used to assess antioxidant activity. Cytotoxicity of the extracts was tested on Artemia salina larvae. The anti-inflammatory activity was evaluated in vivo in an albino mouse paw edema model induced by 5% formalin. The anticancer activity was evaluated in vivo on Wistar rats rendered cancerous by 1,2-dimethylhydrazine (DMH) using 5-fluorouracil as a reference molecule. The results showed that the organs of all three-cassava varieties contained glycosides, flavonoids, saponosides, steroids, tannins, coumarins, and cyanogenic derivatives. Young stems and fresh cassava leaves had the highest amygdalin concentrations, with 11,142.99 µg 10 g⁻¹ and 9251.14 µg 10 g⁻¹, respectively. The Agbeli derivative was more concentrated in amygdalin, with a content of 401.56 µg 10 g⁻¹ than the other derivatives. The antioxidant activity results showed that the amygdalin extracts were DPPH radical scavengers with IC₅₀ values ranging from 0.18 mg mL⁻¹ to 2.35 mg mL⁻¹. The cytotoxicity test showed no toxicity of the extracts toward shrimp larvae. Administration of amygdalin extracts from the leaves of BEN and MJ varieties prevents inflammatory edema. The percentages of edema inhibition varied between 21.77% and 27.89%. These values are similar (p > 0.05) to those of acetylsalicylic acid (25.20%). Amygdalin extract of the BEN variety significantly (p < 0.0001) reduces edema. Both BEN extracts inhibited cancer induction with DMH. In preventive and curative treatments, rats fed with amygdalin extracts showed low anti-cancer activity under the effect of DMH and a significant difference in biochemical results. Thus, the organs of all three cassava varieties studied have secondary metabolites and good antioxidant activity. The leaves contain high levels of amygdalin and can be used as anti-inflammatory and anticancer agents. Full article

(This article belongs to the Special Issue Plant Foods Ingredients as Functional Foods and Nutraceuticals II)

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23 pages, 3546 KiB

Open AccessArticle

Synthesis and In Vitro Biological Evaluation of p-Carborane-Based Di-tert-butylphenol Analogs

by Sebastian Braun, Sanja Jelača, Markus Laube, Sven George, Bettina Hofmann, Peter Lönnecke, Dieter Steinhilber, Jens Pietzsch, Sanja Mijatović, Danijela Maksimović-Ivanić and Evamarie Hey-Hawkins

Molecules 2023, 28(11), 4547; https://doi.org/10.3390/molecules28114547 - 4 Jun 2023

Cited by 3 | Viewed by 2247

Abstract

Targeting inflammatory mediators and related signaling pathways may offer a rational strategy for the treatment of cancer. The incorporation of metabolically stable, sterically demanding, and hydrophobic carboranes in dual cycloxygenase-2 (COX-2)/5-lipoxygenase (5-LO) inhibitors that are key enzymes in the biosynthesis of eicosanoids is [...] Read more.

Targeting inflammatory mediators and related signaling pathways may offer a rational strategy for the treatment of cancer. The incorporation of metabolically stable, sterically demanding, and hydrophobic carboranes in dual cycloxygenase-2 (COX-2)/5-lipoxygenase (5-LO) inhibitors that are key enzymes in the biosynthesis of eicosanoids is a promising approach. The di-tert-butylphenol derivatives R-830, S-2474, KME-4, and E-5110 represent potent dual COX-2/5-LO inhibitors. The incorporation of p-carborane and further substitution of the p-position resulted in four carborane-based di-tert-butylphenol analogs that showed no or weak COX inhibition but high 5-LO inhibitory activities in vitro. Cell viability studies on five human cancer cell lines revealed that the p-carborane analogs R-830-Cb, S-2474-Cb, KME-4-Cb, and E-5110-Cb exhibited lower anticancer activity compared to the related di-tert-butylphenols. Interestingly, R-830-Cb did not affect the viability of primary cells and suppressed HCT116 cell proliferation more potently than its carbon-based R-830 counterpart. Considering all the advantages of boron cluster incorporation for enhancement of drug biostability, selectivity, and availability of drugs, R-830-Cb can be tested in further mechanistic and in vivo studies. Full article

