Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Molecules, Volume 22, Issue 10 (October 2017)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
Cover Story (view full-size image) Isolation and purification of low molecular weight proteins and peptides (potential biomarkers) [...] Read more.
View options order results:
result details:
Displaying articles 1-225
Export citation of selected articles as:
Open AccessArticle Design of Novel, Water Soluble and Highly Luminescent Europium Labels with Potential to Enhance Immunoassay Sensitivities
Molecules 2017, 22(10), 1807; https://doi.org/10.3390/molecules22101807
Received: 29 September 2017 / Revised: 17 October 2017 / Accepted: 19 October 2017 / Published: 24 October 2017
Cited by 1 | PDF Full-text (1682 KB) | HTML Full-text | XML Full-text
Abstract
To meet the continual demands of more-sensitive immunoassays, the synthesis of novel luminescent Eu(III) chelate labels having similar substituted 4-(phenylethynyl)pyridine chromophores in three different chelate structure classes are reported. Significantly enhanced luminescence intensities were obtained, evidently caused by the intra-ligand charge transfer (ILCT)
[...] Read more.
To meet the continual demands of more-sensitive immunoassays, the synthesis of novel luminescent Eu(III) chelate labels having similar substituted 4-(phenylethynyl)pyridine chromophores in three different chelate structure classes are reported. Significantly enhanced luminescence intensities were obtained, evidently caused by the intra-ligand charge transfer (ILCT) mediated sensitization, but the alternative ligands triplet state process cannot be ruled out. Based on the present study, even quite small changes on the chelate structure, and, especially, on the substituents’ donor/acceptor strength on both ends of 4-(phenylethynyl)pyridine subunits have an unpredictable effect on the luminescence. The highest observed brightness was 16,400 M−1cm−1 in solution and 69,500 M−1cm−1 on dry surface, being 3.4 and 8.7 fold higher compared to the reference chelate. The new label chelates provide solutions for improved assay sensitivity up-to tenfold from the present concepts. Full article
(This article belongs to the Special Issue Lanthanide Luminescence: Fundamental Research and Applications)
Figures

Figure 1

Open AccessArticle Enhanced Glucose Uptake in Human Liver Cells and Inhibition of Carbohydrate Hydrolyzing Enzymes by Nordic Berry Extracts
Molecules 2017, 22(10), 1806; https://doi.org/10.3390/molecules22101806
Received: 19 September 2017 / Revised: 18 October 2017 / Accepted: 19 October 2017 / Published: 24 October 2017
PDF Full-text (453 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A Western lifestyle with low physical activity and a diet rich in sugar, fat and processed food contribute to higher incidences of diabetes and obesity. Enhanced glucose uptake in human liver cells was observed after treatment with phenolic extracts from different Nordic berries.
[...] Read more.
A Western lifestyle with low physical activity and a diet rich in sugar, fat and processed food contribute to higher incidences of diabetes and obesity. Enhanced glucose uptake in human liver cells was observed after treatment with phenolic extracts from different Nordic berries. All berry extracts showed higher inhibition against α-amylase and α-glucosidase than the anti-diabetic agent acarbose. Total phenolic content and phenolic profiles in addition to antioxidant activities, were also investigated. The berries were extracted with 80% methanol on an accelerated solvent extraction system (ASE) and then purified by C-18 solid phase extraction (SPE). Among the ASE methanol extracts, black chokeberry, crowberry and elderberry extracts showed high stimulation of glucose uptake in HepG2 cells and also considerable inhibitory effect towards carbohydrate hydrolyzing enzymes. SPE extracts with higher concentrations of phenolics, resulted in increased glucose uptake and enhanced inhibition of α-amylase and α-glucosidase compared to the ASE extracts. Crowberry and cloudberry were the most potent 15-lipoxygenase inhibitors, while bog whortleberry and lingonberry were the most active xanthine oxidase inhibitors. These results increase the value of these berries as a component of a healthy Nordic diet and have a potential benefit against diabetes. Full article
(This article belongs to the collection Bioactive Compounds)
Figures

