Search Results (710)

Recently, vegetable oil-derived monounsaturated fatty acids (MUFAs) have predominantly been utilized in producing bio-based surfactants, resulting in low bioresource utilization and high separation costs. Although polyunsaturated fatty acids (PUFAs) are abundant and often co-exist with MUFAs, bio-based surfactants synthesized from PUFA-rich feedstocks have been less researched due to concerns regarding their interfacial performance. In this study, a novel series of PUFA-based zwitterionic surfactants with strong interfacial activity was synthesized from waste vegetable oils via an eco-friendly three-step process, optimized through an orthogonal experimental design. The structures and conversion rates of the surfactants were confirmed using GC-MS, LC-MS, and ESI-MS. At 0.5 g/L and 3.0 g/L (typical concentrations often used in most oil fields), the bio-based surfactants derived from waste soybean oil (PUFA-to-MUFA ratio ≈ 2.11, C18:2, and C18:1 in large contents) could reduce the interfacial tension between Daqing crude oil and simulated formation groundwater to an ultra-low level of ~10⁻³ mN/m. These results confirm our hypothesis that bio-based zwitterionic surfactants derived from PUFA-rich feedstocks possess excellent interfacial activity, providing a potential sustainable option to be considered for chemically enhanced oil recovery. Full article

Salinomycin is a polyether ionophorous antibiotic with promising antineoplastic properties. Published studies have revealed that the compound also exerts pronounced antidotal activity against cadmium (Cd) and lead (Pb) intoxications. It has been proven that salinomycin with Cd(II) forms a coordination compound of a composition [Cd(C₄₂H₆₉O₁₁)₂(H₂O)₂] and an octahedral molecular geometry, while the coordination compound of the antibiotic with Pb(II) has a square pyramidal structure and composition [Pb(C₄₂H₆₉O₁₁)(NO₃)]. To date, there is no published information about the ability of salinomycin to form complexes with the mercury ion (Hg(II)). Herein, we report, for the first time, a synthetic procedure for a complex compound of salinomycin with Hg(II). The coordination compound was characterized by a variety of methods, such as elemental analysis, attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR), electrospray ionization–mass spectrometry (ESI-MS), powder X-ray diffraction, nuclear magnetic resonance spectroscopy (NMR), thermogravimetry with differential thermal analysis (TG-DTA), and thermogravimetry with mass spectrometry (TG-MS). The elemental analysis data revealed that the new compound is of the chemical composition [Hg(C₄₂H₆₉O₁₁)(H₂O)(OH)]. Based on the results from the spectral analyses, the most probable structure of the complex was proposed. Full article

Marine organism-associated microbes are an important source of structurally diverse and biologically active secondary metabolites exhibiting antimicrobial, anticancer, and anti-inflammatory activities. In this study, we investigated Penicillium brevicompactum MSW10-1, isolated from Hydractinia echinata, a marine invertebrate adapted to extreme intertidal and subtidal environments with variable temperature, salinity, and oxygen conditions. Through a combination of LC/MS-guided chemical analysis and chromatographic purification, eight secondary metabolites were isolated, including brevicolactones A (1) and B (2). The absolute chemical structures of 1 and 2 were determined based on NMR spectroscopic experiments, HR-ESIMS data, and quantum chemical ECD calculations. The isolated compounds (1–8) were evaluated for their ability to inhibit hepatic lipogenesis, a key process in lipid metabolism that is dysregulated in metabolic-dysfunction-associated steatotic liver disease. Furthermore, the inhibitory effects of the isolated compounds on lipid accumulation were further evaluated in primary mouse hepatocytes, using Oil Red O staining. These findings suggested that the isolated compounds may serve as promising candidates for the treatment of metabolic liver diseases associated with lipid dysregulation. Full article

