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Molecules, Volume 27, Issue 5 (March-1 2022) – 296 articles

Cover Story (view full-size image): 2-pyridyl oximes are efficient agents for the removal of toxic Cd(II) from aqueous environments using the liquid–liquid extraction method, whereas 4-pyridyl oximes exhibit poor performance. The molecular basis of these different capabilities has been studied through an inorganic chemistry approach. The synthesis and full characterization of Cd(II) complexes with simple models of the real extractants as ligands reveal that the superior extractant capacity of 2-pyridyl oximes is due to the formation of a stable chelating ring with participation of the 2-pyridyl and oxime nitrogen atoms. The inability of the formation of such chelating rings explains the poor extraction efficacy of 4-pyridyl oximes. Based on our studies, new and perhaps better extractants are proposed. View this paper
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Article
The Highly Efficient Synthesis of 1,2-Disubstituted Benzimidazoles Using Microwave Irradiation
Molecules 2022, 27(5), 1751; https://doi.org/10.3390/molecules27051751 - 07 Mar 2022
Viewed by 659
Abstract
The benzimidazole ring of the heterocyclic pharmacophores is one of the most widespread and studied systems in nature. The benzimidazole derivative synthesis study is a crucial point for the development of a clinically available benzimidazole-based drug. Here, we report a simple microwave assisted [...] Read more.
The benzimidazole ring of the heterocyclic pharmacophores is one of the most widespread and studied systems in nature. The benzimidazole derivative synthesis study is a crucial point for the development of a clinically available benzimidazole-based drug. Here, we report a simple microwave assisted method for the synthesis of 1,2-disubstituted benzimidazoles. The combination of the molar ratio of N-phenyl-o-phenylenediamine:benzaldehyde (1:1) using microwave irradiation and only 1% mol of Er(OTf)3 provides an efficient and environmental mild access to a diversity of benzimidazoles under solvent-free conditions. The proposed method allows for the obtainment of the desired products in a short time and with very high selectivity. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents III)
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Review
Sulforaphane and Its Bifunctional Analogs: Synthesis and Biological Activity
Molecules 2022, 27(5), 1750; https://doi.org/10.3390/molecules27051750 - 07 Mar 2022
Cited by 5 | Viewed by 953
Abstract
For decades, various plants have been studied as sources of biologically active compounds. Compounds with anticancer and antimicrobial properties are the most frequently desired. Cruciferous plants, including Brussels sprouts, broccoli, and wasabi, have a special role in the research studies. Studies have shown [...] Read more.
For decades, various plants have been studied as sources of biologically active compounds. Compounds with anticancer and antimicrobial properties are the most frequently desired. Cruciferous plants, including Brussels sprouts, broccoli, and wasabi, have a special role in the research studies. Studies have shown that consumption of these plants reduce the risk of lung, breast, and prostate cancers. The high chemopreventive and anticancer potential of cruciferous plants results from the presence of a large amount of glucosinolates, which, under the influence of myrosinase, undergo an enzymatic transformation to biologically active isothiocyanates (ITCs). Natural isothiocyanates, such as benzyl isothiocyanate, phenethyl isothiocyanate, or the best-tested sulforaphane, possess anticancer activity at all stages of the carcinogenesis process, show antibacterial activity, and are used in organic synthesis. Methods of synthesis of sulforaphane, as well as its natural or synthetic bifunctional analogues with sulfinyl, sulfanyl, sulfonyl, phosphonate, phosphinate, phosphine oxide, carbonyl, ester, carboxamide, ether, or additional isothiocyanate functional groups, and with the unbranched alkyl chain containing 2–6 carbon atoms, are discussed in this review. The biological activity of these compounds are also reported. In the first section, glucosinolates, isothiocyanates, and mercapturic acids (their metabolites) are briefly characterized. Additionally, the most studied anticancer and antibacterial mechanisms of ITC actions are discussed. Full article
(This article belongs to the Special Issue Featured Reviews in Organic Chemistry)
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Article
Design of Oligourea-Based Foldamers with Antibacterial and Antifungal Activities
Molecules 2022, 27(5), 1749; https://doi.org/10.3390/molecules27051749 - 07 Mar 2022
Viewed by 627
Abstract
There is an urgent need to develop new therapeutic strategies to fight the emergence of multidrug resistant bacteria. Many antimicrobial peptides (AMPs) have been identified and characterized, but clinical translation has been limited partly due to their structural instability and degradability in physiological [...] Read more.
There is an urgent need to develop new therapeutic strategies to fight the emergence of multidrug resistant bacteria. Many antimicrobial peptides (AMPs) have been identified and characterized, but clinical translation has been limited partly due to their structural instability and degradability in physiological environments. The use of unnatural backbones leading to foldamers can generate peptidomimetics with improved properties and conformational stability. We recently reported the successful design of urea-based eukaryotic cell-penetrating foldamers (CPFs). Since cell-penetrating peptides and AMPs generally share many common features, we prepared new sequences derived from CPFs by varying the distribution of histidine- and arginine-type residues at the surface of the oligourea helix, and evaluated their activity on both Gram-positive and Gram-negative bacteria as well as on fungi. In addition, we prepared and tested new amphiphilic block cofoldamers consisting of an oligourea and a peptide segment whereby polar and charged residues are located in the peptide segment and more hydrophobic residues in the oligourea segment. Several foldamer sequences were found to display potent antibacterial activities even in the presence of 50% serum. Importantly, we show that these urea-based foldamers also possess promising antifungal properties. Full article
(This article belongs to the Section Bioorganic Chemistry)
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Article
Ionic Liquid-Assisted Fabrication of Bioactive Heterogeneous Magnetic Nanocatalyst with Antioxidant and Antibacterial Activities for the Synthesis of Polyhydroquinoline Derivatives
Molecules 2022, 27(5), 1748; https://doi.org/10.3390/molecules27051748 - 07 Mar 2022
Cited by 2 | Viewed by 612
Abstract
Antibacterial materials have obtained much attention in recent years due to the presence of hazardous agents causing oxidative stress and observation of pathogens. However, materials with antioxidant and antibacterial activities can cause toxicity due to their low biocompatibility and safety profile, urging scientists [...] Read more.