(This article belongs to the Special Issue New Developments in Boron Chemistry: From Oxidoborates to Hydrido(hetero)borane Derivatives – in Celebration of Professor John D. Kennedy’s 80th Birthday)

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20 pages, 5957 KiB

Open AccessArticle

Photocatalytic Activity of the Blends Based on TiO₂ Nanoparticles and Reduced Graphene Oxide for Degradation of Acetaminophen

by Monica Daescu, Madalina Chivu, Elena Matei, Catalin Negrila, Oana Cramariuc and Mihaela Baibarac

Molecules 2023, 28(11), 4546; https://doi.org/10.3390/molecules28114546 - 4 Jun 2023

Cited by 2 | Viewed by 2381

Abstract

The aim of this work is to highlight the influence of blends based on TiO₂ nanoparticles and reduced graphene oxide (RGO) on the photodegradation of acetaminophen (AC). To this end, the catalysts of TiO₂/RGO blends with RGO sheet concentrations equal [...] Read more.

The aim of this work is to highlight the influence of blends based on TiO₂ nanoparticles and reduced graphene oxide (RGO) on the photodegradation of acetaminophen (AC). To this end, the catalysts of TiO₂/RGO blends with RGO sheet concentrations equal 5, 10, and 20 wt. % were prepared by the solid-state interaction of the two constituents. The preferential adsorption of TiO₂ particles onto the RGO sheets’ surfaces via the water molecules on the TiO₂ particle surface was demonstrated by FTIR spectroscopy. This adsorption process induced an increase in the disordered state of the RGO sheets in the presence of the TiO₂ particles, as highlighted by Raman scattering and scanning electron microscopy (SEM). The novelty of this work lies in the demonstration that TiO₂/RGO mixtures, obtained by the solid-phase interaction of the two constituents, allow an acetaminophen removal of up to 95.18% after 100 min of UV irradiation. This TiO₂/RGO catalyst induced a higher photodegradation efficiency of AC than TiO₂ due to the presence of RGO sheets, which acted as a capture agent for the photogenerated electrons of TiO_2, hindering the electron–hole recombination. The reaction kinetics of AC aqueous solutions containing TiO₂/RGO blends followed a complex first-order kinetic model. Another novelty of this work is the demonstration of the ability of PVC membranes modified with Au nanoparticles to act both as filters for the removal of TiO₂/RGO blends after AC photodegradation and as potential SERS supports, which illustrate the vibrational properties of the reused catalyst. The reuse of the TiO₂/RGO blends after the first cycle of AC photodegradation indicated their suitable stability during the five cycles of pharmaceutical compound photodegradation. Full article

(This article belongs to the Special Issue Green Photocatalysis for Degradation of Organic Contaminants)

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15 pages, 7493 KiB

Open AccessArticle

The Motion Paradigm of Pre-Dock Zearalenone Hydrolase Predictions with Molecular Dynamics and the Docking Phase with Umbrella Sampling

by Xi-Zhi Hong, Zheng-Gang Han, Jiang-Ke Yang and Yi-Han Liu

Molecules 2023, 28(11), 4545; https://doi.org/10.3390/molecules28114545 - 4 Jun 2023

Cited by 1 | Viewed by 1822

Abstract

Zearalenone (ZEN) is one of the most prevalent estrogenic mycotoxins, is produced mainly by the Fusarium family of fungi, and poses a risk to the health of animals. Zearalenone hydrolase (ZHD) is an important enzyme capable of degrading ZEN into a non-toxic compound. [...] Read more.

