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Molecules, Volume 24, Issue 1 (January-1 2019)

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Cover Story (view full-size image) The dilithium hydride, Li2H, is the lightest of the triatomic alkali hydrides. It has recently [...] Read more.
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Open AccessEditorial Acknowledgement to Reviewers of Molecules in 2018
Molecules 2019, 24(1), 214; https://doi.org/10.3390/molecules24010214
Published: 8 January 2019
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Abstract
Rigorous peer-review is the corner-stone of high-quality academic publishing [...] Full article
Open AccessArticle Monitoring Antifungal Agents of Artemisia annua against Fusarium oxysporum and Fusarium solani, Associated with Panax notoginseng Root-Rot Disease
Molecules 2019, 24(1), 213; https://doi.org/10.3390/molecules24010213
Received: 14 December 2018 / Revised: 2 January 2019 / Accepted: 3 January 2019 / Published: 8 January 2019
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Abstract
Root rot of Panax notoginseng has received great attention due to its threat on the plantation and sustainable utilization of P. notoginseng. To suppress the root-rot disease, natural ingredients are of great importance because of their environment friendly properties. In this
[...] Read more.
Root rot of Panax notoginseng has received great attention due to its threat on the plantation and sustainable utilization of P. notoginseng. To suppress the root-rot disease, natural ingredients are of great importance because of their environment friendly properties. In this study, we found that the methanol extract from Artemisia annua leaves has strong antifungal effects on the growth of Fusarium oxysporum and Fusarium solani resulting into root-rot disease. Essential oil (EO) thereof was found to be the most active. GC-MS analysis revealed 58 ingredients and camphor, camphene, β-caryophyllene, and germacrene D were identified as the major ingredients. Further antifungal assays showed that the main compounds exhibit various degrees of inhibition against all the fungi tested. In addition, synergistic effects between A. annua EO and chemical fungicides were examined. Finally, in vivo experiments were conducted and disclosed that P. notoginseng root rot could be largely inhibited by the petroleum ether extract from A. annua, indicating that A. annua could be a good source for controlling P. notoginseng root-rot. Full article
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Open AccessArticle Characteristics of the Water- and Alkali-Soluble Hemicelluloses Fractionated by Sequential Acidification and Graded-Ethanol from Sweet Maize Stems
Molecules 2019, 24(1), 212; https://doi.org/10.3390/molecules24010212
Received: 3 December 2018 / Revised: 24 December 2018 / Accepted: 3 January 2019 / Published: 8 January 2019
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Abstract
Sweet maize stems were treated with hot water and potassium hydroxide to fractionate hemicellulosic polymers. The results showed that the water-soluble hemicelluloses were mainly composed of glucose (27.83%), xylose (27.32%), and galactose (16.81%). In comparison, alkali-soluble hemicelluloses fractionated by acidification and a graded
[...] Read more.
Sweet maize stems were treated with hot water and potassium hydroxide to fractionate hemicellulosic polymers. The results showed that the water-soluble hemicelluloses were mainly composed of glucose (27.83%), xylose (27.32%), and galactose (16.81%). In comparison, alkali-soluble hemicelluloses fractionated by acidification and a graded ethanol solution (10%, 20%, 35%, 50%, 65%, and 80%) were mainly composed of xylose (69.73 to 88.62%) and arabinose (5.41 to 16.20%). More highly branched hemicelluloses tended to be precipitated in a higher concentration of ethanol solution, as revealed by the decreasing xylose to arabinose ratio from 16.43 to 4.21. Structural characterizations indicated that alkali-soluble hemicelluloses fractionated from sweet maize stems were mainly arabinoxylans. The results provided fundamental information on hemicelluloses composition and structure and their potential utilization in the fields of biofuels, biochemicals, and biomaterials. Full article
(This article belongs to the Special Issue Biorefinery and Biomass Conversion and Utilization)
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Open AccessArticle Reduced Efficiency Roll-Off in White Phosphorescent Organic Light-Emitting Diodes Based on Double Emission Layers
Molecules 2019, 24(1), 211; https://doi.org/10.3390/molecules24010211
Received: 12 December 2018 / Revised: 2 January 2019 / Accepted: 5 January 2019 / Published: 8 January 2019
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Abstract
We demonstrate high-efficiency white phosphorescent organic light-emitting diodes with low efficiency roll-off. The feature of the device concept is employing two phosphorescent emission layers (EMLs) separated by a mixed interlayer. Both the EMLs are doped by two phosphorescent dyes. The resulting white device
[...] Read more.
