Search Results (436)

The present study aimed to design, synthesize, and evaluate a new series of thieno[3,2-d]pyrimidin-4(3H)-one-based Schiff bases as potential antileishmanial agents against Leishmania major (L. major). A series of twenty thieno[3,2-d]pyrimidine Schiff base derivatives were synthesized and characterized using FTIR, NMR, and HRMS techniques. Their antipromastigote activities were evaluated in vitro against L. major, while cytotoxic effects were assessed on HUVECs to determine selectivity indices. The most active compound was further investigated using molecular docking against several L. major proteins. Among the tested compounds, compound 12, bearing a 2-hydroxy-5-bromophenyl moiety, exhibited the most potent activity against L. major promastigotes with an IC₅₀ value of 13.7 µM, along with a favorable selectivity index (SI = 17.5), outperforming the reference drug miltefosine (IC₅₀ = 31 µM and SI = 0.2). Docking studies demonstrated that compound 12 showed the strongest binding affinity toward phosphodiesterase B1, supported by a docking score of −9.042 kcal/mol and an MM-GBSA value of −67.21 kcal/mol. This study highlights thieno[3,2-d]pyrimidin-4(3H)-one as a promising scaffold in the context of in vitro antileishmanial screening and suggests the role of ortho-phenolic substitution in enhancing activity and selectivity. Compound 12 emerges as a promising lead, warranting further optimization and biological evaluation in future studies. Full article

A series of critical interactions within the viral core between viral RNA (vRNA) and HIV-1 Integrase (IN) has previously been reported. In these studies, contact points between vRNA and IN were identified using RNA-seq and MS-based protein foot-printing approaches. Several IN amino acids located in its C-terminal domain (CTD) were found to be essential for vRNA binding, and their alanine substitution severely impacted the correct morphogenesis of the mature viral core. Here, we have used the TAR element to extend these studies by performing a comprehensive mapping of the interaction by deploying RNA crosslinking and NMR methodologies. Together, these approaches were able to identify additional contact points between the TAR vRNA and IN. Our results reveal several new basic amino acids located in the IN CTD critical for the vRNA-IN interaction, viral replication and correct morphology of the mature viral core. Full article

Background/Objectives: The emergence of methicillin-resistant Staphylococcus aureus (MRSA) has created an urgent need for the development of novel antimicrobial agents. This study aimed to synthesize and characterize a series of benzimidazolium salts and evaluate their antibacterial, antibiofilm, and molecular interaction properties against MRSA and methicillin-susceptible Staphylococcus aureus (MSSA). Methods: Five benzimidazolium salts bearing different substituents were synthesized and characterized by NMR and FTIR analyses. Their antibacterial activities against MRSA and MSSA were investigated using the resazurin-based minimum inhibitory concentration (MIC) assay and agar diffusion method. Antibiofilm activity was evaluated using crystal violet staining, while scanning electron microscopy (SEM) was employed to examine bacterial morphological changes. Gene expression analysis was performed to assess the effects of the most active compound on virulence- and resistance-related genes. In addition, molecular docking studies were conducted against four target proteins (1MWT, 3ZG5, 1JIJ, and 2Y2M). Results: Among the synthesized compounds, compound 1c exhibited the strongest antibacterial activity, with MIC values of 0.25 µg/mL against MRSA and 0.5 µg/mL against MSSA. It also produced the largest inhibition zone diameter (31.0 ± 0.5 mm). SEM analysis revealed significant morphological alterations in treated bacterial cells, indicating disruption of cellular integrity. Gene expression studies demonstrated that compound 1c downregulated several virulence- and resistance-associated genes, including icaA, dltA, dltB, sarA, norA, and norB. All compounds displayed antibiofilm activity, with compound 1c showing the highest inhibition rate (68.6 ± 0.6%). Molecular docking analysis revealed that compound 1c exhibited the strongest binding affinity toward the 2Y2M target protein, with a docking score of −5.322 kcal/mol. Conclusions: The findings demonstrate that benzimidazolium derivatives, particularly compound 1c, possess potent antibacterial and antibiofilm activities against S. aureus strains and effectively modulate virulence- and resistance-related gene expression. Combined with favorable molecular docking results, these compounds represent promising candidates for the development of new therapeutic agents against resistant S. aureus infections. Full article