Zearalenone (ZEN) is one of the most prevalent estrogenic mycotoxins, is produced mainly by the Fusarium family of fungi, and poses a risk to the health of animals. Zearalenone hydrolase (ZHD) is an important enzyme capable of degrading ZEN into a non-toxic compound. Although previous research has investigated the catalytic mechanism of ZHD, information on its dynamic interaction with ZEN remains unknown. This study aimed to develop a pipeline for identifying the allosteric pathway of ZHD. Using an identity analysis, we identified hub genes whose sequences can generalize a set of sequences in a protein family. We then utilized a neural relational inference (NRI) model to identify the allosteric pathway of the protein throughout the entire molecular dynamics simulation. The production run lasted 1 microsecond, and we analyzed residues 139–222 for the allosteric pathway using the NRI model. We found that the cap domain of the protein opened up during catalysis, resembling a hemostatic tape. We used umbrella sampling to simulate the dynamic docking phase of the ligand–protein complex and found that the protein took on a square sandwich shape. Our energy analysis, using both molecular mechanics/Poisson–Boltzmann (Generalized-Born) surface area (MMPBSA) and Potential Mean Force (PMF) analysis, showed discrepancies, with scores of −8.45 kcal/mol and −1.95 kcal/mol, respectively. MMPBSA, however, obtained a similar score to that of a previous report. Full article

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25 pages, 1930 KiB

Open AccessReview

Insights into the Structural Conformations of the Tau Protein in Different Aggregation Status

by Luca Pinzi, Nicolò Bisi, Claudia Sorbi, Silvia Franchini, Nicolò Tonali and Giulio Rastelli

Molecules 2023, 28(11), 4544; https://doi.org/10.3390/molecules28114544 - 4 Jun 2023

Cited by 5 | Viewed by 3250

Abstract

Tau is a protein characterized by large structural portions displaying extended conformational changes. Unfortunately, the accumulation of this protein into toxic aggregates in neuronal cells leads to a number of severe pathologies, collectively named tauopathies. In the last decade, significant research advancements were [...] Read more.

Tau is a protein characterized by large structural portions displaying extended conformational changes. Unfortunately, the accumulation of this protein into toxic aggregates in neuronal cells leads to a number of severe pathologies, collectively named tauopathies. In the last decade, significant research advancements were achieved, including a better understanding of Tau structures and their implication in different tauopathies. Interestingly, Tau is characterized by a high structural variability depending on the type of disease, the crystallization conditions, and the formation of pathologic aggregates obtained from in vitro versus ex vivo samples. In this review, we reported an up-to-date and comprehensive overview of Tau structures reported in the Protein Data Bank, with a special focus on discussing the connections between structural features, different tauopathies, different crystallization conditions, and the use of in vitro or ex vivo samples. The information reported in this article highlights very interesting links between all these aspects, which we believe may be of particular relevance for a more informed structure-based design of compounds able to modulate Tau aggregation. Full article

(This article belongs to the Special Issue Innovative Computational and Experimental Approaches for Tackling Neurodegenerative Diseases)

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15 pages, 2498 KiB

Open AccessArticle

Adhesive and Flame-Retardant Properties of Starch/Ca²⁺ Gels with Different Amylose Contents

by Peng Liu, Jiandi Ling, Taoyan Mao, Feng Liu, Wenzhi Zhou, Guojie Zhang and Fengwei Xie

Molecules 2023, 28(11), 4543; https://doi.org/10.3390/molecules28114543 - 4 Jun 2023

Cited by 11 | Viewed by 3094

Abstract

Starch, being renewable and biodegradable, is a viable resource for developing sustainable and environmentally friendly materials. The potential of starch/Ca²⁺ gels based on waxy corn starch (WCS), normal corn starch (NCS), and two high-amylose corn starches, G50 (55% amylose content) and G70 [...] Read more.

