Search Results (1,511)

Herein, a novel insensitive diazonium inner salt of 2-nitro-5-oxo[1,2,4]triazolo[1,5-c]pyrimidin-8-diazonium-7-olate (NTPD) was synthesized through a concise three-step route. The structure and performance of this material were comprehensively studied. Single-crystal X-ray diffraction analysis revealed that NTPD possesses a distinctive fused-ring framework featuring an inner salt (zwitterionic) structure, wherein the diazonium and phenolate functionalities are intramolecularly integrated within a compact, highly conjugated heterocyclic system. Furthermore, in comparison with previously reported diazonium compounds, NTPD exhibits a superior combination of enhanced thermal stability and significantly reduced mechanical sensitivity. Specifically, its onset decomposition temperature reaches 206 °C, representing a substantial improvement over conventional diazo derivatives, while its impact sensitivity of 7 J positions it among the least sensitive diazonium-based energetic materials reported to date. The exceptional performance of NTPD is strongly attributed to its nearly planar molecular geometry and the extensive hydrogen-bonding network present within its crystal lattice, which collectively reinforce structural rigidity, enhance packing stability, and effectively dissipate external mechanical stimuli. Full article

Type 2 diabetes mellitus (T2DM) is a metabolic disorder characterized by glycolipid dysregulation and hepatic steatosis. Centella asiatica (CA) and its triterpenoid constituents exert metabolic benefits. In addition, previous metabolomics study found that asiatic acid regulated pyrimidine metabolism in obese mice, while the key target and pathway were undefined. This study investigated the regulatory effects of CA and its active constituents on T2DM-related glycolipid disorders, focusing on the pyrimidine metabolism pathway. T2DM mice were established using a high-fat diet combined with streptozotocin (STZ) and treated with Centella asiatica ethanolic extract or asiatic acid (AA), with glibenclamide as a positive control. Then, glycolipid metabolism, hepatic function, pyrimidine metabolites, and related mechanisms were assessed using biochemical assays, LC–MS/MS, cellular experiments, molecular analyses, and molecular docking. CAE and AA significantly reduced FBG (decreased by 51.01% and 53.01%), improved glucose intolerance, corrected dyslipidemia, alleviated hepatic steatosis, and attenuated insulin resistance in T2DM mice. They elevated hepatic uridine, cytidine, and UDP-glucose (UDPG) levels, promoted glycogen synthesis, inhibited uridine phosphorylase 1 (UPP1) activity, upregulated UDPG synthesis genes (PGM1, UGP2), and downregulated lipogenic genes (ACACA, Fasn, SREBP1/2). Molecular docking indicated specific binding of AA and asiaticoside to UPP1. This work distinguishes from our prior research by identifying UPP1 as a functional target and elucidating the detailed molecular mechanism. CA improves T2DM-associated glycolipid disorders and hepatic injury by modulating the pyrimidine metabolism-UDPG-glycogen synthesis pathway and targeting UPP1, highlighting its therapeutic potential for metabolic diseases. Full article

Background/Objectives: Teriflunomide is an active metabolite of leflunomide and acts as a selective and reversible inhibitor of dihydroorotate dehydrogenase, a key enzyme in de novo pyrimidine biosynthesis. It exhibits immunomodulatory activity by reducing the proliferation of activated T and B lymphocytes and is widely used in the treatment of rheumatoid arthritis and relapsing multiple sclerosis. This study aimed to develop a rapid, accurate, and simple high-performance liquid chromatography (HPLC) method with fluorometric detection for quantifying teriflunomide in human plasma. Methods: Plasma samples were prepared by liquid–liquid extraction followed by pre-column derivatization with NBD-Cl. Teriflunomide was derivatized with 4-chloro-7-nitrobenzofurazan (NBD-Cl) and separated using a reversed-phase C18 column (5 µm, 4.6 × 150 mm) at 30 °C with isocratic elution. The mobile phase consisted of acetonitrile and 0.1% orthophosphoric acid (80:20, v/v) at a flow rate of 1.1 mL/min. Fluorescence detection was performed at λex = 465 nm and λem = 535 nm. The method meets European Medicines Agency (EMA) guidelines for bioanalytical validation and was successfully applied to pharmacokinetic studies, including AUC_0–t, AUC_0–∞, C_max, T_max, and t_½. Results: Teriflunomide showed a retention time of 2.55 ± 0.01 min. The method exhibited linearity in the range of 0.01–30 ng/mL (r² = 0.9998), with a limit of detection and quantification of 0.003 and 0.01 ng/mL, respectively. The relative standard deviation was 3.27%. Conclusions: This work introduces a novel, cost-effective, and highly sensitive HPLC with fluorescence detection (HPLC-FL) method for the determination of teriflunomide in human plasma, providing an efficient alternative to LC-MS/MS for routine pharmacokinetic and bioequivalence studies. Full article

