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Molecules, Volume 24, Issue 22 (November-2 2019) – 190 articles

Cover Story (view full-size image): Chelating bisphosphonate dendrons fitted with oligo(ethylene glycol) chains and terminated by a fluorinated moiety can anchor iron oxide nanoparticles in the phospholipid shells of microbubbles and respond to the presence of a fluorocarbon gas. Here we investigate the miscibility of these dendrons with phospholipids in Langmuir monolayers, as a model interface of microbubble shells. We demonstrate that the dendrons are squeezed out of the mixed monolayers during compression. This suggests that these dendrons can be specifically designed to facilitate the in vivo delivery of magnetic nanoparticles, allowing for the combined use of ultrasound and magnetic resonance for, in particular, tumor imaging. View this paper.
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Open AccessArticle
Marine Collagen Peptides Promote Cell Proliferation of NIH-3T3 Fibroblasts via NF-κB Signaling Pathway
Molecules 2019, 24(22), 4201; https://doi.org/10.3390/molecules24224201 - 19 Nov 2019
Cited by 4 | Viewed by 1008
Abstract
Marine collagen peptides (MCPs) with the ability to promote cell proliferation and migration were obtained from the skin of Nibea japonica. The purpose of MCPs isolation was an attempt to convert the by-products of the marine product processing industry to high value-added [...] Read more.
Marine collagen peptides (MCPs) with the ability to promote cell proliferation and migration were obtained from the skin of Nibea japonica. The purpose of MCPs isolation was an attempt to convert the by-products of the marine product processing industry to high value-added items. MCPs were observed to contain many polypeptides with molecular weights ≤ 10 kDa and most amino acid residues were hydrophilic. MCPs (0.25–10 mg/mL) also exhibited 2, 2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl, superoxide anion, and 2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activities. Furthermore, MCPs promoted the proliferation of NIH-3T3 cells. In vitro scratch assays indicated that MCPs significantly enhanced the scratch closure rate and promoted the migration of NIH-3T3 cells. To further determine the signaling mechanism of MCPs, western blotting was used to study the expression levels of nuclear factor kappa-B (NF-κB) p65, IκB kinase α (IKKα), and IκB kinase β (IKKβ) proteins of the NF-κB signaling pathway. Our results indicated protein levels of NF-κB p65, IKKα and IKKβ increased in MCPs-treated NIH-3T3 cells. In addition, MCPs increased the expression of epidermal growth factor (EGF), fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), and transforming growth factor (TGF-β) in NIH-3T3 cells. Therefore, MCPs, a by-product of N. japonica, exhibited potential wound healing abilities in vitro. Full article
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Open AccessCommunication
Single Production of Kojic Acid by Aspergillus flavus and the Revision of Flufuran
Molecules 2019, 24(22), 4200; https://doi.org/10.3390/molecules24224200 - 19 Nov 2019
Cited by 5 | Viewed by 976
Abstract
Timor Island is very hot and dry due to the high intensity of sunlight experienced throughout the year. The endophytic fungi Aspergillus flavus had been isolated from medicinal plants such as Catharanthus roseus, Annona squamosa and Curcuma xanthorisa. The endophytic fungi [...] Read more.
Timor Island is very hot and dry due to the high intensity of sunlight experienced throughout the year. The endophytic fungi Aspergillus flavus had been isolated from medicinal plants such as Catharanthus roseus, Annona squamosa and Curcuma xanthorisa. The endophytic fungi A. flavus from each plant was cultivated on solid rice media and then analyzed for its capability for producing kojic acid. The production of kojic acid was analyzed by HPLC; the highest amount of kojic acid was observed from the endophytic fungi A. flavus, isolated from the stem of Catharanthus roseus, followed by A. flavus from Annona squamosa and Curcuma xanthorisa. Simple VLC fractionation of the extract of A. flavus from C.roseus led to the isolation of around 11.1 g of pure kojic acid. The structure of kojic acid (1) was confirmed by NMR and MS spectroscopic data. A comparison of the NMR data with the literature supported the revision of the natural product flufuran to kojic acid. To the best of our knowledge, this is the first report of a strain of endophytic fungi producing only kojic acid without any other toxic metabolites such as alfatoxins. Therefore, this Aspergillus flavus strain can be applied as a potential producer of kojic acid for industrial use. Full article
(This article belongs to the Section Natural Products Chemistry)
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Open AccessArticle
Determination of Lactoferrin in Camel Milk by Ultrahigh-Performance Liquid Chromatography-Tandem Mass Spectrometry Using an Isotope-Labeled Winged Peptide as Internal Standard
Molecules 2019, 24(22), 4199; https://doi.org/10.3390/molecules24224199 - 19 Nov 2019
Viewed by 664
Abstract
An ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of lactoferrin in camel milk based on the signature peptide. The camel lactoferrin was purified by heparin affinity chromatography and then used to screen tryptic signature peptides. The signature [...] Read more.
An ultrahigh-performance liquid chromatography-tandem mass spectrometry method was developed and validated for the determination of lactoferrin in camel milk based on the signature peptide. The camel lactoferrin was purified by heparin affinity chromatography and then used to screen tryptic signature peptides. The signature peptide was selected on the basis of sequence database search and identified from the tryptic hydrolysates of purified camel lactoferrin by ultrahigh-performance liquid chromatography and quadrupole time-of-flight tandem mass spectrometry. The pretreatment procedures included the addition of isotope-labeled winged peptide and the disposal of lipids and caseins followed by an enzymatic digestion with trypsin. Analytes were separated on an Acquity UPLC BEH 300 C18 column and then detected on a triple-quadrupole mass spectrometer in 7 min. The limits of detection and quantification were 3.8 mg kg−1 and 11 mg kg−1, respectively. The recoveries ranged from 74.5% to 103.6%, with relative standard deviations below 7.7%. The validated method was applied to determine the lactoferrin in ten samples collected from Xinjiang Province. Full article
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Open AccessArticle
Synthesis and Antimicrobial Activity of Some New Substituted Quinoxalines
Molecules 2019, 24(22), 4198; https://doi.org/10.3390/molecules24224198 - 19 Nov 2019
Cited by 6 | Viewed by 790
Abstract
A number of new symmetrically and asymmetrically 2,3-disubstituted quinoxalines were synthesized through functionalization of 2,3-dichloroquinoxaline (2,3-DCQ) with a variety of sulfur and/or nitrogen nucleophiles. The structures of the obtained compounds were established based on their spectral data and elemental analysis. The antimicrobial activity [...] Read more.
