Variations In Molecular Structure Research Articles

Bioactivities of Nek Kara (Dillenia excelsa (Jack) Martelli ex. Gilg) leaves from forest medicinal plants of Kutai Ethnic

The utilization of traditional medicine and treatment within the community of Kutai Kartanegara, East Kalimantan, Indonesia is characterized by a wide range of practices. Medicinal plant extracts containing secondary metabolites, possessing diverse molecular structures and biological activities, exhibit promising potential for the development of medicines targeting various diseases. Phenolic compounds, present in plants, exhibit numerous biological effects, including antioxidant and antimicrobial properties. These secondary metabolite compounds play a crucial role in safeguarding against disease-induced damage. Nek Kara (Dillenia excelsa (Jack) Martelli ex. Gilg), a forest plant, has been traditionally employed by the local population for the treatment of diabetes. The objective of this study is to investigate the biological activities of the ethanol extract derived from Nek Kara leaves. The analysis encompasses the examination of phytochemical content, toxicity, as well as antioxidant and antimicrobial activities of the extract. The antioxidant activity is assessed through DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity using a spectrophotometer, while toxicity is determined via the BSLT (Brine Shrimp Lethality Test). The antimicrobial activity is evaluated using the diffusion method. The findings reveal the presence of phytochemical content, such as alkaloids, flavonoids, tannins, and steroids, within the ethanol extract derived from Nek Kara leaves. The BSLT results indicate the absence of toxic bioactivities in the ethanol extract. Furthermore, the Nek Kara leaf extract demonstrates potent antioxidant activity and exhibits inhibitory effects on the growth of bacterial and fungal colonies.

Molecular Hybridization of Alkaloids Using 1,2,3-Triazole-Based Click Chemistry.

Alkaloids found in multiple species, known as 'driver species', are more likely to be included in early-stage drug development due to their high biodiversity compared to rare alkaloids. Many synthetic approaches have been employed to hybridize the natural alkaloids in drug development. Click chemistry is a highly efficient and versatile reaction targeting specific areas, making it a valuable tool for creating complex natural products and diverse molecular structures. It has been used to create hybrid alkaloids that address their limitations and serve as potential drugs that mimic natural products. In this review, we highlight the recent advancements made in modifying alkaloids using click chemistry and their potential medicinal applications. We discuss the significance, current trends, and prospects of click chemistry in natural product-based medicine. Furthermore, we have employed computational methods to evaluate the ADMET properties and drug-like qualities of hybrid molecules.

Exploring separation patterns and mechanisms of proanthocyanidins in grape seeds and pomace with diverse molecular weights, compositions, and structures

The function of proanthocyanidins (PAs) relies on their structure and requires high-purity PAs. Though Sephadex LH-20 gel permeation chromatography (GPC) is expected to separate PAs based on structure, its usage rules and mechanisms remain unclear. This study delves into the PAs separation patterns on Sephadex LH-20, first confirming the purification mechanisms of PAs with various mean degrees of polymerization (DP) using the adsorption kinetic model. The study found that an increase in the molecular weight or mean DP of PAs results in decreased polarity, reduced hydrogen bonding actions, and intensified hydrophobic effect, causing delayed extraction of PAs on Sephadex LH-20, with galloylated PA as an exception, which was extracted first despite its high DP. Additionally, the principles for separating specific composition, such as monomers, dimers, etc., were evaluated. The study sheds light on enhancing the purification efficiency of PAs, thus advancing the precise separation technology of diverse proanthocyanidins.

Covalent Triazine Framework Nanosheets: Synthesis and Energy Conversion and Storage†

Comprehensive SummaryCovalent triazine framework nanosheets (CTF NSs), an emerging class of two‐dimensional nanomaterials, have received great attention due to their abundant active sites, permanent porosity, molecular structural diversity, superior chemical/thermal stability, and short charge diffusion path, enabling technological breakthroughs in a myriad of applications. The forefront developments and applications of CTF NSs as photocatalysts and electrochemical electrodes have conferred superior performance and made great impact in the field of energy and advanced catalysis. This forward‐looking review aims to summarize the research trends, synthesis, properties of CTF NSs and their CTF counterpart, and highlight their progress in applications with respect to energy storage and conversion devices. Finally, the current challenges and future perspectives for CTF NSs are also presented.

Molecular Evolution and Protein Structure Variation of Dkk Family.

