Search Results (55)

Understanding the influence of solvent environments on the excited-state charge transfer process remains a fundamental question in molecular photophysics and photochemistry. While twisted intramolecular charge transfer (TICT) is crucial in determining fluorescence efficiency and photostability, the combined effects of solvent polarity and hydrogen bonding interactions are still elusive. Here, we employ steady-state and femtosecond transient absorption (fs-TA) spectroscopy with density functional theory (DFT) calculations to investigate the excited-state dynamics of 7-(diethylamino)coumarin-3-carboxylic acid (7-DCCA) in different solvents. Our findings reveal that in highly polar solvents with strong hydrogen-donating and hydrogen-accepting capabilities, 7-DCCA undergoes significant TICT formation, resulting in fluorescence quenching. Conversely, in environments with low polarity or weak hydrogen-bonding interactions, this transformation is largely suppressed. Quantitative correlation analysis utilizing the Kamlet–Taft and Catalán four-parameter models further elucidates the synergistic role of solvent polarity and specific hydrogen-bonding parameters in modulating the steady-state spectral behavior of 7-DCCA. This study provides microscopic insights into solvent–charge transfer interactions and establishes a general framework for enhancing the luminescence efficiency and structural robustness of organic optoelectronic materials through strategic solvent engineering. Full article

Objective: To develop a stable nanoemulsion loaded with Magnoliae Flos essential oil (MEO-NE) and evaluated its potential as an enhancer for nose-to-brain delivery in both solution and gel formulations. Methods: The MEO-NE was prepared using a low-energy emulsification method, with the formulation optimized via single-factor experiments and Box–Behnken design-response surface methodology. The optimized MEO-NE was characterized for particle size, PDI, morphology, and nasal mucosal irritation. Ex vivo histological imaging in rats was performed using hydrophilic sulfo-cyanine7 carboxylic acid and lipophilic coumarin 6 as fluorescent probes to assess distribution and retention in the trigeminal nerve and brain tissues. Results: The optimized MEO-NE exhibited a small particle size (27.96 ± 0.94 nm), low PDI (0.089 ± 0.013), spherical morphology, a stable O/W structure, and no irritation to the nasal mucosa. Ex vivo imaging revealed that MEO-NE significantly enhanced the distribution and retention of both hydrophilic and lipophilic probes in the trigeminal nerve and brain tissues. Moreover, the gel formulation of MEO-NE demonstrated superior brain-targeting efficiency over the solution within 6 h. Conclusions: MEO-NE served as an effective enhancer for nose-to-brain delivery, improving brain uptake of both hydrophilic and lipophilic drugs, and provided an experimental basis for utilizing herbal essential oils in CNS-targeted delivery systems. Full article

Background/Objective: The rise in bacterial resistance necessitates novel therapeutic strategies beyond conventional antibiotics. Antimicrobial peptides represent promising candidates but face challenges such as instability, enzymatic degradation, and host toxicity. To overcome these limitations, conjugation and structural modifications are being explored. This study focuses on designing peptide-based inhibitors of the quorum-sensing (QS) regulator LasR in Pseudomonas aeruginosa, a key mediator of biofilm formation and antibiotic resistance. Methods: Rationally designed tripeptides and dipeptides conjugated with coumarin-3-carboxylic acid and dihydro-3-amino-2-(3H)-furanone were evaluated using molecular docking. The most promising ligand–protein complexes were further analyzed using molecular dynamics (MD) simulations conducted with the CHARMM-GUI and AMBER tools to assess the stability of the ligand–protein complex systems, and the binding affinities were evaluated using Molecular Mechanics–Poisson Boltzmann Surface Area (MM-PBSA) calculations. Pharmacokinetic and toxicity profiles were predicted using ADMETLab 3.0. Selected compounds were synthesized via solid-phase peptide synthesis, structurally confirmed by ¹H NMR and ESI-MS, and tested for antibacterial and antibiofilm activity against P. aeruginosa ATCC 27853. Results: Computational analyses identified several promising inhibitors with stronger binding affinities than the native autoinducer OdDHL. Coumarin conjugates C004 and C006 showed superior docking scores, while MM-PBSA indicated P004 and C004 had the most favorable binding energies. MD simulations confirmed stable ligand–protein complexes. ADMET predictions highlighted C004 and C006 as having excellent pharmacokinetic properties. Experimental assays showed moderate antibacterial activity (MIC 512–1024 µg/mL) and strong antibiofilm inhibition, particularly for C004 (83% inhibition at ½ MIC). Conclusions: The study demonstrates that peptide–coumarin conjugates, especially C004, are promising tools for disrupting QS and biofilm formation in P. aeruginosa. Further optimization and in vivo validation are needed to advance these compounds toward therapeutic application. Full article