A number of new symmetrically and asymmetrically 2,3-disubstituted quinoxalines were synthesized through functionalization of 2,3-dichloroquinoxaline (2,3-DCQ) with a variety of sulfur and/or nitrogen nucleophiles. The structures of the obtained compounds were established based on their spectral data and elemental analysis. The antimicrobial activity for the prepared compounds was investigated against four bacterial species and two fungal strains. The symmetrically disubstituted quinoxalines 2, 3, 4, and 5 displayed the most significant antibacterial activity, while compounds 6a, 6b, and the pentacyclic compound 10 showed considerable antifungal activity. Furthermore, compounds 3f, 6b showed broad antimicrobial spectrum against most of the tested strains. Full article
(This article belongs to the collection Heterocyclic Compounds)
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Open AccessReview
A Novel Prodrug Approach for Central Nervous System-Selective Estrogen Therapy
Molecules 2019, 24(22), 4197; https://doi.org/10.3390/molecules24224197 - 19 Nov 2019
Cited by 6 | Viewed by 1009
Abstract
Beneficial effects of estrogens in the central nervous system (CNS) results from the synergistic combination of their well-orchestrated genomic and non-genomic actions, making them potential broad-spectrum neurotherapeutic agents. However, owing to unwanted peripheral hormonal burdens by any currently known non-invasive drug administrations, the [...] Read more.
Beneficial effects of estrogens in the central nervous system (CNS) results from the synergistic combination of their well-orchestrated genomic and non-genomic actions, making them potential broad-spectrum neurotherapeutic agents. However, owing to unwanted peripheral hormonal burdens by any currently known non-invasive drug administrations, the development of estrogens as safe pharmacotherapeutic modalities cannot be realized until they are confined specifically and selectively to the site of action. We have developed small-molecule bioprecursor prodrugs carrying the para-quinol scaffold on the steroidal A-ring that are preferentially metabolized in the CNS to the corresponding estrogens. Here, we give an overview of our discovery of these prodrugs. Selected examples are shown to illustrate that, independently of the route of administrations and duration of treatments, these agents produce high concentration of estrogens only in the CNS without peripheral hormonal liability. 10β,17β-Dihydroxyestra-1,4-dien-3-one (DHED) has been the best-studied representative of this novel type of prodrugs for brain and retina health. Specific applications in preclinical animal models of centrally-regulated and estrogen-responsive human diseases, including neurodegeneration, menopausal symptoms, cognitive decline and depression, are discussed to demonstrate the translational potential of our prodrug approach for CNS-selective and gender-independent estrogen therapy with inherent therapeutic safety. Full article
(This article belongs to the Special Issue Facing Novel Challenges in Drug Discovery)
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Open AccessFeature PaperArticle
Synthesis and In Vitro Growth Inhibition of 2-Allylphenol Derivatives Against Phythopthora cinnamomi Rands
Molecules 2019, 24(22), 4196; https://doi.org/10.3390/molecules24224196 - 19 Nov 2019
Cited by 2 | Viewed by 701
Abstract
Phytophthora cinnamomi is a phytopathogen that causes extensive damage in different crops, and therefore, produces important economic losses all around the world. Chemical fungicides are a key factor for the control of this disease. However, ecological and environmental considerations, as well as the [...] Read more.
Phytophthora cinnamomi is a phytopathogen that causes extensive damage in different crops, and therefore, produces important economic losses all around the world. Chemical fungicides are a key factor for the control of this disease. However, ecological and environmental considerations, as well as the appearance of strains that are resistant to commercial fungicides, have prompted the quest for new antifungal agents which are of low ecological impact. In this work, a series of new 2-allylphenol derivatives was synthesized, and their structures were confirmed by FT-IR, NMR, and MS. Some of the synthesized compounds, more specifically nitro derivatives, exhibit strong growth inhibition of P. cinnamomi with EC50 as low as 10.0 µg/mL. This level of activity is similar to that exhibited by METALAXYL MZ 58 WP, a commonly-used commercial fungicide; therefore, these compounds might be of agricultural interest due to their potential use as fungicides against P. cinnamomi. The results indicate that this activity depends on the chemical structures of the 2-allylphenol derivatives, and that it is strongly enhanced in molecules where nitro and hydroxyl groups adopt a -para configuration. These effects are discussed in terms of the electronic distribution of the aromatic ring induced by substituent groups. Full article
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Open AccessArticle
A Study of the Influence of the HCl Concentration on the Composition and Structure of (Hydroxy)Arylsiloxanes from the Hydrolysis–Condensation Reaction of Aryltrichlorosilanes
Molecules 2019, 24(22), 4195; https://doi.org/10.3390/molecules24224195 - 19 Nov 2019
Viewed by 761
Abstract
The hydrolysis–condensation reactions of m-tolyl, m-chlorophenyl, and α-naphtyl-trichlorsilanes, (1, 2, and 3, respectively) in water-acetone solutions were examined for how they were influenced by the change in the concentration of HCl (CHCl). The composition [...] Read more.
The hydrolysis–condensation reactions of m-tolyl, m-chlorophenyl, and α-naphtyl-trichlorsilanes, (1, 2, and 3, respectively) in water-acetone solutions were examined for how they were influenced by the change in the concentration of HCl (CHCl). The composition of the products was monitored by 29Si NMR spectroscopy and atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The acidity of the medium was shown to affect the yields of the products, and so, what products were formed. For 3, e.g., APCI-MS showed peaks of α-naphtyl-T8 and α-naphtyl-T10 as the most abundant in the spectra taken after 48 and 240 h for the reaction conducted at CHCl = 0.037 mol L−1. Unlike this, at CHCl = 0.15 mol L−1, those peaks were of [α-naphtyl(HO)2SiO]2(α-naphtyl)(HO)Si and/or [α-naphtyl(HO)Si]3, [α-naphtyl(HO)Si]4,5, and α-naphtyl-T8 after 192 h. However, at both CHCl values, the main product (and an intermediate) after 24 h was trans-1,1,3,3-tetrahydroxy-1,3-di-α-naphtyldisiloxane. It was isolated and its structure established by 1H-, 29Si-NMR, and X-ray powder diffraction. Full article
(This article belongs to the Special Issue Synthesis of Functional Silicon Compounds)
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Open AccessArticle
Antioxidant System and Biomolecules Alteration in Pisum sativum under Heavy Metal Stress and Possible Alleviation by 5-Aminolevulinic Acid
Molecules 2019, 24(22), 4194; https://doi.org/10.3390/molecules24224194 - 19 Nov 2019
Cited by 6 | Viewed by 848
Abstract
Environmental pollution is the most serious problem that affects crop productivity worldwide. Pisum sativum is a leguminous plant that is cultivated on a large scale in the Nile Delta of Egypt as a winter crop, and many of the cultivated fields irrigated with [...] Read more.
