bluuebunny/crossref_metadata_2025 huggingface dataset:
The Azide-Allene Dipolar Cycloaddition: Is DFT Able to Predict Site- and Regio-Selectivity?
Authors: Molteni Giorgio , Ponti Alessandro
Published: February 2021

The site- and regio-selectivity of thermal, uncatalysed 1,3-dipolar cycloadditions between arylazides and mono- or tetra-substituted allenes with different electronic features have been investigated by both conceptual (reactivity indices) and computational (M08-HX, ωB97X-D, and B3LYP) DFT approaches. Both approaches show that these cycloadditions follow a nonpolar one-step mechanism. The experimental site- and regio-selectivity of arylazides towards methoxycarbonyl- and sulfonyl-allenes as well as tetramethyl- and tetrafluoro-allenes was calculated by DFT transition state calculations, achieving semiquantitative agreement to both previous and novel experimental findings. From the mechanistic standpoint, 1H-NMR evidence of a methylene-1,2,3-triazoline intermediate reinforces the reliability of the computational scheme.
Cu-Doped ZnO Nanoparticles for Non-Enzymatic Glucose Sensing
Authors: Mahmoud Amira , Echabaane Mosaab , Omri Karim , Boudon Julien , Saviot Lucien , Millot Nadine , Chaabane Rafik Ben
Published: February 2021

Copper-doped zinc oxide nanoparticles (NPs) CuxZn1−xO (x = 0, 0.01, 0.02, 0.03, and 0.04) were synthesized via a sol-gel process and used as an active electrode material to fabricate a non-enzymatic electrochemical sensor for the detection of glucose. Their structure, composition, and chemical properties were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared (FTIR) and Raman spectroscopies, and zeta potential measurements. The electrochemical characterization of the sensors was studied using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and differential pulse voltammetry (DPV). Cu doping was shown to improve the electrocatalytic activity for the oxidation of glucose, which resulted from the accelerated electron transfer and greatly improved electrochemical conductivity. The experimental conditions for the detection of glucose were optimized: a linear dependence between the glucose concentration and current intensity was established in the range from 1 nM to 100 μM with a limit of detection of 0.7 nM. The proposed sensor exhibited high selectivity for glucose in the presence of various interfering species. The developed sensor was also successfully tested for the detection of glucose in human serum samples.
HR-MAS NMR Applications in Plant Metabolomics
Authors: Augustijn Dieuwertje , de Groot Huub J. M. , Alia A.
Published: February 2021

Metabolomics is used to reduce the complexity of plants and to understand the underlying pathways of the plant phenotype. The metabolic profile of plants can be obtained by mass spectrometry or liquid-state NMR. The extraction of metabolites from the sample is necessary for both techniques to obtain the metabolic profile. This extraction step can be eliminated by making use of high-resolution magic angle spinning (HR-MAS) NMR. In this review, an HR-MAS NMR-based workflow is described in more detail, including used pulse sequences in metabolomics. The pre-processing steps of one-dimensional HR-MAS NMR spectra are presented, including spectral alignment, baseline correction, bucketing, normalisation and scaling procedures. We also highlight some of the models which can be used to perform multivariate analysis on the HR-MAS NMR spectra. Finally, applications of HR-MAS NMR in plant metabolomics are described and show that HR-MAS NMR is a powerful tool for plant metabolomics studies.
Moisture Resistance, Thermal Stability and Fire Behavior of Unsaturated Polyester Resin Modified with L-histidinium Dihydrogen Phosphate-Phosphoric Acid
Authors: Sałasińska Kamila , Celiński Maciej , Mizera Kamila , Barczewski Mateusz , Kozikowski Paweł , Leszczyński Michał K. , Domańska Agata
Published: February 2021

In this paper, the fire behavior of unsaturated polyester resin (UP) modified with L-histidinium dihydrogen phosphate-phosphoric acid (LHP), being a novel intumescent fire retardant (IFR), was investigated. Thermal and thermomechanical properties of the UP with different amounts of LHP (from 10 to 30 wt. %) were determined by thermogravimetric analysis (TG) as well as dynamic mechanical thermal analysis (DMTA). Reaction to small flames was studied by horizontal burning (HB) test, while fire behavior and smoke emission were investigated with the cone calorimeter (CC) and smoke density chamber. Further, the analysis of volatile products was conducted (TGA/FT-IR). It was observed that the addition of LHP resulted in the formation of carbonaceous char inhibiting the thermal decomposition, burning rate and smoke emission. The most promising results were obtained for the UP containing 30 wt. % of LHP, for which the highest reduction in maximum values of heat release rate (200 kW/m2) and total smoke release (3535 m2/m2) compared to unmodified polymer (792 kW/m2 and 6895 m2/m2) were recorded. However, some important disadvantage with respect to water resistance was observed.
Selective Cytotoxicity of Piperine over Multidrug Resistance Leukemic Cells
Authors: Quarti Julia , Torres Daianne N. M. , Ferreira Erika , Vidal Raphael S. , Casanova Fabiana , Chiarini Luciana B. , Fialho Eliane , Rumjanek Vivian M.
Published: February 2021