Antibacterial materials have obtained much attention in recent years due to the presence of hazardous agents causing oxidative stress and observation of pathogens. However, materials with antioxidant and antibacterial activities can cause toxicity due to their low biocompatibility and safety profile, urging scientists to follow new ways in the synthesis of such materials. Ionic liquids have been employed as a green and environmentally solvent for the fabrication of electrically conductive polymers. In the present study, an antibacterial poly(p-phenylenediamine)@Fe3O4 (Pp[email protected]3O4) nanocomposite was fabricated using [HPy][HSO4] ionic liquid. The chemical preparation of Pp[email protected]3O4 nanocomposite was initiated through the oxidative polymerization of p-phenylenediamine by ammonium persulfate in the presence of [HPy][HSO4]. The Pp[email protected]3O4 nanocomposite exhibited antibacterial properties against Gram-negative (Escherichia coli) and Gram-positive (Bacillus subtilis) bacteria. The Pp[email protected]3O4 nanocomposite was employed as a heterogeneous nanocatalysis for one-pot synthesis of polyhydroquinoline derivatives using aromatic aldehyde, dimedone, benzyl acetoacetate, and ammonium acetate. Polyhydroquinoline derivatives were synthesized in significant yields (90–97%) without a difficult work-up procedure in short reaction times. Additionally, Pp[email protected]3O4 nanocatalyst was recycled for at least five consecutive catalytic runs with a minor decrease in the catalytic activity. In this case, 11 derivatives of polyhydroquinoline showed in vitro antioxidant activity between 70–98%. Full article
(This article belongs to the Special Issue Ionic Liquids for Materials and Energy II)
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Article
Investigating the Effects of Amino Acid Variations in Human Menin
Molecules 2022, 27(5), 1747; https://doi.org/10.3390/molecules27051747 - 07 Mar 2022
Cited by 2 | Viewed by 884
Abstract
Human menin is a nuclear protein that participates in many cellular processes, as transcriptional regulation, DNA damage repair, cell signaling, cell division, proliferation, and migration, by interacting with many other proteins. Mutations of the gene encoding menin cause multiple endocrine neoplasia type 1 [...] Read more.
Human menin is a nuclear protein that participates in many cellular processes, as transcriptional regulation, DNA damage repair, cell signaling, cell division, proliferation, and migration, by interacting with many other proteins. Mutations of the gene encoding menin cause multiple endocrine neoplasia type 1 (MEN1), a rare autosomal dominant disorder associated with tumors of the endocrine glands. In order to characterize the structural and functional effects at protein level of the hundreds of missense variations, we investigated by computational methods the wild-type menin and more than 200 variants, predicting the amino acid variations that change secondary structure, solvent accessibility, salt-bridge and H-bond interactions, protein thermostability, and altering the capability to bind known protein interactors. The structural analyses are freely accessible online by means of a web interface that integrates also a 3D visualization of the structure of the wild-type and variant proteins. The results of the study offer insight into the effects of the amino acid variations in view of a more complete understanding of their pathological role. Full article
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Article
An Orthogonal Synthetic Approach to Nonsymmetrical Bisazolyl 2,4,6-Trisubstituted Pyridines
Molecules 2022, 27(5), 1746; https://doi.org/10.3390/molecules27051746 - 07 Mar 2022
Viewed by 544
Abstract
A three-step synthetic route giving access to nonsymmetrical bisazolyl 2,4,6-trisubstituted pyridines with different substituents on the pyrazole, indazole, and pyridine heterocycles is described. From the readily available 4-bromo-2,6-difluoropyridine, both fluorine atoms allow for easy selective stepwise substitution, and the bromine atom provides easy [...] Read more.
A three-step synthetic route giving access to nonsymmetrical bisazolyl 2,4,6-trisubstituted pyridines with different substituents on the pyrazole, indazole, and pyridine heterocycles is described. From the readily available 4-bromo-2,6-difluoropyridine, both fluorine atoms allow for easy selective stepwise substitution, and the bromine atom provides easy access to additional functionalities through both Suzuki and Sonogashira Pd(0) cross-coupling reactions. These synthons represent optimal structures as building blocks in complexation and metalloorganic structures for the tuning of their chelating and photophysical properties. Full article
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Article
Ferrocene-Containing Pseudorotaxanes in Crystals: Aromatic Interactions with Hammett Correlation
Molecules 2022, 27(5), 1745; https://doi.org/10.3390/molecules27051745 - 07 Mar 2022
Viewed by 525
Abstract
Single crystals of pseudorotaxanes, [(FcCH2NH2CH2Ar)(DB24C8)][PF6] (DB24C8 = dibenzo[24]crown-8, Fc = Fe(C5H4)(C5H5), Ar = -C6H3-3,4-Cl2, -C6H3-3,4-F2, [...] Read more.
Single crystals of pseudorotaxanes, [(FcCH2NH2CH2Ar)(DB24C8)][PF6] (DB24C8 = dibenzo[24]crown-8, Fc = Fe(C5H4)(C5H5), Ar = -C6H3-3,4-Cl2, -C6H3-3,4-F2, -C6H4-4-F, -C6H4-4-Cl, -C6H4-4-Br, -C6H3-3-F-4-Me, -C6H4-4-I) and [(FcCH2NH2CH2C6H4-4-Me)(DB24C8)][Ni(dmit)2] (dmit = 1,3-dithiole-2,4,5-dithiolate), were obtained from solutions containing DB24C8 and ferrocenylmethyl(arylmethyl)ammonium. X-ray crystallographic analyses of the pseudorotaxanes revealed that the aryl ring of the axle moiety and the catechol ring of the macrocyclic component were at close centroid distances and parallel or tilted orientation. The structures with parallel aromatic rings showed correlation of the distances between the centroids to Hammett substituent constants of the aryl groups. Full article
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Article
Influence of Different Microplastic Forms on pH and Mobility of Cu2+ and Pb2+ in Soil
Molecules 2022, 27(5), 1744; https://doi.org/10.3390/molecules27051744 - 07 Mar 2022
Cited by 5 | Viewed by 941
Abstract
Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy [...] Read more.
Microplastics, due to their surface properties, porosity and electrostatic interactions have a high affinity for cations sorption from the aqueous phase. As soil is a complex matrix, interactions between microplastics, soil constituents and heavy metals (HM) may modify the soil microenvironment for heavy metal mobilization/immobilization processes. In order to better understand the problem, three commonly found forms of microplastics in soil (fibers, fragments and microbeads) were mixed with Cu2+- or Pb2+-contaminated soil and incubated at 22 °C for 180 days. In soil samples pH and the content of water and acid exchangeable species of metals were analyzed. The results of this study showed that the presence of microplastics in HM-contaminated soil affected metal speciation, increasing the amount of easily exchangeable and potentially bioavailable forms of Cu2+ or Pb2+ in the tested soil. Soil pH also increased, confirming that microplastic particles affect soil properties relevant to the sorption/desorption process of metal cations. Overall, the smallest microplastic particles (≤1 mm), such as fibers or glitter microbeads, had a greater impact on the change in the sorption and desorption conditions of metals in tested soil than larger particles. The findings of our study show that microplastic form, shape and size should be considered as important factors that influence the soil properties and mobility of heavy metals in soil. Full article
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Article
Screening of Natural Products Inhibitors of SARS-CoV-2 Entry
Molecules 2022, 27(5), 1743; https://doi.org/10.3390/molecules27051743 - 07 Mar 2022
Cited by 5 | Viewed by 1138
Abstract
The COVID-19 pandemic has led to the search for new molecules with antiviral activity against SARS-CoV-2. The entry of the virus into the cell is one of the main targets for inhibiting SARS-CoV-2 infection. Natural products are an important source of new therapeutic [...] Read more.
