Amino Derivatives Research Articles

Fluorescent “OFF–ON” Sensors for the Detection of Sn2+ Ions Based on Amine-Functionalized Rhodamine 6G

These structurally isomeric rhodamine 6G-based amino derivatives are designed to detect Sn2+ ions. The receptors exhibit rapid fluorescent “turn-on” responses towards Sn2+. The absorption (530 nm) and fluorescent intensity (551 nm) of the receptors increase when increasing the concentration of Sn2+. The hydrazine derivative exhibits more rapid sensitivity towards Sn2+ than the ethylene diamine derivative, indicating that the presence of an alkyl chain in the diamine decreases the sensitivity of the receptors towards Sn2+. The presence of carbonyl groups and terminal amino groups strongly influences the sensitivity of the chemosensors toward Sn2+ by a spirolactam ring-opening mechanism. The receptors exhibit 1:1 complexation with Sn2+ as evidenced by Job plot, and the corresponding limit of detection was found to be 1.62 × 10−7 M. The fluorescence images of the receptors and their complexes reveal their potential applications for imaging of Sn2+ in real/online samples.

Cold Exposure Drives Weight Gain and Adiposity following Chronic Suppression of Brown Adipose Tissue.

Therapeutic activation of thermogenic brown adipose tissue (BAT) may be feasible to prevent, or treat, cardiometabolic disease. However, rodents are commonly housed below thermoneutrality (~20 °C) which can modulate their metabolism and physiology including the hyperactivation of brown (BAT) and beige white adipose tissue. We housed animals at thermoneutrality from weaning to chronically supress BAT, mimic human physiology and explore the efficacy of chronic, mild cold exposure (20 °C) and β3-adrenoreceptor agonism (YM-178) under these conditions. Using metabolic phenotyping and exploratory proteomics we show that transfer from 28 °C to 20 °C drives weight gain and a 125% increase in subcutaneous fat mass, an effect not seen with YM-178 administration, thus suggesting a direct effect of a cool ambient temperature in promoting weight gain and further adiposity in obese rats. Following chronic suppression of BAT, uncoupling protein 1 mRNA was undetectable in the subcutaneous inguinal white adipose tissue (IWAT) in all groups. Using exploratory adipose tissue proteomics, we reveal novel gene ontology terms associated with cold-induced weight gain in BAT and IWAT whilst Reactome pathway analysis highlights the regulation of mitotic (i.e., G2/M transition) and metabolism of amino acids and derivatives pathways. Conversely, YM-178 had minimal metabolic-related effects but modified pathways involved in proteolysis (i.e., eukaryotic translation initiation) and RNA surveillance across both tissues. Taken together these findings are indicative of a novel mechanism whereby animals increase body weight and fat mass following chronic suppression of adaptive thermogenesis from weaning. In addition, treatment with a B3-adrenoreceptor agonist did not improve metabolic health in obese animals raised at thermoneutrality.

Analysis of metabolites in young and mature Docynia delavayi (Franch.) Schneid leaves using UPLC-ESI-MS/MS.

Docynia delavayi (Franch.) Schneid is a plant used both as food and traditional folk medicine. The leaves of D. delavayi are rich in polyphenols, plants with phenolic content are known to be extremely beneficial in terms of human nutrition. In the present study, we used metabolome technology (UPLC-ESI-MS/MS) to examine the young and mature D. delavayi leaves on metabolites changes, which were then analyzed and compared. As a result, 477 metabolites (including 111 flavonoids, 47 others (consisted of nine vitamin, 18 saccharides and alcohols, and 20 unassigned metabolites), 71 phenolic acids, 52 amino acids and derivatives, 18 alkaloids, 61 lipids, 24 terpenoids, 33 nucleotides and derivatives, 18 lignans and coumarins, 12 tannins, 30 organic acids) were identified, of which 281 differentially accumulated metabolites, including 146 up-regulated metabolites and 135 down-regulated metabolites. The result of clustering and PCA analyses showed that young and mature leaves were separated, which indicated that there was a great difference in metabolites between young and mature leaves. Meanwhile, we also found that both young and mature leaves displayed unique metabolites with important biological functions. KEGG enrichment analysis showed that 90 of the differential metabolites were mainly concentrated in 68 KEGG pathways. The result will greatly complement the existing knowledge on the D. delavayi leaves for lays a foundation for subsequent development and utilization.