Graphical abstract

Open AccessArticle Dermaseptin-PH: A Novel Peptide with Antimicrobial and Anticancer Activities from the Skin Secretion of the South American Orange-Legged Leaf Frog, Pithecopus (Phyllomedusa) hypochondrialis
Molecules 2017, 22(10), 1805; https://doi.org/10.3390/molecules22101805
Received: 7 September 2017 / Revised: 17 October 2017 / Accepted: 22 October 2017 / Published: 24 October 2017
Cited by 2 | PDF Full-text (5073 KB) | HTML Full-text | XML Full-text
Abstract
The dermaseptin peptides, mainly derived from the skin secretions of Hylidae frogs, belong to a superfamily of antimicrobial peptides and exhibit diverse antimicrobial and anticancer activities with low cytotoxicity. Here, we reported a novel dermaseptin peptide, from the South American orange-legged leaf frogs,
[...] Read more.
The dermaseptin peptides, mainly derived from the skin secretions of Hylidae frogs, belong to a superfamily of antimicrobial peptides and exhibit diverse antimicrobial and anticancer activities with low cytotoxicity. Here, we reported a novel dermaseptin peptide, from the South American orange-legged leaf frogs, Pithecopus (Phyllomedusa) hypochondrialis, processing the shortest peptide length, namely Dermaseptin-PH. The complementary DNA (cDNA) encoding biosynthetic precursor of Dermaseptin-PH was initially identified by the rapid amplification of cDNA ends PCR (RACE-PCR) technique from the skin secretion. The predicted primary structure was confirmed by a combination of reverse-phase high performance liquid chromatography (RP-HPLC) and MS/MS fragmentation from the skin secretion. Chemically-synthetic Dermaseptin-PH was investigated using a range of bioactivity assessment assays to evaluate the biological activities and cytotoxicity of Dermaseptin-PH. Dermaseptin-PH inhibited the growth of Gram-negative bacteria, Gram-positive bacteria, and pathogenic yeast Candida albicans. In addition, Dermaseptin-PH showed a broad-spectrum of anticancer activities against several cancer cell lines including MCF-7, H157, U251MG, MDA-MB-435S, and PC-3. The potent antimicrobial and anticancer activities of Dermaseptin-PH make it a promising candidate in the discovery of new drugs for clinical applications, and the relatively short sequence of Dermaseptin-PH can provide new insight for the research and structural modification of new peptide drugs. Full article
(This article belongs to the Special Issue Bioactive Natural Peptides As A Pipeline For Therapeutics)
Figures

Figure 1

Open AccessArticle Single Actin Bundle Rheology
Molecules 2017, 22(10), 1804; https://doi.org/10.3390/molecules22101804
Received: 20 September 2017 / Revised: 17 October 2017 / Accepted: 19 October 2017 / Published: 24 October 2017
Cited by 1 | PDF Full-text (1869 KB) | HTML Full-text | XML Full-text
Abstract
Bundled actin structures play an essential role in the mechanical response of the actin cytoskeleton in eukaryotic cells. Although responsible for crucial cellular processes, they are rarely investigated in comparison to single filaments and isotropic networks. Presenting a highly anisotropic structure, the determination
[...] Read more.
Bundled actin structures play an essential role in the mechanical response of the actin cytoskeleton in eukaryotic cells. Although responsible for crucial cellular processes, they are rarely investigated in comparison to single filaments and isotropic networks. Presenting a highly anisotropic structure, the determination of the mechanical properties of individual bundles was previously achieved through passive approaches observing bending deformations induced by thermal fluctuations. We present a new method to determine the bending stiffness of individual bundles, by measuring the decay of an actively induced oscillation. This approach allows us to systematically test anisotropic, bundled structures. Our experiments revealed that thin, depletion force-induced bundles behave as semiflexible polymers and obey the theoretical predictions determined by the wormlike chain model. Thickening an individual bundle by merging it with other bundles enabled us to study effects that are solely based on the number of involved filaments. These thicker bundles showed a frequency-dependent bending stiffness, a behavior that is inconsistent with the predictions of the wormlike chain model. We attribute this effect to internal processes and give a possible explanation with regard to the wormlike bundle theory. Full article
(This article belongs to the Special Issue Natural Polymers and Biopolymers)
Figures