Dkks have inhibitory effects on the Wnt signaling pathway, which is involved in the development of skin and its appendages and the regulation of hair growth. The nucleotide sequences were compared and analyzed to further investigate the relationship between the structure and function of the Dkk gene family and vertebrate epidermal hair. The analysis of the molecular evolution of the Dkk family revealed that the evolution rate of the genes changed significantly after speciation, with the Aves and Reptilia branches showing accelerated evolution. Additionally, positive selection was observed at specific sites. The tertiary structure of the protein was also predicted. The analysis of the functional divergence of the Dkk family revealed that the functional divergence coefficient of each gene was greater than 0, with most of the functional divergence sites were located in the Cys-2 domain and a few in the Cys-1 domain. This suggests that the amino acid and functional divergence sites may play a role in regulating the binding of the Dkk family to LRP5/6, and thus affect the inhibition of Wnt signaling, leading to different functions of Dkk1, Dkk2, and Dkk4 in the development of skin hair follicles. In addition, the Dkk families of Aves and Reptilia may have undergone adaptive evolution and functional divergence.

Natural Existence and Bioactivity of Flavonoids: Synthetic Strategies and Mechanistic Pathways

Abstract: A class of chemicals known as flavonoids is widely distributed in various portions of plants, cereals, and vegetables. They have varied phenolic structures and these flavonoid molecules are known for the well-being improvement in living things. Today, a wide range of pharmaceutical, medicinal, & cosmetic materials possessed these key ingredients, known as flavonoids. Flavonoids can modulate the bioactivity of essential enzymes & their properties such as anti-mutagenic, anti-inflammatory, anti-oxidative, & anti-carcinogenic. The current patterns of flavonoid in research & development helps in the identification, isolation, characterization, & functions of flavonoids as well as their applications for better biological activities. In this article, we have discussed the natural existence and structural frameworks of the different classes of potential bioactive flavonoids. In addition to this, different synthetic strategies, and their mechanistic pathways for the preparation of different classes of flavonoids are also discussed thoroughly here. Owing to its tremendous natural existence and bioactivity, more research is still needed to further explore the usefulness of flavonoids for human wellness. The major challenge with the study of such flavonoids is the diversity of molecular structures & scarcity of data on their bioavailability. However, this article will be helpful for understanding the chemical aspect and several potential bioactivities of flavonoids

Electrical conductivity and species distribution of aluminum chloride and 1‐butyl‐3‐methylimidazolium chloride ionic liquid electrolytes

AbstractElectrical conductivity (σ) of aluminum chloride (AlCl3) and 1‐butyl‐3‐methylimidazolium chloride (BMIC) ionic liquid (IL) was investigated as a function of temperature and AlCl3 mole fraction ( ). Electrochemical impedance spectroscopy was used to measure the electrical conductivity. Composition of AlCl3:BMIC ionic liquid was varied by changing the from 0 to 0.67. The temperature was changed from 70°C to 110°C at 10°C intervals. It was found that the electrical conductivity increases with an increase in temperature. Electrical conductivity increases with from 0 to 0.5 and then starts to decrease after = 0.5. A species concentration profile was developed based on thermodynamic model at room temperature for the IL containing , , , , , , and at different . The only anion species presents between 0 and 0.5 are and . Anions like , , , and are found at higher . A good agreement between the model and the experimental data was obtained. The variations in anion concentration, molecular structure, and cation–anion interactions are to be the causes of the changes in electrical conductivity of AlCl3:BMIC system.

Wheat starch particle size distribution regulates the dynamic transition behavior of gluten at different stages of dough mixing

This study investigated the morphology distribution, molecular structure, and aggregative properties variation of gluten protein during dough mixing stage and interpreted the interaction between starch with different sizes and protein. Research results indicated that mixing process induced glutenin macropolymer depolymerization, and promoted the monomeric protein conversion into the polymeric protein. Appropriate mixing (9 min) enhanced the interaction between wheat starch with different particle sizes and gluten protein. Confocal laser scanning microscopy images showed that a moderate increase in B-starch content in the dough system contributed to forming a more continuous, dense, and ordered gluten network. The 50A-50B and 25A-75B doughs mixed for 9 min exhibited a dense gluten network, and the arrangement of A-/B-starch granules and gluten was tight and ordered. The addition of B-starch increased α-helixes, β-turns, and random coil structure. Farinographic properties indicated that 25A-75B composite flour had the highest dough stability time and the lowest degree of softening. The 25A-75B noodle displayed maximum hardness, cohesiveness, chewiness, and tensile strength. The correlation analysis indicated that starch particle size distribution could influence noodle quality by changing the gluten network. The paper can provide theoretical support for regulating dough characteristics by adjusting the starch granule size distribution.

Organic Cathode with Dual-Type Multielectron Reaction Centers for High-Energy-Density Lithium Primary Batteries.