Environmental pollution is the most serious problem that affects crop productivity worldwide. Pisum sativum is a leguminous plant that is cultivated on a large scale in the Nile Delta of Egypt as a winter crop, and many of the cultivated fields irrigated with drainage water that contained many pollutants including heavy metals. The present research aimed to investigate the impact of Cd and Ni on the biochemical and physiological processes in P. sativum and evaluate the potential alleviation of their toxicity by 5-aminolevulinic acid (ALA). Seedlings of P. sativum were grown in Hoagland solution treated with CdCl2 or NiCl2 for 72 h in the growth chamber. Hydrogen peroxide, lipid peroxidation, protein carbonylation, reduced glutathione, oxidized glutathione, proline, phenolics, antioxidant enzymes, as well as Cd and Ni concentrations were measured at 0, 12, 24, 36, 48, 72 h. An experiment of alleviation was conducted where ALA was added to the growth solution at a concentration of 200 µM coupled with 100 µM of either CdCl2 or NiCl2. Hydrogen peroxide, lipid peroxidation, protein carbonylation, reduced glutathione, oxidized glutathione, proline, and phenolics were induced due to the toxicity of Cd and Ni. The activities of antioxidant enzymes [NADH-oxidase (EC: 1.6.3.1), ascorbate peroxidase (EC: 1.11.1.11), glutathione reductase (EC: 1.6.4.2), superoxide dismutase (EC: 1.15.1.1), and catalase (EC: 1.11.1.6)] were induced under the treatments of both metals. On the other hand, the soluble protein decreased gradually depending upon the time of exposure to the heavy metals. The concentration of Cd and Ni in the leaves treated plants increased in time of exposure dependent manner, while their contents remained within the acceptable limits. The addition of ALA decreased the oxidative stress in treated P. sativum plants. The results revealed the significance of using ALA in the cultivation of P. sativum might improve its tolerance against heavy metal stress. Full article
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Open AccessArticle
Identification and Monitoring of Amomi Fructus and its Adulterants Based on DNA Barcoding Analysis and Designed DNA Markers
Molecules 2019, 24(22), 4193; https://doi.org/10.3390/molecules24224193 - 19 Nov 2019
Cited by 2 | Viewed by 691
Abstract
Amomi Fructus is one of the traditional medicines derived from the ripe fruits of the Zingiberaceae family of plants, which include Amomum villosum, A. villosum var. xanthioides, and A. longiligulare. Owing to their highly similar morphological traits, several kinds of [...] Read more.
Amomi Fructus is one of the traditional medicines derived from the ripe fruits of the Zingiberaceae family of plants, which include Amomum villosum, A. villosum var. xanthioides, and A. longiligulare. Owing to their highly similar morphological traits, several kinds of adulterants of Amomi Fructus have been reported. Therefore, accurate and reliable methods of identification are necessary in order to ensure drug safety and quality. We performed DNA barcoding using five regions (ITS, matK, rbcL, rpoB, and trnL-F intergenic spacer) of 23 Amomi Fructus samples and 22 adulterants. We designed specific DNA markers for Amomi Fructus based on the single nucleotide polymorphisms (SNPs) in the ITS. Amomi Fructus was well separated from the adulterants and was classified with the species of origin based on the detected SNPs from the DNA barcoding results. The AVF1/ISR DNA marker for A. villosum produced a 270 bases amplified product, while the ALF1/ISF DNA marker produced a 350 bases product specific for A. longiligulare. Using these DNA markers, the monitoring of commercially distributed Amomi Fructus was performed, and the monitoring results were confirmed by ITS analysis. This method identified samples that were from incorrect origins, and a new species of adulterant was also identified. These results confirmed the accuracy and efficiency of the designed DNA markers; this method may be used as an efficient tool for the identification and verification of Amomi Fructus. Full article
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Open AccessFeature PaperReview
ENPP1, an Old Enzyme with New Functions, and Small Molecule Inhibitors—A STING in the Tale of ENPP1
Molecules 2019, 24(22), 4192; https://doi.org/10.3390/molecules24224192 - 19 Nov 2019
Cited by 5 | Viewed by 1723
Abstract
Ectonucleotide pyrophosphatase/phosphodiesterase I (ENPP1) was identified several decades ago as a type II transmembrane glycoprotein with nucleotide pyrophosphatase and phosphodiesterase enzymatic activities, critical for purinergic signaling. Recently, ENPP1 has emerged as a critical phosphodiesterase that degrades the stimulator of interferon genes (STING) ligand, [...] Read more.
Ectonucleotide pyrophosphatase/phosphodiesterase I (ENPP1) was identified several decades ago as a type II transmembrane glycoprotein with nucleotide pyrophosphatase and phosphodiesterase enzymatic activities, critical for purinergic signaling. Recently, ENPP1 has emerged as a critical phosphodiesterase that degrades the stimulator of interferon genes (STING) ligand, cyclic GMP–AMP (cGAMP). cGAMP or analogs thereof have emerged as potent immunostimulatory agents, which have potential applications in immunotherapy. This emerging role of ENPP1 has placed this “old” enzyme at the frontier of immunotherapy. This review highlights the roles played by ENPP1, the mechanism of cGAMP hydrolysis by ENPP1, and small molecule inhibitors of ENPP1 with potential applications in diverse disease states, including cancer. Full article
(This article belongs to the Special Issue Recent Advances in Non-Canonical Nucleic Acid Structures)
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Open AccessArticle
Synthesis and Antiproliferative Evaluation of Novel Hybrids of Dehydroabietic Acid Bearing 1,2,3-Triazole Moiety
Molecules 2019, 24(22), 4191; https://doi.org/10.3390/molecules24224191 - 19 Nov 2019
Cited by 3 | Viewed by 620
Abstract
To discover novel potent cytotoxic diterpenoids, a series of hybrids of dehydroabietic acid containing 1,2,3-triazole moiety were designed and synthesized. The target compounds were characterized by means of FT-IR, 1H NMR, 13C NMR, ESI-MS and elemental analysis techniques. The in vitro [...] Read more.