Figure 1

Open AccessArticle Association, Distribution, Liberation, and Rheological Balances of Alkyldimethylbenzylammonium Chlorides (C12–C16)
Molecules 2017, 22(10), 1802; https://doi.org/10.3390/molecules22101802
Received: 6 September 2017 / Revised: 20 October 2017 / Accepted: 21 October 2017 / Published: 24 October 2017
PDF Full-text (2228 KB) | HTML Full-text | XML Full-text
Abstract
It is known that cationic surfactants have an antimicrobial effect and act as enhancers. This paper studies three cationic surfactants from the group of alkyldimethylbenzylammonium chlorides (dodecyl-, tetradecyl-, and hexadecyl). Interest is focused on the association of the surfactants with respect to temperature,
[...] Read more.
It is known that cationic surfactants have an antimicrobial effect and act as enhancers. This paper studies three cationic surfactants from the group of alkyldimethylbenzylammonium chlorides (dodecyl-, tetradecyl-, and hexadecyl). Interest is focused on the association of the surfactants with respect to temperature, partition balances and their influence on drug release, rheological properties, and the pH of hydrogels. The critical micelle concentrations (CMC) of the surfactants were estimated from dependencies of conductivity, density, spectrofluorimetry, and UV–VIS spectrophotometry on molarity in the temperature range of 25–50 °C. It was found that the temperature dependence of a CMC is U-shaped, with its minimum at 30 °C, and the CMC value decreases as the length of the chain increases. The pseudo-phase separation model was used for the calculation of various thermodynamic parameters, such as the Gibbs free energies (spontaneous process), enthalpies (exothermic process), and entropies of the micelles’ formation, CMCs, and the degree of counterion binding. All thermodynamic parameters, as functions of the temperature, were estimated. It was found that partition coefficients increase as the length of the alkyl chain and the pH = (5.0–7.0) increase. The influences of surfactants, below and above the CMC, on drug (chlorhexidine dihydrochloride) release from hydrogels, rheological properties, and pH at 30 °C were studied. Also, the amounts of the released drug increase as the alkyl chains of the surfactants prolongate. The amounts of the released drug with the surfactant below the CMC are greater than that above the CMC. All hydrogels (regardless of the length of the alkyl chain) exhibit a non-Newtonian pseudo-plastic flow. The results obtained will be used in the formulation of the drug and surfactants into dosage forms. Full article
Figures

Figure 1a

Open AccessArticle GC-MS Profiling of Volatile Components in Different Fermentation Products of Cordyceps Sinensis Mycelia
Molecules 2017, 22(10), 1800; https://doi.org/10.3390/molecules22101800
Received: 17 September 2017 / Revised: 16 October 2017 / Accepted: 20 October 2017 / Published: 24 October 2017
PDF Full-text (1472 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The fermentation products of Cordyceps sinensis (C. sinensis) mycelia are sustainable substitutes for natural C. sinensis. However, the volatile compositions of the commercial products are still unclear. In this paper, we have developed a simultaneous distillation-extraction (SDE) and gas chromatography-mass
[...] Read more.
The fermentation products of Cordyceps sinensis (C. sinensis) mycelia are sustainable substitutes for natural C. sinensis. However, the volatile compositions of the commercial products are still unclear. In this paper, we have developed a simultaneous distillation-extraction (SDE) and gas chromatography-mass spectrometry (GC-MS) method for the profiling of volatile components in five fermentation products. A total of 64, 39, 56, 52, and 44 components were identified in the essential oils of Jinshuibao capsule (JSBC), Bailing capsule (BLC), Zhiling capsule (ZLC), Ningxinbao capsule (NXBC), and Xinganbao capsule (XGBC), respectively. 5,6-Dihydro-6-pentyl-2H-pyran-2-one (massoia lactone) was first discovered as the dominant component in JSBC volatiles. Fatty acids including palmitic acid (C16:0) and linoleic acid (C18:2) were also found to be major volatile compositions of the fermentation products. The multivariate partial least squares-discriminant analysis (PLS-DA) showed a clear discrimination among the different commercial products as well as the counterfeits. This study may provide further chemical evidences for the quality evaluation of the fermentation products of C. sinensis mycelia. Full article
Figures