The COVID-19 pandemic has led to the search for new molecules with antiviral activity against SARS-CoV-2. The entry of the virus into the cell is one of the main targets for inhibiting SARS-CoV-2 infection. Natural products are an important source of new therapeutic alternatives against diseases. Pseudotyped viruses allow the study of SARS-CoV-2 viral entry inhibitors, and due to their simplicity, they allow the screening of a large number of antiviral candidates in Biosafety Level 2 facilities. We used pseudotyped HIV-1 with the D614G SARS-CoV-2 spike glycoprotein to test its ability to infect ACE2-expressing HEK 293T cells in the presence of diverse natural products, including 21 plant extracts, 7 essential oils, and 13 compounds from plants and fungi. The 50% cytotoxic concentration (CC50) was evaluated using the resazurin method. From these analyses, we determined the inhibitory activity of the extract of Stachytarpheta cayennensis, which had a half-maximal inhibitory concentration (IC50) of 91.65 µg/mL, a CC50 of 693.5 µg/mL, and a selectivity index (SI) of 7.57, indicating its potential use as an inhibitor of SARS-CoV-2 entry. Moreover, our work indicates the usefulness of the pseudotyped-virus system in the screening of SARS-CoV-2 entry inhibitors. Full article
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Article
Immunomodulatory Properties of Polysaccharide-Rich Young Green Barley (Hordeum vulgare) Extract and Its Structural Characterization
Molecules 2022, 27(5), 1742; https://doi.org/10.3390/molecules27051742 - 07 Mar 2022
Cited by 1 | Viewed by 649
Abstract
Young green barley (YGB) water extract has revealed a beneficial impact on natural killer (NK) cells’ ability to recognize and eliminate human colon cancer cells, without any side effects for normal colon epithelial cells. The direct anticancer effect of the tested compounds has [...] Read more.
Young green barley (YGB) water extract has revealed a beneficial impact on natural killer (NK) cells’ ability to recognize and eliminate human colon cancer cells, without any side effects for normal colon epithelial cells. The direct anticancer effect of the tested compounds has been also shown. The mixture of oligosaccharides found in this extract was characterized by chemical analyses and via FT-IR spectroscopy and MALDI-TOF MS techniques. The YGB preparation contained 26.9% of proteins and 64.2% of sugars, mostly glucose (54.7%) and fructose (42.7%), with a small amount of mannose (2.6%) and galactose (less than 0.5%). Mass spectrometry analysis of YGB has shown that fructose oligomers contained from 3 to 19 sugar units. The number of fructans was estimated to be about 10.2% of the dry weight basis of YGB. The presented results suggest the beneficial effect of the consumption of preparations based on young barley on the human body, in the field of colon cancer prevention. Full article
(This article belongs to the Special Issue A Feasible Approach for Natural Products to Treatment of Diseases)
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Article
Assessment of Antimicrobial Properties of Phenolic Acid Extracts from Grain Infected with Fungi from the Genus Fusarium
Molecules 2022, 27(5), 1741; https://doi.org/10.3390/molecules27051741 - 07 Mar 2022
Cited by 1 | Viewed by 606
Abstract
Problems related with biological contamination of plant origin raw materials have a considerable effect on prevention systems at each stage of food production. Concerning the antimicrobial action of phenolic acids, studies were undertaken to investigate antibacterial properties against bacterial strains of Escherichia coli [...] Read more.
Problems related with biological contamination of plant origin raw materials have a considerable effect on prevention systems at each stage of food production. Concerning the antimicrobial action of phenolic acids, studies were undertaken to investigate antibacterial properties against bacterial strains of Escherichia coli (EC), Pseudomonas fluorescence (PF), Micrococcus luteus (ML) and Proteus mirabilis (PM), as well as antifungal properties targeting microscopic fungi Fusarium spp., extracts of phenolic compounds coming from inoculated grain from various genotypes of cereals. This study evaluated the antimicrobial action of phenolic acids extracts obtained from both naturally infested and inoculated with microorganisms. For this purpose a total of 24 cereal cultivars were selected, including 9 winter and 15 spring cultivars. The analyses showed a bactericidal effect in the case of 4 extracts against Micrococcus luteus (ML), 14 extracts against Pseudomonas fluorescence (PF), 17 extracts against Escherichia coli (EC) as well as 16 extracts against Proteus mirabilis (PM). It was found that 3 out of the 24 extracts showed no antibacterial activity. In turn, fungicidal action was observed in the case of 17 extracts against Fusarium culmorum (FC) (NIV), 16 extracts against FC (3AcDON), 12 extracts against Fusarium graminearum (FG) (3AcDON), while 12 other extracts showed antifungal action against FG (NIV) and 19 extracts against Fusarium langsethiae (FL). Based on the conducted analyses it was found that grain of small-grained cereals exposed to fungal infection is a source of bioactive compounds exhibiting antimicrobial properties. It was observed that the qualitative and quantitative profiles of polyphenols vary depending on the cereal cultivar. This extracts may be used to develop an antimicrobial preparation applicable in organic farming. Full article
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Article
Virtual Screening of Natural Chemical Databases to Search for Potential ACE2 Inhibitors
Molecules 2022, 27(5), 1740; https://doi.org/10.3390/molecules27051740 - 07 Mar 2022
Viewed by 836
Abstract
The angiotensin-converting enzyme II (ACE2) is a multifunctional protein in both health and disease conditions, which serves as a counterregulatory component of RAS function in a cardioprotective role. ACE2 modulation may also have relevance to ovarian cancer, diabetes, acute lung injury, fibrotic diseases, [...] Read more.
The angiotensin-converting enzyme II (ACE2) is a multifunctional protein in both health and disease conditions, which serves as a counterregulatory component of RAS function in a cardioprotective role. ACE2 modulation may also have relevance to ovarian cancer, diabetes, acute lung injury, fibrotic diseases, etc. Furthermore, since the outbreak of the coronavirus disease in 2019 (COVID-19), ACE2 has been recognized as the host receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The receptor binding domain of the SARS-CoV-2 S-protein has a strong interaction with ACE2, so ACE2 may be a potent drug target to prevent the virus from invading host cells for anti-COVID-19 drug discovery. In this study, structure- and property-based virtual screening methods were combined to filter natural product databases from ChemDiv, TargetMol, and InterBioScreen to find potential ACE2 inhibitors. The binding affinity between protein and ligands was predicted using both Glide SP and XP scoring functions and the MM-GBSA method. ADME properties were also calculated to evaluate chemical drug-likeness. Then, molecular dynamics (MD) simulations were performed to further explore the binding modes between the highest-potential compounds and ACE2. Results showed that the compounds 154-23-4 and STOCK1N-07141 possess potential ACE2 inhibition activities and deserve further study. Full article
(This article belongs to the Special Issue Small-Molecule Inhibitors: Insights into Drug Design from Structure)
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Article
Effect of Native Reservoir State and Oilfield Operations on Clay Mineral Surface Chemistry
Molecules 2022, 27(5), 1739; https://doi.org/10.3390/molecules27051739 - 07 Mar 2022
Cited by 1 | Viewed by 815
Abstract
An understanding of clay mineral surface chemistry is becoming critical as deeper levels of control of reservoir rock wettability via fluid–solid interactions are sought. Reservoir rock is composed of many minerals that contact the crude oil and control the wetting state of the [...] Read more.