The imidazo[4,5-b]pyridine scaffold, a versatile heterocyclic system, is renowned for its biological and chemical significance, yet its coordination chemistry with biologically relevant metal dications remains underexplored. This study investigates the proton and metal dication affinities of twelve tetracyclic organic molecules based on the imidazo[4,5-b]pyridine core, focusing on their interactions with Ca(II), Mg(II), Zn(II), and Cu(II). Employing a dual approach of electrospray ionization mass spectrometry (ESI-MS) and density functional theory (DFT) calculations, we characterized the formation, stability, and structural features of metal–ligand complexes. ESI-MS revealed distinct binding behaviors, with Cu(II) and Zn(II) forming stable mono- and dinuclear complexes, often accompanied by reduction processes (e.g., Cu(II) to Cu(I)), while Ca(II) and Mg(II) exhibited lower affinities. DFT analysis elucidated the electronic structures and thermodynamic stabilities, highlighting the imidazole nitrogen as the primary binding site and the influence of regioisomeric variations on affinity. Substituent effects were found to modulate binding strength, with electron-donating groups enhancing basicity and metal coordination. These findings provide a comprehensive understanding of the coordination chemistry of imidazo[4,5-b]pyridine derivatives, offering insights into their potential applications in metalloenzyme modulation, metal-ion sensing, and therapeutic chelation. Full article

Accurate address matching is crucial for the analysis, integration, and intelligent management of urban geospatial data and is also a key step in achieving geocoding. However, due to the complexity, diversity, and irregularity of address expression, address matching becomes a challenging task. This paper proposes a multi-semantic feature fusion method for complex address matching of Chinese addresses that formulates address matching as a classification task that directly predicts whether two addresses refer to the same location, without relying on predefined similarity thresholds. First, the address is resolved into address elements, and the Word2vec model is trained to generate word vector representations using these address elements. Then, multi-semantic features of the addresses are extracted using a Text Recurrent Convolutional Neural Network (Text-RCNN) and a Graph Attention Network (GAT). Finally, the Enhanced Sequential Inference Model (ESIM) is used to perform both local inference and inference composition on the multi-semantic features of the addresses to achieve accurate matching of addresses. Experiments were conducted using Points of Interest (POI) address data from Baidu Maps, Tencent Maps, and Amap within the Chengdu area. The results demonstrate that the proposed method outperforms existing address matching methods, with precision, recall, and F1 values all exceeding 95%. In addition, transfer experiments using datasets from five other cities including Beijing, Shanghai, Xi’an, Guangzhou, and Wuhan show that the model maintains strong generalization ability, achieving F1 values above 84% in cities such as Xi’an and Wuhan. Full article

Phenylbutanoids, commonly found in various medicinal plants, have attracted significant attention due to their remarkable biological activities, including antioxidant, anti-inflammatory, and neuroprotective effects, as well as for their versatility as starting materials in organic synthesis. Among phenylbutanoids, phenyl-1,3-butadienes represent a unique class of conjugated dienes, characterized by a phenyl (C₆H₅) group attached to a 1,3-butadiene (-CH=CH-CH=CH₂) backbone. In this study, we synthesized the hydroxylated biphenyl 5,5′-di((E)-buta-1,3-dien-1-yl)-2,2′,3,3′-tetramethoxy-1,1′-biphenyl 1, closely related to its corresponding monomer 2, which is known for its broad range of pharmacological activities. The synthesis was carried out using microwave-assisted technologies. The structure of the synthesized compound was confirmed through elemental analysis, ¹³C-NMR, ¹H-NMR, and ESI-MS spectrometry. Furthermore, we computed this novel compound’s conformational energy profile (CEP), evaluating how its energy varies with changes in the dihedral bond angle. Full article