Differential Metabolomic Responses of Kentucky Bluegrass Cultivars to Low Nitrogen Stress.

Kentucky bluegrass (Poa pratensis L.) is a cool-season turfgrass species that responds strongly to nitrogen (N), but the metabolomic responses of this grass species to N supply is unknown. The N-tolerant cultivar Bluemoon and N-sensitive cultivar Balin were exposed to normal N (15 mM) and low N (0.5 mM) for 21 days for identification of differentially expressed metabolites (DEMs) between normal N and low N treatments. Balin had more reductions of chlorophyll and total soluble protein concentrations and a higher accumulation of superoxide radicals under low N stress. A total of 99 known DEMs were identified in either cultivar or both including 22 amino acids and derivatives, 16 carbohydrates, 29 organic acids, and 32 other metabolites. In Bluemoon, β-alanine metabolism was most enriched, followed by alanine, aspartate, and glutamate metabolism, biosynthesis of valine, leucine, and isoleucine biosynthesis, and glycine, serine, and threonine metabolism. In Balin, alanine, aspartate, and glutamate metabolism were most enriched, followed by the tricarboxylic acid (TCA), glyoxylate and decarbohydrate metabolism, and carbon fixation. Bluemoon generally maintained higher TCA cycle capacity and had more downregulated amino acids, while changes in more organic acids occurred in Balin under low N stress. Some metabolite changes by low-N stress were cultivar-specific. The results suggested that regulation of metabolites related to energy production or energy saving could contribute to low N tolerance in Kentucky bluegrass.

Study on parameter optimization of 3D bioprinting of hybrid bio-inks

Used mainly for manufacturing operative tissue structures to replace damaged ones, three-dimensional (3D) bioprinting is a burgeoning area of medical science with enormous potential. Since the technology is still relatively new, 3D bioprinting heavily relies on the trial-and-error approach for advancement, but the general process currently involves a mixture of various biomaterials in hydrogel form. The quality of the results is affected significantly by the parameters by which the print is made. Even the most seemingly minute details can drastically change the outcome of the print, including temperature, print time, print speed and nozzle diameter, and dispensing pressure. The biomaterial used is also of the utmost importance. Based on current results, an ideal biomaterial should include the same or similar chemical, biological, mechanical, and practical properties of the target end structure. It is critical to ascertain the closest parameters available to ensure a quality end resulting print. This study aims to determine and streamline process parameters to the nearest possible degree to optimize the bioprinting process of hybrid bio-inks. Using material made from unchanged alginate, alginate with gelatin and combined amino acids and derivatives with diphenylalanine, the medical properties of each biomaterial are examined, as well as their flow behavior, allowing a certain level of predictability on printing parameters. Printing parameters are the parameters by which we can predict how well a target structure can be accurately constructed using various bio-inks. Results for the study indicated that air pressure, nozzle speed, and diameter, as well as offset and angular pattern, all play significant roles in affecting printing quality. Ultimately, the results have also indicated that printing parameters primarily hinge on the composition of the hydrogels used. This study also presented a detailed frame of reference to assess amino acids and derivatives with diphenylalanine systematically, which can also be used in other areas of 3D bioprinting. The results of this study would be crucial in establishing 3D bioprinting as a one-stop manufacturing solution for biopharmaceutical industries.

Infrared Spectrum of the Amantadine Cation: Opening of the Diamondoid Cage upon Ionization.