We demonstrate high-efficiency white phosphorescent organic light-emitting diodes with low efficiency roll-off. The feature of the device concept is employing two phosphorescent emission layers (EMLs) separated by a mixed interlayer. Both the EMLs are doped by two phosphorescent dyes. The resulting white device with the optimized doping concentration shows a maximum efficiency of 31.0 cd/A with extremely low efficiency roll-off of 30.7 cd/A at 1000 cd/m2, 27.2 cd/A at 5000 cd/m2, and 25.5 cd/A at 10,000 cd/m2, respectively, without any outcoupling structures. This is enabled by the balanced charge carrier transport in EMLs, leading to broader exciton recombination zone. Full article
(This article belongs to the Special Issue Organic Light Emitting Diodes II)
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Open AccessReview Beneficial Effects of Natural Bioactive Compounds from Hibiscus sabdariffa L. on Obesity
Molecules 2019, 24(1), 210; https://doi.org/10.3390/molecules24010210
Received: 29 November 2018 / Revised: 3 January 2019 / Accepted: 8 January 2019 / Published: 8 January 2019
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Abstract
Obesity is a condition associated with the accumulation of excess fat in the body, energy imbalance, lipogenesis, etc., which increases adipose tissue mass through adipogenesis and poses a health risk. Its prevalence has become an economic burden to the health care system and
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Obesity is a condition associated with the accumulation of excess fat in the body, energy imbalance, lipogenesis, etc., which increases adipose tissue mass through adipogenesis and poses a health risk. Its prevalence has become an economic burden to the health care system and the world at large. One of the alternatives to tackling obesity involves the use of bioactive compounds. We critically examined the effects of Hibiscus sabdariffa extract (HSE) on various parameters associated with the development of obesity such as; the effect of HSE on body weight, the effect of HSE on lipid accumulation, cholesterol metabolism and plasma parameters, the inhibitory effect of HSE on pancreatic lipase, and the effect of HSE on adipocyte differentiation/adipogenesis. This review has gathered reports on the various anti-obesity effects of H. sabdariffa bioactive compounds in cell and animal models, as well as in humans. Available toxicology information on the consumption of H. sabdariffa revealed that its toxicity is dose-dependent and may cause an adverse effect when administered over a long period of time. Reports have shown that H. sabdariffa derived bioactive compounds are potent in the treatment of obesity with an evident reduction in body weight, inhibition of lipid accumulation and suppression of adipogenesis through the PPARγ pathway and other transcriptional factors. Full article
(This article belongs to the Special Issue Natural Bioactives in Anti-Obesity Therapy)
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Open AccessCommunication Curve Effect on Singlet Diradical Contribution in Kekulé-type Diradicals: A Sensitive Probe for Quinoidal Structure in Curved π-Conjugated Molecules
Molecules 2019, 24(1), 209; https://doi.org/10.3390/molecules24010209
Received: 29 November 2018 / Revised: 3 January 2019 / Accepted: 4 January 2019 / Published: 8 January 2019
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Abstract
Curved (non-planar) aromatic compounds have attracted significant research attention in the fields of basic chemistry and materials science. The contribution of the quinoidal structure in the curved π-conjugated structures has been proposed to be the key for materials functions. In this study, the
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Curved (non-planar) aromatic compounds have attracted significant research attention in the fields of basic chemistry and materials science. The contribution of the quinoidal structure in the curved π-conjugated structures has been proposed to be the key for materials functions. In this study, the curve effect on the quinoidal contribution was investigated in Kekulé-type singlet diradicals (S-DR1-4) as a sensitive probe for quinoidal structures in curved π-conjugated molecules. The quinoidal contribution in S-DR1-4 was found to increase with increasing the curvature of the curved structure, which was quantitatively analyzed using NBO analysis and the natural orbital occupation numbers computed by the CASSCF method. The curve effect on the singlet-triplet energy gap was examined by the CASPT2 method. The singlet-triplet energy gaps for the highly π-conjugated diradicals were determined for the first time using the CASPT2 method. Substantial quinoidal contribution was found in the curved structures of the delocalized singlet diradicals S-DR1-4, in contrast to its absence in the corresponding triplet states T-DR1-4. Full article
(This article belongs to the Special Issue Open-Shell Systems for Functional Materials)
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Open AccessFeature PaperArticle Erubescensoic Acid, a New Polyketide and a Xanthonopyrone SPF-3059-26 from the Culture of the Marine Sponge-Associated Fungus Penicillium erubescens KUFA 0220 and Antibacterial Activity Evaluation of Some of Its Constituents
Molecules 2019, 24(1), 208; https://doi.org/10.3390/molecules24010208
Received: 4 December 2018 / Revised: 2 January 2019 / Accepted: 3 January 2019 / Published: 8 January 2019
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Abstract
A new polyketide erubescensoic acid (1), and the previously reported xanthonopyrone, SPF-3059-26 (2), were isolated from the uninvestigated fractions of the ethyl acetate crude extract of the marine sponge-associated fungus Penicillium erubescens KUFA0220. The structures of the new compound,
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A new polyketide erubescensoic acid (1), and the previously reported xanthonopyrone, SPF-3059-26 (2), were isolated from the uninvestigated fractions of the ethyl acetate crude extract of the marine sponge-associated fungus Penicillium erubescens KUFA0220. The structures of the new compound, erubescensoic acid (1), and the previously reported SPF-3059-26 (2), were elucidated by extensive analysis of 1D and 2D-NMR spectra as well as HRMS. The absolute configuration of the stereogenic carbon of erubescensoic acid (1) was determined by X-ray analysis. Erubescensoic acid (1) and SPF-3059-26 (2), together with erubescenschromone B (3), penialidin D (4), and 7-hydroxy-6-methoxy-4-oxo-3-[(1E)-3-oxobut-1-en-1-yl]-4H-chromen-5-carboxylic acid (5), recently isolated from this fungus, were assayed for their antibacterial activity against gram-positive and gram-negative reference strains and the multidrug-resistant (MDR) strains from the environment. The capacity of these compounds to interfere with the bacterial biofilm formation and their potential synergism with clinically relevant antibiotics for the MDR strains were also investigated. Full article
(This article belongs to the collection Bioactive Compounds)
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Open AccessArticle Corrosion Resistance of Aluminum against Acid Activation: Impact of Benzothiazole-Substituted Gallium Phthalocyanine
Molecules 2019, 24(1), 207; https://doi.org/10.3390/molecules24010207
Received: 17 December 2018 / Revised: 3 January 2019 / Accepted: 4 January 2019 / Published: 8 January 2019
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Abstract
This study describes the adsorption behavior of organic inhibitors at the aluminum-HCl solution interface and their corrosion inhibition performance. The organic inhibitors employed are: 4-(benzo [d]thiazol-2ylthio)phthalonitrile (BTThio) and tetrakis[(benzo[d]thiazol-2-yl-thio)phthalo- cyaninato]gallium(III) chloride (ClGaBTThioPc). The corrosion behavior of these inhibitors is investigated using electrochemical and