Multidrug resistance (MDR) is the main challenge in the treatment of chronic myeloid leukemia (CML), and P-glycoprotein (P-gp) overexpression is an important mechanism involved in this resistance process. However, some compounds can selectively affect MDR cells, inducing collateral sensitivity (CS), which may be dependent on P-gp. The aim of this study was to investigate the effect of piperine, a phytochemical from black pepper, on CS induction in CML MDR cells, and the mechanisms involved. The results indicate that piperine induced CS, being more cytotoxic to K562-derived MDR cells (Lucena-1 and FEPS) than to K562, the parental CML cell. CS was confirmed by analysis of cell metabolic activity and viability, cell morphology and apoptosis. P-gp was partially required for CS induction. To investigate a P-gp independent mechanism, we analyzed the possibility that poly (ADP-ribose) polymerase-1 (PARP-1) could be involved in piperine cytotoxic effects. It was previously shown that only MDR FEPS cells present a high level of 24 kDa fragment of PARP-1, which could protect these cells against cell death. In the present study, piperine was able to decrease the 24 kDa fragment of PARP-1 in MDR FEPS cells. We conclude that piperine targets selectively MDR cells, inducing CS, through a mechanism that might be dependent or not on P-gp.
Chemical and Pharmacological Potential of Coccoloba cowellii, an Endemic Endangered Plant from Cuba
Authors: Méndez Daniel , Escalona-Arranz Julio C. , Foubert Kenn , Matheeussen An , Van der Auwera Anastasia , Piazza Stefano , Cuypers Ann , Cos Paul , Pieters Luc
Published: February 2021

Coccoloba cowellii Britton (Polygonaceae) is an endemic and critically endangered plant that only grows in Camagüey, a province of Cuba. In this study, a total of 13 compounds were identified in a methanolic leaf extract, employing a dereplication of the UHPLC-HRMS data by means of feature-based molecular networking (FBMN) analysis in the Global Natural Products Social Molecular Network (GNPS), together with the interpretation of the MS/MS data and comparison with the literature. The major constituents were glucuronides and glycosides of myricetin and quercetin, as well as epichatechin-3-O-gallate, catechin, epicatechin and gallic acid, all of them being reported for the first time in C. cowellii leaves. The leaf extract was also tested against various microorganisms, and it showed a strong antifungal effect against Candida albicans ATCC B59630 (azole-resistant) (IC50 2.1 µg/mL) and Cryptococcus neoformans ATCC B66663 (IC50 4.1 µg/mL) with no cytotoxicity (CC50 > 64.0 µg/mL) on MRC-5 SV2 cells, determined by the resazurin assay. Additionally, the extract strongly inhibited COX-1 and COX-2 enzyme activity using a cell-free experiment in a dose-dependent manner, being significantly more active on COX-1 (IC50 4.9 µg/mL) than on COX-2 (IC50 10.4 µg/mL). The constituents identified as well as the pharmacological activities measured highlight the potential of C. cowellii leaves, increasing the interest in the implementation of conservation strategies for this species.
Field-Template, QSAR, Ensemble Molecular Docking, and 3D-RISM Solvation Studies Expose Potential of FDA-Approved Marine Drugs as SARS-CoVID-2 Main Protease Inhibitors
Authors: Kalhotra Poonam , Chittepu Veera C. S. R. , Osorio-Revilla Guillermo , Gallardo-Velazquez Tzayhri
Published: February 2021

Currently, SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) has infected people among all countries and is a pandemic as declared by the World Health Organization (WHO). SARS-CoVID-2 main protease is one of the therapeutic drug targets that has been shown to reduce virus replication, and its high-resolution 3D structures in complex with inhibitors have been solved. Previously, we had demonstrated the potential of natural compounds such as serine protease inhibitors eventually leading us to hypothesize that FDA-approved marine drugs have the potential to inhibit the biological activity of SARS-CoV-2 main protease. Initially, field-template and structure–activity atlas models were constructed to understand and explain the molecular features responsible for SARS-CoVID-2 main protease inhibitors, which revealed that Eribulin Mesylate, Plitidepsin, and Trabectedin possess similar characteristics related to SARS-CoVID-2 main protease inhibitors. Later, protein–ligand interactions are studied using ensemble molecular-docking simulations that revealed that marine drugs bind at the active site of the main protease. The three-dimensional reference interaction site model (3D-RISM) studies show that marine drugs displace water molecules at the active site, and interactions observed are favorable. These computational studies eventually paved an interest in further in vitro studies. Finally, these findings are new and indeed provide insights into the role of FDA-approved marine drugs, which are already in clinical use for cancer treatment as a potential alternative to prevent and treat infected people with SARS-CoV-2.
An Approach to the Use of Glycol Alkoxysilane–Polysaccharide Hybrids in the Conservation of Historical Building Stones
Authors: Meléndez-Zamudio Miguel , Bravo-Flores Ileana , Ramírez-Oliva Eulalia , Guerra-Contreras Antonio , Álvarez-Guzmán Gilberto , Zárraga-Nuñez Ramón , Villegas Antonio , Martínez-Rosales Merced , Cervantes Jorge
Published: February 2021

Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic media. In the search for a “greener” alternative based on silicon that has potential use in this field, the use of tetrakis(2-hydroxyethyl)silane (THEOS) and tris(2-hydroxyethyl)methyl silane (MeTHEOS) as precursors, due their high water solubility and stability, is proposed in this paper. It is already known that THEOS and MeTHEOS possess remarkable compatibility with different natural polysaccharides. The investigated approach uses the water-soluble silanes THEOS–chitosan and MeTHEOS–chitosan as a basis for obtaining hybrid consolidants and hydrophobic formulations for the conservation of siliceous and calcareous stones. In the case of calcareous systems, their incompatibility with alkoxysilanes is known and is expected to be solved by the developed hybrid consolidant. Their application in the conservation of building stones from historical and archeological sites from Guanajuato, México was studied. The evaluation of the consolidant and hydrophobic formulation treatment was mainly conducted by determining the mechanical properties and contact angle measurements with satisfactory results in terms of the performance and compatibility with the studied stones.
A New Photoactivatable Ruthenium(II) Complex with an Asymmetric Bis-Thiocarbohydrazone: Chemical and Biological Investigations
Authors: Pioli Marianna , Orsoni Nicolò , Scaccaglia Mirco , Alinovi Rossella , Pinelli Silvana , Pelosi Giorgio , Bisceglie Franco
Published: February 2021

The synthesis, photoactivation and biological activity of a new piano-stool Ru(II) complex is herein reported. The peculiarity of this complex is that its monodentate ligand which undergoes the photodissociation is an asymmetric bis-thiocarbohydrazone ligand that possesses a pyridine moiety binding to Ru(II) and the other moiety contains a quinoline that endows the ligand with the capacity of chelating other metal ions. In this way, upon dissociation, the ligand can be released in the form of a metal complex. In this article, the double ability of this new Ru(II) complex to photorelease the ligand and to chelate copper and nickel is explored and confirmed. The biological activity of this compound is studied in cell line A549 revealing that, after irradiation, proliferation inhibition is reached at very low half maximal inhibitory concentration (IC50) values. Further, biological assays reveal that the dinuclear complex containing Ni is internalized in cells.
Isolation of Industrial Important Bioactive Compounds from Microalgae
Authors: Balasubramaniam Vimala , Gunasegavan Rathi Devi-Nair , Mustar Suraiami , Lee June Chelyn , Mohd Noh Mohd Fairulnizal
Published: February 2021

Microalgae are known as a rich source of bioactive compounds which exhibit different biological activities. Increased demand for sustainable biomass for production of important bioactive components with various potential especially therapeutic applications has resulted in noticeable interest in algae. Utilisation of microalgae in multiple scopes has been growing in various industries ranging from harnessing renewable energy to exploitation of high-value products. The focuses of this review are on production and the use of value-added components obtained from microalgae with current and potential application in the pharmaceutical, nutraceutical, cosmeceutical, energy and agri-food industries, as well as for bioremediation. Moreover, this work discusses the advantage, potential new beneficial strains, applications, limitations, research gaps and future prospect of microalgae in industry.
A Molecular Tetrahedral Cobalt–Seleno-Based Complex as an Efficient Electrocatalyst for Water Splitting
Authors: Abdullahi Ibrahim Munkaila , Masud Jahangir , Ioannou Polydoros-Chrisovalantis , Ferentinos Eleftherios , Kyritsis Panayotis , Nath Manashi
Published: February 2021

The cobalt–seleno-based coordination complex, [Co{(SePiPr2)2N}2], is reported with respect to its catalytic activity in oxygen evolution and hydrogen evolution reactions (OER and HER, respectively) in alkaline solutions. An overpotential of 320 and 630 mV was required to achieve 10 mA cm−2 for OER and HER, respectively. The overpotential for OER of this CoSe4-containing complex is one of the lowest that has been observed until now for molecular cobalt(II) systems, under the reported conditions. In addition, this cobalt–seleno-based complex exhibits a high mass activity (14.15 A g−1) and a much higher turn-over frequency (TOF) value (0.032 s−1) at an overpotential of 300 mV. These observations confirm analogous ones already reported in the literature pertaining to the potential of molecular cobalt–seleno systems as efficient OER electrocatalysts.
A Rationale for Drug Design Provided by Co-Crystal Structure of IC261 in Complex with Tubulin
Authors: Xian Jinghong , Bu Faqian , Wang Yuxi , Long Fangyi , Zhang Zhixiong , Wu Chengyong , Tao Yiran , Wang Ting , Wang Guan
Published: February 2021

Microtubules composed of α/β tubulin heterodimers are an essential part of the cytoskeleton of eukaryotic cells and are widely regarded as targets for cancer chemotherapy. IC261, which is discovered as an ATP-competitive inhibitor of serine/threonine-specific casein kinase 1 (CK1), has shown its inhibitory activity on microtubule polymerization in recent studies. However, the structural information of the interaction between tubulin and IC261 is still unclear. Here, we provided a high-resolution (2.85 Å) crystal structure of tubulin and IC261 complex, revealed the intermolecular interaction between tubulin and IC261, and analyzed the structure–activity relationship (SAR). Subsequently, the structure of tubulin-IC261 complex was compared with tubulin-colchicine complex to further elucidate the novelty of IC261. Furthermore, eight optimal candidate compounds of new IC261-based microtubule inhibitors were obtained through molecular docking studies. In conclusion, the co-crystal structure of tubulin-IC261 complex paves a way for the design and development of microtubule inhibitor drugs.
Antihyperglycemic and Lipid Profile Effects of Salvia amarissima Ortega on Streptozocin-Induced Type 2 Diabetic Mice
Authors: Solares-Pascasio Jesus Ivan , Ceballos Guillermo , Calzada Fernando , Barbosa Elizabeth , Velazquez Claudia
Published: February 2021