Antibiotic-resistant bacteria are widely distributed and threaten public health. Photocatalytic antimicrobial technology can effectively inactivate multidrug-resistant bacteria without readily inducing resistance. We previously showed that oxygen-rich vacancy Bi₂MoO₆ (OBM) exhibits excellent activity against methicillin-resistant Staphylococcus aureus (MRSA), but the underlying molecular mechanisms remain poorly understood. Here, we employed integrated transcriptomics and metabolomics, with qRT-PCR validation, to systematically elucidate the antibacterial mechanism of OBM against MRSA. OBM treatment induced profound transcriptional and metabolic alterations: 231 differentially expressed genes and 206 differentially abundant metabolites were identified. Functional enrichment analysis revealed cooperative involvement in multiple critical pathways, including inhibition of amino acid biosynthesis and protein translation, disruption of cell wall and membrane integrity, induction of oxidative stress, collapse of energy metabolism (suppression of oxidative phosphorylation and impaired ATP synthesis), and imbalance in nucleotide metabolism (down-regulation of DNA helicase and mismatch repair genes, dysregulation of purine/pyrimidine metabolism). These findings demonstrate that OBM photocatalytically inactivates MRSA through a multi-target systemic attack at both the transcriptional and metabolic levels, providing a novel theoretical foundation for the development of photocatalytic materials aimed at controlling MRSA and other drug-resistant bacteria. Full article

Diabetes mellitus remains a major metabolic disorder requiring the development of new and effective α-glucosidase inhibitors. The present study aimed to identify, design, and optimize novel 3-amino-2,4-diarylbenzo[4,5]imidazo[1,2-α]pyrimidine derivatives with promising inhibitory activity against the α-glucosidase enzyme using a comprehensive in silico strategy. Approximately 300 molecular descriptors were calculated to characterize a dataset of 32 compounds (Peytam et al.) and to investigate the structural factors governing their biological activity. Based on these descriptors, a multiple linear regression model was developed to predict the inhibitory activities of the compounds against alpha-glucosidase. The developed model demonstrated satisfactory predictive performance and was internally and externally validated to ensure its accuracy, robustness, and reproducibility. In addition, the applicability domain analysis confirmed the reliability of the predictions. Using the validated QSAR model, seven new derivatives were designed with predicted pIC₅₀ values exceeding the maximum activity of the parent compounds. The leverage analysis demonstrated that all newly designed compounds were located within the applicability domain of the model, supporting the reliability of the predictions. To further evaluate their inhibitory potential, molecular docking studies were performed to investigate the interactions between the designed compounds and the α-glucosidase active site. The docking results revealed favorable binding interactions comparable to those reported for known α-glucosidase inhibitors. Furthermore, ADMET analysis indicated generally favorable pharmacokinetic properties, although potential CYP3A4 inhibition-related pharmacokinetic risks were identified and discussed. Molecular dynamics simulations, including replicated runs and MM/GBSA binding free energy calculations, confirmed the stability of the most promising protein–ligand complexes throughout the simulation period. In conclusion, this study proposes a robust and integrated computational workflow combining descriptor generation, QSAR modeling, applicability domain analysis, molecular docking, ADMET prediction, and molecular dynamics simulations for the rational design of potential α-glucosidase inhibitors. The findings highlight the therapeutic potential of the designed derivatives and provide a valuable in silico framework for the future development of antidiabetic agents. Full article