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This study describes the adsorption behavior of organic inhibitors at the aluminum-HCl solution interface and their corrosion inhibition performance. The organic inhibitors employed are: 4-(benzo [d]thiazol-2ylthio)phthalonitrile (BTThio) and tetrakis[(benzo[d]thiazol-2-yl-thio)phthalo- cyaninato]gallium(III) chloride (ClGaBTThioPc). The corrosion behavior of these inhibitors is investigated using electrochemical and computational techniques. Open circuit potential results reveal predominant cathodic character for the mechanism of aluminum corrosion inhibition by the inhibitors. Inhibition efficiency values from potentiodynamic polarization measurements increase from 46.9 to 70.8% for BTThio and 59.7 to 81.0% for ClGaBTThioPc within the concentration range of 2 to 10 μM. Scanning electron microscopy (SEM) measurements reveal protection of the metal surface from acid attack, in the presence of the inhibitors and energy dispersive X-ray (EDX) measurements show that the most probable way by which the inhibitors protect the metal surface would be by shielding it from the corrosion attacks of Cl from the acid. Quantum chemical parameters corroborate well with experimental findings. Full article
(This article belongs to the Section Electrochemistry)
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Open AccessArticle Short Peptides with Uncleavable Peptide Bond Mimetics as Photoactivatable Caspase-3 Inhibitors
Molecules 2019, 24(1), 206; https://doi.org/10.3390/molecules24010206
Received: 7 December 2018 / Revised: 28 December 2018 / Accepted: 3 January 2019 / Published: 8 January 2019
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Abstract
Chemical probes that covalently interact with proteases have found increasing use for the study of protease function and localization. The design and synthesis of such probes is still a bottleneck, as the strategies to target different families are highly diverse. We set out
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Chemical probes that covalently interact with proteases have found increasing use for the study of protease function and localization. The design and synthesis of such probes is still a bottleneck, as the strategies to target different families are highly diverse. We set out to design and synthesize chemical probes based on protease substrate specificity with inclusion of an uncleavable peptide bond mimic and a photocrosslinker for covalent modification of the protease target. With caspase-3 as a model target protease, we designed reduced amide and triazolo peptides as substrate mimetics, whose sequences can be conveniently constructed by modified solid phase peptide synthesis. We found that these probes inhibited the caspase-3 activity, but did not form a covalent bond. It turned out that the reduced amide mimics, upon irradiation with a benzophenone as photosensitizer, are oxidized and form low concentrations of peptide aldehydes, which then act as inhibitors of caspase-3. This type of photoactivation may be utilized in future photopharmacology experiments to form protease inhibitors at a precise time and location. Full article
(This article belongs to the Section Chemical Biology)
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Open AccessArticle Spectroscopic and Structural Study of Some Oligosilanylalkyne Complexes of Cobalt, Molybdenum and Nickel
Molecules 2019, 24(1), 205; https://doi.org/10.3390/molecules24010205
Received: 6 December 2018 / Revised: 23 December 2018 / Accepted: 27 December 2018 / Published: 8 January 2019
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Abstract
Metal induced stabilization of α-carbocations is well known for cobalt- and molybdenum complexed propargyl cations. The same principle also allows access to reactivity enhancement of metal coordinated halo- and hydrosilylalkynes. In a previous study, we have shown that coordination of oligosilanylalkynes to the
[...] Read more.
Metal induced stabilization of α-carbocations is well known for cobalt- and molybdenum complexed propargyl cations. The same principle also allows access to reactivity enhancement of metal coordinated halo- and hydrosilylalkynes. In a previous study, we have shown that coordination of oligosilanylalkynes to the dicobalthexacarbonyl fragment induces striking reactivity to the oligosilanyl part. The current paper extends this set of oligosilanylalkyne complexes to a number of new dicobalthexacarbonyl complexes but also to 1,2-bis(cyclopentadienyl)tetracarbonyldimolybdenum and (dippe)Ni complexes. NMR-Spectroscopic and crystallographic analysis of the obtained complexes clearly show that the dimetallic cobalt and molybdenum complexes cause rehybridization of the alkyne carbon atoms to sp3, while in the nickel complexes one π-bond of the alkyne is retained. For the dicobalt and dimolybdenum complexes, strongly deshielded 29Si NMR resonances of the attached silicon atoms indicate enhanced reactivity, whereas the 29Si NMR shifts of the respective nickel complexes are similar to that of respective vinylsilanes. Full article
(This article belongs to the Special Issue Advances in Silicon Chemistry 2018)
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Open AccessArticle Biological Activities and Chemical Composition of Santolina africana Jord. et Fourr. Aerial Part Essential Oil from Algeria: Occurrence of Polyacetylene Derivatives
Molecules 2019, 24(1), 204; https://doi.org/10.3390/molecules24010204
Received: 24 November 2018 / Revised: 28 December 2018 / Accepted: 29 December 2018 / Published: 8 January 2019
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Abstract
The chemical composition of 18 oil samples of Santolina africana isolated from aerial parts at full flowering, collected in three locations in eastern Algeria was determined by GC(RI), GC/MS and 13C-NMR analysis. The major components were: germacrene D, myrcene, spathulenol, α-bisabolol, β-pinene,
[...] Read more.
The chemical composition of 18 oil samples of Santolina africana isolated from aerial parts at full flowering, collected in three locations in eastern Algeria was determined by GC(RI), GC/MS and 13C-NMR analysis. The major components were: germacrene D, myrcene, spathulenol, α-bisabolol, β-pinene, 1,8-cineole, cis-chrysanthenol, capillene, santolina alcohol, camphor, terpinen-4-ol and lyratol. The chemical composition appeared homogeneous and characterized by the occurrence of four derivatives which exhibited a conjugated alkene dialkyne moiety. They were identified for the first time in an essential oil from S. africana. The collective oil sample exhibited moderate antimicrobial and antioxidant activities whereas the anti-inflammatory activity presented a real potential. IC50 value of Santolina africana essential oil (0.065 ± 0.004 mg/mL) is 5-fold higher than IC50 value of NDGA used as positive control. Full article
(This article belongs to the Special Issue Biological Activities of Essential Oils)
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Open AccessArticle Biosynthetic Gene Content of the ‘Perfume Lichens’ Evernia prunastri and Pseudevernia furfuracea
Molecules 2019, 24(1), 203; https://doi.org/10.3390/molecules24010203
Received: 14 December 2018 / Revised: 29 December 2018 / Accepted: 4 January 2019 / Published: 8 January 2019
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Abstract
Lichen-forming fungi produce a vast number of unique natural products with a wide variety of biological activities and human uses. Although lichens have remarkable potential in natural product research and industry, the molecular mechanisms underlying the biosynthesis of lichen metabolites are poorly understood.
[...] Read more.