Monomer-to-excimer transition has become a valuable technique in fluorescence imaging because of its ability to enhance imaging contrast. However, from a practical perspective, the accuracy of excimer formation at target sites warrants further exploration. Enzyme-triggered peptide self-assembly provides a promising solution to this limitation. As a proof-of-concept, in this study, we developed a furin-triggered peptide self-assembling fluorescent probe RF-Cou by coupling a coumarin dye 7-(diethylamino)-2-oxo-2H-chromene-3-carboxylic acid (Cou) with a furin-responsive peptide scaffold for precision live-cell imaging. Upon entering furin-overexpressing 4T1 tumor cells, RF-Cou underwent enzymatic cleavage, releasing an amphiphilic peptide motif and self-assembling into nanoparticles largely concentrated in the Golgi apparatus to confine the diffusion of Cou. During this process, the Cou excimers were formed and induced a red shift in the fluorescence emission, validating the feasibility of RF-Cou in efficient excimer imaging of furin-overexpressing tumor cells. We expect that our findings will highlight the potential of stimuli-responsive small molecular peptide probes to advance excimer-based imaging platforms, particularly for enzyme-specific cell imaging and therapeutic monitoring. Full article

In vertebrates, vitamin K is a cofactor for the gamma-glutamyl carboxylase (GGCX) involved in the carboxylation of glutamic acid residues. During the vitamin K cycle, vitamin K is oxidised by GGCX, and then reduced by vitamin K epoxide reductase (VKOR), which is inhibited by the synthetic coumarin warfarin. GGCX and VKOR are present in Drosophila melanogaster, but the existence of a vitamin K cycle remains unproven. Semi-lethal concentrations (LC₅₀) of K₃, menadione sodium bisulfite (MSB), and warfarin to neutralise the negative effect of MSB were selected for the Drosophila cultivation medium. LC-MS analysis was used for vitamin K measurement in flies’ extracts. The EPR method and RT-PCR were used for ROS level measurement and gene transcription assessment, respectively. The LC₅₀ of MSB in the medium resulted in a more than 20-fold increase in endogenous K₂ in flies, demonstrating the mechanism of K₃-to-K₂ conversion. Administration of 1 mM warfarin in the medium with MSB completely neutralised its negative effect on viability. Developed flies had decreased K₂ level, confirming the existence of a vitamin K cycle, and both reduced ROS level and hsp22 gene transcription. The biochemical pathways affected by elevated K₂ concentrations involves both elements of the vitamin K cycle and the adaptive mitochondrial antioxidant system. Full article

