Search Results (1,171)

This study investigated the structural and anti-inflammatory properties of Zophobas morio lipids (ZMLs). The fatty acid (FAs) composition showed a higher proportion of unsaturated FAs, mainly consisting of oleic (30.30%) and linoleic acids (20.05%), than saturated FAs, including palmitic (24.80%) and stearic acids (12.96%). In addition, FT-IR and ¹H-NMR analyses confirmed that ZML possessed a typical triglyceride structure, with long-chain alkyl groups. Thermogravimetric analysis (TGA) indicated that ZML exhibited high thermal stability, with a degradation peak at 369 °C. Differential scanning calorimetry (DSC) displayed a thermal transition at −8 °C, corresponding to the crystallization of unsaturated FAs in ZML. ZML significantly inhibits lipopolysaccharide (LPS)-induced pro-inflammatory M1 macrophage polarization by suppressing nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways, thereby attenuating the expression of inflammatory mediators. Additionally, ZML alleviated inflammatory oxidative stress by activating the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant pathway. Notably, ZML not only induced M2 macrophage polarization in quiescent macrophages but also reprogrammed M1 macrophages toward the anti-inflammatory M2 phenotype. These findings suggest that ZML is a natural nutritional lipid source and a potential therapeutic agent for modulating inflammatory response. Full article

Background: The escalating spread of drug-resistant bacteria is intensifying the antibiotic resistance crisis, necessitating the urgent development of novel antimicrobial agents to address the resulting high global mortality rates and significant socioeconomic burden. Objectives: This study aimed to aminate the C-6 position of β-carboline and investigate the antibacterial activity and mechanism of action of the derivatives. Results: For the first time, 16 derivatives with various nitrogen-containing moieties, including aliphatic- and phenyl-amino, imidazolium, pyridinium, and quinolinium, were synthesized via amination at the C-6 position of β-carboline. These compounds exhibited moderate to good activity against Gram-positive methicillin-resistant Staphylococcus aureus (MRSA) and Bacillus subtilis, with minimum inhibitory concentration (MIC) values ranging from 1.56 to 100 μg/mL. The study reveals that elongating an alkyl chain, incorporating a cationic scaffold, and expanding a π-delocalized system can enhance antibacterial activity. The most potent derivative from each series was selected for further mechanistic investigation against MRSA. All studied compounds demonstrated low hemolytic activity and low cytotoxicity. Studies on the antibacterial mechanism indicated that the compounds exert their antibacterial effects by disrupting bacterial cell walls and membranes. Additionally, two of the compounds were found to potentially disrupt the secondary structure of DNA. All tested compounds exhibited antibiofilm activity. Conclusions: Our findings demonstrate that amination modification at the C-6 position of β-carboline can enhance antibacterial activity by disrupting the cell wall membranes and interacting with bacterial DNA. These results provide a basis for further optimization of antibacterial agents based on β-carboline. Full article

In this work, the volumetric properties of nine binary systems composed of ethyl propanoate and n-alkylcyclohexanes (from cyclohexane to decylcyclohexane) were investigated. Densities were measured at atmospheric pressure (101 kPa) over the entire composition range and at temperatures from 288.15 K to 328.15 K. A total of 525 density data points were obtained. Excess molar volumes were derived from the experimental densities and correlated using a Redlich–Kister equation, while mixture densities were modeled with the Jouyban–Acree model. All systems exhibit positive excess molar volumes over the studied temperature and composition ranges, indicating volume expansion upon mixing due to dominant repulsive interactions. The magnitude of the excess molar volume increases with increasing alkyl chain length of the branched naphthenic compound: for an equimolar mixture, V^E is about 0.65 cm³·mol⁻¹ for the methylcylohexane + ethyl propanoate mixture and reaches 0.83 cm³·mol⁻¹ for the heptylcylohexane + ethyl propanoate binary system, although a plateau tendency is observed for longer alkyl chains. Excess molar volumes increase linearly with temperature, with a more pronounced temperature effect for shorter-chain alkylcyclohexanes. The Jouyban–Acree model provides an excellent correlation of the density data, yielding average relative deviations between 0.02% and 0.04%, and allows reliable predictions within the investigated temperature range. Full article