This study evaluated how graded dietary nucleotide supplementation (0, 0.25, 0.5, 0.75, 1.0, and 2.0 g/kg) affects growth performance, antioxidant capacity, intestinal morphology, and gut microbiota in swamp eel (Monopterus albus) (initial body weight 10.07 ± 0.92 g). Three hundred sixty fish were randomly assigned to six diets, each in triplicate, for eight weeks. Compared with the control, nucleotide addition significantly increased final body weight, weight gain rate, and specific growth rate, and decreased feed conversion ratio (p < 0.05), with optimal results at 0.75 g/kg (HS3). Survival was 100% in all groups. Supplemented fish showed lower serum and intestinal malondialdehyde levels and higher superoxide dismutase and catalase activities (p < 0.05). Serum total protein, albumin, and triglycerides increased, whereas alanine aminotransferase, aspartate aminotransferase, and γ-glutamyl transpeptidase decreased (p < 0.05), pointing to improved hepatic and lipid metabolism. Intestinal trypsin, lipase, and amylase activities also rose markedly (p < 0.05), peaking in HS3. Histological examination revealed greater mucosal thickness and villus height (p < 0.05); in HS3, these values reached approximately 0.95 mm and 0.87 mm, respectively. Metagenomic analysis showed that 0.75–1.0 g/kg nucleotides increased alpha diversity and restructured the microbial community, enriching Bacteroidetes- and Prevotella-related taxa while reducing Proteobacteria, including Acinetobacter baumannii and Escherichia coli. LEfSe identified dose-specific discriminant taxa, and refined KEGG Level 3 pathway analysis predicted enhanced butyrate and propanoate biosynthesis, starch utilization, and purine/pyrimidine interconversion at moderate doses. Genus-level abundances of Prevotella and Bacteroides correlated inversely with serum oxidative and hepatic stress markers. Quadratic regression estimated the optimal dietary nucleotide level at 764 mg/kg (0.76 g/kg), consistent with the best-performing 0.75 g/kg group. Collectively, 0.75–0.76 g/kg dietary nucleotides optimize growth and intestinal health in M. albus through coordinated improvements in antioxidant status, digestive function, mucosal architecture, and beneficial gut microbiota remodeling. Full article

The dimorphic fungus Talaromyces marneffei causes talaromycosis, a life-threatening fungal disease with limited treatment options. Olorofim, a first-in-class orotomide antifungal that targets pyrimidine synthesis essential for fungal growth, has low minimum inhibitory concentration (MIC) against T. marneffei and clinical efficacy against other invasive fungal diseases. Here, we tested the hypothesis that olorofim synergistically enhances amphotericin B (AmB), a potent membrane-targeting antifungal, against T. marneffei in 55 clinical isolates using a validated colorimetric checkerboard assay. The MIC was defined as the lowest drug concentration inhibiting ≥ 95% of fungal growth. Drug interactions were assessed using the fractional inhibitory concentration index (FICI), which defines ≤0.5 as synergy, 0.5 < FICI ≤ 4.0 as indifference, and FICI > 4 as antagonism. We found that interactions between AmB and olorofim were indifferent across all 55 isolates (0.5 < FICI ≤ 1.03). Time-kill assays showed an expected concentration-dependent fungicidal activity for AmB, but a concentration-independent fungistatic activity for olorofim against T. marneffei. Combinations of AmB and olorofim were also indifferent in time-kill experiments. Although synergy was not observed, and olorofim is unlikely to enhance AmB induction therapy, olorofim may have a role in the consolidation and maintenance therapy of talaromycosis. Full article