Lichen-forming fungi produce a vast number of unique natural products with a wide variety of biological activities and human uses. Although lichens have remarkable potential in natural product research and industry, the molecular mechanisms underlying the biosynthesis of lichen metabolites are poorly understood. Here we use genome mining and comparative genomics to assess biosynthetic gene clusters and their putative regulators in the genomes of two lichen-forming fungi, which have substantial commercial value in the perfume industry, Evernia prunastri and Pseudevernia furfuracea. We report a total of 80 biosynthetic gene clusters (polyketide synthases (PKS), non-ribosomal peptide synthetases and terpene synthases) in E. prunastri and 51 in P. furfuracea. We present an in-depth comparison of 11 clusters, which show high homology between the two species. A ketosynthase (KS) phylogeny shows that biosynthetic gene clusters from E. prunastri and P. furfuracea are widespread across the Fungi. The phylogeny includes 15 genomes of lichenized fungi and all fungal PKSs with known functions from the MIBiG database. Phylogenetically closely related KS domains predict not only similar PKS architecture but also similar cluster architecture. Our study highlights the untapped biosynthetic richness of lichen-forming fungi, provides new insights into lichen biosynthetic pathways and facilitates heterologous expression of lichen biosynthetic gene clusters. Full article
(This article belongs to the Special Issue Lichens: Chemistry, Ecological and Biological Activities II)
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Open AccessArticle Self-Assembly of Short Elastin-like Amphiphilic Peptides: Effects of Temperature, Molecular Hydrophobicity and Charge Distribution
Molecules 2019, 24(1), 202; https://doi.org/10.3390/molecules24010202
Received: 21 December 2018 / Revised: 31 December 2018 / Accepted: 7 January 2019 / Published: 8 January 2019
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Abstract
A novel type of self-assembling peptides has been developed by introducing the basic elastomeric β-turn units of elastin protein into the amphiphilic peptide molecules. The self-assembly behaviors of such peptides are affected by the overall molecular hydrophobicity, charge distribution and temperature. The molecules
[...] Read more.
A novel type of self-assembling peptides has been developed by introducing the basic elastomeric β-turn units of elastin protein into the amphiphilic peptide molecules. The self-assembly behaviors of such peptides are affected by the overall molecular hydrophobicity, charge distribution and temperature. The molecules with higher hydrophobicity exhibit better self-assembling capability to form long fibrillar nanostructures. For some peptides, the temperature increase can not only promote the self-assembly process but also change the self-assembly routes. The self-assembly of the peptides with two charges centralized on one terminal show higher dependence on temperature than the peptides with two charges distributed separately on the two terminals. The study probes into the self-assembly behaviors of short elastin-like peptides and is of great help for developing novel self-assembling peptides with thermo sensitivity. Full article
(This article belongs to the Special Issue Recent Advances in Self-Assembled Peptides)
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Open AccessArticle Effect of Planarity of Aromatic Rings Appended to o-Carborane on Photophysical Properties: A Series of o-Carboranyl Compounds Based on 2-Phenylpyridine- and 2-(Benzo[b]thiophen-2-yl)pyridine
Molecules 2019, 24(1), 201; https://doi.org/10.3390/molecules24010201
Received: 5 December 2018 / Revised: 31 December 2018 / Accepted: 3 January 2019 / Published: 7 January 2019
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Abstract
Herein, we investigated the effect of ring planarity by fully characterizing four pyridine-based o-carboranyl compounds. o-Carborane was introduced to the C4 position of the pyridine rings of 2-phenylpyridine and 2-(benzo[b]thiophen-2-yl)pyridine (CB1 and CB2, respectively), and the compounds
[...] Read more.
Herein, we investigated the effect of ring planarity by fully characterizing four pyridine-based o-carboranyl compounds. o-Carborane was introduced to the C4 position of the pyridine rings of 2-phenylpyridine and 2-(benzo[b]thiophen-2-yl)pyridine (CB1 and CB2, respectively), and the compounds were subsequently borylated to obtain the corresponding CN-chelated compounds CB1B and CB2B. Single-crystal X-ray diffraction analysis of the molecular structures of CB2 and CB2B confirmed that o-carborane is appended to the aryl moiety. In photoluminescence experiments, CB2, but not CB1, showed an intense emission, assignable to intramolecular charge transfer (ICT) transition between the aryl and o-carborane moieties, in both solution and film states. On the other hand, in both solution and film states, CB1B and CB2B demonstrated a strong emission, originating from π-π * transition in the aryl groups, that tailed off to 650 nm owing to the ICT transition. All intramolecular electronic transitions in these o-carboranyl compounds were verified by theoretical calculations. These results distinctly suggest that the planarity of the aryl groups have a decisive effect on the efficiency of the radiative decay due to the ICT transition. Full article
(This article belongs to the Special Issue Advances in Materials Derived from Polyhedral Boron Clusters)
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Open AccessArticle Synthesis and Spectroscopic Identification of Certain Imidazole-Semicarbazone Conjugates Bearing Benzodioxole Moieties: New Antifungal Agents
Molecules 2019, 24(1), 200; https://doi.org/10.3390/molecules24010200
Received: 28 November 2018 / Revised: 24 December 2018 / Accepted: 3 January 2019 / Published: 7 January 2019
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Abstract
During the last three decades the extent of life-threatening fungal infections has increased remarkably worldwide. Synthesis and structure elucidation of certain imidazole-semicarbazone conjugates 5ao are reported. Single crystal X-ray analysis of compound 5e unequivocally confirmed its assigned chemical structure and the
[...] Read more.
During the last three decades the extent of life-threatening fungal infections has increased remarkably worldwide. Synthesis and structure elucidation of certain imidazole-semicarbazone conjugates 5ao are reported. Single crystal X-ray analysis of compound 5e unequivocally confirmed its assigned chemical structure and the (E)-configuration of its imine double bond. Compound 5e crystallized in the triclinic system, P-1, a = 6.3561 (3) Å, b = 12.5095 (8) Å, c = 14.5411 (9) Å, α = 67.073 (4)°, β = 79.989 (4)°, γ =84.370 (4)°, V = 1048.05 (11) Å3, Z = 2. In addition, DIZ and MIC assays were used to examine the in vitro antifungal activity of the title conjugates 5ao against four fungal strains. Compound 5e, bearing a 4-ethoxyphenyl fragment, showed the best MIC value (0.304 µmol/mL) against both C. tropicalis and C. parapsilosis species, while compounds 5c (MIC = 0.311 µmol/mL), 5k, and 5l (MIC = 0.287 µmol/mL) exhibited the best anti-C. albicans activity. Full article
(This article belongs to the Section Medicinal Chemistry)
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Open AccessArticle Small Multitarget Molecules Incorporating the Enone Moiety
Molecules 2019, 24(1), 199; https://doi.org/10.3390/molecules24010199
Received: 7 December 2018 / Revised: 24 December 2018 / Accepted: 28 December 2018 / Published: 7 January 2019
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Abstract
Chalcones represent a class of small drug/druglike molecules with different and multitarget biological activities. Small multi-target drugs have attracted considerable interest in the last decade due their advantages in the treatment of complex and multifactorial diseases, since “one drug-one target” therapies have failed
[...] Read more.