This study investigates the key performance-related fuel properties of emulsifier–diesel solutions and ethanol-in-diesel microemulsions. This work begins with the in situ polymerization of long alkyl chain-substituted glycidyl methacrylate (R-GMA) in diesel and the optional presence of a second methacrylate monomer. The resulting diesel-soluble oligomer functions as a nonionic emulsifier. Controlled amounts of ethanol are subsequently incorporated into the emulsifier–diesel solution to form a stable microemulsion, referred to as E-Diesel. This study examines how the structure of the emulsifier influences key fuel properties, including (i) ethanol–diesel miscibility, (ii) gross calorific value, (iii) Ramsbottom carbon residue (% of fuel), (iv) entrapped polycyclic aromatic hydrocarbons (PAHs), and (v) fuel lubricity. Both the hydrophilic–hydrophobic balance and the structure of the emulsifier side chains are found to significantly affect these properties. Compared with neat diesel, oligomeric emulsifiers enable the substantial dispersion of ethanol in diesel (up to 18 wt.%). The resulting fuel exhibits a gross calorific value exceeding the theoretical sum of diesel and ethanol at the same composition (a synergistic effect) and achieves an enhancement in lubricity up to 49.5% relative to neat diesel at a 5% emulsifier loading. Although the presence of emulsifiers leads to an increase in the carbon residue by up to 54.7% compared to neat diesel during controlled pyrolysis, it simultaneously reduces the PAH content in the exhaust. Overall, this study establishes fundamental correlations among microemulsion stability, combustion synergy, carbon residue formulation, and fuel lubricity, which are governed by the structure of the emulsifier. Full article

The hydroformylation of alkenylbenzenes remains insufficiently defined, despite the relevance of these substrates as biomass-derived aromatic feedstocks within sustainable chemical transformations. In this work, we present an experimental (catalytic and kinetic) study of their conversion into aldehydes under rhodium-phosphine catalysis, using complexes bearing mono-, bi- and tridentate phosphine ligands, [Rh(H)(CO)₂(PPh₃)₂], [Rh(H)(CO)(triphos)] and [Rh(H)(CO)₂(dppe)], under mild reaction conditions (80 °C and 2–30 bar of syngas for eugenol; 80 °C and 20–50 bar of syngas for estragole and trans-anethole). The catalytic activity order of the complexes was Rh (PPh₃) > Rh(triphos) > Rh(dppe), while the substrate reactivity followed the trend eugenol > estragole >> trans-anethole. Reaction rates were measured across a wide CO and H₂ pressure range, revealing redistribution between the active monocarbonyl species and an off-cycle (acyl)dicarbonyl complex that becomes dominant at elevated p(CO). The kinetic behavior observed for eugenol hydroformylation with Rh(PPh₃) was consistent with the established hydroformylation sequence involving alkene coordination, hydride migration to substrate and the CO-dependent re-coordination steps that determine catalyst speciation; the subsequent transfer of the alkyl group to the carbonyl ligand and hydrogenolysis complete the catalytic cycle; the H₂ addition or the hydride transfer to the alkene was identified as the rate-determining step, depending on whether low or high p(H₂) values were employed. To obtain statistically reliable kinetic parameters- often challenging in hydroformylation because of parameter covariance and restricted identifiability- we complemented conventional nonlinear regression with Bayesian inference based on the Markov Chain Monte Carlo approach. The resulting posterior distributions were well centered, exhibited realistic variance and provided parameter sets that are sufficiently robust to support mechanistic interpretation and subsequent kinetic modeling. Full article

The preparation of the novel optically active sulfoxides (-)-(S)-1,1,1,3,3,3-hexafluoro-2-[o-(p-tolylsulfinyl)phenyl]propan-2-ol 1, (-)-(S)-1,1,1,3,3,3-hexafluoro-2-[o-(methylsulfinyl)phenyl]propan-2-ol 2 and (-)-(S)-1,1,1,3,3,3-hexafluoro-2-[o-(t-butyl-sulfinyl)phenyl]propan-2-ol 3 according to the Andersen methodology and their spectroscopic characterization is presented. The NMR and CD spectroscopic evidence of the existence of the equilibrium between sulfoxide and hypervalent sulfurane forms of these compounds in solution and attempts at the isolation of corresponding sulfuranes are shown. For compound 3, the unprecedented subsequent irreversible transformation in solution into corresponding cyclic sulfinate ester–sultine 17 was established on the basis of NMR spectroscopy measurements. The mechanism of this transformation was investigated by means of GC-MS analysis and confirmed on the basis of synthesized long alkyl chain analog 23 transformation in solution. Moreover, the oxidation properties of obtained sulfoxides 2 and 3 for the selected compounds are described. Full article