Salvia amarissima Ortega was evaluated to determinate its antihyperglycemic and lipid profile properties. Petroleum ether extract of fresh aerial parts of S. amarissima (PEfAPSa) and a secondary fraction (F6Sa) were evaluated to determine their antihyperglycemic activity in streptozo-cin-induced diabetic (STID) mice, in oral tolerance tests of sucrose, starch, and glucose (OSTT, OStTT, and OGTT, respectively), in terms of glycated hemoglobin (HbA1c), triglycerides (TG), and high-density lipoprotein (HDL). In acute assays at doses of 50 mg/kg body weight (b.w.), PEfAPSa and F6Sa showed a reduction in hyperglycemia in STID mice, at the first and fifth hour after of treatment, respectively, and were comparable with acarbose. In the sub-chronic test, PEfAPSa and F6Sa showed a reduction of glycemia since the first week, and the effect was greater than that of the acarbose control group. In relation to HbA1c, the treatments prevented the increase in HbA1c. In the case of TG and HDL, PEfAPSa and F6Sa showed a reduction in TG and an HDL increase from the second week. OSTT and OStTT showed that PEfAPSa and F6Sa significantly lowered the postprandial peak at 1 h after loading but only in sucrose or starch such as acarbose. The results suggest that S. amarissima activity may be mediated by the inhibition of disaccharide hydrolysis, which may be associated with an α-glucosidase inhibitory effect.
Single Molecule Characterization of Amyloid Oligomers
Authors: Yang Jie , Perrett Sarah , Wu Si
Published: February 2021

The misfolding and aggregation of polypeptide chains into β-sheet-rich amyloid fibrils is associated with a wide range of neurodegenerative diseases. Growing evidence indicates that the oligomeric intermediates populated in the early stages of amyloid formation rather than the mature fibrils are responsible for the cytotoxicity and pathology and are potentially therapeutic targets. However, due to the low-populated, transient, and heterogeneous nature of amyloid oligomers, they are hard to characterize by conventional bulk methods. The development of single molecule approaches provides a powerful toolkit for investigating these oligomeric intermediates as well as the complex process of amyloid aggregation at molecular resolution. In this review, we present an overview of recent progress in characterizing the oligomerization of amyloid proteins by single molecule fluorescence techniques, including single-molecule Förster resonance energy transfer (smFRET), fluorescence correlation spectroscopy (FCS), single-molecule photobleaching and super-resolution optical imaging. We discuss how these techniques have been applied to investigate the different aspects of amyloid oligomers and facilitate understanding of the mechanism of amyloid aggregation.
Structural Determination, Biological Function, and Molecular Modelling Studies of Sulfoaildenafil Adulterated in Herbal Dietary Supplement
Authors: Kodchakorn Kanchanok , Viriyakhasem Nawarat , Wongwichai Tunchanok , Kongtawelert Prachya
Published: February 2021

Unapproved ingredients included in herbal medicines and dietary supplements have been detected as adulterated synthetic drugs used for erectile dysfunction. Extraction from a dietary supplement was performed to isolate the compounds by HPLC analysis. The structural characterization was confirmed using mass spectrometry (ESI-TOF/MS and LC-MS/MS), 1H NMR, and 13C NMR spectroscopy techniques. Results identified the thus-obtained compound to be sulfoaildenafil, a thioketone analogue of sildenafil. The biological activities of this active compound have been focused for the first time by the experimental point of view performance in vitro. The results revealed that sulfoaildenafil can affect the therapeutic level of nitric oxide through the upregulation of nitric oxide synthase and phosphodiesterase type 5 (PDE5) gene expressions. This bulk material, which displays structural similarity to sildenafil, was analyzed for the presence of a PDE5 inhibitor using a theoretical calculation. These unique features of the potential activity of PDE5 protein and its inhibitors, sildenafil and sulfoaildenafil, may play a key consideration for understanding the mode of actions and predicting the biological activities of PDE5 inhibitors.
Exceptionally Long Covalent CC Bonds—A Local Vibrational Mode Study
Authors: Delgado Alexis Antoinette Ann , Humason Alan , Kalescky Robert , Freindorf Marek , Kraka Elfi
Published: February 2021

For decades one has strived to synthesize a compound with the longest covalent C−C bond applying predominantly steric hindrance and/or strain to achieve this goal. On the other hand electronic effects have been added to the repertoire, such as realized in the electron deficient ethane radical cation in its D3d form. Recently, negative hyperconjugation effects occurring in diamino-o-carborane analogs such as di-N,N-dimethylamino-o-carborane have been held responsible for their long C−C bonds. In this work we systematically analyzed CC bonding in a diverse set of 53 molecules including clamped bonds, highly sterically strained complexes such as diamondoid dimers, electron deficient species, and di-N,N-dimethylamino-o-carborane to cover the whole spectrum of possibilities for elongating a covalent C−C bond to the limit. As a quantitative intrinsic bond strength measure, we utilized local vibrational CC stretching force constants ka(CC) and related bond strength orders BSO n(CC), computed at the ωB97X-D/aug-cc-pVTZ level of theory. Our systematic study quantifies for the first time that whereas steric hindrance and/or strain definitely elongate a C−C bond, electronic effects can lead to even longer and weaker C−C bonds. Within our set of molecules the electron deficient ethane radical cation, in D3d symmetry, acquires the longest C−C bond with a length of 1.935 Å followed by di-N,N-dimethylamino-o-carborane with a bond length of 1.930 Å. However, the C−C bond in di-N,N-dimethylamino-o-carborane is the weakest with a BSO n value of 0.209 compared to 0.286 for the ethane radical cation; another example that the longer bond is not always the weaker bond. Based on our findings we provide new guidelines for the general characterization of CC bonds based on local vibrational CC stretching force constants and for future design of compounds with long C−C bonds.
Opuntia ficus-indica (L.) Mill.: A Multi-Benefit Potential to Be Exploited
Authors: Silva Mafalda Alexandra , Albuquerque Tânia Gonçalves , Pereira Paula , Ramalho Renata , Vicente Filipa , Oliveira Maria Beatriz P. P. , Costa Helena S.
Published: February 2021