Chalcones represent a class of small drug/druglike molecules with different and multitarget biological activities. Small multi-target drugs have attracted considerable interest in the last decade due their advantages in the treatment of complex and multifactorial diseases, since “one drug-one target” therapies have failed in many cases to demonstrate clinical efficacy. In this context, we designed and synthesized potential new small multi-target agents with lipoxygenase (LOX), acetyl cholinesterase (AChE) and lipid peroxidation inhibitory activities, as well as antioxidant activity based on 2-/4- hydroxy-chalcones and the bis-etherified bis-chalcone skeleton. Furthermore, the synthesized molecules were evaluated for their cytotoxicity. Simple chalcone b4 presents significant inhibitory activity against the 15-human LOX with an IC50 value 9.5 µM, interesting anti-AChE activity, and anti-lipid peroxidation behavior. Bis-etherified chalcone c12 is the most potent inhibitor of AChE within the bis-etherified bis-chalcones followed by c11. Bis-chalcones c11 and c12 were found to combine anti-LOX, anti-AchE, and anti-lipid peroxidation activities. It seems that the anti-lipid peroxidation activity supports the anti-LOX activity for the significantly active bis-chalcones. Our circular dichroism (CD) study identified two structures capable of interfering with the aggregation process of Aβ. Compounds c2 and c4 display additional protective actions against Alzheimer’s disease (AD) and add to the pleiotropic profile of the chalcone derivatives. Predicted results indicate that the majority of the compounds with the exception of c11 (144 Å) can cross the Blood Brain Barrier (BBB) and act in CNS. The results led us to propose new leads and to conclude that the presence of a double enone group supports better biological activities. Full article
(This article belongs to the Special Issue Small Molecule Drug Design)
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Open AccessArticle Effects of Population Dynamics on Establishment of a Restriction-Modification System in a Bacterial Host
Molecules 2019, 24(1), 198; https://doi.org/10.3390/molecules24010198
Received: 21 November 2018 / Revised: 28 December 2018 / Accepted: 3 January 2019 / Published: 7 January 2019
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Abstract
In vivo dynamics of protein levels in bacterial cells depend on both intracellular regulation and relevant population dynamics. Such population dynamics effects, e.g., interplay between cell and plasmid division rates, are, however, often neglected in modeling gene expression regulation. Including them in a
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In vivo dynamics of protein levels in bacterial cells depend on both intracellular regulation and relevant population dynamics. Such population dynamics effects, e.g., interplay between cell and plasmid division rates, are, however, often neglected in modeling gene expression regulation. Including them in a model introduces additional parameters shared by the dynamical equations, which can significantly increase dimensionality of the parameter inference. We here analyse the importance of these effects, on a case of bacterial restriction-modification (R-M) system. We redevelop our earlier minimal model of this system gene expression regulation, based on a thermodynamic and dynamic system modeling framework, to include the population dynamics effects. To resolve the problem of effective coupling of the dynamical equations, we propose a “mean-field-like” procedure, which allows determining only part of the parameters at a time, by separately fitting them to expression dynamics data of individual molecular species. We show that including the interplay between kinetics of cell division and plasmid replication is necessary to explain the experimental measurements. Moreover, neglecting population dynamics effects can lead to falsely identifying non-existent regulatory mechanisms. Our results call for advanced methods to reverse-engineer intracellular regulation from dynamical data, which would also take into account the population dynamics effects. Full article
(This article belongs to the Special Issue Protein-DNA Interactions: From Biophysics to Genomics)
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Open AccessArticle Separation of Five Iridoid Glycosides from Lonicerae Japonicae Flos Using High-Speed Counter-Current Chromatography and Their Anti-Inflammatory and Antibacterial Activities
Molecules 2019, 24(1), 197; https://doi.org/10.3390/molecules24010197
Received: 12 December 2018 / Revised: 27 December 2018 / Accepted: 28 December 2018 / Published: 7 January 2019
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Abstract
A high-speed counter-current chromatography (HSCCC) method, using a two-phase solvent system composed of ethyl acetate/n-butanol/methanol/water (5:1:1:5, v/v/v/v), was successfully established to separate the five iridoid glucosides 7-O-ethyl sweroside (1), secologanin
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A high-speed counter-current chromatography (HSCCC) method, using a two-phase solvent system composed of ethyl acetate/n-butanol/methanol/water (5:1:1:5, v/v/v/v), was successfully established to separate the five iridoid glucosides 7-O-ethyl sweroside (1), secologanin dimethylacetal (2), adinoside F (3), (7R)-secologain n-butyl methyl acetal (4) and adinoside G (5) from Lonicerae Japonicae Flos. Their purities were 96.8%, 98.5%, 93.3%, 98.0% and 99.9%, respectively. All the iridoid glucosides were identified by HR-ESI-MS, 1D and 2D NMR. Compounds 3 and 5 are new iridoid glucosides. The anti-inflammatory tests showed that compounds 15 all expressed moderate inhibitory effects on β-glucuronidase release in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor (PAF) with IC50 values ranging from 4.52 to 6.50 µM, while the antibacterial assays demonstrated that all the compounds displayed mild inhibitory activities against Staphylococcus aureus ATCC 25923 with MIC values ranging from 13.7 to 26.0 µg/mL. Full article
(This article belongs to the Section Natural Products Chemistry)
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Open AccessArticle An Unusual Benzoisoquinoline-9-one Derivative and Other Related Compounds with Antiproliferative Activity from Hawaiian Endophytic Fungus Peyronellaea sp. FT431
Molecules 2019, 24(1), 196; https://doi.org/10.3390/molecules24010196
Received: 8 December 2018 / Revised: 2 January 2019 / Accepted: 4 January 2019 / Published: 7 January 2019
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Abstract
A new polyketide containing the benzoisoquinoline-9-one moiety, peyronetide A (1), and three other new derivatives peyronetides B–D (24), as well as one known compound (5) were purified from the cultured broth of the endophytic fungus
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A new polyketide containing the benzoisoquinoline-9-one moiety, peyronetide A (1), and three other new derivatives peyronetides B–D (24), as well as one known compound (5) were purified from the cultured broth of the endophytic fungus Peyronellaea sp. FT431, which was isolated from the Hawaiian indigenous plant, Verbena sp. The structures of the new compounds were determined through the analysis of HRMS and NMR spectroscopic data. Compounds 1, 2, and 5 showed cytotoxic activities against TK-10 (human kidney adenocarcinoma cells), cisplatin sensitive A2780S (human ovarian carcinoma cells), and cisplatin resistant A2780CisR cell lines, with IC50 values between 6.7 to 29.2 μM. Full article