Nitro-functionalized heterocycles, such as nitroimidazoles, are significant environmental contaminants and have been identified as components of secondary organic aerosols (SOA) and biomass-burning organic aerosols (BBOA). Their strong absorption in the near-UV (300–400 nm) makes photochemistry a critical aspect of their atmospheric processing. This study investigates both the direct near-UV photochemistry and hydroxyl radical (OH) oxidation of 4-nitroimidazole (4-NI). The atmospheric photolysis rate of 4-NI in the near-UV (300–400 nm) was found to be J_4-NI = 4.3 × 10⁻⁵ (±0.8) s⁻¹, corresponding to an atmospheric lifetime of 391 (±77) min under bulk aqueous conditions simulating aqueous aerosols and cloud water. Electrospray ionization mass spectrometry (ESI-MS) analysis following irradiation indicated loss of the nitro group, while NO elimination was observed as a more minor channel in direct photolysis. In addition, the rate constant for the reaction of 4-NI with OH radicals, k_NI+OH, was determined to be 2.9 × 10⁹ (±0.6) M⁻¹s⁻¹. Following OH oxidation, ESI-MS results show the emergence of a dominant peak at m/z = 130 amu, consistent with hydroxylation of 4-NI. Computational results indicate that OH radical addition occurs with the lowest barrier at the C2 and C5 positions of 4-NI. The combined results from direct photolysis and OH oxidation experiments suggest that OH-mediated degradation is likely to dominate under aerosol-phase conditions, where OH radical concentrations are elevated, while direct photolysis is expected to be the primary loss mechanism in high-humidity environments and bulk cloud water. Full article

Platycladus orientalis, an evergreen tree belonging to the Cupressaceae family, has been traditionally used to treat various ailments, including fever, cough, diarrhea, diuresis, cold symptoms, and gastrointestinal disorders in folk medicine. As part of our ongoing investigation aimed at discovering bioactive natural products and elucidating their mechanisms of action from various natural sources, we investigated a methanol (MeOH) extract of P. orientalis leaves. This investigation led to the isolation and identification of a labdane-type diterpene, lambertianic acid (LA), via column chromatography and HPLC purification. The structure of LA was elucidated using LC/MS and NMR spectroscopic analyses, including HR-ESIMS, while its absolute configuration was confirmed through electronic circular dichroism (ECD) calculations. Recent studies have reported that labdane-type diterpenes exhibit diverse pharmacological activities, such as anticancer, anti-inflammatory, anti-obesity, and hypolipidemic effects. Notably, LA has been shown to modulate adipocyte metabolism via AMPK signaling; however, its role in skeletal muscle atrophy remains unexplored. Therefore, in this study, we investigated the effects of LA on dexamethasone (Dex)-induced muscle atrophy in C2C12 myotubes. Treatment with LA at concentrations of 25 µM and 50 µM significantly rescued myotube diameter and reduced the expression of atrophy-related proteins, including MuRF-1 and atrogin-1/MAFbx, without compromising cell viability at these moderate concentrations. These findings suggest that LA derived from P. orientalis exerts protective effects against skeletal muscle atrophy, highlighting its potential as a promising natural therapeutic candidate for muscle-wasting disorders. Full article

The marine environment is vital for sustaining life on Earth and offers a significant, untapped source of bioresources that could enhance the blue economy. The present investigation used our protocol to quickly identify bioactive molecules in Aplysina cauliformis organic extracts. This procedure combines a bioassay-guided approach with the dereplication of mass data through bioinformatic analysis. This approach identified the compound N,N,N-trimethyl-3,5-dibromotyramine, a bromo-tyramine analog that showed promising antiproliferative activity on HepG2 cell lines, with an IC₅₀ value of 37.49 ± 1.94 μg/mL after 24 h. Furthermore, the evaluation of related gene expression confirmed the mechanism of cell death to be apoptosis. N,N,N-trimethyl-3,5-dibromotyramine increased the expression of pro-apoptotic β-cell lymphoma 2-associated X protein (BAX) and Poly (ADP-ribose) polymerase (PARP-1) cleavage (c-PARP-1) and downregulated the anti-apoptotic β-cell lymphoma 2 (BCL-2) and phospho-Akt (p-AKT). This report presents N,N,N-trimethyl-3,5-dibromotyramine from Aplysina cauliformis and its antiproliferative activity against the HepG2 cell line. Full article