Despite the discovery of many chemotherapeutic drugs that prevent uncontrolled cell division processes, the development of compounds with higher anticancer efficacy and a lower level of side effects is an important task in modern pharmaceutical chemistry. Herein, a mild and convenient method for the preparation of N1-substituted 3-(1,2,3-triazolyl-methoxycarbonyl)coumarins or bis(coumarine-3-carboxylate)bis(triazole)alkandiyl by the copper(I)-catalyzed Huisgen cycloaddition reaction of readily available coumarin-3-carboxylic acid propynyl ester with azides or diazides has been presented. The synthesized compounds have been tested for their cytotoxicity on various cancer and noncancerous cell lines using the MTT assay. All new compounds were nontoxic on normal epithelial VERO cells. Two derivatives exhibited selectivity towards HPV-negative human cervical cancer cells, C33 A, with excellent activities in low concentrations (GI₅₀ 4.4–7.0 µM). In vitro mechanistic studies showed that bis(coumarine)bis(triazolylester) conjugate 3 induced time-dependent apoptosis in cervical cancer cell lines C33 A and CaSki, at the GI₅₀ concentration, as measured by Annexin V-FITC/PI staining. The most active coumarin–triazolyl ester conjugate 2g possessed anticancer activities, as indicated by its ability to induce S/G2 phase cell cycle arrest at a low concentration and early apoptosis in CaSki cells. The obtained results revealed the potential of new compounds as anticancer agents, particularly against cervical cancer. Full article

Due to their remarkable biological and pharmacological activities such as antibacterial, antifungal, anticoagulant, antioxidant, anticancer, and anti-inflammatory properties, synthesis of coumarins and their derivatives has attracted considerable attention in research and development among both organic and medicinal chemists. In this paper, we demonstrated for the first time a two-step tandem enzymatic synthesis of coumarin bioamide derivatives through sustainable continuous-flow technology. Salicylaldehyde and dimethyl malonate were firstly reacted to obtain coumarin carboxylate methyl derivatives, which were then reacted with various biogenic amines at 50 °C for about 40 min under the catalysis of lipase TL IM from Thermomyces lanuginosus to obtain coumarin bioamide derivatives in continuous-flow reactors. Reaction parameters such as reaction solvent, reaction catalyst type, reactant ratio, residence time, reaction temperature and comparative experiments with traditional batch process were studied. Ideal product yields (62.7–87.1%) were obtained. Environmentally friendly methanol was applied as the reaction medium. Substantially shorter reaction times as well as a significant increase in the product yield were obtained as compared to the batch process. This innovative approach provides a promising green, efficient and rapid synthesis strategy for pharmaceutical synthesis and further research on novel coumarin bioamide derivatives. Full article

Herein, we present the synthesis of N-(4-methoxyphenethyl)-2-oxo-2H-chromene-3-carboxamide. The synthesized compound has been thoroughly characterized using melting point analysis, ¹H- and ¹³C-NMR spectroscopy, infrared spectroscopy, and mass spectrometry. The comprehensive data obtained from these techniques confirm the successful synthesis and structural integrity of the newly synthesized molecule. Full article

The real-time measurement of the content of impurities such as iron and aluminium ions is one of the keys to quality evaluation in the production process of high-purity lithium carbonate; however, impurity detection has been a time-consuming process for many years, which limits the optimisation of the production of high-purity lithium carbonate. In this context, this work explores the possibility of using water-soluble fluorescent probes for the rapid detection of impurity ions. Salicylaldehyde was modified with the hydrophilic group dl-alanine to synthesise a water-soluble Al³⁺ fluorescent probe (Probe A). Moreover, a water-soluble Fe³⁺ fluorescent probe (Probe B) was synthesised from coumarin-3-carboxylic acid and 3-hydroxyaminomethane. Probe A and Probe B exhibited good stability in the pH range of 4–9 in aqueous solutions, high sensitivity, as well as high selectivity for Al³⁺ and Fe³⁺; the detection limits for Al³⁺ and Fe³⁺ were 1.180 and 1.683 μmol/L, whereas the response times for Al³⁺ and Fe³⁺ were as low as 10 and 30 s, respectively. Electrostatic potential (ESP) analysis and density functional theory calculations identified the binding sites and fluorescence recognition mechanism; theoretical calculations showed that the enhanced fluorescence emission of Probe A when detecting Al³⁺ was due to the excited intramolecular proton transfer (ESIPT) effect, whereas the fluorescence quenching of Probe B when detecting Fe³⁺ was due to the electrons turning off fluorescence when binding through the photoelectron transfer (PET) mechanism. Full article