Graphical abstract

Open AccessArticle Equol, a Clinically Important Metabolite, Inhibits the Development and Pathogenicity of Magnaporthe oryzae, the Causal Agent of Rice Blast Disease
Molecules 2017, 22(10), 1799; https://doi.org/10.3390/molecules22101799
Received: 28 September 2017 / Revised: 16 October 2017 / Accepted: 18 October 2017 / Published: 24 October 2017
PDF Full-text (5037 KB) | HTML Full-text | XML Full-text
Abstract
Equol, a metabolite of soybean isoflavone daidzein, has been proven to have various bioactivities related to human health, but little is known on its antifungal activity to plant fungal pathogens. Magnaporthe oryzae is a phytopathogenic fungus that causes rice blast, a devastating disease
[...] Read more.
Equol, a metabolite of soybean isoflavone daidzein, has been proven to have various bioactivities related to human health, but little is known on its antifungal activity to plant fungal pathogens. Magnaporthe oryzae is a phytopathogenic fungus that causes rice blast, a devastating disease on rice. Here, we demonstrated that equol influences the development and pathogenicity of M. oryzae. Equol showed a significant inhibition to the mycelial growth, conidial generation and germination, and appressorial formation of M. oryzae. As a result, equol greatly reduced the virulence of M. oryzae on rice and barley leaves. The antifungal activity of equol was also found in several other plant fungal pathogens. These findings expand our knowledge on the bioactivities of equol. Full article
(This article belongs to the collection Bioactive Compounds)
Figures

Figure 1a

Open AccessReview Pharmabiotics as an Emerging Medication for Metabolic Syndrome and Its Related Diseases
Molecules 2017, 22(10), 1795; https://doi.org/10.3390/molecules22101795
Received: 31 August 2017 / Revised: 17 October 2017 / Accepted: 20 October 2017 / Published: 24 October 2017
Cited by 1 | PDF Full-text (613 KB) | HTML Full-text | XML Full-text
Abstract
Metabolic syndrome (MetS) is a cluster of metabolic risk factors associated with central obesity, hyperglycemia, insulin resistance, dyslipidemia and high blood pressure. In recent decades, because of the remarkable increase in both prevalence and severity, MetS and its related diseases such as cardiovascular
[...] Read more.
Metabolic syndrome (MetS) is a cluster of metabolic risk factors associated with central obesity, hyperglycemia, insulin resistance, dyslipidemia and high blood pressure. In recent decades, because of the remarkable increase in both prevalence and severity, MetS and its related diseases such as cardiovascular diseases (CVDs), obesity, hypertension and diabetes have become the main global burden and challenge in strategic management involving prevention and treatment. However, currently, the preventions and treatments based on pharmaceutical interventions do not provide a solution for MetS and its related diseases. Recently, gut microbiota showed clear evidence of preventing and/or treating MetS, shedding light on treating MetS and its related diseases through a completely different approach. In this review, we will interpret the effects of current pharmaceutical drugs used in preventing and treating MetS and its related diseases to understand remaining issues of those interventions. We will explore the possibility of developing gut microbiota as pharmabiotics in a completely new medication option for treating MetS and its related diseases. Full article
(This article belongs to the Special Issue Bioactive Compounds for Metabolic Syndrome and Type 2 Diabetes)
Figures