An understanding of clay mineral surface chemistry is becoming critical as deeper levels of control of reservoir rock wettability via fluid–solid interactions are sought. Reservoir rock is composed of many minerals that contact the crude oil and control the wetting state of the rock. Clay minerals are one of the minerals present in reservoir rock, with a high surface area and cation exchange capacity. This is a first-of-its-kind study that presents zeta potential measurements and insights into the surface charge development process of clay minerals (chlorite, illite, kaolinite, and montmorillonite) in a native reservoir environment. Presented in this study as well is the effect of fluid salinity, composition, and oilfield operations on clay mineral surface charge development. Experimental results show that the surface charge of clay minerals is controlled by electrostatic and electrophilic interactions as well as the electrical double layer. Results from this study showed that clay minerals are negatively charged in formation brines as well as in deionized water, except in the case of chlorite, which is positively charged in formation water. In addition, a negative surface charge results from oilfield operations, except for operations at a high alkaline pH range of 10–13. Furthermore, a reduction in the concentrations of Na, Mg, Ca, and bicarbonate ions does not reverse the surface charge of the clay minerals; however, an increase in sulfate ion concentration does. Established in this study as well, is a good correlation between the zeta potential value of the clay minerals and contact angle, as an increase in fluid salinity results in a reduction of the negative charge magnitude and an increase in contact angle from 63 to 102 degree in the case of chlorite. Lastly, findings from this study provide vital information that would enhance the understanding of the role of clay minerals in the improvement of oil recovery. Full article
(This article belongs to the Special Issue Dispersed Systems in Physical Chemistry)
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Article
Completion of the Total Synthesis of Several Bioactive Sarpagine/Macroline Alkaloids including the Important NF-κB Inhibitor N4-Methyltalpinine
Molecules 2022, 27(5), 1738; https://doi.org/10.3390/molecules27051738 - 07 Mar 2022
Cited by 1 | Viewed by 688
Abstract
The unification of the general synthetic strategy regarding the important and emerging group of C-19 methyl-substituted sarpagine/macroline alkaloids has culminated in the completion of the total synthesis of several bioactive alkaloids. Key transformations include an ACE-Cl mediated late-stage N(4)-demethylation and an anhydrous acid-mediated [...] Read more.
The unification of the general synthetic strategy regarding the important and emerging group of C-19 methyl-substituted sarpagine/macroline alkaloids has culminated in the completion of the total synthesis of several bioactive alkaloids. Key transformations include an ACE-Cl mediated late-stage N(4)-demethylation and an anhydrous acid-mediated intramolecular quaternary hemiaminal formation between a tertiary amine and an aldehyde function to allow efficient access to several biologically important alkaloids from this group. Herein, the enantiospecific total synthesis of the first known sarpagine/macroline alkaloid with NF-κB inhibitory activity, N(4)-methyltalpinine (as a chloride salt), as well as the anticancer alkaloids talpinine, O-acetyltalpinine, and macrocarpines F–G, are described. Full article
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Article
Long-Term Stability of Redox Mediators in Carbonate Solvents
Molecules 2022, 27(5), 1737; https://doi.org/10.3390/molecules27051737 - 07 Mar 2022
Viewed by 535
Abstract
Scanning electrochemical microscopy (SECM) used in the feedback mode is one of the most powerful versatile analytical tools used in the field of battery research. However, the application of SECM in the field of lithium-ion batteries (LIBs) faces challenges associated with the selection [...] Read more.
Scanning electrochemical microscopy (SECM) used in the feedback mode is one of the most powerful versatile analytical tools used in the field of battery research. However, the application of SECM in the field of lithium-ion batteries (LIBs) faces challenges associated with the selection of a suitable redox mediator due to its high reactivity at low potentials at lithium metal or lithiated graphite electrodes. In this regard, the electrochemical/chemical stability of 2,5-di-tert-butyl-1,4-dimethoxybenzene (DBDMB) is evaluated and benchmarked with ferrocene. This investigation is systematically carried out in both linear and cyclic carbonates of the electrolyte recipe. Measurements of the bulk current with a microelectrode prove that while DBDMB decomposes in ethyl methyl carbonate (EMC)-containing electrolyte, bulk current remains stable in cyclic carbonates, ethylene carbonate (EC) and propylene carbonate (PC). Ferrocene was studied as an alternative redox mediator, showing superior electrochemical performance in ethyl methyl carbonate-containing electrolytes in terms of degradation. The resulting robustness of ferrocene with SECM is essential for a quantitative analysis of battery materials over extended periods. SECM approach curves depict practical problems when using the decomposing DBDMB for data acquisition and interpretation. This study sheds light towards the use of SECM as a probing tool enabled by redox mediators. Full article
(This article belongs to the Section Electrochemistry)
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Article
Exploring Peptaibol’s Profile, Antifungal, and Antitumor Activity of Emericellipsin A of Emericellopsis Species from Soda and Saline Soils
Molecules 2022, 27(5), 1736; https://doi.org/10.3390/molecules27051736 - 07 Mar 2022
Cited by 1 | Viewed by 623
Abstract
Features of the biochemical adaptations of alkaliphilic fungi to exist in extreme environments could promote the production of active antibiotic compounds with the potential to control microorganisms, causing infections associated with health care. Thirty-eight alkaliphilic and alkalitolerant Emericellopsis strains (E. alkalina, [...] Read more.
Features of the biochemical adaptations of alkaliphilic fungi to exist in extreme environments could promote the production of active antibiotic compounds with the potential to control microorganisms, causing infections associated with health care. Thirty-eight alkaliphilic and alkalitolerant Emericellopsis strains (E. alkalina, E. cf. maritima, E. cf. terricola, Emericellopsis sp.) isolated from different saline soda soils and belonging to marine, terrestrial, and soda soil ecological clades were investigated for emericellipsin A (EmiA) biosynthesis, an antifungal peptaibol previously described for Emericellopsis alkalina. The analysis of the Emericellopsis sp. strains belonging to marine and terrestrial clades from chloride soils revealed another novel form with a mass of 1032.7 Da, defined by MALDI-TOF Ms/Ms spectrometers, as the EmiA lacked a hydroxyl (dEmiA). EmiA displayed strong inhibitory effects on cell proliferation and viability of HCT 116 cells in a dose- and time-dependent manners and induced apoptosis. Full article
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Article
(−)-Naringenin 4′,7-dimethyl Ether Isolated from Nardostachys jatamansi Relieves Pain through Inhibition of Multiple Channels
Molecules 2022, 27(5), 1735; https://doi.org/10.3390/molecules27051735 - 07 Mar 2022
Viewed by 616
Abstract
(−)-Naringenin 4′,7-dimethyl ether ((−)-NRG-DM) was isolated for the first time by our lab from Nardostachys jatamansi DC, a traditional medicinal plant frequently used to attenuate pain in Asia. As a natural derivative of analgesic, the current study was designed to test the potential [...] Read more.