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Open AccessArticle Protective Effect of Phenolic Compounds Isolated from Mugwort (Artemisia argyi) against Contrast-Induced Apoptosis in Kidney Epithelium Cell Line LLC-PK1
Molecules 2019, 24(1), 195; https://doi.org/10.3390/molecules24010195
Received: 26 November 2018 / Revised: 3 January 2019 / Accepted: 3 January 2019 / Published: 7 January 2019
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Abstract
We investigated whether 14 phenolic compounds isolated from Artemisia argyi could prevent the apoptotic damage caused by iodixanol, an iodinated contrast agent, on LLC-PK1 cells. Iodixanol was used to induce cytotoxicity in LLC-PK1 cells. Apoptotic cell death was observed as the fluorescence intensity
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We investigated whether 14 phenolic compounds isolated from Artemisia argyi could prevent the apoptotic damage caused by iodixanol, an iodinated contrast agent, on LLC-PK1 cells. Iodixanol was used to induce cytotoxicity in LLC-PK1 cells. Apoptotic cell death was observed as the fluorescence intensity emitted by annexin V and Hoechst 33342 stains. Western blotting was used to detect specific proteins. Seven phenolic compounds protected against iodixanol-induced LLC-PK1 cell death in a concentration-dependent manner. Among them, methyl caffeate exerted the strongest protective effect, and co-treatment with 50 and 100 μM methyl caffeate decreased intracellular reactive oxygen species elevated by 25 mg/mL iodixanol. In addition, the treatment of LLC-PK1 cells with iodixanol resulted in an increase in apoptotic cell death, which decreased by co-treatment with methyl caffeate. Iodixanol caused a cytotoxicity-related increase in the phosphorylation of extracellular-signal-regulated kinase, c-Jun N-terminal kinase, and P38; and a similar increase in the expression levels of kidney injury molecule-1 and cleaved caspase-3. However, the up-regulation of these proteins was reversed by co-treatment with methyl caffeate. These findings suggest that phenolic compounds isolated from A. argyi play an important role in protecting kidney epithelium cells against apoptotic damage caused by iodixanol. Full article
(This article belongs to the Special Issue The Potential Use of Herbal Medicinal Products in Chronic Disorders)
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Open AccessCorrection Correction: Cho, K.H., et al. Blood pressure Lowering Effect of Cuban Policosanol is Accompanied by Improvement of Hepatic Inflammation, Lipoprotein profile, and HDL Quality in Spontaneously Hypertensive Rats. Molecules 2018, 23, 1080
Molecules 2019, 24(1), 194; https://doi.org/10.3390/molecules24010194
Received: 13 December 2018 / Accepted: 24 December 2018 / Published: 7 January 2019
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Abstract
The authors wish to make the following correction to their paper [...] Full article
(This article belongs to the Section Medicinal Chemistry)
Open AccessReview Anti-Cancer Effects of Green Tea Polyphenols Against Prostate Cancer
Molecules 2019, 24(1), 193; https://doi.org/10.3390/molecules24010193
Received: 22 October 2018 / Revised: 3 January 2019 / Accepted: 3 January 2019 / Published: 7 January 2019
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Abstract
Prostate cancer is the most common cancer among men. Green tea consumption is reported to play an important role in the prevention of carcinogenesis in many types of malignancies, including prostate cancer; however, epidemiological studies show conflicting results regarding these anti-cancer effects. In
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Prostate cancer is the most common cancer among men. Green tea consumption is reported to play an important role in the prevention of carcinogenesis in many types of malignancies, including prostate cancer; however, epidemiological studies show conflicting results regarding these anti-cancer effects. In recent years, in addition to prevention, many investigators have shown the efficacy and safety of green tea polyphenols and combination therapies with green tea extracts and anti-cancer agents in in vivo and in vitro studies. Furthermore, numerous studies have revealed the molecular mechanisms of the anti-cancer effects of green tea extracts. We believe that improved understanding of the detailed pathological roles at the molecular level is important to evaluate the prevention and treatment of prostate cancer. Therefore, in this review, we present current knowledge regarding the anti-cancer effects of green tea extracts in the prevention and treatment of prostate cancer, with a particular focus on the molecular mechanisms of action, such as influencing tumor growth, apoptosis, androgen receptor signaling, cell cycle, and various malignant behaviors. Finally, the future direction for the use of green tea extracts as treatment strategies in patients with prostate cancer is introduced. Full article
(This article belongs to the collection Natural Products: Anticancer Potential and Beyond)
Open AccessArticle Thiophene Derivatives as Anticancer Agents and Their Delivery to Tumor Cells Using Albumin Nanoparticles
Molecules 2019, 24(1), 192; https://doi.org/10.3390/molecules24010192
Received: 27 November 2018 / Revised: 27 December 2018 / Accepted: 29 December 2018 / Published: 6 January 2019
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Abstract
A series of thiophene derivatives (TPs) were synthesized and evaluated for cytotoxicity in HepG2 and SMMC-7721 cell lines by MTT assay. TP 5 was identified as a potential anticancer agent based on its ability to inhibit tumor cell growth. Drawbacks of TPs, including
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A series of thiophene derivatives (TPs) were synthesized and evaluated for cytotoxicity in HepG2 and SMMC-7721 cell lines by MTT assay. TP 5 was identified as a potential anticancer agent based on its ability to inhibit tumor cell growth. Drawbacks of TPs, including poor solubility and high toxicity, were overcome through delivery using self-assembling HSA nanoparticles (NPs). The optimum conditions for TP 5-NPs synthesis obtained by adjusting the temperature and concentration of TP 5. The NPs had an encapsulation efficiency of 99.59% and drug-loading capacity of 3.70%. TP 5 was slowly released from TP 5-NPs in vitro over 120 h. HepG2 and SMMC-7721 cell lines were employed to study cytotoxicity of TP 5-NPs, which exhibited high potency. ROS levels were elevated and mitochondrial membrane potentials reversed when the two cell lines were treated with TP 5-NPs for 12 h. Cellular uptake of fluorescence-labeled TP 5-NPs in vitro was analyzed by flow cytometry and laser confocal scanning microscopy. Fluorescence intensity increased over time, suggesting that TP 5-NPs were efficiently taken up by tumor cells. In conclusion, TP 5-NPs showed great promise as an anticancer therapeutic agent. Full article
(This article belongs to the Special Issue Application of Novel Method in Pharmaceutical Study)