Figure 1

Open AccessArticle Ni(II) Complexes with Schiff Base Ligands: Preparation, Characterization, DNA/Protein Interaction and Cytotoxicity Studies
Molecules 2017, 22(10), 1772; https://doi.org/10.3390/molecules22101772
Received: 14 September 2017 / Accepted: 16 October 2017 / Published: 24 October 2017
Cited by 3 | PDF Full-text (5276 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
In this study, two Ni(II) complexes, namely [Ni(HL1)2(OAc)2] (1) and [Ni(L2)2] (2) (where HL1 and HL2 are (E)-1-((1-(2-hydroxyethyl)-1H-pyrazol-5-ylimino)methyl)-naphthalen-2-ol) and (E)-ethyl-5-((2-hydroxynaphthalen-1-yl)methyleneamino)-1-methyl-1H-pyrazole-4-carboxylate, respectively), were synthesized and characterized
[...] Read more.
In this study, two Ni(II) complexes, namely [Ni(HL1)2(OAc)2] (1) and [Ni(L2)2] (2) (where HL1 and HL2 are (E)-1-((1-(2-hydroxyethyl)-1H-pyrazol-5-ylimino)methyl)-naphthalen-2-ol) and (E)-ethyl-5-((2-hydroxynaphthalen-1-yl)methyleneamino)-1-methyl-1H-pyrazole-4-carboxylate, respectively), were synthesized and characterized by X-ray crystallography, Electrospray Ionization Mass Spectrometry (ESI-MS), elemental analysis, and IR. Their uptake in biological macromolecules and cancer cells were preliminarily investigated through electronic absorption (UV-Vis), circular dichroism (CD) and fluorescence quenching measurements. Bovine serum albumin (BSA) interaction experiments were investigated by spectroscopy which showed that the complexes and ligands could quench the intrinsic fluorescence of BSA through an obvious static quenching process. The spectroscopic studies indicated that these complexes could bind to DNA via groove, non-covalent, and electrostatic interactions. Furthermore, in vitro methyl thiazolyl tetrazolium (MTT) assays and Annexin V/PI flow cytometry experiments were performed to assess the antitumor capacity of the complexes against eight cell lines. The results show that both of the complexes possess reasonable cytotoxicities. Full article
(This article belongs to the Special Issue Metal Complexes of Biological Ligands)
Figures

Figure 1

Open AccessArticle Synthesis and Antitumor Activity of Triazole-Containing Sorafenib Analogs
Molecules 2017, 22(10), 1759; https://doi.org/10.3390/molecules22101759
Received: 20 September 2017 / Revised: 13 October 2017 / Accepted: 15 October 2017 / Published: 24 October 2017
Cited by 1 | PDF Full-text (1661 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Using a highly effective binuclear Cu complex as the catalyst, the 1,3-dipolar cycloaddition reactions between 16 alkynes and two azides were successfully performed and resulted in the production of 25 new triazole-containing sorafenib analogs. Several compounds were evaluated as potent antitumor agents. Among
[...] Read more.
Using a highly effective binuclear Cu complex as the catalyst, the 1,3-dipolar cycloaddition reactions between 16 alkynes and two azides were successfully performed and resulted in the production of 25 new triazole-containing sorafenib analogs. Several compounds were evaluated as potent antitumor agents. Among them, 4-(4-(4-(3-fluorophenyl)-1H-1,2,3-triazol-1-yl)phenoxy)-N-methylpicolinamide (8f) potently suppressed the proliferation of HT-29 cancer cells by inducing apoptosis and almost completely inhibited colony formation at a low micromolar concentration. Full article
Figures

Graphical abstract

Open AccessArticle Molecular Affinity of Mabolo Extracts to an Octopamine Receptor of a Fruit Fly
Molecules 2017, 22(10), 1677; https://doi.org/10.3390/molecules22101677
Received: 5 September 2017 / Revised: 22 September 2017 / Accepted: 24 September 2017 / Published: 24 October 2017
PDF Full-text (896 KB) | HTML Full-text | XML Full-text
Abstract
Essential oils extracted from plants are composed of volatile organic compounds that can affect insect behavior. Identifying the active components of the essential oils to their biochemical target is necessary to design novel biopesticides. In this study, essential oils extracted from Diospyros discolor
[...] Read more.
Essential oils extracted from plants are composed of volatile organic compounds that can affect insect behavior. Identifying the active components of the essential oils to their biochemical target is necessary to design novel biopesticides. In this study, essential oils extracted from Diospyros discolor (Willd.) were analyzed using gas chromatography mass spectroscopy (GC-MS) to create an untargeted metabolite profile. Subsequently, a conformational ensemble of the Drosophila melanogaster octopamine receptor in mushroom bodies (OAMB) was created from a molecular dynamics simulation to resemble a flexible receptor for docking studies. GC-MS analysis revealed the presence of several metabolites, i.e. mostly aromatic esters. Interestingly, these aromatic esters were found to exhibit relatively higher binding affinities to OAMB than the receptor’s natural agonist, octopamine. The molecular origin of this observed enhanced affinity is the π -stacking interaction between the aromatic moieties of the residues and ligands. This strategy, computational inspection in tandem with untargeted metabolomics, may provide insights in screening the essential oils as potential OAMB inhibitors. Full article
Figures