Background/Objectives: Resistant pathogenic bacteria and fungi are a growing problem worldwide; therefore, the discovery of new active ingredients is an important challenge for which the functionalization of natural terpenes with biologically active heterocycles can provide a basis. To reach this goal, a series of 1,4-disubstituted-1,2,3-triazole conjugates was designed and synthesized starting from commercially available α-santonin. Methods: The key azido derivative intermediate was prepared according to literature procedures via Michael addition between dehydrosantonin and the TMSN₃/AcOH/Et₃N system at its highly reactive α-methylene-γ-lactone motif. Subsequently, the obtained azide was applied to regioselective Huisgen 1,3-dipolar cycloaddition reaction with a wide range of terminal alkynes bearing N-, S- and O-heterocycles. These include pyridine, pyrimidine, purine, quinoline, indol, or coumarin to afford the sesquiterpene–heterocycle chimaeras. All triazole conjugates were screened for in vitro antiproliferative activity by MTT assay against HeLa, MDA-MB231, SiHa, MCF-7 and A2780 human cancer cell lines compared with fibroblast cells (NIH/3T3) to check their cytotoxicity and antimicrobial effects on two Gram-positive (B. subtilis, S. aureus) pathogenic bacteria, two Gram-negative (E. coli and P. aeruginosa) pathogenic bacteria, and two yeasts (C. krusei and C. albicans). Results: The results indicated that most of the examined compounds expressed weak activity against human cell lines, while some of them showed moderate activity against S. aureus (up to 99% inhibition at 100 µg/mL conc.), C. krusei (up to 51% inhibition at 10 µg/mL conc.) and C. albicans (up to 52% inhibition at 10 µg/mL conc.). Conclusions: Further structural modification of the best, selective antibacterial and antifungal compounds may open the possibility to the development of effective natural sesquiterpene-based selective antimicrobial agents. Full article

Rice straw incorporation is a paddy soil management practice that can reduce environmental pollution, mitigate soil degradation, and minimize nutrient loss. In this study, temporal shifts in soil microbial communities and metabolic profiles were investigated across three key rice growth stages—pre-planting (BS), tillering (TI), and harvest (HA)—to elucidate the ecological effects of straw incorporation. The Shannon diversity and Pielou evenness indices were significantly higher under straw incorporation than under the control at the BS and TI stages, but significantly lower at the HA stage. Straw incorporation also increased the relative abundance of key bacterial taxa, including Polaromonas sp. AER18D145, Sphingomonas sediminicola, and Thiobacillus denitrificans. Functional annotation indicated that the microbial community was mainly associated with amino acid biosynthesis and glycolysis. Metabolomic analysis revealed significant changes in steroids and their derivatives, terpenoid lipids, and carboxylic acids and their derivatives. Three metabolites—3-hexa-isoprenyl-4,5-dihydroxybenzoic acid, LysoPE (16:1(9Z)/0:0), and stachyose—differed significantly across all stages, suggesting their potential as metabolic indicators of straw incorporation. KEGG enrichment analysis identified significant alterations in arachidonic acid, purine, galactose, and pyrimidine metabolism. Redundancy analysis further revealed positive associations of LysoPE (16:1(9Z)/0:0) and stachyose with Brevundimonas sp. Root608 and Polaromonas sp. AER18D145. Full article