Plant botanical extracts are recognized for being a source of biologically active phytochemicals that potentially have diverse applications. The phytochemical composition, potential cytotoxicity, and insecticidal effectiveness of three leaf extracts from the folkloric medicinal plant Mammea americana L. (Calophyllaceae) were investigated. Micro-Soxhlet extraction with chloroform, dichloromethane, and methanol was used, and key phytochemicals were identified via Gas Chromatography-Mass Spectrometry (GC-MS). The extracts were mainly composed of sesquiterpenes, carboxylic acids, coumarins, esters, diterpenes, and other bioactive compounds. Potential cytotoxicity was assessed using brine shrimp lethality tests, where all extracts displayed high toxicity to Artemia salina. The dichloromethane extract (MAD) had the lowest LC₅₀ value (8.39 μg/mL), followed by methanol extract (MAM, 11.66 μg/mL) and chloroform extract (MAC, 12.67 μg/mL). Insecticidal activity was tested against Ferrisia sp. (Hemiptera:Pseudococcidae), demonstrating the highest efficacy with the methanolic extract (LC₅₀ = 5.90 mg/mL after 48 h). These findings provide a basis for further research into the bioactive components of Mammea americana leaves, particularly their antibacterial, anti-inflammatory, and anticancer properties. It also highlights the potential of Mammea americana L. leaf extracts as botanical insecticides due to their high bioactivity against agricultural pests of economic significance. This is the first study that evaluates the insecticidal activity of Mammea americana leaf extracts against Ferrisia sp. insects, offering valuable insights into using plant-based natural products in pest control. Full article

Two new Ag(I) complexes with coumaric carboxylic acid derivatives have been synthesized. Structural studies of these noncrystalline complexes have been performed using a methodology that combines laboratory and synchrotron techniques, supported by density functional theory calculations. The arrangement of ligands around the Ag(I) cation has been refined using infrared, extended X-ray absorption fine structure, and X-ray absorption near edge structure spectroscopies. Different coordination modes of carboxylate ligands are observed for the studied compounds. Carboxylate bridges are characteristic for the Ag(I) complex with 4-oxo-4H-1-benzopyran-2-carboxylic acid (1), while a bidentate chelating motif was found for the complex with 2-oxo-2H-1-benzopyran-3-carboxylic acid (2). Additionally, the carbonyl oxygen atom of the coumarin ring coordinates to the silver cation in complex 2, while it is inactive in complex 1. Antimicrobial evaluation has been performed for both compounds. The complexes show activity against selected bacteria as well as Candida yeast. This activity is slightly lower for bacteria and the same or higher for Candida in relation to the reference substances: ciprofloxacin or fluconazole. Full article

In this study, we explore the synthesis and solid-state characterization of four coumarin-3-carboxylic acid esters, each modified at the C-3 position with different cycloalkyl groups: cyclohexyl, menthyl, and iso-pulegyl. We conducted a detailed analysis of these compounds utilizing a variety of techniques such as a single-crystal X-ray diffraction, nuclear magnetic resonance (NMR), and Fourier-transform infrared (FTIR) spectroscopy. Additionally, we calculated the dipole moments for these molecules. Our findings include a thorough structural assessment, highlighting the role of noncovalent interactions through Full Interaction Maps and Hirshfeld surface analysis. This study reveals the critical influence of the weak C-H…O hydrogen bonds in determining the solid-state architecture of these esters, whereas π-π stacking interactions appear to be negligible among the studied derivatives. Full article