Organic electrode materials are composed of abundant elements, have diverse and designable molecular structures, and are relatively easily synthesized, promising a bright future for low-cost and large-scale energy storage. However, they are facing low specific capacity and low energy density. Herein, we report a high-energy-density organic electrode material, 1,5-dinitroanthraquinone, which is composed of two kinds of electrochemically active sites of nitro and carbonyl groups. They experience six- and four-electron reduction and are transformed into amine and methylene groups, respectively, in the presence of fluoroethylene carbonate (FEC) in the electrolyte. Drastically increased specific capacity and energy density are demonstrated with an ultrahigh specific capacity of 1321 mAh g-1 and a high voltage of ∼2.62 V, corresponding to a high energy density of 3400 Wh kg-1. This surpasses the electrode materials in commercial lithium batteries. Our findings provide an effective strategy to design high-energy-density and novel lithium primary battery systems.

An in vitro analysis of the hemostatic efficacy of fibrinogen precipitation with varied keratin fraction compositions

In preclinical studies, human hair has demonstrated effective hemostatic properties, potentially attributed to keratin proteins facilitating rapid conversion of fibrinogen to fibrin during coagulation. However, the rational use of human hair keratin for hemostasis remains unclear, given its complex mixture of proteins with diverse molecular weights and structures, leading to variable hemostatic capacity. To optimize the rational utilization of human hair keratin for hemostasis, we investigated the effects of different keratin fractions on keratin-mediated fibrinogen precipitation using a fibrin generation assay. Our study focused on high molecular weight keratin intermediate filaments (KIFs) and lower molecular weight keratin-associated proteins (KAPs) combined in various ratios during the fibrin generation. Scanning electron microscope analysis of the precipitates revealed a filamentous pattern with a broad distribution of fiber diameters, likely due to the diversity of keratin mixtures involved. An equal proportion of KIFs and KAPs in the mixture yielded the most extensive precipitation of soluble fibrinogen in an in vitro study, potentially due to structure-induced exposure of active sites. However, all hair protein samples exhibited diverse catalytic behaviors compared to thrombin, highlighting the potential of utilizing specific hair fractions to develop hair protein-based hemostatic materials with optimized capacity.

Diverse Molecular Structures across the Whole Star-forming Disk of M83: High-fidelity Imaging at 40 pc Resolution

We present Atacama Large Millimeter/submillimeter Array (ALMA) imaging of molecular gas across the full star-forming disk of the barred spiral galaxy M83 in CO(J = 1–0). We jointly deconvolve the data from ALMA’s 12 m, 7 m, and Total Power arrays using the MIRIAD package. The data have a mass sensitivity and resolution of 104 M ⊙ (3σ) and 40 pc—sufficient to detect and resolve a typical molecular cloud in the Milky Way with a mass and diameter of 4 × 105 M ⊙ and 40 pc, respectively. The full disk coverage shows that the characteristics of molecular gas change radially from the center to outer disk, with the locally measured brightness temperature, velocity dispersion, and integrated intensity (surface density) decreasing outward. The molecular gas distribution shows coherent large-scale structures in the inner part, including the central concentration, offset ridges along the bar, and prominent molecular spiral arms. However, while the arms are still present in the outer disk, they appear less spatially coherent, and even flocculent. Massive filamentary gas concentrations are abundant even in the interarm regions. Building up these structures in the interarm regions would require a very long time (≳100 Myr). Instead, they must have formed within stellar spiral arms and been released into the interarm regions. For such structures to survive through the dynamical processes, the lifetimes of these structures and their constituent molecules and molecular clouds must be long (≳100 Myr). These interarm structures host little or no star formation traced by Hα. The new map also shows extended CO emission, which likely represents an ensemble of unresolved molecular clouds.

Interfacial dilational rheological behaviors of N-acyl amino acid surfactants: effects of amino acid residues

Amino acid surfactants have attracted increasing interest in recent years. As biological raw materials, amino acids have diverse molecular structures, which grant the derived surfactants various properties. Herein, the effects of N-methyl and polar, nonpolar, and aromatic α-substituents of amino acids on the interfacial behaviors of amino acid surfactants were systematically studied using interfacial dilational rheological experiments. The amide groups in the glycinate surfactant formed hydrogen bonds, which enhanced the intermolecular interactions. In comparison, an extra N-methyl group in sarcosinate surfactants prevented intermolecular hydrogen bonding and thus decreased the interfacial dilational modulus. The nonpolar α-substituents of alaninate and valinate surfactants enhanced the tendency of surfactant molecules to adsorb to the interface, but caused steric repulsion for hydrogen bond formation, which decreased the dilational modulus but promoted the relaxation processes. The polar α-substituents of serinate and threoninate surfactants enhanced the intermolecular hydrogen bonding and slowed down relaxation processes. The aromatic α-substituent in phenylalanate surfactant improved its interfacial activity. Moreover, the phenyl enhanced the intermolecular interactions through NH-π and π-π interactions. As a result, the interfacial dilational modulus was significantly enhanced. The systematic study of the relationship between amino acid structure and the interfacial behaviors of surfactants provides the research basis for the development and application of N-acyl amino acid surfactants.