(−)-Naringenin 4′,7-dimethyl ether ((−)-NRG-DM) was isolated for the first time by our lab from Nardostachys jatamansi DC, a traditional medicinal plant frequently used to attenuate pain in Asia. As a natural derivative of analgesic, the current study was designed to test the potential analgesic activity of (−)-NRG-DM and its implicated mechanism. The analgesic activity of (−)-NRG-DM was assessed in a formalin-induced mouse inflammatory pain model and mustard oil-induced mouse colorectal pain model, in which the mice were intraperitoneally administrated with vehicle or (−)-NRG-DM (30 or 50 mg/kg) (n = 10 for each group). Our data showed that (−)-NRG-DM can dose dependently (30~50 mg/kg) relieve the pain behaviors. Notably, (−)-NRG-DM did not affect motor coordination in mice evaluated by the rotarod test, in which the animals were intraperitoneally injected with vehicle or (−)-NRG-DM (100, 200, or 400 mg/kg) (n = 10 for each group). In acutely isolated mouse dorsal root ganglion neurons, (−)-NRG-DM (1~30 μM) potently dampened the stimulated firing, reduced the action potential threshold and amplitude. In addition, the neuronal delayed rectifier potassium currents (IK) and voltage-gated sodium currents (INa) were significantly suppressed. Consistently, (−)-NRG-DM dramatically inhibited heterologously expressed Kv2.1 and Nav1.8 channels which represent the major components of the endogenous IK and INa. A pharmacokinetic study revealed the plasma concentration of (−)-NRG-DM is around 7 µM, which was higher than the effective concentrations for the IK and INa. Taken together, our study showed that (−)-NRG-DM is a potential analgesic candidate with inhibition of multiple neuronal channels (mediating IK and INa). Full article
(This article belongs to the Section Natural Products Chemistry)
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Occurrence of Mycosporine-like Amino Acids (MAAs) from the Bloom-Forming Cyanobacteria Aphanizomenon Strains
Molecules 2022, 27(5), 1734; https://doi.org/10.3390/molecules27051734 - 07 Mar 2022
Cited by 1 | Viewed by 755
Abstract
Mycosporine-like amino acids (MAAs) are widespread in various microbes and protect them against harsh environments. Here, four different Aphanizomenon species were isolated from severely eutrophic waterbodies, Lake Dianchi and the Guanqiao fishpond. Morphological characters and molecular phylogenetic analysis verified that the CHAB5919, 5921, [...] Read more.
Mycosporine-like amino acids (MAAs) are widespread in various microbes and protect them against harsh environments. Here, four different Aphanizomenon species were isolated from severely eutrophic waterbodies, Lake Dianchi and the Guanqiao fishpond. Morphological characters and molecular phylogenetic analysis verified that the CHAB5919, 5921, and 5926 strains belonged to the Aphanizomenon flos-aquae clade while Guanqiao01 belonged to the Aphanizomenon gracile clade. Full wavelength scanning proved that there was obvious maximal absorption at 334 nm through purified methanol extraction, and these substances were further analyzed by HPLC and UPLC-MS-MS. The results showed that two kinds of MAAs were discovered in the cultured Aphanizomenon strains. One molecular weight was 333.28 and the other was 347.25, and the daughter fragment patterns were in accordance with the previously articles reported shinorine and porphyra-334 ion characters. The concentration of the MAAs was calibrated from semi-prepared MAAs standards from dry cells of Microcystis aeruginosa PCC7806 algal powder, and the purity of shinorine and porphyra-334 were 90.2% and 85.4%, respectively. The average concentrations of shinorine and porphyra-334 were 0.307–0.385 µg/mg and 0.111–0.136 µg/mg in Aphanizomenon flos-aquae species, respectively. And there was only one kind of MAAs (shinorine) in Aphanizomenon gracile species.,with a content of 0.003–0.049 µg/mg dry weight among all Aphanizomenon gracile strains. The shinorine concentration in Aphanizomenon flos-aquae was higher than that in Aphanizomenon gracile strains. The total MAAs production can be ranked as Aphanizomenon flos-aquae > Aphanizomenon gracile. Full article
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Article
Efficacy and Limitations of Chemically Diverse Small-Molecule Enzyme-Inhibitors against the Synergistic Coagulotoxic Activities of Bitis Viper Venoms
Molecules 2022, 27(5), 1733; https://doi.org/10.3390/molecules27051733 - 07 Mar 2022
Viewed by 634
Abstract
Snakebite remains a significant public health burden globally, disproportionately affecting low-income and impoverished regions of the world. Recently, researchers have begun to focus on the use of small-molecule inhibitors as potential candidates for the neutralisation of key snake venom toxins and as potential [...] Read more.
Snakebite remains a significant public health burden globally, disproportionately affecting low-income and impoverished regions of the world. Recently, researchers have begun to focus on the use of small-molecule inhibitors as potential candidates for the neutralisation of key snake venom toxins and as potential field therapies. Bitis vipers represent some of the most medically important as well as frequently encountered snake species in Africa, with a number of species possessing anticoagulant phospholipase A2 (PLA2) toxins that prevent the prothrombinase complex from inducing clot formation. Additionally, species within the genus are known to exert pseudo-procoagulant activity, whereby kallikrein enzymatic toxins cleave fibrinogen to form a weak fibrin clot that rapidly degrades, thereby depleting fibrinogen levels and contributing to the net anticoagulant state. Utilising well-validated coagulation assays measuring time until clot formation, this study addresses the in vitro efficacy of three small molecule enzyme inhibitors (marimastat, prinomastat and varespladib) in neutralising these aforementioned activities. The PLA2 inhibitor varespladib showed the greatest efficacy for the neutralisation of PLA2-driven anticoagulant venom activity, with the metalloproteinase inhibitors prinomastat and marimastat both showing low and highly variable degrees of cross-neutralisation with PLA2 anticoagulant toxicity. However, none of the inhibitors showed efficacy in neutralising the pseudo-procoagulant venom activity exerted by the venom of B. caudalis. Our results highlight the complex nature of snake venoms, for which single-compound treatments will not be universally effective, but combinations might prove highly effective. Despite the limitations of these inhibitors with regards to in vitro kallikrein enzyme pseudo-procoagulant venom activity, our results further support the growing body of literature indicating the potential use of small molecule inhibitors to enhance first-aid treatment of snakebite envenoming, particularly in cases where hospital and thus antivenom treatment is either unavailable or far away. Full article
(This article belongs to the Special Issue Natural Molecules in Drug Discovery and Pharmacology)
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Article
Investigation of Different Winemaking Protocols to Mitigate Smoke Taint Character in Wine
Molecules 2022, 27(5), 1732; https://doi.org/10.3390/molecules27051732 - 07 Mar 2022
Cited by 1 | Viewed by 934
Abstract
There is an increase in the levels of volatile phenols in wine made with smoke-impacted grapes. These compounds are present in wood smoke resulting from the pyrolysis (thermal decomposition) of lignin and at high levels give overpowering smoky and ashy characters to a [...] Read more.