Satureja bachtiarica is an endemic plant from the Lamiaceae family, growing in the Zagros mountain range in Iran. Even if S. bachtiarica is reported to possess many biological activities, little is known about its chemical composition. For this reason, in the present research, a phytochemical investigation of this species was carried out. To have a preliminary metabolite profile of S. bachtiarica, the n-BuOH extract was analyzed using LC-ESI/LTQOrbitrap/MS/MS in negative ion mode, allowing the identification of specialized metabolites belonging to flavonoid, monoterpene, indol, phenylpropanoid, phenolic, lignan, coumarin, biphenyl, and triterpene classes. The LC-MS/MS analysis guided the isolation of compounds, and their structures were characterized using spectroscopic methods including 1D- and 2D-NMR experiments and HRMSⁿ analysis. In this way, a compound never reported before belonging to the biphenyl class was identified. Total flavonoid content of the extract along with the antioxidant activity were assessed. Based on the traditional uses of S. bachtiarica suggesting potential antibacterial properties, an evaluation of the biofilm inhibitory activity of the extract and isolated compounds against mature biofilms of Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, as well as their influence on the metabolism of sessile bacterial cells, was conducted. The results evidenced that some compounds including parmentin B, biphenyls, and 1-(1H-indole-3-carboxylate)-β-D-glucopyranoside might inhibit some changes occurring in the bacterial cells, which increases their virulence. In particular, biphenyl derivatives at a concentration of 80 μg/mL were capable of limiting remarkably the mature biofilms of A. baumannii and L. monocytogenes remarkably at a percentage ranging between 52.76% and 75.02%, and they reached an inhibition percentage of 69.28 % against E. coli. Biphenyl derivatives were also effective in exerting an inhibitory action against the mature biofilm of P. aeruginosa (inhibition ranging from 59.38% to 81.08%) and Staphylococcus aureus (inhibition percentage reached 82.94%). Of note, the biphenyl derivatives resulted in being capable of acting on the metabolism of the cells within the biofilm of all five pathogens. Full article

The extracts of whole plants or specific organs from different plant species are gaining increasing attention for their phytotherapy applications. Accordingly, we prepared standardized gemmotherapy extracts (GTEs) from young shoots/buds of olive (Olea europaea), sweet almond (Prunus amygdalus), and black mulberry (Morus nigra), and analyzed the corresponding phytonutrient profiles. We identified 42, 103, and 109 phytonutrients in the olive, almond, and black mulberry GTEs, respectively, containing amino acids, vitamins, polyphenols, flavonoids, coumarins, alkaloids, iridoids, carboxylic acids, lignans, terpenoids, and others. In order to assess the physiological effects generated by the GTEs, we developed a translational nutrition model based on Drosophila melanogaster and Cyprinus carpio. The results indicate that GTEs could influence, to a variable extent, viability and ATP synthesis, even though both are dependent on the specific carbohydrate load of the applied diet and the amino acid and polyphenol pools provided by the GTEs. It seems, therefore, likely that the complex chemical composition of the GTEs offers nutritional properties that cannot be separated from the health-promoting mechanisms that ultimately increase viability and survival. Such an approach sets the paves the way for the nutritional genomic descriptions regarding GTE-associated health-promoting effects. Full article

Scientists have been interested in hybrid coumarin derivatives due to their wide clinical anticancer use. Herein, ethyl 8-methoxycoumarin-3-carboxylate (Compound 1) served as the starting material for the synthesis of a series of novel hybrid coumarin derivatives (Compounds 3–6). Their structure was determined using ¹³C NMR, ¹H NMR, elemental analysis, and mass spectrometry. The in vitro cytotoxic activities of coumarin derivatives (Compounds 3, 5, and 6) and brominated coumarin derivatives (Compounds 4, 8, and 9) against MCF-7 and MDA-MB-231 were evaluated. Several substances have been identified as promising candidates for future study, especially Compound 6 due to its potent activity against β-tubulin (TUB) polymerization, sulfatase, and aromatase enzymes. It also has a role in inducing cell-cycle arrest at the S phase in the MCF-7 cell line, as well as apoptosis. Full article