Graphical abstract

Open AccessArticle Pharmacological Effects of Two Novel Bombesin-Like Peptides from the Skin Secretions of Chinese Piebald Odorous Frog (Odorrana schmackeri) and European Edible Frog (Pelophylax kl. esculentus) on Smooth Muscle
Molecules 2017, 22(10), 1798; https://doi.org/10.3390/molecules22101798
Received: 24 September 2017 / Revised: 17 October 2017 / Accepted: 21 October 2017 / Published: 23 October 2017
PDF Full-text (1731 KB) | HTML Full-text | XML Full-text
Abstract
Bombesin-like peptides, which were identified from a diversity of amphibian skin secretions, have been demonstrated to possess several biological functions such as stimulation of smooth muscle contraction and regulation of food intake. Here, we report two novel bombesin-like peptides, bombesin-OS and bombesin-PE, which
[...] Read more.
Bombesin-like peptides, which were identified from a diversity of amphibian skin secretions, have been demonstrated to possess several biological functions such as stimulation of smooth muscle contraction and regulation of food intake. Here, we report two novel bombesin-like peptides, bombesin-OS and bombesin-PE, which were isolated from Odorrana schmackeri and Pelophylax kl. esculentus, respectively. The mature peptides were identified and structurally confirmed by high performance Scliquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Subsequently, the effects of these purified chemically-synthetic peptides on smooth muscle were determined in bladder, uterus, and ileum. The synthetic replications were revealed to have significant pharmacological effects on these tissues. The EC50 values of bombesin-OS for bladder, uterus and ileum, were 10.8 nM, 33.64 nM, and 12.29 nM, respectively. Furthermore, compared with bombesin-OS, bombesin-PE showed similar contractile activity on ileum smooth muscle and uterus smooth muscle, but had a higher potency on bladder smooth muscle. The EC50 value of bombesin-OS for bladder was around 1000-fold less than that of bombesin-PE. This suggests that bombesin-OS and bombesin-PE have unique binding properties to their receptors. The precursor of bombesin-OS was homologous with that of a bombesin-like peptide, odorranain-BLP-5, and bombesin-PE belongs to the ranatensin subfamily. We identified the structure of bombesin-OS and bombesin-PE, two homologues peptides whose actions may provide a further clue in the classification of ranid frogs, also in the provision of new drugs for human health. Full article
(This article belongs to the Special Issue Bioactive Natural Peptides As A Pipeline For Therapeutics)
Figures

Figure 1

Open AccessArticle Ureidopyrazine Derivatives: Synthesis and Biological Evaluation as Anti-Infectives and Abiotic Elicitors
Molecules 2017, 22(10), 1797; https://doi.org/10.3390/molecules22101797
Received: 29 September 2017 / Revised: 18 October 2017 / Accepted: 20 October 2017 / Published: 23 October 2017
PDF Full-text (1658 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) has become a frequently deadly infection due to increasing antimicrobial resistance. This serious issue has driven efforts worldwide to discover new drugs effective against Mtb. One research area is the synthesis and evaluation
[...] Read more.
Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) has become a frequently deadly infection due to increasing antimicrobial resistance. This serious issue has driven efforts worldwide to discover new drugs effective against Mtb. One research area is the synthesis and evaluation of pyrazinamide derivatives as potential anti-TB drugs. In this paper we report the synthesis and biological evaluations of a series of ureidopyrazines. Compounds were synthesized by reacting alkyl/aryl isocyanates with aminopyrazine or with propyl 5-aminopyrazine-2-carboxylate. Reactions were performed in pressurized vials using a CEM Discover microwave reactor with a focused field. Purity and chemical structures of products were assessed, and the final compounds were tested in vitro for their antimycobacterial, antibacterial, and antifungal activities. Propyl 5-(3-phenylureido)pyrazine-2-carboxylate (compound 4, MICMtb = 1.56 μg/mL, 5.19 μM) and propyl 5-(3-(4-methoxyphenyl)ureido)pyrazine-2-carboxylate (compound 6, MICMtb = 6.25 μg/mL, 18.91 μM) had high antimycobacterial activity against Mtb H37Rv with no in vitro cytotoxicity on HepG2 cell line. Therefore 4 and 6 are suitable for further structural modifications that might improve their biological activity and physicochemical properties. Based on the structural similarity to 1-(2-chloropyridin-4-yl)-3-phenylurea, a known plant growth regulator, two selected compounds were evaluated for similar activity as abiotic elicitors. Full article
Figures