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

Background/Objectives: Diabetes mellitus (DM) is a critical metabolic condition with escalated blood glucose levels caused by insulin resistance, restricted insulin production, and the activity of alpha-amylase and alpha-glucosidase enzymes. Methods: This current work focuses on the synthesis and evaluation of novel Pyrimidine-derived pyrazole-based thiadiazole derivatives to target DM by inhibiting α-amylase and α-glucosidase. Results: The findings exhibited that, except for three compounds, all other synthesized derivatives inhibited α-amylase and α-glucosidase enzymes with IC₅₀ values ranging from 5.17 μM to 29.84 μM on α-amylase and 7.60 μM to 31.62 μM on α-glucosidase, in comparison to the standard drug Acarbose (α-amylase IC₅₀ = 8.25 ± 0.80 μM; α-glucosidase IC₅₀ = 10.75 ± 1.10 μM). Analogs 8g, 8k, and 8b displayed superior or comparable inhibitory activity compared to the reference drug Acarbose. The inhibition potential of the derivatives can be attributed to their stable contacts with crucial amino acid residues of targeted enzymes, as shown through molecular docking analysis. Moreover, DFT-calculated HOMO–LUMO parameters and electrostatic potential (ESP) maps were used to gain complementary insight into the electronic characteristics, charge distribution, and potential interaction behavior of the synthesized derivatives, which supported the molecular docking observations. Conclusions: Experimental outcomes and in silico support display that these derivatives serve as potential leads for anti-diabetic drug development. These potent pyrimidine-derived pyrazole-based thiadiazole derivatives were comparable to an existing diabetic mellitus inhibitor, specifying potential for further therapeutic development and optimization against diabetic mellitus. Full article

A series of substituted pyrrolo[2,3-d]pyrimidines was designed, synthesized, and evaluated in vitro against two protozoan parasites: Plasmodium falciparum and Trypanosoma brucei brucei. Pharmacological studies revealed antiprotozoal activity with IC₅₀ values in the submicromolar to micromolar range. Additionally, the in vitro cytotoxicity of these new compounds was assessed using human HepG2 cells. Among them, the pyrrolopyrimidine derivative 1d emerged as the most potent antimalarial compound, exhibiting a selectivity index (SI) of 600.81 against the P. falciparum chloroquine-resistant W2 strain. For the chloroquine-sensitive 3D7 strain, the most notable selectivity index (SI) was observed for pyrrolo[2,3-d]pyrimidine 1c, with a value of approximately 123. Furthermore, compound 1b demonstrated the most interesting activity against Trypanosoma brucei brucei, with an SI of 39.52, marking it as a promising trypanocidal agent. FRET melting assays confirmed that these nitrogen-containing heterocyclic compounds bind to telomeric G-quadruplexes in P. falciparum and Trypanosoma. However, no clear correlation was found between G-quadruplex binding and antiparasitic activity or selectivity, suggesting that G-quadruplex targeting is unlikely to be the main mechanism underlying cytotoxicity. Full article

Cordyceps militaris, a medicinal and edible mushroom, is renowned for its bioactive constituents and health-promoting effects. This study investigated the effects of vacuum freeze drying (VF), vacuum drying (VD), oven drying (OV), and sun drying (SU) on the metabolite profiles and antioxidant activities of C. militaris. VF showed the highest levels of total phenolics, total carotenoids, cordycepin, and N⁶-(2-hydroxyethyl)-adenosine, whereas VD better preserved total flavonoids. VF- and VD-treated samples also exhibited stronger antioxidant capacities than those processed by OV and SU in 1,1-diphenyl-2-picrylhydrazyl radical (DPPH•), 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) radical (ABTS^•+), hydroxyl radical (•OH), and ferric reducing antioxidant power (FRAP) assays. Metabolomics analysis identified 193 significantly altered metabolites after drying treatments. VF, VD, and SU increased carbohydrates, vitamins, and phenolic acids, while leading to reductions in amino acids, nucleotides, and fatty acids. KEGG analysis revealed that drying significantly affected pathways related to purine and pyrimidine metabolism, amino acid biosynthesis, and phenylpropanoid biosynthesis. Network pharmacology further identified 8 key compounds potentially associated with antioxidant effects through interactions with 37 core targets. These findings highlight the importance of selecting appropriate drying methods to preserve the bioactive compounds and functional quality of C. militaris. Full article