There is an increase in the levels of volatile phenols in wine made with smoke-impacted grapes. These compounds are present in wood smoke resulting from the pyrolysis (thermal decomposition) of lignin and at high levels give overpowering smoky and ashy characters to a wine. This research aimed to compare all the suggested wine mitigation strategies that evolved from prior research using smoke-impacted grapes under identical winemaking conditions except for the parameter under investigation. Cabernet Sauvignon grapes were received from three areas with varying amounts of smoke exposure in Northern California. Gas chromatography combined with mass spectrometry (GC-MS) and descriptive analyses were performed to correlate the volatile phenol composition to smoke taint characteristics. The winemaking variables investigated were the use of different fermentation yeasts, oak additions, and fermentation temperatures. Among other attributes, smokiness and ashy aftertaste were significantly different among the wines, showing a clear difference between the wines made from smoke-impacted fruit and the control wines made from non-impacted fruit. Findings indicate that mitigation strategies during red wine fermentation have a limited impact on the extraction of smoke-taint markers and the expression of smoke-taint sensory characteristics. Full article
(This article belongs to the Special Issue Smoke Taint in Grapes and Wine)
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Article
Biological and Cheminformatics Studies of Newly Designed Triazole Based Derivatives as Potent Inhibitors against Mushroom Tyrosinase
Molecules 2022, 27(5), 1731; https://doi.org/10.3390/molecules27051731 - 07 Mar 2022
Cited by 2 | Viewed by 622
Abstract
A series of nine novel 1,2,4-triazole based compounds were synthesized through a multistep reaction pathway and their structures were scrutinized by using spectral methods such as FTIR, LC-MS, 1H NMR, and 13C NMR. The synthesized derivatives were screened for inhibitory activity against the [...] Read more.
A series of nine novel 1,2,4-triazole based compounds were synthesized through a multistep reaction pathway and their structures were scrutinized by using spectral methods such as FTIR, LC-MS, 1H NMR, and 13C NMR. The synthesized derivatives were screened for inhibitory activity against the mushroom tyrosinase and we found that all the synthesized compounds demonstrated decent inhibitory activity against tyrosinase. However, among the series of compounds, N-(4-fluorophenyl)-2-(5-(2-fluorophenyl)-4-(4-fluorophenyl)-4H-1,2,4-triazol-3-ylthio) acetamide exhibited more prominent activity when accompanied with the standard drug kojic acid. Furthermore, the molecular docking studies identified the interaction profile of all synthesized derivatives at the active site of tyrosinase. Based on these results, N-(4-fluorophenyl)-2-(5-(2-fluorophenyl)-4-(4-fluorophenyl)-4H-1,2,4-triazol-3-ylthio) acetamide could be used as a novel scaffold to design some new drugs against melanogenesis. Full article
(This article belongs to the Special Issue Drug Discovery and Molecular Docking II)
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Article
Anthraquinones from the Aerial Parts of Rubia cordifolia with Their NO Inhibitory and Antibacterial Activities
Molecules 2022, 27(5), 1730; https://doi.org/10.3390/molecules27051730 - 07 Mar 2022
Cited by 1 | Viewed by 617
Abstract
The present study aimed to identify the composition of the aerial parts of Rubia cordifolia L. A chemical investigation on the EtOAc extracts from the aerial parts of Rubia cordifolia resulted in the isolation of four new anthraquinones, namely Cordifoquinone A–D (1 [...] Read more.
The present study aimed to identify the composition of the aerial parts of Rubia cordifolia L. A chemical investigation on the EtOAc extracts from the aerial parts of Rubia cordifolia resulted in the isolation of four new anthraquinones, namely Cordifoquinone A–D (14), along with 16 known anthraquinones. Their structures were elucidated on the basis of NMR and HR-ESIMS data. All isolates were assessed for their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophage cells. Compounds 1, 3 and 10 exhibited significant inhibitory activities with IC50 values of 14.05, 23.48 and 29.23 μmol·L−1, respectively. Their antibacterial activities of four bacteria, Escherichia coli (ATCC 25922), Staphylococcus aureus subsp. aureus (ATCC 29213), Salmonella enterica subsp. enterica (ATCC 14028) and Pseudomonas aeruginosa (ATCC 27853), were also evaluated. Our results indicated that the antibacterial activity of these compounds is inactive. Full article
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Article
Nonlinear Finite Element Analysis of γ-Graphyne Structures under Shearing
Molecules 2022, 27(5), 1729; https://doi.org/10.3390/molecules27051729 - 07 Mar 2022
Cited by 1 | Viewed by 470
Abstract
In this study, a nonlinear, spring-based finite element approach is employed in order to predict the nonlinear mechanical response of graphyne structures under shear loading. Based on Morse potential functions, suitable nonlinear spring finite elements are formulated simulating the interatomic interactions of different [...] Read more.
In this study, a nonlinear, spring-based finite element approach is employed in order to predict the nonlinear mechanical response of graphyne structures under shear loading. Based on Morse potential functions, suitable nonlinear spring finite elements are formulated simulating the interatomic interactions of different graphyne types. Specifically, the four well-known types of γ-graphyne, i.e., graphyne-1 also known as graphyne, graphyne-2 also known as graphdiyne, graphyne-3, and graphyne-4 rectangular sheets are numerically investigated applying appropriate boundary conditions representing shear load. The obtained finite element analysis results are employed to calculate the in-plane shear stress–strain behaviour, as well as the corresponding mechanical properties as shear modulus and shear strength. Comparisons of the present graphyne shearing response predictions with other corresponding estimations are performed to validate the present research results. Full article
(This article belongs to the Special Issue Nanotechnology in Europe)
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Article
Stability Studies of UV Laser Irradiated Promethazine and Thioridazine after Exposure to Hypergravity Conditions
Molecules 2022, 27(5), 1728; https://doi.org/10.3390/molecules27051728 - 07 Mar 2022
Viewed by 593
Abstract
Pharmaceuticals carried into space are subjected to different gravitational conditions. Hypergravity is encountered in the first stage, during spacecraft launching. The stability of medicines represents a critical element of space missions, especially long-duration ones. Therefore, stability studies should be envisaged before the implementation [...] Read more.