5-(1-(4-Hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-phenylethyl)-1,3-dimethylpyrimidine-2,4,6(1H,3H,5H)-trione

Multicomponent reactions have been demonstrated as a promising tool for the creation of diverse molecular structures with enhanced efficiency, reduced waste, and a high atom economy. Arylglyoxal monohydrates with two different carbonyl groups are well known as worthwhile synthons in organic synthesis. 2-Pyrone and pyrimidine-2,4,6-trione are versatile building blocks for the synthesis of key intermediates in synthetic organic chemistry as well as in medicinal chemistry. A simple and efficient tandem Knoevenagel–Michael protocol for the synthesis of the previously unknown 5-(1-(4-hydroxy-6-methyl-2-oxo-2H-pyran-3-yl)-2-oxo-2-phenylethyl)-1,3-dimet-hylpyrimidine-2,4,6(1H,3H,5H)-trione was elaborated. The suggested method is based on the multicomponent reaction of phenylglyoxal hydrate, 1,3-dimethylbarbituric acid, and 4-hydroxy-6-methyl-2H-pyran-2-one. The structure of the synthesized compound was proven by 1H, 13C-NMR, and IR spectroscopy, mass spectrometry, and elemental analysis. A procedure for predicting the possible types of its biological activity was carried out for the title compound.

On the Biochemistry and Biophysics of Living Cell Formation.

A description is given of a sequence of events which would have led to the appearance of the organic compounds and living cells present on Earth, one of which is human cells. The evolutionary events involved are proposed as having taken place in phosphate ion-dominated aqueous pools formed in regions associated with volcanoes. The mechanism involved the unique molecular structure variations and chemical properties of polyphosphoric acid and compounds of this acid producing urea as the first organic compound formed on Earth and derivatives of urea giving rise to DNA and RNA. The occurrence of the process in present times is considered possible.

Thermodynamic properties analysis of warm-mix recycled asphalt binders using molecular dynamics simulation

This study aims at investigating the effect of warm-mix recycled on the thermodynamic properties of aged asphalt binders using molecular dynamics simulation. The molecular models of asphalt binders in the virgin, long-term aged, recycled and warm-mix recycled states were developed based on the proportional relationships between the asphalt components as well as oxidation functional indicators. The mean square displacement, molecular radial distribution function and fractional free volume were used to evaluate the molecular structure variations in different asphalt states. Based on this study, it is found that the composite regenerator cannot completely degrade the oxidation functional groups in the aged asphalt, but rather mainly rely on small molecular structures penetrating and filling the intermolecular aggregation spaces of the asphaltene to reduce asphalt brittleness and hardness. The warm mix recycling processes mainly depend on increasing the activity of the lighter components to improve the diffusion properties of the aged asphalt.

Those That Remain: Sorption/Desorption Behaviour and Kinetics of the Neonicotinoids Still in Use

In January 2023, the derogation loophole was closed on "emergency authorisations" for the use of three out of five neonicotinoids in all EU states. In this study, we analysed the sorption/desorption behaviour and kinetic parameters of acetamiprid and thiacloprid, the two neonicotinoids that are still approved for use, either regularly or under emergency authorisations in the EU, and widely used worldwide. Sorption and desorption curves in four soils with different organic matter content were analysed using four kinetic models, namely, Lagergren's pseudo first-order model, two-site model (TSM), Weber-Morris intraparticle diffusion model and Elovich's model. Kinetic parameters were correlated to soil physico-chemical characteristics. To determine the mutual influence of soil characteristics and sorption/desorption parameters in the analysed soils, a factor analysis based on principal component analysis (PCA) was performed. Even though the two insecticides are very similar in size and chemical structure, the results showed different sorption/desorption kinetics. The model that best fits the experimental data was TSM. Thiacloprid showed a more rapid sorption compared to acetamiprid, and, in all soils, a higher proportion sorbed at equilibrium. Intra-particle diffusion seemed to be a relevant process in acetamiprid sorption, but not for thiacloprid. Desorption results showed that acetamiprid is more easily and more thoroughly desorbed than thiacloprid, in all soils. The kinetic behaviour differences stem from variations in molecular structure, causing disparate water solubility, lipophilicity, and acid-base properties.