Consumer interest in foods with enhanced nutritional quality has increased in recent years. The nutritional and bioactive characterization of fruits and their byproducts, as well as their use in the formulation of new food products, is advisable, contributing to decrease the global concerns related to food waste and food security. Moreover, the compounds present in these raw materials and the study of their biological properties can promote health and help to prevent some chronic diseases. Opuntia ficus-indica (L.) Mill. (prickly pear) is a plant that grows wild in the arid and semi-arid regions of the world, being a food source for ones and a potential for others, but not properly valued. This paper carries out an exhaustive review of the scientific literature on the nutritional composition and bioactive compounds of prickly pear and its constituents, as well as its main biological activities and applications. It is a good source of dietary fiber, vitamins and bioactive compounds. Many of its natural compounds have interesting biological activities such as anti-inflammatory, hypoglycemic and antimicrobial. The antioxidant power of prickly pear makes it a good candidate as an ingredient of new food products with fascinating properties for health promotion and/or to be used as natural extracts for food, pharmaceutic or cosmetic applications. In addition, it could be a key player in food security in many arid and semi-arid regions of the world, where there are often no more plants.
Construction of Supramolecular Polymers with Different Topologies by Orthogonal Self-Assembly of Cryptand–Paraquat Recognition and Metal Coordination
Authors: Wang Kai , Shao Yuan-Guang , Yan Feng-Zhi , Zhang Zibin , Li Shijun
Published: February 2021

Recently, metal-coordinated orthogonal self-assembly has been used as a feasible and efficient method in the construction of polymeric materials, which can also provide supramolecular self-assembly complexes with different topologies. Herein, a cryptand with a rigid pyridyl group on the third arm derived from BMP32C10 was synthesized. Through coordination-driven self-assembly with a bidentate organoplatinum(II) acceptor or tetradentate Pd(BF4)2•4CH3CN, a di-cryptand complex and tetra-cryptand complex were prepared, respectively. Subsequently, through the addition of a di-paraquat guest, linear and cross-linked supramolecular polymers were constructed through orthogonal self-assembly, respectively. By comparing their proton nuclear magnetic resonance (1H NMR) and diffusion-ordered spectroscopy (DOSY) spectra, it was found that the degrees of polymerization were dependent not only on the concentrations of the monomers but also on the topologies of the supramolecular polymers.
The Role of the Inflammasome in Neurodegenerative Diseases
Authors: Piancone Federica , La Rosa Francesca , Marventano Ivana , Saresella Marina , Clerici Mario
Published: February 2021

Neurodegenerative diseases are chronic, progressive disorders that occur in the central nervous system (CNS). They are characterized by the loss of neuronal structure and function and are associated with inflammation. Inflammation of the CNS is called neuroinflammation, which has been implicated in most neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease (PD), amyotrophic lateral sclerosis (ALS) and multiple sclerosis (MS). Much evidence indicates that these different conditions share a common inflammatory mechanism: the activation of the inflammasome complex in peripheral monocytes and in microglia, with the consequent production of high quantities of the pro-inflammatory cytokines IL-1β and IL-18. Inflammasomes are a group of multimeric signaling complexes that include a sensor Nod-like receptor (NLR) molecule, the adaptor protein ASC, and caspase-1. The NLRP3 inflammasome is currently the best-characterized inflammasome. Multiple signals, which are potentially provided in combination and include endogenous danger signals and pathogens, trigger the formation of an active inflammasome, which, in turn, will stimulate the cleavage and the release of bioactive cytokines including IL-1β and IL-18. In this review, we will summarize results implicating the inflammasome as a pivotal player in the pathogenesis of neurodegenerative diseases and discuss how compounds that hamper the activation of the NLRP3 inflammasome could offer novel therapeutic avenues for these diseases.
The Promising Ability of Humulus lupulus L. Iso-α-acids vs. Diabetes, Inflammation, and Metabolic Syndrome: A Systematic Review
Authors: Ponticelli Maria , Russo Daniela , Faraone Immacolata , Sinisgalli Chiara , Labanca Fabiana , Lela Ludovica , Milella Luigi
Published: February 2021