Starch, being renewable and biodegradable, is a viable resource for developing sustainable and environmentally friendly materials. The potential of starch/Ca²⁺ gels based on waxy corn starch (WCS), normal corn starch (NCS), and two high-amylose corn starches, G50 (55% amylose content) and G70 (68% amylose content) as flame-retardant adhesives has been explored. Being stored at 57% relative humidity (RH) for up to 30 days, the G50/Ca²⁺ and G70/Ca²⁺ gels were stable without water absorption or retrogradation. The starch gels with increasing amylose content displayed increased cohesion, as reflected by significantly higher tensile strength and fracture energy. All the four starch-based gels showed good adhesive properties on corrugated paper. For wooden boards, because of the slow diffusion of the gels, the adhesive abilities are weak initially but improve with storage extension. After storage, the adhesive abilities of the starch-based gels are essentially unchanged except for G70/Ca²⁺, which peels from a wood surface. Moreover, all the starch/Ca²⁺ gels exhibited excellent flame retardancy with limiting oxygen index (LOI) values all around 60. A facile method for the preparation of starch-based flame-retardant adhesives simply by gelating starch with a CaCl₂ solution, which can be used in paper or wood products, has been demonstrated. Full article

(This article belongs to the Special Issue Recent Insights into Biopolymer Processing, from Preparation to Fundamental Properties and Industrial Applications)

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12 pages, 1835 KiB

Open AccessArticle

Preeminent Flame-Retardant and Smoke Suppression Properties of PCaAl-LDHs Nanostructures on Bamboo Scrimber

by Fei Yang, Ailian Hu, Chungui Du, Jiawei Zhu, Yuting Wang, Yuran Shao, Qichao Bao and Yin Ran

Molecules 2023, 28(11), 4542; https://doi.org/10.3390/molecules28114542 - 3 Jun 2023

Cited by 2 | Viewed by 1563

Abstract

Bamboo scrimber is widely used in interior decoration, architecture, and many other fields. However, it has caused huge security risks due to its inherent flammability and easy-to-produce toxic volatiles after combustion. In this work, the bamboo scrimber with superior flame retardant and smoke [...] Read more.

Bamboo scrimber is widely used in interior decoration, architecture, and many other fields. However, it has caused huge security risks due to its inherent flammability and easy-to-produce toxic volatiles after combustion. In this work, the bamboo scrimber with superior flame retardant and smoke suppression properties was produced via the coupling of phosphocalcium-aluminum hydrotalcite (PCaAl-LDHs) with bamboo bundles. The results demonstrated that the flame-retardant bamboo scrimber (FRBS) heat release rate (HRR) and total heat release (THR) were, respectively, reduced by 34.46% and 15.86% compared with that of untreated bamboo scrimber. At the same time, the unique multi-layer structure of PCaAl-LDHs effectively slowed down the release rate of flue gas by extending its escape path. Cone calorimetry showed that the total smoke emissions (TSR) and specific extinction area (SEA) of FRBS were, respectively, reduced by 65.97% and 85.96% when the concentration of the flame retardant was 2%, which greatly developed the fire safety of the bamboo scrimber. This method not only improves the fire safety of bamboo scrimber but can also be expected to broaden its use scenarios. Full article

(This article belongs to the Special Issue Flame-Resistant Materials)

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24 pages, 25733 KiB

Open AccessArticle

An In Silico Molecular Modelling-Based Prediction of Potential Keap1 Inhibitors from Hemidesmus indicus (L.) R.Br. against Oxidative-Stress-Induced Diseases

by Senthilkumar Vellur, Parasuraman Pavadai, Ewa Babkiewicz, Sureshbabu Ram Kumar Pandian, Piotr Maszczyk and Selvaraj Kunjiappan

Molecules 2023, 28(11), 4541; https://doi.org/10.3390/molecules28114541 - 3 Jun 2023

Cited by 8 | Viewed by 2525

Abstract

The present study investigated the antioxidant potential of aqueous methanolic extracts of Hemidesmus indicus (L.) R.Br., followed by a pharmacoinformatics-based screening of novel Keap1 protein inhibitors. Initially, the antioxidant potential of this plant extract was assessed via antioxidant assays (DPPH, ABTS radical scavenging, [...] Read more.