To discover novel potent cytotoxic diterpenoids, a series of hybrids of dehydroabietic acid containing 1,2,3-triazole moiety were designed and synthesized. The target compounds were characterized by means of FT-IR, 1H NMR, 13C NMR, ESI-MS and elemental analysis techniques. The in vitro cytotoxicity of these compounds was evaluated by standard MTT (methyl thiazolytetrazolium) assay against CNE-2 (nasopharynx), HepG2 (liver), HeLa (epithelial cervical), BEL-7402 (liver) human carcinoma cell lines and human normal liver cell (HL-7702). The screening results revealed that most of the hybrids showed significantly improved cytotoxicity over parent compound DHAA. Among them, [1-(3-fluorobenzyl)-1H-1,2,3-triazole-4-yl]dehydroabietic acid methyl ester (3c), and [1-(2-nitrobenzyl)-1H-1,2,3-triazole-4-yl]dehydroabietic acid methyl ester (3k) displayed better antiproliferative activity with IC50 (50% inhibitory concentration) values of 5.90 ± 0.41 and 6.25 ± 0.37 µM toward HepG2 cells compared to cisplatin, while they exhibited lower cytotoxicity against HL-7702. Therefore, the 1,2,3-triazole-hybrids could be a promising strategy for the synthesis of antitumor diterpenoids and it also proved the essential role of 1,2,3-triazole moiety of DHAA in the biological activity. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessReview
A Survey of Molecular Imaging of Opioid Receptors
Molecules 2019, 24(22), 4190; https://doi.org/10.3390/molecules24224190 - 19 Nov 2019
Cited by 5 | Viewed by 1490
Abstract
The discovery of endogenous peptide ligands for morphine binding sites occurred in parallel with the identification of three subclasses of opioid receptor (OR), traditionally designated as μ, δ, and κ, along with the more recently defined opioid-receptor-like (ORL1) receptor. Early efforts in opioid [...] Read more.
The discovery of endogenous peptide ligands for morphine binding sites occurred in parallel with the identification of three subclasses of opioid receptor (OR), traditionally designated as μ, δ, and κ, along with the more recently defined opioid-receptor-like (ORL1) receptor. Early efforts in opioid receptor radiochemistry focused on the structure of the prototype agonist ligand, morphine, although N-[methyl-11C]morphine, -codeine and -heroin did not show significant binding in vivo. [11C]Diprenorphine ([11C]DPN), an orvinol type, non-selective OR antagonist ligand, was among the first successful PET tracers for molecular brain imaging, but has been largely supplanted in research studies by the μ-preferring agonist [11C]carfentanil ([11C]Caf). These two tracers have the property of being displaceable by endogenous opioid peptides in living brain, thus potentially serving in a competition-binding model. Indeed, many clinical PET studies with [11C]DPN or [11C]Caf affirm the release of endogenous opioids in response to painful stimuli. Numerous other PET studies implicate μ-OR signaling in aspects of human personality and vulnerability to drug dependence, but there have been very few clinical PET studies of μORs in neurological disorders. Tracers based on naltrindole, a non-peptide antagonist of the δ-preferring endogenous opioid enkephalin, have been used in PET studies of δORs, and [11C]GR103545 is validated for studies of κORs. Structures such as [11C]NOP-1A show selective binding at ORL-1 receptors in living brain. However, there is scant documentation of δ-, κ-, or ORL1 receptors in healthy human brain or in neurological and psychiatric disorders; here, clinical PET research must catch up with recent progress in radiopharmaceutical chemistry. Full article
(This article belongs to the Special Issue Radiolabelled Molecules for Brain Imaging with PET and SPECT)
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Open AccessReview
DNA-Templated Fluorescent Nanoclusters for Metal Ions Detection
Molecules 2019, 24(22), 4189; https://doi.org/10.3390/molecules24224189 - 19 Nov 2019
Cited by 4 | Viewed by 851
Abstract
DNA-templated fluorescent nanoclusters (NCs) have attracted increasing research interest on account of their prominent features, such as DNA sequence-dependent fluorescence, easy functionalization, wide availability, water solubility, and excellent biocompatibility. Coupling DNA templates with complementary DNA, aptamers, G-quadruplex, and so on has generated a [...] Read more.
DNA-templated fluorescent nanoclusters (NCs) have attracted increasing research interest on account of their prominent features, such as DNA sequence-dependent fluorescence, easy functionalization, wide availability, water solubility, and excellent biocompatibility. Coupling DNA templates with complementary DNA, aptamers, G-quadruplex, and so on has generated a large number of sensors. Additionally, the preparation and applications of DNA-templated fluorescent NCs in these sensing have been widely studied. This review firstly focuses on the properties of DNA-templated fluorescent NCs, and the synthesis of DNA-templated fluorescent NCs with different metals is then discussed. In the third part, we mainly introduce the applications of DNA-templated fluorescent NCs for sensing metal ions. At last, we further discuss the future perspectives of DNA-templated fluorescent NCs in the synthesis and sensing metal ions in the environmental and biological fields. Full article
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Open AccessReview
The Versatile Role of Matrix Metalloproteinase for the Diverse Results of Fibrosis Treatment
Molecules 2019, 24(22), 4188; https://doi.org/10.3390/molecules24224188 - 19 Nov 2019
Cited by 1 | Viewed by 763
Abstract
Fibrosis is a type of chronic organ failure, resulting in the excessive secretion of extracellular matrix (ECM). ECM protects wound tissue from infection and additional injury, and is gradually degraded during wound healing. For some unknown reasons, myofibroblasts (the cells that secrete ECM) [...] Read more.
Fibrosis is a type of chronic organ failure, resulting in the excessive secretion of extracellular matrix (ECM). ECM protects wound tissue from infection and additional injury, and is gradually degraded during wound healing. For some unknown reasons, myofibroblasts (the cells that secrete ECM) do not undergo apoptosis; this is associated with the continuous secretion of ECM and reduced ECM degradation even during de novo tissue formation. Thus, matrix metalloproteinases (MMPs) are considered to be a potential target of fibrosis treatment because they are the main groups of ECM-degrading enzymes. However, MMPs participate not only in ECM degradation but also in the development of various biological processes that show the potential to treat diseases such as stroke, cardiovascular diseases, and arthritis. Therefore, treatment involving the targeting of MMPs might impede typical functions. Here, we evaluated the links between these MMP functions and possible detrimental effects of fibrosis treatment, and also considered possible approaches for further applications. Full article
(This article belongs to the Special Issue Metalloproteins)
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Open AccessReview
NAD Analogs in Aid of Chemical Biology and Medicinal Chemistry
Molecules 2019, 24(22), 4187; https://doi.org/10.3390/molecules24224187 - 19 Nov 2019
Cited by 1 | Viewed by 1341
Abstract
Nicotinamide adenine dinucleotide (NAD) serves as an essential redox co-factor and mediator of multiple biological processes. Besides its well-established role in electron transfer reactions, NAD serves as a substrate for other biotransformations, which, at the molecular level, can be classified as protein post-translational [...] Read more.