Pharmaceuticals carried into space are subjected to different gravitational conditions. Hypergravity is encountered in the first stage, during spacecraft launching. The stability of medicines represents a critical element of space missions, especially long-duration ones. Therefore, stability studies should be envisaged before the implementation of drugs for future deep space travel, where the available pharmaceuticals would be limited and restocking from Earth would be impossible. Multipurpose drugs should be proposed for this reason, such as phenothiazine derivatives that can be transformed by optical methods into antimicrobial agents. Within this preliminary study, promethazine and thioridazine aqueous solutions were exposed to UV laser radiation that modified their structures and generated a mixture of photoproducts efficient against particular bacteria. Subsequently, they were subjected to 20 g in the European Space Agency’s Large Diameter Centrifuge. The aim was to evaluate the impact of hypergravity on the physico-chemical and spectral properties of unirradiated and laser-irradiated medicine solutions through pH assay, UV-Vis/FTIR absorption spectroscopy, and thin-layer chromatography. The results revealed no substantial alterations in centrifuged samples when compared to uncentrifuged ones. Due to their stability after high-g episodes, laser-exposed phenothiazines could be considered for future space missions. Full article
(This article belongs to the Special Issue Spectroscopic Investigations of Novel Pharmaceuticals)
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Article
Phytochemical Characterization of Rhus coriaria L. Extracts by Headspace Solid-Phase Micro Extraction Gas Chromatography, Comprehensive Two-Dimensional Liquid Chromatography, and Antioxidant Activity Evaluation
Molecules 2022, 27(5), 1727; https://doi.org/10.3390/molecules27051727 - 07 Mar 2022
Cited by 1 | Viewed by 743
Abstract
Rhus coriaria L. (Anacardiaceae), commonly known as sumac, has been used since ancient times for many different applications, and nowadays is used mostly as a spice obtained from its in the Mediterranean and the Middle ground fruits and employed for flavoring and garnishing [...] Read more.
Rhus coriaria L. (Anacardiaceae), commonly known as sumac, has been used since ancient times for many different applications, and nowadays is used mostly as a spice obtained from its in the Mediterranean and the Middle ground fruits and employed for flavoring and garnishing food, predominantly Eastern regions. Traditionally, sumac has been also used in popular medicine for the treatment of many ailments including hemorrhoids, wound healing, diarrhea, ulcers, and eye inflammation. Sumac drupes are indeed rich in various classes of phytochemicals including organic acids, flavonoids, tannins, and others, which are responsible of their powerful antioxidant capacity, from which treatment of many common diseases such as cardiovascular disease, diabetes, and cancer could benefit. In this work we evaluated the influence of fruit ripeness, conservation, and processing. To this aim, a phytochemical characterization of six different samples of Rhus coriaria L. was carried out. Specifically, headspace solid-phase micro extraction gas chromatography coupled to mass spectrometry and comprehensive two-dimensional liquid chromatography coupled to photodiode array and mass spectrometry detection, were employed. A total of 263 volatile compounds, including terpene hydrocarbons, acids, and aldehydes, as well as 83 polyphenolic compounds, mainly gallic acid derivatives, were positively identified. All samples showed a significant antioxidant activity by means of oxygen radical absorbance capacity, in line with their polyphenolic content and composition. Such findings set a solid ground to support the utilization of this plant as an attractive target for novel nutraceutical approaches and for drug discovery. Full article
(This article belongs to the Special Issue Isolation, Identification and Bioactivity of Food-Derived Compounds)
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Article
Characterization of Cabernet Sauvignon Wines by Untargeted HS-SPME GC-QTOF-MS
Molecules 2022, 27(5), 1726; https://doi.org/10.3390/molecules27051726 - 07 Mar 2022
Cited by 1 | Viewed by 592
Abstract
Untargeted metabolomics approaches are emerging as powerful tools for the quality evaluation and authenticity of food and beverages and have been applied to wine science. However, most fail to report the method validation, quality assurance and/or quality control applied, as well as the [...] Read more.
Untargeted metabolomics approaches are emerging as powerful tools for the quality evaluation and authenticity of food and beverages and have been applied to wine science. However, most fail to report the method validation, quality assurance and/or quality control applied, as well as the assessment through the metabolomics-methodology pipeline. Knowledge of Mexican viticulture, enology and wine science remains scarce, thus untargeted metabolomics approaches arise as a suitable tool. The aim of this study is to validate an untargeted HS-SPME-GC-qTOF/MS method, with attention to data processing to characterize Cabernet Sauvignon wines from two vineyards and two vintages. Validation parameters for targeted methods are applied in conjunction with the development of a recursive analysis of data. The combination of some parameters for targeted studies (repeatability and reproducibility < 20% RSD; linearity > 0.99; retention-time reproducibility < 0.5% RSD; match-identification factor < 2.0% RSD) with recursive analysis of data (101 entities detected) warrants that both chromatographic and spectrometry-processing data were under control and provided high-quality results, which in turn differentiate wine samples according to site and vintage. It also shows potential biomarkers that can be identified. This is a step forward in the pursuit of Mexican wine characterization that could be used as an authentication tool. Full article
(This article belongs to the Special Issue Wine Chemistry: The Key behind Wine Quality—2nd Edition)
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Review
Exploring the Potential of Natural Product-Based Nanomedicine for Maintaining Oral Health
Molecules 2022, 27(5), 1725; https://doi.org/10.3390/molecules27051725 - 07 Mar 2022
Cited by 2 | Viewed by 1031
Abstract
Oral diseases pose a major threat to public health across the globe. Diseases such as dental caries, periodontitis, gingivitis, halitosis, and oral cancer affect people of all age groups. Moreover, unhealthy diet practices and the presence of comorbidities aggravate the problem even further. [...] Read more.
Oral diseases pose a major threat to public health across the globe. Diseases such as dental caries, periodontitis, gingivitis, halitosis, and oral cancer affect people of all age groups. Moreover, unhealthy diet practices and the presence of comorbidities aggravate the problem even further. Traditional practices such as the use of miswak for oral hygiene and cloves for toothache have been used for a long time. The present review exhaustively explains the potential of natural products obtained from different sources for the prevention and treatment of dental diseases. Additionally, natural medicine has shown activity in preventing bacterial biofilm resistance and can be one of the major forerunners in the treatment of oral infections. However, in spite of the enormous potential, it is a less explored area due to many setbacks, such as unfavorable physicochemical and pharmacokinetic properties. Nanotechnology has led to many advances in the dental industry, with various applications ranging from maintenance to restoration. However, can nanotechnology help in enhancing the safety and efficacy of natural products? The present review discusses these issues in detail. Full article
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Article
Crystal Structure, Topology, DFT and Hirshfeld Surface Analysis of a Novel Charge Transfer Complex (L3) of Anthraquinone and 4-{[(anthracen-9-yl)meth-yl] amino}-benzoic Acid (L2) Exhibiting Photocatalytic Properties: An Experimental and Theoretical Approach
Molecules 2022, 27(5), 1724; https://doi.org/10.3390/molecules27051724 - 06 Mar 2022
Cited by 3 | Viewed by 852
Abstract
Here, we report a facile route to the synthesizing of a new donor–acceptor complex, L3, using 4-{[(anthracen-9-yl)meth-yl] amino}-benzoic acid, L2, as donor moiety with anthraquinone as an acceptor moiety. The formation of donor–acceptor complex L3 was facilitated via H-bonding and characterized by single-crystal [...] Read more.