Two phenoxy-ketimines ligands, 2-(1-(benzylimino)ethyl)phenol (HL^BSMe) and 2-((benzylimino)(phenyl)methyl)phenol (HL^BSPh), were synthesized and used as supporting ligands of new copper(II), copper(I), and silver(I) complexes. In order to confer different solubility properties to the metal complexes and to stabilize Cu and Ag in their +1 oxidation state, the lipophilic triphenylphosphine (PPh₃) and the hydrophilic 1,3,5-triaza-7-phosphaadamantane (PTA) were selected as co-ligands in the syntheses of the Cu(I) and Ag(I) complexes. All compounds were characterized by CHN analysis, NMR, FT-IR spectroscopy, and electrospray ionization mass spectrometry (ESI-MS); the molecular structure of the copper(II) complex [Cu(L^BSPh)₂] was also determined by single-crystal X-ray diffraction. Finally, the antibacterial activity of the metal complexes, the Schiff base ligands and phosphane co-ligands, were assessed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) against Gram-negative (Escherichia coli) and Gram-positive bacteria (Staphylococcus aureus). Full article

Phytochemical investigation of the methanol extract of Embelia parviflora Wall. Ex A. DC. leaves (Primulaceae family) led to the isolation of sixteen compounds including three sterols (1–3), one triterpene (4), four flavonoids (5–8), four megastigmanes (9–12), three phenolic compounds (13–15), and one furan derivative (16). Their chemical structures were determined based on ESI-MS and NMR spectral data. This is the first chemical study of E. parviflora. Compounds 3, 8–13, and 16 were found in the Embelia genus for the first time. Compounds 9–11, 13, and 16 represent the first isolation from the Primulaceae family. In the α-glucosidase activity assay, MeOH extract, compounds 4 and 5 strongly inhibited enzyme α-glucosidase activity. A molecular docking study revealed that compounds 4 and 5 showed different interactions with enzyme α-glucosidase. Full article

1,2,4-Oxadiazole derivatives containing anisic acid or cinnamic acid were designed and synthesized, which were expected to be an effective Succinate dehydrogenase (SDH) inhibitor, and their structures were characterized by ¹H NMR, ¹³C NMR, and ESI-MS. The antifungal activity of the compounds against plant pathogenic fungi was screened by the mycelial growth inhibition test in vitro. Compounds 4f and 4q showed significant antifungal activities against Rhizoctonia solani (R. solani), Fusarium graminearum (F. graminearum), Exserohilum turcicum (E. turcicum), Botrytis cinerea (B. cinerea), and Colletotrichum capsica (C. capsica). The EC₅₀ values of 4q were 38.88 μg/mL, 149.26 μg/mL, 228.99 μg/mL, and 41.67 μg/mL against R. solani, F. graminearum, E. turcicum, and C. capsica, respectively, and the EC₅₀ values of 4f were 12.68 μg/mL, 29.97 μg/mL, 29.14 μg/mL, and 8.81 μg/mL, respectively. Compound 4f was better than commercial carbendazim against Exserohilum turcicum. Compounds 4f and 4q showed an antifungal effect on C. capsica of capsicum in vivo. Molecular docking simulation showed that 4f and 4q interacted with the target protein through the hydrogen bond and hydrophobic interaction, in which 4q can form hydrogen bonds with TRP173 and ILE27 of SDH, and 4f had hydrogen bonds with TYR58, TRP173, and SER39. This also explains the possible mechanism of action between the inhibitor and target protein. Full article