For centuries, natural medicines have represented the only option for treating human diseases and, nowadays, plant phytochemicals are considered as promising compounds to treat or prevent chronic conditions. Among them, hop flowers (Humulus lupulus L.), typically used in brewing industries to give the typical aroma and flavor to beer, have attracted particular attention for their health promoting properties. Several in vivo/vitro studies and human interventional trials have demonstrated the beneficial effects of these molecules on weight gain, lipid metabolism, glucose homeostasis, insulin sensitivities, and inflammation by acting on different targets. All these activities suggest a possible role of bitter hop acid in preventing metabolic syndrome and its related diseases. A systematic quest on PubMed and Scopus databases was performed to identify pre-clinical and clinical studies focusing on this topic. This systematic review summarizes the results obtained by different cell lines, animal models, and human interventional trials to propose iso-α-acids as medical nutrition therapy to treat or prevent metabolic syndrome and its related disorders as diabetes, dislipidemia inflammation, etc.
Oligonucleotide-Based Approaches to Inhibit Dengue Virus Replication
Authors: Panda Kingshuk , Alagarasu Kalichamy , Parashar Deepti
Published: February 2021

Dengue fever is one of the most common viral infections affecting humans. It is an expanding public health problem, particularly in tropical and subtropical regions. No effective vaccine or antiviral therapies against Dengue virus (DENV) infection are available. Therefore, there is a strong need to develop safe and effective therapeutic strategies that can reduce the burden and duration of hospitalizations due to this life-threatening disease. Oligonucleotide-based strategies are considered as an attractive means of inhibiting viral replication since oligonucleotides can be designed to interact with any viral RNA, provided its sequence is known. The resultant targeted destruction of viral RNA interferes with viral replication without inducing any adverse effects on cellular processes. In this review, we elaborate the ribozymes, RNA interference, CRISPR, aptamer and morpholino strategies for the inhibition of DENV replication and discuss the challenges involved in utilizing such approaches.
Organic Semiconductor Micro/Nanocrystals for Laser Applications
Authors: Álvarez-Conde Javier , García-Frutos Eva M. , Cabanillas-Gonzalez Juan
Published: February 2021

Organic semiconductor micro/nanocrystals (OSMCs) have attracted great attention due to their numerous advantages such us free grain boundaries, minimal defects and traps, molecular diversity, low cost, flexibility and solution processability. Due to all these characteristics, they are strong candidates for the next generation of electronic and optoelectronic devices. In this review, we present a comprehensive overview of these OSMCs, discussing molecular packing, the methods to control crystallization and their applications to the area of organic solid-state lasers. Special emphasis is given to OSMC lasers which self-assemble into geometrically defined optical resonators owing to their attractive prospects for tuning/control of light emission properties through geometrical resonator design. The most recent developments together with novel strategies for light emission tuning and effective light extraction are presented.
Essential Oil Analysis and Antimicrobial Evaluation of Three Aromatic Plant Species Growing in Saudi Arabia
Authors: El-Said Hamdi , Ashgar Sami S. , Bader Ammar , AlQathama Aljawharah , Halwani Majed , Ascrizzi Roberta , Flamini Guido
Published: February 2021

Arabian flora is a rich source of bioactive compounds. In this study, we investigated three aromatic plant species with the aim of finding valuable sources of antimicrobial agents against common pathogenic microorganisms. We focused especially on microorganisms, which cause outbreaks of infectious disease during mass gatherings and pilgrimages season in Saudi Arabia. The essential oils of three aromatic plant species were hydrodistilled from flowering aerial parts of Lavandula pubescens Decne. and Pulicaria incisa subsp. candolleana E.Gamal-Eldin, and from leaves, stems, ripe and unripe fruits of Juniperus procera Hochst. Ex Endl. They were subsequently analyzed by gas chromatography-mass spectrometry (GC-MS). The main constituents of L. pubescens were found to be carvacrol (55.7%), methyl carvacrol (13.4%), and β-bisabolene (9.1%). P. incisa subsp. Candolleana essential oil was rich in linalool (33.0%), chrysanthenone (10.3%), eugenol (8.9%), and cis-chrysanthenol (8.0%); the major components of J. procera essential oil were α-pinene (31.3–62.5%) and δ-3-carene (7.3–30.3%). These essential oils were tested against thirteen American Type Culture Collection (ATCC) strains of Gram-positive and Gram-negative bacteria using the agar diffusion assay. The only effective essential oil was that of L. pubescens and the most sensitive strains were Acinetobacter baumannii, Salmonella typhimurium, Shigella sonnei, Enterococcus faecalis and Staphylococcus epidermidis. Carvacrol, the major constituent of L. pubescens, was tested on these strains and was compared with vancomycin, amikacin, and ciprofloxacin. The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) assays of L. pubescens essential oil and carvacrol revealed that Gram-negative strains were more susceptible than the Gram-positive ones.
Comparative Research of Chemical Profiling in Different Parts of Fissistigma oldhamii by Ultra-High-Performance Liquid Chromatography Coupled with Hybrid Quadrupole-Orbitrap Mass Spectrometry
Authors: Hu Haibo , Lee-Fong Yau , Peng Jinnian , Hu Bin , Li Jialin , Li Yaoli , Huang Hao
Published: February 2021