All-trans retinoic acid (atRA) is known to regulate lipid metabolism, adipocyte differentiation, and the immune system in mammals and other aquatic species. However, studies on atRA in crustaceans, especially in Eriocheir sinensis, are still scarce. The present study aimed to investigate the regulatory effects of dietary or injected atRA on female crabs during the fattening period. In the dietary regulation experiment, 270 female crabs were fed diets containing different doses of atRA (0, 150, 300, 600, 1200, and 2400 mg/kg) for a total of 49 days. In the in vivo injection experiment, 90 females were divided into an experimental group (injected with a 0.3 μg/g dose of atRA) and a control group (injected with the same amount of DMSO solvent). Injections were given weekly throughout the 35-day experimental period. Results: Both dietary atRA and atRA injection promoted ovarian development, as evidenced by increased GSI, elevated serum Vg levels, decreased GIH, and upregulated expression of vg, vgr, and rxr genes. In terms of mechanism, dietary atRA promoted ovarian development via the upregulation of pyrimidine nucleotides and dehydroepiandrosterone, which supplied nucleic acid precursors and hormonal support. Furthermore, RXR was identified as a potential key target of atRA in inducing ovarian development, as molecular docking revealed that atRA could spontaneously bind to RXR. Moreover, following atRA injection, the expression of rxr, along with key genes involved in ovarian development, lipid synthesis, and lipid transport, was significantly upregulated. In addition, the atRA diet created a favorable microenvironment for ovarian development by reducing pro-inflammatory lipid levels in the ovary. Transcriptomic and metabolomic analyses revealed that atRA modulates energy and lipid metabolism by activating the AMPK pathway. In terms of the bacterial community structure, the atRA diet significantly decreased Fusobacterium abundance and enriched Parabacteroides as the signature beneficial bacterium. In terms of nutritional quality, the atRA diet markedly reduced saturated and trans-fatty acids while increasing monounsaturated fatty acids and various key essential amino acids. Conclusions: This study revealed that atRA plays a key role in promoting ovarian development, improving nutritional quality, and modulating the structure of the microbiota, thereby providing theoretical support for healthy aquaculture of female crabs during the fattening period. Full article

Severe cutaneous adverse reactions (SCARs) are rare, life-threatening drug hypersensitivity syndromes. Although pharmacovigilance can identify drugs disproportionately reported with SCARs, it does not reveal which local chemistries recur among them. To address this, we assessed whether drugs with FAERS-derived SCAR disproportionality signals share interpretable chemical motifs. We screened FAERS data from 2004Q1 to 2024Q3, identified 5523 drugs with available Simplified Molecular-Input Line-Entry System (SMILES) representations, and constructed a signal-enriched dataset of 1676 compounds with nominally significant broad-SCAR associations after excluding predefined therapeutic/supportive confounders. Compounds were assigned to positive-signal [natural logarithm of reporting odds ratio (lnROR) > 0, n = 1219] or non-positive-signal (lnROR ≤ 0, n = 457) classes and encoded with 9753 explicitly mappable atom-centered local substructure descriptors. A LightGBM signal-classification model evaluated using random repeated nested cross-validation (six-fold outer × 50 repeats) achieved moderate internal discrimination (mean area under the receiver operating characteristic curve = 0.7041 ± 0.0337). Descriptor-space cluster-based repeated nested cross-validation, designed to reduce train–test structural leakage, yielded lower but still above-chance performance (mean ROC AUC = 0.6409; permutation p = 0.001), indicating that random-split estimates should be interpreted as optimistic for structurally novel compounds. Sensitivity analyses using minimum SCAR case-count thresholds and retention of predefined therapeutic/supportive drugs showed broadly similar performance and motif rankings. SHapley Additive exPlanations (SHAP) analysis revealed a fragment-level contrast: allylamine-like, ethanolamine-related, and diaminopropane-related motifs were associated with higher positive-signal class probability, whereas phenol and pyrimidine motifs were associated with lower positive-signal class probability. These findings suggest that FAERS-derived broad-SCAR signal direction is not chemically random within the selected dataset. Overall, the proposed framework should be viewed not as a direct predictor of absolute clinical SCAR risk but as an exploratory, pharmacovigilance-driven cheminformatics approach for prioritizing compounds and motif families for further SCAR-focused evaluation. Full article