The biosynthetic gene cluster (BGC) responsible for producing diaporthinic acid has remained genetically unassigned despite repeated isolation of this metabolite from several fungal species. In this study, we activated the dia BGC in Trichoderma reesei by overexpressing the cluster-associated zinc cluster protein DiaR1 to identify the BGC’s in vivo metabolic output and reconstruct the corresponding biosynthetic pathway. Metabolite production was analyzed by HPLC-MS/MS, and the major product was isolated and structurally confirmed by NMR spectroscopy. Individual genes of the dia cluster were deleted in the activated background to assess their functional roles, and transcript levels were quantified by RT-qPCR. Activation of the cluster resulted in the predominant accumulation of diaporthinic acid, accompanied by several related isocoumarin derivatives, while antibacterial and antifungal assays showed no detectable activity of diaporthinic acid under the tested conditions. Deletion analyses demonstrated that the polyketide synthase Dia1, the bifunctional halogenase/methyltransferase Dia5, and the FAD-dependent oxidoreductase Dia4 are essential for diaporthinic acid formation, whereas Dia2 and Dia3 are dispensable in vivo despite the previously proposed roles of their Aspergillus oryzae homologs based on in vitro studies. On the basis of intermediate accumulation patterns, we propose that Dia4 catalyzes the oxidation of dichlorodiaporthin to diaporthinic acid. Together, these results genetically link diaporthinic acid to the dia BGC and refine the previously proposed biosynthetic model derived from A. oryzae. Full article

This study evaluated reduced dietary crude protein (CP) with graded methionine (Met) supplementation in growing and finishing pigs. In each phase, 48 crossbred barrows were assigned to four treatments with four replicate pens per treatment and three pigs per pen. The growing and finishing trials lasted 43 and 50 d, respectively. Growing pigs received CON (16% CP, 0.37% Met) or low-CP diets (15% CP) with 0.37%, 0.41%, or 0.44% Met; finishing pigs received CON (14% CP, 0.27% Met) or low-CP diets (13% CP) with 0.27%, 0.30%, or 0.32% Met. Nitrogen excretion and apparent total tract digestibility of nitrogen were assessed through metabolism trials. Serum biochemical parameters were analyzed at the end of each phase, and untargeted ¹H-NMR-based serum metabolomic analysis was performed in finishing pigs. Most growth performance variables, nitrogen excretion, and nitrogen digestibility were not significantly affected by treatment, whereas selected blood urea nitrogen concentrations were reduced in low-CP diets with Met supplementation. Serum metabolomic profiling suggested exploratory shifts in energy-related metabolites. Overall, these findings suggest that a one-percentage-point reduction in dietary CP with Met supplementation can maintain overall pig performance while inducing selected nitrogen-related biochemical and metabolic responses under the conditions of this study. Full article

Polysaccharide-based pre-emulsions offer a promising strategy for reducing saturated fat in emulsified meat products. In this study, a pre-emulsion stabilized by rice bran dietary fiber modified with alkaline hydrogen peroxide (MRF) was used to replace pork back fat in emulsified meat gels. Four model systems were prepared, varying in fat content (20% and 50%) and chopping intensity (low vs. high). MRF pre-emulsion significantly reduced fat globule size (e.g., D_[4,3] decreased by 18–34%, D_[3,2] by up to 83%) and improved shear stability, as reflected in the weaker frequency dependence of the storage modulus (G′). In high-chopping systems, MRF substitution increased gel elasticity but lowered hardness (by 25–30%), chewiness, and shear force (by 20–25%). Low-field NMR analysis revealed a partial shift from immobilized to free water, which raised cooking loss by 2–4 percentage points while enhancing perceived juiciness. Color measurements indicated that MRF effectively offset the loss of lightness typically associated with fat reduction. Both quantitative descriptive analysis (QDA) and temporal dominance of sensations (TDS) confirmed that MRF-substituted samples showed a markedly lower dominance of fatty sensation during the late oral processing stage (30–40% reduction in dominance rate), whereas the overall dynamic sensory profile remained similar to that of full-fat controls. Collectively, these results demonstrate that MRF, as a functional polysaccharide, stabilizes the system through hydration-induced swelling, hydrogen bonding with myofibrillar proteins, and the formation of a composite interfacial film around fat globules. These mechanisms enhance emulsion stability and successfully mimic the oral textural properties of animal fat, supporting the use of MRF as an effective polysaccharide-based fat replacer in reduced-fat meat products. Full article