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Open AccessArticle Synthesis and Antifungal Potential of Some Novel Benzimidazole-1,3,4-Oxadiazole Compounds
Molecules 2019, 24(1), 191; https://doi.org/10.3390/molecules24010191
Received: 5 December 2018 / Revised: 24 December 2018 / Accepted: 30 December 2018 / Published: 6 January 2019
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Abstract
Discovery of novel anticandidal agents with clarified mechanisms of action, could be a rationalist approach against diverse pathogenic fungal strains due to the rise of resistance to existing drugs. In support to this hypothesis, in this paper, a series of benzimidazole-oxadiazole compounds were
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Discovery of novel anticandidal agents with clarified mechanisms of action, could be a rationalist approach against diverse pathogenic fungal strains due to the rise of resistance to existing drugs. In support to this hypothesis, in this paper, a series of benzimidazole-oxadiazole compounds were synthesized and subjected to antifungal activity evaluation. In vitro activity assays indicated that some of the compounds exhibited moderate to potent antifungal activities against tested Candida species when compared positive control amphotericin B and ketoconazole. The most active compounds 4h and 4p were evaluated in terms of inhibitory activity upon ergosterol biosynthesis by an LC-MS-MS method and it was determined that they inhibited ergosterol synthesis concentration dependently. Docking studies examining interactions between most active compounds and lanosterol 14-α-demethylase also supported the in vitro results. Full article
(This article belongs to the Special Issue Recent Advances in Nitrogen-Containing Aromatic Heterocycles)
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Open AccessArticle Effects of Hydrogen Sulfide on Carbohydrate Metabolism in Obese Type 2 Diabetic Rats
Molecules 2019, 24(1), 190; https://doi.org/10.3390/molecules24010190
Received: 9 December 2018 / Revised: 27 December 2018 / Accepted: 29 December 2018 / Published: 6 January 2019
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Abstract
Hydrogen sulfide (H2S) is involved in the pathophysiology of type 2 diabetes. Inhibition and stimulation of H2S synthesis has been suggested to be a potential therapeutic approach for type 2 diabetes. The aim of this study was therefore to
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Hydrogen sulfide (H2S) is involved in the pathophysiology of type 2 diabetes. Inhibition and stimulation of H2S synthesis has been suggested to be a potential therapeutic approach for type 2 diabetes. The aim of this study was therefore to determine the effects of long-term sodium hydrosulfide (NaSH) administration as a H2S releasing agent on carbohydrate metabolism in type 2 diabetic rats. Type 2 diabetes was established using high fat-low dose streptozotocin. Rats were treated for 9 weeks with intraperitoneal injections of NaSH (0.28, 0.56, 1.6, 2.8, and 5.6 mg/kg). Serum glucose was measured weekly for one month and then at the end of the study. Serum insulin was measured before and after the treatment. At the end of the study, glucose tolerance, pyruvate tolerance and insulin secretion were determined and blood pressure was measured. In diabetic rats NaSH at 1.6–5.6 mg/kg increased serum glucose (11%, 28%, and 51%, respectively) and decreased serum insulin, glucose tolerance, pyruvate tolerance and in vivo insulin secretion. In controls, NaSH only at 5.6 mg/kg increased serum glucose and decreased glucose tolerance, pyruvate tolerance and insulin secretion. Chronic administration of NaSH in particular at high doses impaired carbohydrate metabolism in type 2 diabetic rats. Full article
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Open AccessArticle Synthesis of diN-Substituted Glycyl-Phenylalanine Derivatives by Using Ugi Four Component Reaction and Their Potential as Acetylcholinesterase Inhibitors
Molecules 2019, 24(1), 189; https://doi.org/10.3390/molecules24010189
Received: 24 November 2018 / Revised: 25 December 2018 / Accepted: 28 December 2018 / Published: 6 January 2019
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Abstract
Ugi four component reaction (Ugi-4CR) isocyanide-based multicomponent reactions were used to synthesize diN-substituted glycyl-phenylalanine (diNsGF) derivatives. All of the synthesized compounds were characterized by spectroscopic and spectrometric techniques. In order to evaluate potential biological applications, the synthesized compounds were tested in computational models
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Ugi four component reaction (Ugi-4CR) isocyanide-based multicomponent reactions were used to synthesize diN-substituted glycyl-phenylalanine (diNsGF) derivatives. All of the synthesized compounds were characterized by spectroscopic and spectrometric techniques. In order to evaluate potential biological applications, the synthesized compounds were tested in computational models that predict the bioactivity of organic molecules by using only bi-dimensional molecular information. The diNsGF derivatives were predicted as cholinesterase inhibitors. Experimentally, all of the synthesized diNsGF derivatives showed moderate inhibitory activities against acetylcholinesterase (AChE) and poor activities against butyrylcholinesterase (BuChE). Compound 7a has significant activity and selectivity against AChE, which reveals that the diNsGF scaffold could be improved to reach novel candidates by combining other chemical components of the Ugi-4CR in a high-throughput combinatorial screening experiment. Molecular docking experiments of diNsGF derivatives inside AChE suggest that these compounds placed the phenylalanine group at the peripheral site of AChE. The orientations and chemical interactions of diNsGF derivatives were analyzed, and the changeable groups were identified for future exploration of novel candidates that could lead to the improvement of diNsGF derivative inhibitory activities. Full article
(This article belongs to the Special Issue Design and Synthesis of Bioactive Compounds)
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Open AccessArticle Discorhabdin N, a South African Natural Compound, for Hsp72 and Hsc70 Allosteric Modulation: Combined Study of Molecular Modeling and Dynamic Residue Network Analysis
Molecules 2019, 24(1), 188; https://doi.org/10.3390/molecules24010188
Received: 1 December 2018 / Revised: 1 January 2019 / Accepted: 2 January 2019 / Published: 6 January 2019
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Abstract
The human heat shock proteins (Hsps), predominantly Hsp72 and Hsp90, have been strongly implicated in various critical stages of oncogenesis and progression of human cancers. While drug development has extensively focused on Hsp90 as a potential anticancer target, much less effort has been