Radical cations of diamondoids, a fundamental class of highly stable cycloalkanes, are intermediates in functionalization reactions and possibly present in the interstellar medium. Herein, we characterize the structure of the radical cation of 1-amantadine (1-C10H15NH2+, Ama+), the amino derivative of the parent adamantane (C10H16+, Ada+), by infrared spectroscopy and density functional theory calculations. The structural isomers of Ama+ produced by electron ionization are probed by infrared photodissociation of cold Ar-tagged ions. In addition to the canonical nascent Ama+ isomer with an intact C10H15 cage, we identify two distonic bicyclic iminium isomers in which the adamantyl cage opens upon ionization, one of which is lower in energy than the cage isomer. The reaction profile with barriers and intermediates for this cage-opening reaction are determined. Comparison with Ada+ suggests that this type of ionization-induced cage-opening may be a common feature for diamondoids and important for their reactivity.

Small Molecule Fluorescent Probes for Sensing and Bioimaging of Nitroreductase

AbstractHypoxia is a condition caused by a decrease in oxygen and is often seen in cases of cardiac ischemia, solid tumors, inflammation, and other diseases. Tumor hypoxia can result in cancer invasion, metastasis, decreased apoptosis, and resistance to various therapies (chemotherapy, immunotherapy, and radiotherapy), ultimately reducing overall survival rates. These effects of hypoxia underline the need to monitor hypoxia‐associated specific markers for more effective therapeutic intervention. Nitroreductase (NTR) is a common biomarker of hypoxia, via its reduction activity with nitroaromatic compounds to corresponding amino derivatives using NADH and NADPH as cofactor. The NTR expression level can be correlated to cellular hypoxia. Therefore, developing a diagnostic tool for measuring NTR activity is of immense importance for improving treatment efficacies. To leverage NTR activity as a proxy of hypoxia, small molecule based fluorescent probes have been developed as quantifiable probes. To date, several NTR‐sensitive fluorescent probes have been reported. This review is focuses on the advances in these fluorescent NTR probes over the last five years.

Evaluation of corrosion inhibition performance of thiazolidine-2,4-diones and its amino derivative: Gravimetric, electrochemical, spectroscopic, and surface morphological studies

To produce effective, less expensive molecules with minimum impact on the environment, the study aims to develop green corrosion inhibitors, which can significantly protect mild steel during its pickling and descaling treatment. Therefore, the present study describes the corrosion inhibition performance of two thiazole derivatives, namely thiazolidine-2,4-diones and its amino derivative 2-aminothiazolidin-4-one designated as TZD, and AT, respectively mild steel in 5%HCl solution through gravimetric measurement, electrochemical measurement (open circuit potential, electrochemical Impedance Spectroscopy, and potentiodynamic polarization). The spectroscopic measurement like FT-IR, UV–vis, X-ray photoelectron spectroscopy (XPS) along with surface morphological analysis like scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) and atomic force microscopy (AFM) was also carried out. Gravimetric studies suggested that the inhibitory effects of the proposed compounds improves with an increase in the concentration of TZD and AT and solution temperature, having the most significant efficiencies of 98.0% and 99.7%, respectively, at 5 × 10−4 M at 60 °C. According to electrochemical tests, the analyzed inhibitor molecules function as mixed-type corrosion inhibitors and improve corrosion charge transfer resistance. AFM, SEM, and EDS investigations indicated that TZD and AT molecules adhere and construct a surface protective layer.

Оптические метки на основе золотых нанозвёзд для ГКР-картирования тканей с использованием красных медицинских лазеров

Star-shaped gold nanoparticles modified with cyanine 5.5 derivatives were studied as optical tags for bioimaging by surface-enhanced Raman scattering (SERS). Obtained tags showed a plasmon resonance band at 640 nm in the absorption spectra which ensures them a maximum efficiency when excited by red lasers. SERS measurements were carried out for the modified particles in the solution phase and after incubation with the PANC-1 cell line. The SERS spectra of the solutions revealed a characteristic signal of cyanine 5.5 amino derivative in the range of 100–1000 cm–1, where there is no high fluorescent background. In cell samples, the SERS spectrum of the dye was recorded from the cytoplasm and was not detected outside the cells. In order to confirm the intracellular localization of the tags, the SERS spectra were also scanned in height. The test on cytotoxicity showed that the studied tags are not toxic in the concentration range from 0.05 to 1 mg/l on atomic gold.