Prognosis of Biomarker of Alzheimer's Disease in the Function of the Retina and Secondary Molecular Structure Variation of the Retina and Brain.

Alzheimer's disease (AD) is one of the most serious neurodegenerative diseases in the globe. As a result, there is an acute need to discover indications that allow for early disease detection. There is growing scientific data showing the similarities between the eye and other central nervous system components, suggesting that information obtained in ophthalmic research might be valuable in the study and diagnosis of AD. Fifty male albino Wistar rats were separated into five groups: the first group served as control, and the other four groups of animals were administrated aluminium chloride (AlCl3) in a dose of 100 mg/kg body weight (b.w.) for 2, 4, 6, and 8 weeks, respectively. Insights into the function of the retina by electroretinogram (ERG) and the changes thought to have occurred in the molecular structure of the retina and brain using Fourier transform infrared spectroscopy (FTIR) as a result of AD progression induced by AlCl3 in rats were done. Moreover, the measurement of acetylcholinesterase (AchE) was done. After 6 and 8 weeks of AlCl3 injection, there was a substantial reduction (p ≤ 0.05) in a- and b-wave amplitudes and a significant rise (p ≤ 0.05) in implicit time compared to controls. A significant elevation (p ≤ 0.05) of AchE content was observed after 4, 6, and 8 weeks. FTIR revealed a significant increase (p ≤ 0.05) of β-turn and β-sheet content associated with significant decrease (p ≤ 0.05) of α-helix content for all groups administrated with AlCl3. Our findings suggest that retinal biomarkers such as ERG of the retina may be used as a screening tool for detection of AD. Secondary structural changes in the proteins of the retina and the brain were similar in AD rats' model and precede retinal dysfunction.

The Castagnoli-Cushman Reaction.

Since the first reports of the reaction of imines and cyclic anhydrides by Castagnoli and Cushman, this procedure has been applied to the synthesis of a variety of lactams, some of them with important synthetic or biological interest. The scope of the reaction has been extended to the use of various Schiff bases and anhydrides as well as to different types of precursors for these reagents. In recent years, important advances have been made in understanding the mechanism of the reaction, which has historically been quite controversial. This has helped to develop reaction conditions that lead to pure diastereomers and even homochiral products. In addition, these mechanistic studies have also led to the development of new multicomponent versions of the Castagnoli-Cushman reaction that allow products with more diverse and complex molecular structures to be easily obtained.

Comparative evaluation for detection of brain tumor using machine learning algorithms

<span lang="EN-US">Automated flaw identification has become more important in medical imaging. For patient preparation, unaided prediction of tumor (brain) detection in the magnetic resonance imaging process (MRI) is critical. Traditional ways of recognizing z are intended to make radiologists' jobs easier. The size and variety of molecular structures in brain tumors is one of the issues with MRI brain tumor diagnosis. Deep learning (DL) techniques (artificial neural network (ANN), naive Bayes (NB), multi-layer perceptron (MLP)) are used in this article to detect brain cancers in MRI data. The preprocessing techniques are used to eliminate textural features from the brain MRI images. These characteristics are then utilized to train a machine-learning system.</span>

Molecular docking and dynamics simulation study of medicinal fungi derived secondary metabolites as potential inhibitor for COVID-19 treatment

The severity of COVID-19, lack of specific treatment, and controversies on the vaccine's efficacy demand the development of new drugs against SARS-CoV-2. Fungi produce various metabolites with diverse molecular structures that have emerged as promising antiviral drug candidates. Therefore, the present study aimed to investigate medicinal fungi derived secondary metabolites as potential inhibitors of 3 different targets associated with viral entry (human TMPRSS2) and replication (main and papain-like protease) through molecular docking and dynamic simulation studies. Based on our findings, we identified Phelligridin E, Lepiotaprocerine G, and Inoscavin A as the potential blockers of SARS-CoV-2 main protease, papain-like protease, and human TMPRSS2, respectively. These compounds strongly interacted with their corresponding target, passed Lipinski Rule's and had acceptable ADMET properties. Drug-protein complexes showed good stability during MD simulation. Estimation of binding free energy using the MM-GBSA method validated the inhibitor potential of identified compounds. Taken together, we believe that further in vitro and in vivo investigations on our proposed molecules may contribute to expanding the therapeutic arsenal in our fight against COVID-19.