The present study investigated the antioxidant potential of aqueous methanolic extracts of Hemidesmus indicus (L.) R.Br., followed by a pharmacoinformatics-based screening of novel Keap1 protein inhibitors. Initially, the antioxidant potential of this plant extract was assessed via antioxidant assays (DPPH, ABTS radical scavenging, and FRAP). Furthermore, 69 phytocompounds in total were derived from this plant using the IMPPAT database, and their three-dimensional structures were obtained from the PubChem database. The chosen 69 phytocompounds were docked against the Kelch–Neh2 complex protein (PDB entry ID: 2flu, resolution 1.50 Å) along with the standard drug (CPUY192018). H. indicus (L.) R.Br. extract (100 µg × mL⁻¹) showed 85 ± 2.917%, 78.783 ± 0.24% of DPPH, ABTS radicals scavenging activity, and 161 ± 4 μg × mol (Fe (II)) g⁻¹ ferric ion reducing power. The three top-scored hits, namely Hemidescine (−11.30 Kcal × mol⁻¹), Beta-Amyrin (−10.00 Kcal × mol⁻¹), and Quercetin (−9.80 Kcal × mol⁻¹), were selected based on their binding affinities. MD simulation studies showed that all the protein–ligand complexes (Keap1–HEM, Keap1–BET, and Keap1–QUE) were highly stable during the entire simulation period, compared with the standard CPUY192018–Keap1 complex. Based on these findings, the three top-scored phytocompounds may be used as significant and safe Keap1 inhibitors, and could potentially be used for the treatment of oxidative-stress-induced health complications. Full article

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21 pages, 4507 KiB

Open AccessArticle

Novel Imine-Tethering Cationic Surfactants: Synthesis, Surface Activity, and Investigation of the Corrosion Mitigation Impact on Carbon Steel in Acidic Chloride Medium via Various Techniques

by Hany M. Abd El-Lateef, Ahmed H. Tantawy, Kamal A. Soliman, Salah Eid and Mohamed A. Abo-Riya

Molecules 2023, 28(11), 4540; https://doi.org/10.3390/molecules28114540 - 3 Jun 2023

Cited by 2 | Viewed by 1354

Abstract

Novel imine-tethering cationic surfactants, namely (E)-3-((2-chlorobenzylidene)amino)-N-(2-(decyloxy)-2-oxoethyl)-N,N-dimethylpropan-1-aminium chloride (ICS-10) and (E)-3-((2-chlorobenzylidene)amino)-N,N-dimethyl-N-(2-oxo-2-(tetradecyloxy)ethyl)propan-1-aminium chloride (ICS-14), were synthesized, and the chemical structures were elucidated by various spectroscopic approaches. The surface properties of the target-prepared imine-tethering cationic surfactants were investigated. [...] Read more.

Novel imine-tethering cationic surfactants, namely (E)-3-((2-chlorobenzylidene)amino)-N-(2-(decyloxy)-2-oxoethyl)-N,N-dimethylpropan-1-aminium chloride (ICS-10) and (E)-3-((2-chlorobenzylidene)amino)-N,N-dimethyl-N-(2-oxo-2-(tetradecyloxy)ethyl)propan-1-aminium chloride (ICS-14), were synthesized, and the chemical structures were elucidated by various spectroscopic approaches. The surface properties of the target-prepared imine-tethering cationic surfactants were investigated. The effects of both synthesized imine surfactants on carbon steel corrosion in a 1.0 M HCl solution were investigated by weight loss (WL), potentiodynamic polarization (PDP), and scanning electron microscopy (SEM) methods. The outcomes show that the inhibition effectiveness rises with raising the concentration and diminishes with raising the temperature. The inhibition efficiency of 91.53 and 94.58 % were attained in the presence of the optimum concentration of 0.5 mM of ICS-10 and ICS-14, respectively. The activation energy (E_a) and heat of adsorption (Q_ads) were calculated and explained. Additionally, the synthesized compounds were investigated using density functional theory (DFT). Monte Carlo (MC) simulation was utilized to understand the mechanism of adsorption of inhibitors on the Fe (110) surface. Full article

(This article belongs to the Special Issue Synthesis, Characterization and Application of Surfactants II)