Multi-site functional cathode interlayers for high-performance binary organic solar cells

Bis(2-hydroxyethyl) amino derivatives are used as multi-site functional interlayers, whose chemical stability with non-fullerene acceptors is clarified, affording a remarkable efficiency of 18.50%, among the highest in binary organic photovoltaics.

Gold nanostars for SERS mapping of tissues using red medical lasers

Star-shaped gold nanoparticles modified with cyanine 5.5 derivatives were studied as optical tags for bioimaging by surface-enhanced Raman scattering (SERS). Obtained tags showed a plasmon resonance band at 640 nm in the absorption spectra which ensures them a maximum efficiency when excited by red lasers. SERS measurements were carried out for the modified particles in the solution phase and after incubation with the PANC-1 cell line. The SERS spectra of the solutions revealed a characteristic signal of cyanine 5.5 amino derivative in the range of 100-1000 cm-1, where there is no high fluorescent background. In cell samples, the SERS spectrum of the dye was recorded from the cytoplasm and was not detected outside the cells. In order to confirm the intracellular localization of the tags, the SERS spectra were also scanned in height. The test on cytotoxicity showed that the studied tags are not toxic in the concentration range from 0.05 to 1 mg/l on atomic gold. Keywords: surface-enhanced Raman scattering, gold nanostar, cyanine, optical tags, bioimaging

Comparison of metabolome characteristics and screening of chemical markers in Chrysanthemum indicum from different habitats.

The online version contains supplementary material available at 10.1007/s12298-022-01137-z.

Metabolomics Analysis of Metabolites in Forsythia suspense Fruit Using UPLC/ESI-Q TRAP-MS/MS

Forsythiae Fructus, the fruit of Forsythia suspense is a traditional Chinese hebal medicine that has the antiviral and antioxidant effects in China. Modern analytical chemistry studies showed that the extracts of Forsythiae Fructus contain many bioactive components, such as flavonoids, lignans, phenolic acids, and terpenoids, which can be used to anti-inflammatory and treat toxicity, tonsillitis, ulcers, pharyngitis and acute nephritis. In order to study the types and quantities of metabolites in Forsythiae Fructus, we isolated, identified and analysed metabolites between two varieties of Forsythiae Fructus using UPLC/ESI-Q TRAP-MS/MS. The results showed that a total of 407 metabolites were identified in Forsythiae Fructus using UPLC/ESI-Q TRAP-MS/MS, including 21 terpenoids, 68 phenolic acids, 63 flavonoids, 43 amino acids and derivatives, 22 alkaloids, 55 lipids, 24 lignans and coumarins, 31 nucleotides and derivatives, 29 organic acids, and 51 other metabolites. Among, lignans and coumarins, terpenoids, organic acids, lipids, and phenolic acids were rich in Forsythiae Fructus, which accounted for more than 60% of the total metabolite content. Differential metabolite analysis revealed that 80 metabolites differed significantly between the two types of Forsythiae Fructus. Our results greatly enrich the Forsythiae Fructus phytochemical composition database and provide valuable information for further study of the metabolites of Forsythiae Fructus.

Unleashing non-conjugated polymers as charge relay mediators.

The core factors affecting the efficiency of photocatalysis are predominantly centered on controllable modulation of anisotropic spatial charge separation/transfer and regulating vectorial charge transport pathways in photoredox catalysis, yet it still meets with limited success. Herein, we first conceptually demonstrate the rational design of unidirectional cascade charge transfer channels over transition metal chalcogenide nanosheets (TMC NSs: ZnIn2S4, CdS, CdIn2S4, and In2S3), which is synergistically enabled by a solid-state non-conjugated polymer, i.e., poly(diallyldimethyl ammonium chloride) (PDDA), and MXene quantum dots (MQDs). In such elaborately designed photosystems, an ultrathin PDDA layer functions as an intermediate charge transport mediator to relay the directional electron transfer from TMC NSs to MQDs that serve as the ultimate electron traps, resulting in a considerably boosted charge separation/migration efficiency. The suitable energy level alignment between TMC NSs and MQDs, concurrent electron-withdrawing capabilities of the ultrathin PDDA interim layer and MQDs, and the charge transport cascade endow the self-assembled TMC/PDDA/MQD heterostructured photosystems with conspicuously improved photoactivities toward anaerobic selective reduction of nitroaromatics to amino derivatives and photocatalytic hydrogen evolution under visible light irradiation. Furthermore, we ascertain that this concept of constructing a charge transfer cascade in such TMC-insulating polymer-MQD photosystems is universal. Our work would afford novel insights into smart design of spatial vectorial charge transport pathways by precise interface modulation via non-conjugated polymers for solar energy conversion.