An Arctic marine-derived strain, MNP-1, was characterized by a combined methodological approach, incorporating a variety of analytical techniques including morphological features, biochemical characteristics, and 16S ribosomal RNA (rRNA) sequence analysis. The chemical investigation of Streptomyces sp. MNP-1 using the OSMAC (one strain many compounds) strategy yielded the isolation of twenty known compounds (1–20), which were unambiguously identified by various spectroscopic approaches including ¹H and ¹³C NMR and ESI-MS (previously reported data). Bioassay results indicated that compounds 2, 3, 5, 9, 14, 15, and 20 had antimicrobial activity against human pathogenic strains including Staphylococcus aureus, Escherichia coli, and Candida albicans with MIC values ranging from 4 to 32 μg/mL, and compounds 3 and 14 exhibited moderate inhibitory activity on A549, MCF-7, and HepG2 tumor lines showing IC₅₀ values within the range of 19.88 to 35.82 µM. These findings suggest that Streptomyces sp. MNP-1 is one of the prolific manufacturers of bioactive secondary metabolites with therapeutic potential. Full article

Ralstonia solanacearum is an important pathogen causing bacterial wilt in pepper (Capsicum annuum L.). The concurrent infection of R. solanacearum and root-knot nematodes (Meloidogyne spp.) exacerbates the severity of bacterial wilt in pepper. Utilizing plant endophytic bacteria to control these mixed diseases is a viable strategy. Waltheria indica L. (Sterculiaceae) is a traditional medicine plant. A total of 209 endophytic bacteria were isolated from W. indica, and Pseudomonas aeruginosa W-126 showed an efficient antagonistic effect against R. solanacearum. Based on active compound tracking principles, a compound was isolated through silica gel column chromatography and preparative HPLC combined with TLC analysis. It was identified as phenazine-1-carboxamide (PCN) by spectral techniques (ESI-MS, ¹H-NMR, ¹³C-NMR). PCN displayed excellent inhibitory activity against R. solanacearum, with an EC₅₀ of 64.16 μg/mL in vitro. In addition, it showed certain nematocide activity, with an LC₅₀ value of 118.63 μg/mL at 72 h. PCN also showed certain inhibitory activity against five other phytopathogenic bacteria. The structure−activity relationship indicated that the phenazine skeleton and acylamide groups were the key pharmacophores for the activity of phenazine-related compounds against R. solanacearum. PCN controlled the complex diseases of R. solanacearum and M. incognita in a pot experiment, with respective 51.41 and 39.80% inhibitory rates. The exploration of secondary metabolites of biocontrol bacteria can provide reference for the development of novel and efficient pesticides. Full article

Background: Glutathione (GSH) is an essential antioxidant that protects against oxidative stress, but its oral bioavailability is below 1% due to enzymatic degradation and poor gastrointestinal absorption. Improving the oral bioavailability of GSH could significantly enhance its therapeutic efficacy. Methods: This study synthesised GSH analogues with chemical modifications to improve bioavailability. Seven GSH derivatives were designed: three analogues with altered stereochemistry (1.62, 1.63, and 1.64) and three N-methylated derivatives (1.65, 1.70, and 1.71), alongside a native GSH (1.61). The analogues were synthesised via Fmoc-solid-phase peptide synthesis, and they were characterised using reverse-phase high-performance liquid chromatography (RP-HPLC), electrospray ionisation mass spectrometry (ESI-MS), Fourier-transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. Their toxicity was assessed on Caco-2 cells for viability, and their antioxidant activity was assessed on UVA-irradiated fibroblast cells, enzymatic resistance, and interactions with GSH-metabolising enzymes. Results: Among the tested analogues, the N-methylated cysteine Compound (1.70) emerged as the most promising candidate. Compound 1.70 demonstrated superior resistance to enzymatic degradation, as well as showing enhanced cell viability and improved antioxidant activity. In vivo studies revealed a 16.8-fold increase in plasma half-life (t½) and a 16.1-fold increase in oral bioavailability compared to native GSH. Conclusions: Chemical modification strategies, particularly the N-methylation of GSH, present a viable approach to enhancing oral bioavailability. Compound 1.70 showed significant potential for therapeutic applications, warranting further investigation and development in clinical settings. Full article