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11 pages, 940 KiB

Open AccessArticle

A Fast and Efficient Procedure of Iron Species Determination Based on HPLC with a Short Column and Detection in High Resolution ICP OES

by Aleksandra Orłowska, Jędrzej Proch and Przemysław Niedzielski

Molecules 2023, 28(11), 4539; https://doi.org/10.3390/molecules28114539 - 3 Jun 2023

Cited by 2 | Viewed by 2092

Abstract

The optimization and application of a new hyphenated procedure for iron ionic speciation, i.e., high performance liquid chromatography (HPLC) with short cation–exchange column (50 mm × 4 mm) coupled to high resolution inductively coupled plasma optical emission spectrometry (ICP hrOES), is presented in [...] Read more.

The optimization and application of a new hyphenated procedure for iron ionic speciation, i.e., high performance liquid chromatography (HPLC) with short cation–exchange column (50 mm × 4 mm) coupled to high resolution inductively coupled plasma optical emission spectrometry (ICP hrOES), is presented in this paper. Fe(III) and Fe(II) species were separated on the column with the mobile phase containing pyridine–2,6–dicarboxylic acid (PDCA). The total time of the analysis was approx. 5 min, with a significantly low eluent flow rate (0.5 mL min⁻¹) compared to the literature. Additionally, a long cation-exchange column (250 mm × 4.0 mm) was used as reference. Depending on the total iron content in the sample, two plasma views were chosen, e.g., an attenuated axial (<2 g kg⁻¹) and an attenuated radial. The standard addition method was performed for the method’s accuracy studies, and the applicability was presented on three types of samples: sediments, soils, and archaeological pottery. This study introduces a fast, efficient, and green method for leachable iron speciation in both geological and pottery samples. Full article

(This article belongs to the Special Issue Advances in Elemental Speciation Analysis)

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22 pages, 6156 KiB

Open AccessArticle

Efficient Adsorption Capacity of MgFe-Layered Double Hydroxide Loaded on Pomelo Peel Biochar for Cd (II) from Aqueous Solutions: Adsorption Behaviour and Mechanism

by Yongxiang Huang, Chongmin Liu, Litang Qin, Mingqi Xie, Zejing Xu and Youkuan Yu

Molecules 2023, 28(11), 4538; https://doi.org/10.3390/molecules28114538 - 3 Jun 2023

Cited by 7 | Viewed by 2061

Abstract

A novel pomelo peel biochar/MgFe-layered double hydroxide composite (PPBC/MgFe-LDH) was synthesised using a facile coprecipitation approach and applied to remove cadmium ions (Cd (II)). The adsorption isotherm demonstrated that the Cd (II) adsorption by the PPBC/MgFe-LDH composite fit the Langmuir model well, and [...] Read more.

A novel pomelo peel biochar/MgFe-layered double hydroxide composite (PPBC/MgFe-LDH) was synthesised using a facile coprecipitation approach and applied to remove cadmium ions (Cd (II)). The adsorption isotherm demonstrated that the Cd (II) adsorption by the PPBC/MgFe-LDH composite fit the Langmuir model well, and the adsorption behaviour was a monolayer chemisorption. The maximum adsorption capacity of Cd (II) was determined to be 448.961 (±12.3) mg·g⁻¹ from the Langmuir model, which was close to the actual experimental adsorption capacity 448.302 (±1.41) mg·g⁻¹. The results also demonstrated that the chemical adsorption controlled the rate of reaction in the Cd (II) adsorption process of PPBC/MgFe-LDH. Piecewise fitting of the intra-particle diffusion model revealed multi-linearity during the adsorption process. Through associative characterization analysis, the adsorption mechanism of Cd (II) of PPBC/MgFe-LDH involved (i) hydroxide formation or carbonate precipitation; (ii) an isomorphic substitution of Fe (III) by Cd (II); (iii) surface complexation of Cd (II) by functional groups (-OH); and (iv) electrostatic attraction. The PPBC/MgFe-LDH composite demonstrated great potential for removing Cd (II) from wastewater, with the advantages of facile synthesis and excellent adsorption capacity. Full article

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