Synthesis, characterization of nitro or amino substituted pyridyl ligands bridged by an ester or ether bond, and their antibacterial assessment against drug resistant bacteria

A series of ester and ether bridged compounds bearing the nitro and amino moieties were synthesized and characterized, in order to assess their ability to potentially serve as antibacterial agents against drug resistant bacteria. All the compounds were obtained at considerable yields while characterization techniques confirmed their successful synthesis. Furthermore, their antimicrobial assessments showed that all the compounds exhibited antibacterial activity against the Gram-negative bacterial strains, both Klebsiella pneumoniae and its drug resistant counterpart. On the contrary, they were poorly active against S. aureus and MRSA. According to the MIC data, all the compounds showed activity of 0.22 to 0.24 mM towards MDR-K. pneumoniae which was higher than the 0.13 mM of the control AgSD. As for K. pneumoniae, the nitro derivatives L1 and L4 showed significantly higher MIC of 0.23 and 0.26 mM, respectively; while the amino derivatives L2 and L3 were more active, with MIC values of 0.16 mM that was better than the 0.18 mM of the control AgSD. Finally, the time kill kinetics study showed that L2, L3 and the control AgSD were bacteriostatic, while L1 and L4 initially showed a bactericidal trend towards K. pneumoniae but eventually changed to an exponential growth. However, all the compounds were bactericidal towards MDR- K. pneumoniae.

Novel C[sbnd]H•••O hydrogen-bonded supramolecular complexes of 18-crown-6 with 1-alkylpyridinium iodide and its amino derivatives: Third-order nonlinear optical properties and Hirshfeld surface analysis

Five supramolecular complexes of 18-crown-6 (18C6) with 1-alkylpyridinium iodide and its amino derivatives were synthesized successfully from methanolic solution by slow evaporation solution growth technique. Crystal structure elucidated by single-crystal X-ray diffraction reveals that all the cocrystals belong to the monoclinic system. Cocrystals bis(1-methylpyridinium iodide)-18C6 (I), bis(4-amino-1-methylpyridin-1-ium iodide)-18C6 (IV), and bis(4-amino-1-ethylpyridin-1-ium iodide)-18C6 (V) crystallize centrosymmetrically with space group C2/m and other two crystals bis(2-amino-1-methylpyridin-1-ium iodide)-18C6 (II) and bis(3-amino-1-methylpyridin-1-ium iodide)-18C6 (III) crystallize in P21/n centric space group. Intra- and inter-molecular hydrogen bonding interactions and weak Van der Walls forces construct the supramolecular architecture in the crystal packing. Interestingly, all the 1-alkylpyridin-1-ium cations interact with 18C6 moiety through C-H•••O hydrogen bonding interactions and N-H•••O interactions are observed only in the case of (II). Fingerprint plots of Hirshfeld surfaces were used to locate and analyze the percentage of hydrogen bonding interactions. Direct band gap energies are estimated using diffuse reflectance data by the application of the Kubelka – Munk algorithm. The third-order nonlinear optical susceptibilities (χ(3)) for the compounds are, 5.57 × 10−6 esu for (I), 3.62 × 10−6 esu for (II), 4.37 × 10−6 esu for (III), 5.30 × 10−6 esu for (IV), and 4.24 × 10−6 esu for (V), respectively.