The roots of Fissistigma oldhamii (FO) are widely used as medicine with the effect of dispelling wind and dampness, promoting blood circulation and relieving pains, and its fruits are considered delicious. However, Hakka people always utilize its above-ground parts as a famous folk medicine, Xiangteng, with significant differences from literatures. Studies of chemical composition showed there were multiple aristolactams that possessed high nephrotoxicity, pending evaluation research about their distribution in FO. In this study, a sensitive, selective, rapid and reliable method was established to comparatively perform qualitative and semi-quantitative analysis of the constituents in roots, stems, leaves, fruits and insect galls, using an Ultra-High-Performance Liquid Chromatography coupled with Hybrid Quadrupole Orbitrap Mass Spectrometry (UPLC-Q-Exactive Orbitrap MS, or Q-Exactive for short). To make more accurate identification and comparison of FO chemicals, all MS data were aligned and screened by XCMS, then their structures were elucidated according to MSn ion fragments between the detected and standards, published ones or these generated by MS fragmenter. A total of 79 compounds were identified, including 33 alkaloids, 29 flavonoids, 11 phenylpropanoids, etc. There were 54 common components in all five parts, while another 25 components were just detected in some parts. Six toxic aristolactams were detected in this experiment, including aristolactam AII, AIIIa, BII, BIII, FI and FII, of which the relative contents in above-ground stems were much higher than roots. Meanwhile, multivariate statistical analysis was performed and showed significant differences both in type and content of the ingredients within all FO parts. The results implied that above-ground FO parts should be carefully valued for oral administration and eating fruits. This study demonstrated that the high-resolution mass spectrometry coupled with multivariate statistical methods was a powerful tool in compound analysis of complicated herbal extracts, and the results provide the basis for its further application, scientific development of quality standard and utilization.
Waterborne Polyurethane Dispersions and Thin Films: Biodegradation and Antimicrobial Behaviors
Authors: Madbouly Samy A.
Published: February 2021

Biodegradable and antimicrobial waterborne polyurethane dispersions (PUDs) and their casted solid films have recently emerged as important alternatives to their solvent-based and non-biodegradable counterparts for various applications due to their versatility, health, and environmental friendliness. The nanoscale morphology of the PUDs, dispersion stability, and the thermomechanical properties of the solid films obtained from the solvent cast process are strongly dependent on several important parameters, such as the preparation method, polyols, diisocyanates, solid content, chain extension, and temperature. The biodegradability, biocompatibility, antimicrobial properties and biomedical applications can be tailored based on the nature of the polyols, polarity, as well as structure and concentration of the internal surfactants (anionic or cationic). This review article provides an important quantitative experimental basis and structure evolution for the development and synthesis of biodegradable waterborne PUDs and their solid films, with prescribed macromolecular properties and new functions, with the aim of understanding the relationships between polymer structure, properties, and performance. The review article will also summarize the important variables that control the thermomechanical properties and biodegradation kinetics, as well as antimicrobial and biocompatibility behaviors of aqueous PUDs and their films, for certain industrial and biomedical applications.
Identification of Mushroom and Murine Tyrosinase Inhibitors from Achillea biebersteinii Afan. Extract
Authors: Strzępek-Gomółka Marcelina , Gaweł-Bęben Katarzyna , Angelis Apostolis , Antosiewicz Beata , Sakipova Zuriyadda , Kozhanova Kaldanay , Głowniak Kazimierz , Kukula-Koch Wirginia
Published: February 2021

Growing scientific evidence indicates that Achillea biebersteinii is a valuable source of active ingredients with potential cosmetic applications. However, the data on its composition and pharmacological properties are still insufficient. This study aims to optimize the extraction procedure of the plant material, evaluate its phytochemical composition, and compare anti-tyrosinase potential of A. biebersteinii extracts obtained by various methods. In order to identify compounds responsible for the tyrosinase inhibitory activity of A. biebersteinii, the most active anti-tyrosinase extract was fractionated by column chromatography. The fractions were examined for their skin lightening potential by mushroom and murine tyrosinase inhibitory assays and melanin release assay. HPLC-ESI-Q-TOF-MS/MS analysis of the total extract revealed the presence of several phenolic acids, flavonoids, flavonoid glucosides, and carboxylic acid. Among them, fraxetin-8-O-glucoside, quercetin-O-glucopyranose, schaftoside/isoschaftoside, gmelinin B, 1,3-dicaffeoylquinic acid (1,3-DCQA), and ferulic acid were found in the fractions with the highest skin lightening potential. Based on obtained qualitative and quantitative analysis of the fractions, it was assumed that the caffeoylquinic acid derivatives and dicaffeoylquinic acid derivatives are more likely responsible for mushroom tyrosinase inhibitory activity of A. biebersteinii extracts and fractions. Ferulic acid was proposed as the most active murine tyrosinase inhibitor, responsible also for the reduced melanin release from B16F10 murine melanoma cells.
Monoterpenes and Sesquiterpenes of Essential Oils from Psidium Species and Their Biological Properties
Authors: Silva Renan Campos e , Costa Jamile S. da , Figueiredo Raphael O. de , Setzer William N. , Silva Joyce Kelly R. da , Maia José Guilherme S. , Figueiredo Pablo Luis B.
Published: February 2021

Psidium (Myrtaceae) comprises approximately 266 species, distributed in tropical and subtropical regions of the world. Psidium taxa have great ecological, economic, and medicinal relevance due to their essential oils’ chemical diversity and biological potential. This review reports 18 Psidium species growing around the world and the chemical and biological properties of their essential oils. Chemically, 110 oil records are reported with significant variability of volatile constituents, according to their seasonality and collection sites. Monoterpenes and sesquiterpenes with acyclic (C10 and C15), p-menthane, pinane, bisabolane, germacrane, caryophyllane, cadinane, and aromadendrane skeleton-types, were the primary constituents. The essential oils showed various biological activities, including antioxidant, antifungal, antibacterial, phytotoxic, larvicidal, anti-inflammatory, and cytotoxic properties. This review contributes to the Psidium species rational and economic exploration as natural sources to produce new drugs.
Zincbindpredict—Prediction of Zinc Binding Sites in Proteins
Authors: Ireland Sam M. , Martin Andrew C. R.
Published: February 2021