Nicotinamide adenine dinucleotide (NAD) serves as an essential redox co-factor and mediator of multiple biological processes. Besides its well-established role in electron transfer reactions, NAD serves as a substrate for other biotransformations, which, at the molecular level, can be classified as protein post-translational modifications (protein deacylation, mono-, and polyADP-ribosylation) and formation of signaling molecules (e.g., cyclic ADP ribose). These biochemical reactions control many crucial biological processes, such as cellular signaling and recognition, DNA repair and epigenetic modifications, stress response, immune response, aging and senescence, and many others. However, the links between the biological effects and underlying molecular processes are often poorly understood. Moreover, NAD has recently been found to tag the 5′-ends of some cellular RNAs, but the function of these NAD-capped RNAs remains largely unrevealed. Synthetic NAD analogs are invaluable molecular tools to detect, monitor, structurally investigate, and modulate activity of NAD-related enzymes and biological processes in order to aid their deeper understanding. Here, we review the recent advances in the design and development of NAD analogs as probes for various cellular NAD-related enzymes, enzymatic inhibitors with anticancer or antimicrobial therapeutic potential, and other NAD-related chemical biology tools. We focus on research papers published within the last 10 years. Full article
(This article belongs to the Special Issue Design and Synthesis of Bioactive Compounds)
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Open AccessArticle
Determination of Urinary Hydroxyl PAHs Using Graphene [email protected] Based Solid-Phase Extraction and High-Performance Liquid Chromatography
Molecules 2019, 24(22), 4186; https://doi.org/10.3390/molecules24224186 - 19 Nov 2019
Cited by 1 | Viewed by 547
Abstract
A diatomite supported graphene oxide composite ([email protected]–NH2) was fabricated and explored as a solid-phase extraction adsorbent coupled with high performance liquid chromatography to determine the trace hydroxyl polycyclic aromatic hydrocarbons (2-hydroxy-naphthalene, 2-hydroxy-fluorene, 1-hydroxy-phenanthrene, and 1-hydroxy-pyrene) in urine samples. The fabricated composites [...] Read more.
A diatomite supported graphene oxide composite ([email protected]–NH2) was fabricated and explored as a solid-phase extraction adsorbent coupled with high performance liquid chromatography to determine the trace hydroxyl polycyclic aromatic hydrocarbons (2-hydroxy-naphthalene, 2-hydroxy-fluorene, 1-hydroxy-phenanthrene, and 1-hydroxy-pyrene) in urine samples. The fabricated composites were characterized by X-ray powder diffractometry and scanning electron microscopy. [email protected]–NH2 offered enhanced adsorption affinity towards the analytes compared with the bare diatomite. The amount of graphene oxide and the factors affecting solid-phase extraction were investigated in detail. Under the optimized conditions, the method gave good linearity (0.30–200 ng/mL) and a low detection limit (0.10–0.15 ng/mL) for the hydroxyl polycyclic aromatic hydrocarbons. The average recovery for spiked urine samples with three levels ranged from 90.6% to 100%. The intra-day and inter-day relative standard deviations were in the range of 1.8–6.4% and 2.7–11.8%, respectively. Besides, the [email protected]–NH2 provided enrichment factors of 18–20 and superior purification ability. The developed method was successfully applied to the determination of hydroxyl polycyclic aromatic hydrocarbons in urine samples from smoking volunteers. Full article
(This article belongs to the Section Analytical Chemistry)
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Open AccessFeature PaperArticle
Identifying Promiscuous Compounds with Activity against Different Target Classes
Molecules 2019, 24(22), 4185; https://doi.org/10.3390/molecules24224185 - 18 Nov 2019
Cited by 2 | Viewed by 999
Abstract
Compounds with multitarget activity are of high interest for polypharmacological drug discovery. Such promiscuous compounds might be active against closely related target proteins from the same family or against distantly related or unrelated targets. Compounds with activity against distinct targets are not only [...] Read more.
Compounds with multitarget activity are of high interest for polypharmacological drug discovery. Such promiscuous compounds might be active against closely related target proteins from the same family or against distantly related or unrelated targets. Compounds with activity against distinct targets are not only of interest for polypharmacology but also to better understand how small molecules might form specific interactions in different binding site environments. We have aimed to identify compounds with activity against drug targets from different classes. To these ends, a systematic analysis of public biological screening data was carried out. Care was taken to exclude compounds from further consideration that were prone to experimental artifacts and false positive activity readouts. Extensively assayed compounds were identified and found to contain molecules that were consistently inactive in all assays, active against a single target, or promiscuous. The latter included more than 1000 compounds that were active against 10 or more targets from different classes. These multiclass ligands were further analyzed and exemplary compounds were found in X-ray structures of complexes with distinct targets. Our collection of multiclass ligands should be of interest for pharmaceutical applications and further exploration of binding characteristics at the molecular level. Therefore, these highly promiscuous compounds are made publicly available. Full article
(This article belongs to the Special Issue Multitarget Ligands)
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Open AccessArticle
Two-Step Azidoalkenylation of Terminal Alkenes Using Iodomethyl Sulfones
Molecules 2019, 24(22), 4184; https://doi.org/10.3390/molecules24224184 - 18 Nov 2019
Cited by 3 | Viewed by 748
Abstract
The radical azidoalkylation of alkenes that was initially developed with α-iodoesters and α-iodoketones was extended to other activated iodomethyl derivatives. By using iodomethyl aryl sulfones, the preparation of γ-azidosulfones was easily achieved. Facile conversion of these azidosulfones to homoallylic azides using a Julia–Kocienski [...] Read more.
The radical azidoalkylation of alkenes that was initially developed with α-iodoesters and α-iodoketones was extended to other activated iodomethyl derivatives. By using iodomethyl aryl sulfones, the preparation of γ-azidosulfones was easily achieved. Facile conversion of these azidosulfones to homoallylic azides using a Julia–Kocienski olefination reaction is reported, making the whole process equivalent to the azidoalkenylation of terminal alkenes. Full article
(This article belongs to the Special Issue Biomimetic Radical Chemistry and Applications) Printed Edition available
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Open AccessArticle
Optimization of Ultrasound-Assisted Extraction Conditions Followed by Solid Phase Extraction Fractionation from Orthosiphon stamineus Benth (Lamiace) Leaves for Antiproliferative Effect on Prostate Cancer Cells
Molecules 2019, 24(22), 4183; https://doi.org/10.3390/molecules24224183 - 18 Nov 2019
Cited by 2 | Viewed by 836
Abstract
Primarily, optimization of ultrasonic-assisted extraction (UAE) conditions of Orthospihon stamineus was evaluated and verified using a central composite design (CCD) based on three factors including extraction time (minutes), ultrasound amplitude (A), and solvent concentration (%). The response surface methodology (RSM) was performed to [...] Read more.