Metagenomic landscape of taxonomy, metabolic potential and resistome of Sardinella longiceps gut microbiome.

Fish gut microbiota, encompassing a colossal reserve of microbes represents a dynamic ecosystem, influenced by a myriad of environmental and host factors. The current study presents a comprehensive insight into Sardinella longiceps gut microbiome using whole metagenome shotgun sequencing. Taxonomic profiling identified the predominance of phylum Proteobacteria, comprising of Photobacterium, Vibrio and Shewanella sp. Functional annotation revealed the dominance of Clustering based subsystems, Carbohydrate, and Amino acids and derivatives. Analysis of Virulence, disease and defense subsystem identified genes conferring resistance to antibiotics and toxic compounds, like multidrug resistance efflux pumps and resistance genes for fluoroquinolones and heavy metals like cobalt, zinc, cadmium and copper. The presence of overlapping genetic mechanisms of resistance to antibiotics and heavy metals, like the efflux pumps is a serious cause of concern as it is likely to aggravate co-selection pressure, leading to an increased dissemination of these resistance genes to fish and humans.

RECENT ADVANCES IN ANTIMICROBIAL ACTIVITY OF PYRIMIDINES: A REVIEW

Over the past era, development of small heterocycles as potential therapeutics has been a zone of major interest. A large number of pyrimidine derivatives are of considerable biological and chemical interest. Pyrimidine derivatives have shown numerous biological activities such as antimicrobial, antitubercular, anticancer, anticonvulsant, antidiabetic, antiviral, and anti-inflammatory. Being a heterocyclic compound, Pyrimidine finds its use for designing synthesis of newer biologically active structures, as its aromaticity makes it relatively stable, also reactive sites which allow for functionalization. Several amino derivatives of nitrogen-containing heterocycles such as pyrimidine, pyridine possess an antimicrobial activity. In this review, recent advancements in the antimicrobial activity of pyrimidine derivatives have been reported.

Widely targeted metabolomics analysis reveals the effect of fermentation on the chemical composition of bee pollen

Microbial fermentation can break the bee pollen wall. However, the global profiling of bee pollen metabolites under fermentation remains unclear. This study aims to comprehensively elucidate the changes in the composition of bee pollen after microbial fermentation. Ultra-performance liquid chromatography-electron spray ionization-mass spectrometry (UPLC-ESI-MS) based on widely targeted metabolomics analysis was used to compare the chemical composition of unfermented bee pollen (UBP) and fermented bee pollen (FBP). Among the 890 metabolites detected, a total of 668 differential metabolites (classified into 17 categories) were identified between UBP and FBP. Fermentation significantly increased the contents of primary metabolites such as 74 amino acids and derivatives, 42 polyunsaturated fatty acids and 66 organic acids, as well as some secondary metabolites such as 38 phenolic acids, 80 flavone aglycones and 22 phenolamides. The results indicate that fermentation is a promising strategy to improve the nutritional value of bee pollen.

4,6-Dichloro-5-Nitrobenzofuroxan: Different Polymorphisms and DFT Investigation of Its Reactivity with Nucleophiles.

This research focuses on the X-ray structure of 4,6-dichloro-5-nitrobenzofuroxan 1 and of some of its amino derivatives (4a, 4e, 4g, and 4l) and on DFT calculations concerning the nucleophilic reactivity of 1. We have found that by changing the solvent used for crystallization, it is possible to obtain 4,6-dichloro-5-nitrobenzofuroxan (1) in different polymorphic structures. Moreover, the different torsional angles observed for the nitro group in 1 and in its amino derivatives (4a, 4e, 4g, and 4l) are strictly dependent on the steric hindrance of the substituent at C-4. DFT calculations on the course of the nucleophilic substitution confirm the role of the condensed furoxan ring in altering the aromaticity of the carbocyclic frame, while chlorine atoms strongly influence the dihedral angle and the rotational barrier of the nitro group. These results corroborate previous observations based on experimental kinetic data and give a deep picture of the reaction with amines, which proceeds via a “non-aromatic” nucleophilic substitution.