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The human heat shock proteins (Hsps), predominantly Hsp72 and Hsp90, have been strongly implicated in various critical stages of oncogenesis and progression of human cancers. While drug development has extensively focused on Hsp90 as a potential anticancer target, much less effort has been put against Hsp72. This work investigated the therapeutic potential of Hsp72 and its constitutive isoform, Hsc70, via in silico-based screening against the South African Natural Compounds Database (SANCDB). A comparative modeling approach was used to obtain nearly full-length 3D structures of the closed conformation of Hsp72 and Hsc70 proteins. Molecular docking of SANCDB compounds identified one potential allosteric modulator, Discorhabdin N, binding to the allosteric β substrate binding domain (SBDβ) back pocket, with good binding affinities in both cases. This allosteric region was identified in one of our previous studies. Subsequent all-atom molecular dynamics simulations and free energy calculations exhibited promising protein–ligand association characteristics, indicative of strong binding qualities. Further, we utilised dynamic residue network analysis (DRN) to highlight protein regions actively involved in cross-domain communication. Most residues identified agreed with known allosteric signal regulators from literature, and were further investigated for the purpose of deducing meaningful insights into the allosteric modulation properties of Discorhabdin N. Full article
(This article belongs to the Section Natural Products Chemistry)
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Open AccessArticle Triterpenoids from Cyclocarya paliurus that Enhance Glucose Uptake in 3T3-L1 Adipocytes
Molecules 2019, 24(1), 187; https://doi.org/10.3390/molecules24010187
Received: 8 December 2018 / Revised: 26 December 2018 / Accepted: 30 December 2018 / Published: 6 January 2019
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Abstract
Four previously undescribed compounds, including three rarely occurring seco-dammarane triterpenoid glycosides and a pentacyclic triterpenic acid, were isolated from a 70% ethanol extract of the leaves of Cyclocarya paliurus (Juglandaceae), along with eleven known triterpenoids. Their structures were determined by spectroscopic techniques,
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Four previously undescribed compounds, including three rarely occurring seco-dammarane triterpenoid glycosides and a pentacyclic triterpenic acid, were isolated from a 70% ethanol extract of the leaves of Cyclocarya paliurus (Juglandaceae), along with eleven known triterpenoids. Their structures were determined by spectroscopic techniques, including 2D NMR and HRESIMS, as well as chemical methods. Among them, several triterpenoids enhanced insulin stimulated glucose uptake in both 3T3-L1 adipocytes and C2C12 myotubes. Furthermore, compound 1 dose-dependently increased glucose uptake through activating AMP-activated protein kinase (AMPK)-p38 pathway. Collectively, triterpenoids from C. paliurus could be developed as insulin sensitizers, which might have therapeutic potential for insulin resistance and hyperglycemia. Full article
(This article belongs to the Special Issue Natural Products in Prevention and Treatment of Metabolic Syndrome)
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Open AccessReview Vibrational Approach to the Dynamics and Structure of Protein Amyloids
Molecules 2019, 24(1), 186; https://doi.org/10.3390/molecules24010186
Received: 13 December 2018 / Revised: 31 December 2018 / Accepted: 2 January 2019 / Published: 6 January 2019
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Abstract
Amyloid diseases, including neurodegenerative diseases such as Alzheimer’s and Parkinson’s, are linked to a poorly understood progression of protein misfolding and aggregation events that culminate in tissue-selective deposition and human pathology. Elucidation of the mechanistic details of protein aggregation and the structural features
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Amyloid diseases, including neurodegenerative diseases such as Alzheimer’s and Parkinson’s, are linked to a poorly understood progression of protein misfolding and aggregation events that culminate in tissue-selective deposition and human pathology. Elucidation of the mechanistic details of protein aggregation and the structural features of the aggregates is critical for a comprehensive understanding of the mechanisms of protein oligomerization and fibrillization. Vibrational spectroscopies, such as Fourier transform infrared (FTIR) and Raman, are powerful tools that are sensitive to the secondary structure of proteins and have been widely used to investigate protein misfolding and aggregation. We address the application of the vibrational approaches in recent studies of conformational dynamics and structural characteristics of protein oligomers and amyloid fibrils. In particular, introduction of isotope labelled carbonyl into a peptide backbone, and incorporation of the extrinsic unnatural amino acids with vibrational moieties on the side chain, have greatly expanded the ability of vibrational spectroscopy to obtain site-specific structural and dynamic information. The applications of these methods in recent studies of protein aggregation are also reviewed. Full article
(This article belongs to the Special Issue Vibrational Probes of Biomolecular Structure and Dynamics)
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Open AccessArticle Chemical Eustress Elicits Tailored Responses and Enhances the Functional Quality of Novel Food Perilla frutescens
Molecules 2019, 24(1), 185; https://doi.org/10.3390/molecules24010185
Received: 21 December 2018 / Accepted: 29 December 2018 / Published: 6 January 2019
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Abstract
Consumer demand for fresh and functional horticultural products is on the rise. Perilla frutescens, L. Britt (Lamiaceae) is a potential specialty/niche crop for consumption and therapeutic uses with high contents of phenolic and volatile compounds. Plant growth, mineral composition, polyphenol
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Consumer demand for fresh and functional horticultural products is on the rise. Perilla frutescens, L. Britt (Lamiaceae) is a potential specialty/niche crop for consumption and therapeutic uses with high contents of phenolic and volatile compounds. Plant growth, mineral composition, polyphenol profile and aroma volatile components of two perilla genotypes in response to salinity (non-salt control, 10, 20 or 30 mM NaCl) applied as chemical eustressor were assessed. Salinity suppressed growth and yield of both genotypes, although the red-pigmented genotype was less sensitive than the green-pigmented one. Mild (10 mM NaCl) and moderate (20 and 30 mM NaCl) salinity suppressed foliar potassium, magnesium, nitrate and chlorophyll a concentrations of both genotypes and increased the levels of rosmarinic acid, total polyphenols and target aroma volatile components. Green perilla showed higher yield and biomass production and higher content of protein, dry matter, calcium, magnesium, perilla ketone and cis-jasmone, whereas red perilla exhibited higher content of potassium, chlorophyll a, rosmarinic acid, total polyphenols, perilla aldehyde and benzaldehyde. Our findings support that chemical eustressors such as mild to moderate salinity offer valuable means to manipulate phytochemical and aroma profiles. Full article
(This article belongs to the collection Bioactive Compounds)
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