In this study, a novel composite hydrogel was developed based on oxidized sodium alginate (OSA), synthesized via sodium periodate oxidation, and incorporated into a carboxymethyl chitosan (CMCS) matrix. Scallop active peptides (SAPs), a marine-derived bioactive component with outstanding antioxidant and pro-regenerative activities, was introduced to endow the hydrogel with enhanced biological functions, which is of great significance for breaking the functional limitations of traditional single-component hydrogels. The construction of a dynamic covalent network, driven by the Schiff base reaction, was confirmed through structural characterization using FT-IR and ¹H-NMR. The hydrogel exhibited favorable physicochemical properties, including shear-thinning behavior, significant self-healing capability, and a uniform porous microstructure that effectively mimics the extracellular matrix (ECM). In vitro evaluations revealed excellent biocompatibility and potent pro-angiogenic potential, as evidenced by enhanced HUVEC migration and tube formation. In a rat model of full-thickness skin wounds, the CMCS/OSA/SAPs hydrogel significantly accelerated wound closure and promoted re-epithelialization and organized collagen deposition. Furthermore, immunohistochemical analysis confirmed upregulated VEGF and α-SMA expression, alongside reduced inflammatory levels (decreased iNOS), indicating potent tissue-regenerative and immunomodulatory functions. Overall, this work presents a multifunctional hydrogel system that integrates antioxidant, anti-inflammatory, and tissue-regenerative properties, offering a promising strategy for deep-wound healing. This study highlights the significant potential of marine-derived bioactive proteins/peptides in the development of advanced biomedical materials. Full article

The 3,4-dihydropyrimidin-2(1H)-one (DHPM) scaffold possesses diverse biological activities and chemical tunability, allowing structural modifications to modulate antiviral, anticancer, and anti-inflammatory effects. In this study, a series of DHPM derivatives with varied substituents were designed and synthesized, and their structures were characterized by ¹H NMR, ¹³C NMR and HRMS. Their antiviral activities against pseudorabies virus (PRV) and vesicular stomatitis virus (VSV) were evaluated. In vitro assays revealed that several compounds exhibited significant antiviral effects, with 4bf (SI = 243.08 against PRV), 4ce (SI = 196.4 against VSV), and 4be (SI = 124.2 against PRV; SI = 181.1 against VSV) showing the most potent activity. Further studies demonstrated effective inhibition of viral titers, and Western blot and qRT-PCR analyses confirmed downregulation of viral proteins and related genes. Cytotoxicity tests indicated that 4bf, 4ce, and 4be had CC₅₀ values of 270.0, 147.1, and 190.9 μg/mL, respectively, suggesting favorable safety profiles. In vivo experiments showed that 4bf, without affecting normal growth, alleviated PRV-induced pulmonary inflammation and tissue damage, and improved survival in mice. Taken together, DHPM-based compounds demonstrate promising potential as candidate antiviral agents, warranting further development. Full article

Interactions between resveratrol and biological or carrier systems play a key role in determining its bioavailability, stability, and delivery performance. These interactions involve proteins, lipids, cyclodextrins, nucleic acids, polysaccharides, and other formulation matrices, and are governed by noncovalent forces such as hydrogen bonding, hydrophobic interactions, π–π stacking, and desolvation effects. This review examines how complementary spectroscopic, calorimetric, structural, and computational techniques are used to characterize resveratrol interactions. Fluorescence, UV–visible spectroscopy, circular dichroism, FTIR, NMR, ITC, DSC, X-ray diffraction, molecular docking, and molecular dynamics simulations are discussed according to their contribution to binding analysis, conformational assessment, thermodynamic interpretation, structural organization, and complex stability. By integrating these approaches, this review provides a technique-oriented framework for understanding resveratrol binding and guiding the development of more stable resveratrol-based carrier systems and bioactive formulations. Full article