Background: Zinc binding proteins make up a significant proportion of the proteomes of most organisms and, within those proteins, zinc performs rôles in catalysis and structure stabilisation. Identifying the ability to bind zinc in a novel protein can offer insights into its functions and the mechanism by which it carries out those functions. Computational means of doing so are faster than spectroscopic means, allowing for searching at much greater speeds and scales, and thereby guiding complimentary experimental approaches. Typically, computational models of zinc binding predict zinc binding for individual residues rather than as a single binding site, and typically do not distinguish between different classes of binding site—missing crucial properties indicative of zinc binding. Methods: Previously, we created ZincBindDB, a continuously updated database of known zinc binding sites, categorised by family (the set of liganding residues). Here, we use this dataset to create ZincBindPredict, a set of machine learning methods to predict the most common zinc binding site families for both structure and sequence. Results: The models all achieve an MCC ≥ 0.88, recall ≥ 0.93 and precision ≥ 0.91 for the structural models (mean MCC = 0.97), while the sequence models have MCC ≥ 0.64, recall ≥ 0.80 and precision ≥ 0.83 (mean MCC = 0.87), with the models for binding sites containing four liganding residues performing much better than this. Conclusions: The predictors outperform competing zinc binding site predictors and are available online via a web interface and a GraphQL API.
Boulton-Katritzky Rearrangement of 5-Substituted Phenyl-3-[2-(morpholin-1-yl)ethyl]-1,2,4-oxadiazoles as a Synthetic Path to Spiropyrazoline Benzoates and Chloride with Antitubercular Properties
Authors: Kayukova Lyudmila , Vologzhanina Anna , Praliyev Kaldybai , Dyusembaeva Gulnur , Baitursynova Gulnur , Uzakova Asem , Bismilda Venera , Chingissova Lyailya , Akatan Kydyrmolla
Published: February 2021

The analysis of stability of biologically active compounds requires an accurate determination of their structure. We have found that 5-aryl-3-(2-aminoethyl)-1,2,4-oxadiazoles are generally unstable in the presence of acids and bases and are rearranged into the salts of spiropyrazolinium compounds. Hence, there is a significant probability that it is the rearranged products that should be attributed to biological activity and not the primarily screened 5-aryl-3-(2-aminoethyl)-1,2,4-oxadiazoles. A series of the 2-amino-8-oxa-1,5-diazaspiro[4.5]dec-1-en-5-ium (spiropyrazoline) benzoates and chloride was synthesized by Boulton–Katritzky rearrangement of 5-substituted phenyl-3-[2-(morpholin-1-yl)ethyl]-1,2,4-oxadiazoles and characterized using FT-IR and NMR spectroscopy and X-ray diffraction. Spiropyrazolylammonium chloride demonstrates in vitro antitubercular activity on DS (drug-sensitive) and MDR (multidrug-resistant) of MTB (M. tuberculosis) strains (1 and 2 µg/mL, accordingly) equal to the activity of the basic antitubercular drug rifampicin; spiropyrazoline benzoates exhibit an average antitubercular activity of 10–100 μg/mL on MTB strains. Molecular docking studies revealed a series of M. tuberculosis receptors with the energies of ligand–receptor complexes (−35.8–−42.8 kcal/mol) close to the value of intermolecular pairwise interactions of the same cation in the crystal of spiropyrazolylammonium chloride (−35.3 kcal/mol). However, only in complex with transcriptional repressor EthR2, both stereoisomers of the cation realize similar intermolecular interactions.
Effect of Concentrated Salts Solutions on the Stability of Immobilized Enzymes: Influence of Inactivation Conditions and Immobilization Protocol
Authors: Braham Sabrina Ait , Siar El-Hocine , Arana-Peña Sara , Carballares Diego , Morellon-Sterling Roberto , Bavandi Hossein , de Andrades Diandra , Kornecki Jakub F. , Fernandez-Lafuente Roberto
Published: February 2021

This paper aims to investigate the effects of some salts (NaCl, (NH4)2SO4 and Na2SO4) at pH 5.0, 7.0 and 9.0 on the stability of 13 different immobilized enzymes: five lipases, three proteases, two glycosidases, and one laccase, penicillin G acylase and catalase. The enzymes were immobilized to prevent their aggregation. Lipases were immobilized via interfacial activation on octyl agarose or on glutaraldehyde-amino agarose beads, proteases on glyoxyl agarose or glutaraldehyde-amino agarose beads. The use of high concentrations of salts usually has some effects on enzyme stability, but the intensity and nature of these effects depends on the inactivation pH, nature and concentration of the salt, enzyme and immobilization protocol. The same salt can be a stabilizing or a destabilizing agent for a specific enzyme depending on its concentration, inactivation pH and immobilization protocol. Using lipases, (NH4)2SO4 generally permits the highest stabilities (although this is not a universal rule), but using the other enzymes this salt is in many instances a destabilizing agent. At pH 9.0, it is more likely to find a salt destabilizing effect than at pH 7.0. Results confirm the difficulty of foreseeing the effect of high concentrations of salts in a specific immobilized enzyme.