Primarily, optimization of ultrasonic-assisted extraction (UAE) conditions of Orthospihon stamineus was evaluated and verified using a central composite design (CCD) based on three factors including extraction time (minutes), ultrasound amplitude (A), and solvent concentration (%). The response surface methodology (RSM) was performed to develop an extraction method with maximum yield and high rosmarinic acid content. The optimal UAE conditions were as follows: extraction time 21 min, ultrasound amplitudes 62 A, and solvent composition 70% ethanol in water. The crude extract was further fractionated using solid-phase extraction (SPE), where six sequential fractions that varied in polarity (0–100% Acetonitrile in water) were obtained. Next, the six fractions were evaluated for their antioxidant and anti-cancer properties. This study found that Fraction 2 (F2) contained the highest rosmarinic acid content and showed the strongest antioxidant activity. Additionally, F2 showed an anti-proliferative effect against prostate cancer (DU145) with no harmful effect on normal cells. Full article
(This article belongs to the Special Issue Current Trends in the Analysis of Medicinal Plants)
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Open AccessFeature PaperReview
Current Trends on Seaweeds: Looking at Chemical Composition, Phytopharmacology, and Cosmetic Applications
Molecules 2019, 24(22), 4182; https://doi.org/10.3390/molecules24224182 - 18 Nov 2019
Cited by 19 | Viewed by 1953
Abstract
Seaweeds have received huge interest in recent years given their promising potentialities. Their antioxidant, anti-inflammatory, antitumor, hypolipemic, and anticoagulant effects are among the most renowned and studied bioactivities so far, and these effects have been increasingly associated with their content and richness in [...] Read more.
Seaweeds have received huge interest in recent years given their promising potentialities. Their antioxidant, anti-inflammatory, antitumor, hypolipemic, and anticoagulant effects are among the most renowned and studied bioactivities so far, and these effects have been increasingly associated with their content and richness in both primary and secondary metabolites. Although primary metabolites have a pivotal importance such as their content in polysaccharides (fucoidans, agars, carragenans, ulvans, alginates, and laminarin), recent data have shown that the content in some secondary metabolites largely determines the effective bioactive potential of seaweeds. Among these secondary metabolites, phenolic compounds feature prominently. The present review provides the most remarkable insights into seaweed research, specifically addressing its chemical composition, phytopharmacology, and cosmetic applications. Full article
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Open AccessArticle
8-Hydroxyquinoline Glycoconjugates: Modifications in the Linker Structure and Their Effect on the Cytotoxicity of the Obtained Compounds
Molecules 2019, 24(22), 4181; https://doi.org/10.3390/molecules24224181 - 18 Nov 2019
Cited by 4 | Viewed by 944
Abstract
Small molecule nitrogen heterocycles are very important structures, widely used in the design of potential pharmaceuticals. Particularly, derivatives of 8-hydroxyquinoline (8-HQ) are successfully used to design promising anti-cancer agents. Conjugating 8-HQ derivatives with sugar derivatives, molecules with better bioavailability, selectivity, and solubility are [...] Read more.
Small molecule nitrogen heterocycles are very important structures, widely used in the design of potential pharmaceuticals. Particularly, derivatives of 8-hydroxyquinoline (8-HQ) are successfully used to design promising anti-cancer agents. Conjugating 8-HQ derivatives with sugar derivatives, molecules with better bioavailability, selectivity, and solubility are obtained. In this study, 8-HQ derivatives were functionalized at the 8-OH position and connected with sugar derivatives (D-glucose or D-galactose) substituted with different groups at the anomeric position, using copper(I)-catalyzed 1,3-dipolar azide-alkyne cycloaddition (CuAAC). Glycoconjugates were tested for inhibition of the proliferation of cancer cell lines (HCT 116 and MCF-7) and inhibition of β-1,4-galactosyltransferase activity, which overexpression is associated with cancer progression. All glycoconjugates in protected form have a cytotoxic effect on cancer cells in the tested concentration range. The presence of additional amide groups in the linker structure improves the activity of glycoconjugates, probably due to the ability to chelate metal ions present in many types of cancers. The study of metal complexing properties confirmed that the obtained glycoconjugates are capable of chelating copper ions, which increases their anti-cancer potential. Full article
(This article belongs to the Special Issue Synthesis and Application of Quinolines and Quinoline Derivatives)
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Open AccessArticle
Key-Marker Volatile Compounds in Aromatic Rice (Oryza sativa) Grains: An HS-SPME Extraction Method Combined with GC×GC-TOFMS
Molecules 2019, 24(22), 4180; https://doi.org/10.3390/molecules24224180 - 18 Nov 2019
Cited by 3 | Viewed by 922
Abstract
The aroma of rice essentially contributes to the quality of rice grains. For some varieties, their aroma properties really drive consumer preferences. In this paper, using a dynamic headspace solid-phase microextraction (HS-SPME) system coupled to a two-dimensional gas chromatography (GC×GC) using a time-of-flight [...] Read more.
The aroma of rice essentially contributes to the quality of rice grains. For some varieties, their aroma properties really drive consumer preferences. In this paper, using a dynamic headspace solid-phase microextraction (HS-SPME) system coupled to a two-dimensional gas chromatography (GC×GC) using a time-of-flight mass spectrometric detector (TOFMS) and multivariate analysis, the volatile compounds of aromatic and non-aromatic rice grains were contrasted to define some chemical markers. Fifty-one volatile compounds were selected for principal component analysis resulting in eight key-marker volatile compounds (i.e., pentanal, hexanal, 2-pentyl-furan, 2,4-nonadienal, pyridine, 1-octen-3-ol and (E)-2-octenal) as responsible for the differences between aromatic and non-aromatic rice varieties. The factors that are most likely to affect the HS-SPME efficiency for the aforementioned key-marker compounds were evaluated using a 2 I I I 5 2 fractional factorial design in conjunction with multi-response optimisation. The method precision values, expressed as % of coefficient of variation (CV), were ranging from 1.91% to 26.90% for repeatability (n = 9) and 7.32% to 37.36% for intermediate precision (n = 3 × 3). Furthermore, the method was successfully applied to evaluate the volatile compounds of rice varieties from some Asian countries. Full article
(This article belongs to the Special Issue Analysis of Volatile and Odor Compounds in Food)
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Open AccessArticle
Curcumin Nicotinate Selectively Induces Cancer Cell Apoptosis and Cycle Arrest through a P53-Mediated Mechanism
Molecules 2019, 24(22), 4179; https://doi.org/10.3390/molecules24224179 - 18 Nov 2019
Cited by 7 | Viewed by 940
Abstract
Curcumin is an anticancer agent, but adverse effects and low bioavailability are its main drawbacks, which drives efforts in chemical modifications of curcumin. This study evaluated antiproliferative activity and cancer cell selectivity of a curcumin derivative, curcumin nicotinate (CN), in which two niacin [...] Read more.