Figure 1

Open AccessReview Cyclodipeptides: An Overview of Their Biosynthesis and Biological Activity
Molecules 2017, 22(10), 1796; https://doi.org/10.3390/molecules22101796
Received: 27 September 2017 / Revised: 18 October 2017 / Accepted: 19 October 2017 / Published: 23 October 2017
Cited by 2 | PDF Full-text (1239 KB) | HTML Full-text | XML Full-text
Abstract
Cyclodipeptides (CDP) represent a diverse family of small, highly stable, cyclic peptides that are produced as secondary functional metabolites or side products of protein metabolism by bacteria, fungi, and animals. They are widespread in nature, and exhibit a broad variety of biological and
[...] Read more.
Cyclodipeptides (CDP) represent a diverse family of small, highly stable, cyclic peptides that are produced as secondary functional metabolites or side products of protein metabolism by bacteria, fungi, and animals. They are widespread in nature, and exhibit a broad variety of biological and pharmacological activities. CDP synthases (CDPSs) and non-ribosomal peptide synthetases (NRPSs) catalyze the biosynthesis of the CDP core structure, which is further modified by tailoring enzymes often associated with CDP biosynthetic gene clusters. In this review, we provide a comprehensive summary of CDP biosynthetic pathways and modifying enzymes. We also discuss the biological properties of some known CDPs and their possible applications in metabolic engineering. Full article
Figures

Figure 1

Open AccessArticle Silver Nanoparticles Stabilised by Cationic Gemini Surfactants with Variable Spacer Length
Molecules 2017, 22(10), 1794; https://doi.org/10.3390/molecules22101794
Received: 30 September 2017 / Revised: 18 October 2017 / Accepted: 18 October 2017 / Published: 23 October 2017
PDF Full-text (8082 KB) | HTML Full-text | XML Full-text
Abstract
The present study is focused on the synthesis and investigation of the physicochemical and biological properties of silver nanoparticles stabilized with a series of cationic gemini surfactants having a polymethylene spacer of variable length. UV-VIS spectroscopy, dynamic light scattering, scanning electron microscopy and
[...] Read more.
The present study is focused on the synthesis and investigation of the physicochemical and biological properties of silver nanoparticles stabilized with a series of cationic gemini surfactants having a polymethylene spacer of variable length. UV-VIS spectroscopy, dynamic light scattering, scanning electron microscopy and zeta potential measurements were applied to provide physicochemical characterization of the silver nanoparticles. The mean size values of the nanoparticles were found to be in the 50 to 115 nm range. From the nanoparticle size distributions and scanning electron microscopy images it results that a population of small nanoparticles with the size of several nanometers was confirmed if the nanoparticles were stabilized with gemini molecules with either a short methylene spacer (two or four −CH2− groups) or a long spacer (12 −CH2− groups). The average zeta potential value for silver nanoparticles stabilized with gemini molecules is roughly independent of gemini surfactant spacer length and is approx. +58 mV. An interaction model between silver nanoparticles and gemini molecules which reflects the gained experimental data, is suggested. Microbicidal activity determinations revealed that the silver nanoparticles stabilized with gemini surfactants are more efficient against Gram-negative bacteria and yeasts, which has a direct relation to the interaction mechanism of nanoparticles with the bacterial cell membrane and its structural composition. Full article
Figures

Graphical abstract

Back to Top