Belonging to the Euphorbiaceae family, the Jatropha genus is a promising source for the discovery of antitumor compounds. Jatropha ribifolia is a traditionally used species in folk medicine in the semi-arid region of Brazil, with a few chemical and pharmacological reports. Based on that, the aim of the current work is to isolate, structurally characterize, and assess the cytotoxic activity of isolated compounds through in vitro and in silico analyses. To achieve these main goals, the underground parts were dried, extracted and purified using classical and instrumental chromatographic techniques, leading to the isolation of 16 compounds. Altogether with HR-ESI-MS, IR, one- and two-dimensional NMR experiments, eight previously unreported diterpenes, named ribifolones A-H, along with eight known compounds, were obtained and are herein described. Regarding their activity against melanoma (SK-MEL-28) and colorectal cancer (HCT-116) cell lines, jatrophone was the most potent with IC₅₀ values of 6.19 µM and 10.09 µM, followed by ribifolone C that exhibited a moderate cytotoxicity with IC₅₀ values of 50.71 µM and 33.39 µM, respectively. Network pharmacology analysis suggests the involvement of the PI3K-AKT-mTOR pathway in the activity of both compounds; meanwhile, molecular docking and dynamics simulations demonstrate the main interactions with key proteins in the pathway, indicating putative targets. This work opens new perspectives for the discovery of bioactive compounds found in Euphorbiaceae species, especially from those occurring in Caatinga. Full article

High internal phase Pickering emulsions (HIPEs) stabilized with biopolymer-based particles have sparked widespread interest due to their excellent stability and potential as fat replacements in food systems. In this study, soy protein isolate (SPI) and sodium alginate (SA) were mixed to create composite colloidal particles capable of stabilizing HIPEs with an oil phase percentage of 80%. SA significantly regulated the particle size and surface hydrophobicity of the composite particles. The optimal formulation with 1.0% SA presented a uniform particle size and desirable interfacial properties. The contact angle increased from 62.3° for pure SPI to 80.8°, which effectively improved the wettability at the oil–water interface. The interfacial protein adsorption reached a maximum of 83.7%, enabling adequate coverage of oil droplets. Low-field NMR demonstrated an increase in bound water (T₂₂) from 21.893 to 30.031 (a.u.), while CLSM images confirmed the formation of compact interfacial layers. The HIPEs possessed excellent stability against heat treatment (100 °C), freeze–thaw cycling (3 cycles), high ionic strength (up to 0.6 M NaCl), and ambient storage for 30 days. These findings demonstrate that SPI-SA complexes are excellent natural stabilizers for fabricating robust, environmentally friendly HIPEs with broad prospects for functional food applications. Full article

Enhancing the freeze–thaw resistance of cement-based materials in a green and efficient manner is crucial for hydraulic structures in cold regions. This study investigated the effects of soybean antifreeze protein (AFP) on the freeze–thaw durability of cement mortar through mechanical testing, low-temperature microscopy, NMR analysis, and frost-heaving stress monitoring. The results show that AFP improves freeze–thaw durability, with 0.5% dosage outperforming 1.0%. Relative to the control, the relative ice content at −20 °C decreased from 62.81% to 40.01%, and frost-heaving stress declined from 321.15 kPa to 123.04 kPa. Microscopy and pore structure analyses revealed that AFP transforms ice crystals from needle-like to fine granular forms, inhibiting ordered growth and retarding pore coarsening. A frost-heaving stress model based on the Gibbs–Thomson effect and ice-crystal fractal characteristics indicated that AFP suppresses stress development by reducing effective ice formation, weakening stress transfer, and increasing ice-crystal boundary complexity. This study offers insights for developing green antifreeze admixtures for cement-based materials in cold regions. Full article

The immunomodulatory potential of natural polysaccharides is often limited by their structural complexity and high molecular weight. In this study, DFIP-A3-1 (M_w = 8.68 × 10³ g/mol) was obtained from the leaves of Isatis indigotica Fort. by ultrafiltration, DEAE-650M, and Sephadex G-100 chromatography, followed by acid degradation. Fortunately, DFIP-A3-1 exhibited the most potent immunostimulatory activity in vitro. HPGPC, HPSEC-MALLS-RID, GC-MS, FT-IR, Congo red tests, SEM, and AFM were used to characterize their structure, and 1D/2D NMR was used for further investigation of DFIP-A3-1 for in-depth structural clarification. DFIP-A3-1 was primarily composed of Rha and Gal. Based on methylation and NMR analyses, the structure of DFIP-A3-1 was elucidated as follows: →1)-β-Galp-(4→1,4)-α-Rhap-(2→1,4)-α-Rhap-(2→1)-β-Galp-(6→1)-β-Galp-(6→1,6)-β-Galp-(3→1,6)-β-Galp-(3→. Furthermore, DFIP-A3-1 was found to exhibit a triple-helix conformation. DFIP-A3-1 markedly upregulated the secretion of NO, IL-6, and TNF-α and enhanced the mRNA expression levels of their related genes in RAW 264.7 cells. Moreover, DFIP-A3-1 activated p-IκBα, p-p65, and TLR4, while co-treatment with TAK-242 markedly suppressed the expression of these pathway-related proteins. All of the aforementioned findings suggested that DFIP-A3-1 is a promising natural immunomodulatory drug deserving of additional research and use. Full article