Curcumin is an anticancer agent, but adverse effects and low bioavailability are its main drawbacks, which drives efforts in chemical modifications of curcumin. This study evaluated antiproliferative activity and cancer cell selectivity of a curcumin derivative, curcumin nicotinate (CN), in which two niacin molecules were introduced. Our data showed that CN effectively inhibited proliferation and clonogenic growth of colon (HCT116), breast (MCF-7) and nasopharyngeal (CNE2, 5-8F and 6-10B) cancer cells with IC50 at 27.7 μM, 73.4 μM, 64.7 μM, 46.3 μM, and 31.2 μM, respectively. In cancer cells, CN induced apoptosis and cell cycle arrest at G2/M phase through a p53-mediated mechanism, where p53 was activated, p21 and pro-apoptotic proteins Bid and Bak were upregulated, and PARP was cleaved. In non-transformed human mammary epithelial cells MCF10A, CN at 50 µM had no cytotoxicity and p53 was not activated, but curcumin at 12.5 µM activated p53 and p21 and inhibited MCF10A cell growth. These data suggest that CN inhibits cell growth and proliferation through p53-mediated apoptosis and cell cycle arrest with cancer cell selectivity. Full article
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Open AccessArticle
A Newly Discovered Phenylethanoid Glycoside from Stevia rebaudiana Bertoni Affects Insulin Secretion in Rat INS-1 Islet β Cells
Molecules 2019, 24(22), 4178; https://doi.org/10.3390/molecules24224178 - 18 Nov 2019
Cited by 4 | Viewed by 730
Abstract
The tea-like beverage Stevia rebaudiana Bertoni (Stevia) is popular in China because it reduces blood glucose and has a sweet taste. In this work, a comprehensive quality assessment of Stevia led to the discovery of five phenylethanoid glycosides, namely steviophethanoside ( [...] Read more.
The tea-like beverage Stevia rebaudiana Bertoni (Stevia) is popular in China because it reduces blood glucose and has a sweet taste. In this work, a comprehensive quality assessment of Stevia led to the discovery of five phenylethanoid glycosides, namely steviophethanoside (1), cuchiloside (2), salidroside (3), icariside D (4), and tyrosol (5). Of them, compound 1 is a novel compound. Mass spectrometry and NMR spectroscopy were employed to confirm the absolute configuration. A hydrolytic step with 4 N TFA at 95 °C for 4 h was used to confirm the monosaccharides. In addition, Discovery Studio 4.0 was used to predict the ADME and toxicity activity of compound 1. The results suggested that compound 1 was biocompatible and had poor toxicity, which was verified by rat INS-1 islet β cells through an MTT assay. Meanwhile, a significant stimulatory effect on INS-1 cells was observed, which indicated a hypoglycemic effect of compound 1. This is the first report that describes a natural, novel, and hypoglycemic phenylethanoid glycoside in Stevia. Full article
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Open AccessArticle
Cu(II)-Catalyzed C-N Coupling of (Hetero)aryl Halides and N-Nucleophiles Promoted by α-Benzoin Oxime
Molecules 2019, 24(22), 4177; https://doi.org/10.3390/molecules24224177 - 18 Nov 2019
Cited by 2 | Viewed by 936
Abstract
We first reported the new application of a translate metal chelating ligand α-benzoin oxime for improving Cu-catalyzed C-N coupling reactions. The system could catalyse coupling reactions of (hetero)aryl halides with a wide of nucleophiles (e.g., azoles, piperidine, pyrrolidine and amino acids) in moderate [...] Read more.
We first reported the new application of a translate metal chelating ligand α-benzoin oxime for improving Cu-catalyzed C-N coupling reactions. The system could catalyse coupling reactions of (hetero)aryl halides with a wide of nucleophiles (e.g., azoles, piperidine, pyrrolidine and amino acids) in moderate to excellent yields. The protocol allows rapid access to the most common scaffolds found in FDA-approved pharmaceuticals. Full article
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Open AccessArticle
Carnosic Acid Attenuates Cadmium Induced Nephrotoxicity by Inhibiting Oxidative Stress, Promoting Nrf2/HO-1 Signalling and Impairing TGF-β1/Smad/Collagen IV Signalling
Molecules 2019, 24(22), 4176; https://doi.org/10.3390/molecules24224176 - 18 Nov 2019
Cited by 3 | Viewed by 823
Abstract
Cadmium (Cd) imparts nephrotoxicity via triggering oxidative stress and pathological signal transductions in renal cells. The present study was performed to explore the protective mechanism of carnosic acid (CA), a naturally occurring antioxidant compound, against cadmium chloride (CdCl2)-provoked nephrotoxicity employing suitable [...] Read more.
Cadmium (Cd) imparts nephrotoxicity via triggering oxidative stress and pathological signal transductions in renal cells. The present study was performed to explore the protective mechanism of carnosic acid (CA), a naturally occurring antioxidant compound, against cadmium chloride (CdCl2)-provoked nephrotoxicity employing suitable in vitro and in vivo assays. CA (5 µM) exhibited an anti-apoptotic effect against CdCl2 (40 µM) in normal kidney epithelial (NKE) cells evidenced from cell viability, image, and flow cytometry assays. In this study, CdCl2 treatment enhanced oxidative stress by triggering free radical production, suppressing the endogenous redox defence system, and inhibiting nuclear factor erythroid 2-related factor 2 (Nrf2) activation in NKE cells and mouse kidneys. Moreover, CdCl2 treatment significantly endorsed apoptosis and fibrosis via activation of apoptotic and transforming growth factor (TGF)-β1/mothers against decapentaplegic homolog (Smad)/collagen IV signalling pathways, respectively. In contrast, CA treatment significantly attenuated Cd-provoked nephrotoxicity via inhibiting free radicals, endorsing redox defence, suppressing apoptosis, and inhibiting fibrosis in renal cells in both in vitro and in vivo systems. In addition, CA treatment significantly (p < 0.05–0.01) restored blood and urine parameters to near-normal levels in mice. Histological findings further confirmed the protective role of CA against Cd-mediated nephrotoxicity. Molecular docking predicted possible interactions between CA and Nrf2/TGF-β1/Smad/collagen IV. Hence, CA was found to be a potential therapeutic agent to treat Cd-mediated nephrotoxicity. Full article
(This article belongs to the Special Issue The Antioxidant Capacities of Natural Products 2019)
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Open AccessArticle
Anti-Acetylcholinesterase Activities of Mono-Herbal Extracts and Exhibited Synergistic Effects of the Phytoconstituents: A Biochemical and Computational Study
Molecules 2019, 24(22), 4175; https://doi.org/10.3390/molecules24224175 - 18 Nov 2019
Cited by 8 | Viewed by 1020
Abstract
Alzheimer’s disease (AD), a neurodegenerative disease, is the most common form of dementia. Inhibition of acetylcholinesterase (AChE) is a common strategy for the treatment of AD. In this study, aqueous, hydro-methanolic, and methanolic extracts of five potent herbal extracts were tested for their [...] Read more.