Here, we report a facile route to the synthesizing of a new donor–acceptor complex, L3, using 4-{[(anthracen-9-yl)meth-yl] amino}-benzoic acid, L2, as donor moiety with anthraquinone as an acceptor moiety. The formation of donor–acceptor complex L3 was facilitated via H-bonding and characterized by single-crystal X-ray diffraction. The X-ray diffraction results confirmed the synthesized donor–acceptor complex L3 crystal belongs to the triclinic system possessing the P-1 space group. The complex L3 was also characterized by other spectral techniques, viz., FTIR and UV absorption spectroscopy, which confirmed the formation of new bonds between donor L2 moiety and acceptor anthraquinone molecule. The crystallinity and thermal stability of the newly synthesized complex L3 was confirmed by powdered XRD and TGA analysis and theoretical studies; Hirshfeld surface analysis was performed to define the type of interactions occurring in the complex L3. Interestingly, theoretical results were successfully corroborated with experimental results of FTIR and UV absorption. The density functional theory (DFT) calculations were employed for HOMO to LUMO; the energy gap (∆E) was calculated to be 3.6463 eV. The complex L3 was employed as a photocatalyst for the degradation of MB dye and was found to be quite efficient. The results showed MB dye degraded about 90% in 200 min and followed the pseudo-first-order kinetic with rate constant k = 0.0111 min−1 and R2 = 0.9596. Additionally, molecular docking reveals that the lowest binding energy was −10.8 Kcal/mol which indicates that the L3 complex may be further studied for its biological applications. Full article
(This article belongs to the Special Issue Applications of Density Functional Theory in Crystalline Materials)
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Article
Poly(vinylbenzyl Pyridinium Salts) as Novel Sorbents for Hazardous Metals Ions Removal
Molecules 2022, 27(5), 1723; https://doi.org/10.3390/molecules27051723 - 06 Mar 2022
Viewed by 608
Abstract
Novel efficient complexing resins—poly(vinylbenzyl pyridinium salts) fabricated through poly(vinylbenzyl halogene-co-divinylbenzene) quaternization of N-decyloxy-1-(pyridin-3-yl)ethaneimine and N-decyloxy-1-(pyridin-4-yl)ethaneimine—were tested as adsorbents of Pb(II), Cd(II), Cu(II), Zn(II), and Ni(II) from aqueous solutions. The structure of these materials was established by 13C CP-MAS NMR, X-ray [...] Read more.
Novel efficient complexing resins—poly(vinylbenzyl pyridinium salts) fabricated through poly(vinylbenzyl halogene-co-divinylbenzene) quaternization of N-decyloxy-1-(pyridin-3-yl)ethaneimine and N-decyloxy-1-(pyridin-4-yl)ethaneimine—were tested as adsorbents of Pb(II), Cd(II), Cu(II), Zn(II), and Ni(II) from aqueous solutions. The structure of these materials was established by 13C CP-MAS NMR, X-ray photoelectron spectroscopy, elemental analysis, and Fourier transform infrared spectroscopy, as well as thermogravimetric and differential thermal analyses. The textural properties were determined using scanning electron microscopy and low-temperature N2 sorption. Based on the conducted sorption studies, it was shown that the uptake behavior of the metal ions towards novel resins depended on the type of functionalities, contact time, pH, metal concentrations, and the resin dosage. The Langmuir model was investigated to be the best one for fitting isothermal adsorption equilibrium data, and the corresponding adsorption capacities were predicted to be 296.4, 201.8, 83.8, 38.1, and 39.3 mg/g for Pb(II), Zn(II), Cd(II), Cu(II), and Ni(II), respectively. These results confirmed that owing to the presence of the functional pyridinium groups, the resins demonstrated proficient metal ion removal capacities. Furthermore, VBBr-D4EI could be successfully used for the selective uptake of Pb(II) from wastewater. It was also shown that the novel resins can be regenerated without significant loss of their sorption capacity. Full article
(This article belongs to the Special Issue Polymers Based Materials for Water Treatment)
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Article
Wound Healing, Antimicrobial and Antioxidant Properties of Clinacanthus nutans (Burm.f.) Lindau and Strobilanthes crispus (L.) Blume Extracts
Molecules 2022, 27(5), 1722; https://doi.org/10.3390/molecules27051722 - 06 Mar 2022
Cited by 1 | Viewed by 864
Abstract
Clinacanthus nutans is known to be an anticancer and antiviral agent, and Strobilanthes crispus has proven to be an antidiuretic and antidiabetic agent. However, there is a high possibility that these plants possess multiple beneficial properties, such as antimicrobial and wound healing properties. [...] Read more.
Clinacanthus nutans is known to be an anticancer and antiviral agent, and Strobilanthes crispus has proven to be an antidiuretic and antidiabetic agent. However, there is a high possibility that these plants possess multiple beneficial properties, such as antimicrobial and wound healing properties. This study aims to assess the wound healing, antioxidant, and antimicrobial properties of Clinacanthus nutans and Strobilanthes crispus. The Clinacanthus nutans and Strobilanthes crispus leaves were dried, ground, and extracted with ethanol, acetone, and chloroform through cold maceration. In a modified scratch assay with co-incubation of skin fibroblast and Methicillin-resistant Staphylococcus aureus, Clinacanthus nutans and Strobilanthes crispus extracts were assessed for their wound healing potential, and the antimicrobial activities of Clinacanthus nutans and Strobilanthes crispus extracts were performed on a panel of Gram-positive and Gram-negative bacteria on Mueller–Hinton agar based on a disc diffusion assay. To assess for antioxidant potential, 2,2-diphenyl-1-picrylhydrazyl (DPPH), total phenolic and total flavonoid assays were conducted. In the modified scratch assay, Clinacanthus nutans extracts aided in the wound healing activity while in the presence of MRSA, and Strobilanthes crispus extracts were superior in antimicrobial and wound healing activities. In addition, Strobilanthes crispus extracts were superior to Clinacanthus nutans extracts against Pseudomonas aeruginosa on Mueller–Hinton agar. Acetone-extracted Clinacanthus nutans contained the highest level of antioxidant in comparison with other Clinacanthus nutans extracts. Full article
(This article belongs to the Special Issue The Natural Products in Topical Infections and Wound Healing)
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