A zinc complex of chelidonic acid (4-oxo-4H-pyran-2,6-dicarboxylic acid) was obtained by reaction with zinc oxide under isothermal conditions. Its composition was confirmed by elemental and thermogravimetric analyses, and its molecular structure was characterized using NMR and IR spectroscopy. Single-crystal X-ray diffraction revealed that the complex crystallizes as a one-dimensional coordination polymer, [ZnChel(H₂O)₄]_n, in the triclinic space group P-1, featuring a distorted octahedral Zn(II) center coordinated by two chelidonate ligands and four water molecules. This six-coordinate arrangement contrasts with previously described tetra-coordinated Zn–chelidonate complexes. Quantum-chemical calculations and molecular dynamics simulations indicated that, in aqueous solution, Zn(II) preferentially forms a monodentate ZnChel(H₂O)₅ species, consistent with the solid-state coordination environment. The interaction of the complex with bovine serum albumin (BSA) was examined by fluorescence, UV–Vis absorption, and circular dichroism spectroscopy, revealing a mixed static–dynamic quenching mechanism, moderate binding affinity, and hydrogen-bonding/van der Waals contributions accompanied by alterations in BSA secondary structure. These results expand the structural chemistry of chelidonic acid and provide biophysical insight into the protein-binding behavior of zinc chelidonate, supporting its potential relevance as a zinc-based bioactive compound. Full article

Background: Breast cancer (BC) remains the most prevalent malignancy among women worldwide, with one in eight at risk during their lifetime. Platinum-based chemotherapeutic drugs, despite of their binding to the DNA of cancer cells, are plagued by toxicity and resistance, necessitating the need for safer and more effective alternatives, such as organometallic complexes. Both synthetic organometallic complexes and natural compounds have attracted attention in this regard. Organotin(IV) complexes are promising chemotherapeutics due to their structural versatility and bioactivity, while vitamins such as Vitamin D (VD) and Vitamin E (VE) exhibit antiproliferative, anti-inflammatory, and antioxidant properties, making them valuable candidates for combination therapy. Methodology: In this study, six novel organotin(IV) dithiocarbamate complexes [LMe₃Sn (Complex 1), LBu₃Sn (Complex 2), LPh₃Sn (Complex 3), LMe₂SnCl (Complex 4), LBu₂SnCl (Complex 5), and L₂Me₂Sn (Complex 6), where L = (E)-4-styrylpiperazine-1-carbodithioate], were synthesized and characterized by FT-IR, ¹H-, ¹³C-NMR, and elemental analysis. Results: Structural studies confirmed penta- and hexacoordination geometries. In silico docking against six BC-related proteins identified Complexes 2 and 4 with both vitamins as promising candidates, exhibiting strong binding affinities, with stable interaction profiles. However, integration of pharmacokinetic, antioxidant, and anti-inflammatory analyses highlighted Complex 4 with both vitamins as the most potent candidate owing to its superior ADME characteristics and balanced biological properties. Subsequent in vitro assays confirmed these findings, as Complex 4 demonstrated strong cytotoxic activity against both MCF-7 (>1.16-fold) and MDA-MB-231 (>1.46-fold) cell lines, surpassing the efficacy of cisplatin. Remarkably, co-administration of VD or VE with Complex 4 further enhanced its anticancer potential, with Chou–Talalay combination index values < 1 (0.66–0.91) indicating a synergistic interaction. Conclusions: Collectively, these results identify Complex 4 as a promising lead compound, and its synergistic activity with natural vitamins may promote cell death, likely through apoptosis induction and modulation of oxidative stress, underscoring its potential as an effective and less toxic therapeutic strategy for breast cancer management. Full article