Alzheimer’s disease (AD), a neurodegenerative disease, is the most common form of dementia. Inhibition of acetylcholinesterase (AChE) is a common strategy for the treatment of AD. In this study, aqueous, hydro-methanolic, and methanolic extracts of five potent herbal extracts were tested for their in vitro anti-AChE activity. Among all, the Tinospora cordifolia (Giloy) methanolic fraction performed better with an IC50 of 202.64 µg/mL. Of the HPLC analyzed components of T. cordifolia (methanolic extract), palmatine and berberine performed better (IC50 0.66 and 0.94 µg/mL, respectively) as compared to gallic acid and the tool compound “galantamine hydrobromide” (IC50 7.89 and 1.45 µg/mL, respectively). Mode of inhibition of palmatine and berberine was non-competitive, while the mode was competitive for the tool compound. Combinations of individual alkaloids palmatine and berberine resulted in a synergistic effect for AChE inhibition. Therefore, the AChE inhibition by the methanolic extract of T. cordifolia was probably due to the synergism of the isoquinoline alkaloids. Upon molecular docking, it was observed that palmatine and berberine preferred the peripheral anionic site (PAS) of AChE, with π-interactions to PAS residue Trp286, indicating that it may hinder the substrate binding by partially blocking the entrance of the gorge of the active site or the product release. Full article
(This article belongs to the Section Natural Products Chemistry)
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Open AccessArticle
Experimental Data and Modelling of the Solubility of High-Carotenoid Paprika Extract in Supercritical Carbon Dioxide
Molecules 2019, 24(22), 4174; https://doi.org/10.3390/molecules24224174 - 18 Nov 2019
Cited by 2 | Viewed by 580
Abstract
The studies of solubility of the paprika extract with a high concentration of carotenoids in carbon dioxide under the pressure of 20–50 MPa and at temperatures of 313.15–333.15 K were carried out using the static method. The highest solubility of paprika extract was [...] Read more.
The studies of solubility of the paprika extract with a high concentration of carotenoids in carbon dioxide under the pressure of 20–50 MPa and at temperatures of 313.15–333.15 K were carried out using the static method. The highest solubility of paprika extract was achieved at the temperature of 333.15 K and under the pressure of 50 MPa. The obtained experimental data were correlated with five density-based models, applied for prediction of solubility in the supercritical carbon dioxide (the Chrastil, del Valle and Aguilera, Adachi and Lu, Sparks et al. and Bian et al. models). The accuracy of particular models with reference to measurement results was specified with the average absolute relative deviation (AARD) and coefficient of determination (R2). Results showed that solubility calculated based on the selected models was compliant with experimental data. Full article
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Open AccessFeature PaperArticle
The Analogs of Temporin-GHa Exhibit a Broader Spectrum of Antimicrobial Activity and a Stronger Antibiofilm Potential against Staphylococcus aureus
Molecules 2019, 24(22), 4173; https://doi.org/10.3390/molecules24224173 - 18 Nov 2019
Cited by 2 | Viewed by 898
Abstract
The abuse of antibiotics has led to the emergence of multidrug-resistant bacteria, which is becoming a serious worldwide problem people have to face. In our previous study, temporin-GHa (GHa) cloned from Hylarana guentheri showed antimicrobial activity against Gram-positive bacteria. In order to improve [...] Read more.
The abuse of antibiotics has led to the emergence of multidrug-resistant bacteria, which is becoming a serious worldwide problem people have to face. In our previous study, temporin-GHa (GHa) cloned from Hylarana guentheri showed antimicrobial activity against Gram-positive bacteria. In order to improve its therapeutic potential, we used a template-based and a database-assisted design to obtain three derived peptides by replacing the histidine at both ends of GHa with lysine, which exhibited faster and stronger bactericidal activity and a broader spectrum than the parent peptide. GHaK and GHa4K targeted to the bacterial membrane to exert their antibacterial activities at a faster membrane damage rate. The derived peptides inhibited the initial adhesion and the formation of Staphylococcus aureus biofilms, and eradicated the mature biofilms, which indicated that the derived peptides effectively penetrated the biofilm and killed bacteria. The therapeutic index (TI) and cell selectivity index (CSI) of the derived peptides increased significantly, which means a broader therapeutic window of the derived peptides. The derived peptides with improved activity and cell selectivity have the potential to be the promising candidates for the treatment of S. aureus infections. Our research also provides new insights into the design and development of antimicrobial peptides. Full article
(This article belongs to the Special Issue Synthetic Antibiofilm Agents: Design, Synthesis and Applications)
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Open AccessArticle
Arginine-Induced Self-Assembly of Protoporphyrin to Obtain Effective Photocatalysts in Aqueous Media Under Visible Light
Molecules 2019, 24(22), 4172; https://doi.org/10.3390/molecules24224172 - 18 Nov 2019
Cited by 2 | Viewed by 1353
Abstract
The fabrication of controlled supramolecular nanostructures via self-assembly of protoporphyrin IX (PPIX) was studied with enantiomerically pure l-arginine and d-arginine, and we have shown that stoichiometry controlled the morphology formed. The nanostructure morphology was mainly influenced by the delicate balance of [...] Read more.
The fabrication of controlled supramolecular nanostructures via self-assembly of protoporphyrin IX (PPIX) was studied with enantiomerically pure l-arginine and d-arginine, and we have shown that stoichiometry controlled the morphology formed. The nanostructure morphology was mainly influenced by the delicate balance of π-π stacking interactions between PPIX cores, as well as H-bonding between the deprotonated acidic head group of PPIX with the guanidine head group of arginine. PPIX self-assembled with l-/d-arginine to create rose-like nanoflower structures for four equivalents of arginine that were 5–10 μm in length and 1–4 μm diameter. We employed UV-vis, fluorescence spectroscopy, scanning electron microscopy (SEM), X-ray diffraction (XRD), dynamic light scattering (DLS) and Fourier transform infrared spectroscopy (FT-IR) techniques to characterize the resulting self-assembled nanostructures. Furthermore, we investigated the catalytic activity of PPIX and arginine co-assembled materials. The fabricated PPIX–arginine nanostructure showed high enhancement of photocatalytic activity through degradation of rhodamine B (RhB) with a decrease in dye concentration of around 78–80% under simulated visible radiation. Full article
(This article belongs to the Special Issue Spatial Organization of Multi-Porphyrins for Pre-Defined Properties)
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