Rhizopus oryzae lipase (ROL) is a key enzyme involved in olive oil spoilage and acts as a virulence factor in fungal infections. Natural lipophilic lipase inhibitors are crucial for mitigating economic losses resulting from lipid degradation in stored or decaying olive fruits. This study evaluated a series of enzymatically synthesized piperate esters with varying alkyl chain lengths (butyryl, C4; octyl, C8; dodecyl, C12) for their inhibitory effects on ROL activity. Octyl piperate (C8) demonstrated the highest potency, with IC₅₀ values of 0.05 mg/mL using methods B and C or 0.25 mg/mL using method A. Molecular docking indicated that C8 achieved the most favorable predicted binding energy (Gscore: –11.134 kcal/mol), primarily through hydrophobic interactions (Val329, Ala212, Phe209) and hydrogen bonds with oxyanion hole residues (Ser268, Thr206, Gln241). Molecular dynamics simulations confirmed that C8 maintained stable binding and stabilized the catalytic residues. In comparison, C4 exhibited weaker interactions, and the longer C12 chain induced conformational instability and steric hindrance. These results establish a parabolic structure–activity relationship, identifying the octyl chain (C8) as optimal for ROL inhibition among the tested derivatives. The rational design of lipophilic, biodegradable lipase inhibitors thus positions octyl piperate as a promising candidate for extending olive storage and shelf life, and as a scaffold for developing natural antifungal agents targeting virulent R. oryzae strains. Full article

To elucidate the mechanisms by which the hydrophobic hydrocarbon chain length of emulsifiers and the surface properties of aggregates influence the adhesive performance at the emulsified asphalt–aggregate interface, this study employed molecular dynamics simulations to construct interface models. Key parameters, including relative concentration, diffusion coefficients, and interfacial adhesion work, were systematically analysed to reveal the intrinsic effects of imidazoline-type emulsifier chain length and aggregate type on interfacial behaviour. The results indicate that increasing the hydrophobic chain length of the emulsifier suppresses the adsorption of emulsified asphalt at the aggregate interface. The diffusion coefficients of both emulsifier and asphalt molecules initially increase and subsequently decrease with chain length, with the non-polar asphalt components (aromatics and saturates) exhibiting greater sensitivity to chain length variations. Moderate extension of the hydrophobic chain enhances interfacial adhesion work, whereas exceeding the optimal chain length reverses this trend, weakening adhesion. Aggregate surface properties exert a significant influence on interfacial behaviour. Compared with the acidic SiO₂ (0 0 1) surface, the basic CaCO₃ (1 0 4) surface exhibits lower peak relative concentrations of emulsified asphalt, reduced sensitivity to variations in emulsifier chain length, lower molecular diffusion coefficients, and stronger interactions with asphalt molecules, resulting in superior interfacial adhesion. This study provides a molecular-level theoretical basis for the targeted design of emulsifier structures and the efficient adaptation of emulsified asphalt to different aggregate systems. Full article

Dietary lipids not only enhance the flavor and nutritional value of food, but more importantly, they offer essential fatty acids and energy for metabolism. The importance of lipid unsaturation has gained increasing attention; however, the impact of the alky chain length on biofunction of dietary lipids remains unclear. This article discusses the effects of the alkyl chain length on the biological function of lipids, focusing on physical and chemical properties, digestion and absorption, and nutritional functions. Firstly, with the increase in the chain length, the melting point of the crystal increases, the symmetry increases, and the hypersensitivity induction decreases. Secondly, the alkyl chain length affects the contact between lipid droplets and lipase, as well as the fatty acids release rate. Finally, medium-chain and short-chain lipids can partially reverse the effect of long-chain lipids. Understanding the effect of the alkyl chain length on the biofunction of dietary lipids can provide valuable insights for designing nutritious diet. Full article

Ordered mesoporous silica (OMS) is widely investigated as a mineral carrier for bioactive compounds; however, the adsorption of poorly soluble flavonoids such as quercetin on unmodified silica remains limited, and the effect of cationic surfactant modification on adsorption performance is still insufficiently understood. This study evaluates the adsorption of quercetin on OMS modified with tetrabutylammonium bromide (TBA-Br) and hexadecyltrimethylammonium bromide (HDTMA-Br). Batch adsorption experiments were analyzed using various adsorption isotherm models, and the quality of fit was evaluated based on the coefficient of determination (R²) and the reduced chi-square statistic (χ²/DoF). The results indicated that quercetin adsorption followed a physisorption mechanism, predominantly governed by hydrophobic interactions and surface heterogeneity. Silica modified with HDTMA-Br exhibited a significantly higher maximum sorption capacity compared to OMS-TBA-Br, reaching g_max values of up to 5.2 mg·g⁻¹, whereas the maximum adsorption for OMS-TBA-Br did not exceed 4.2 mg·g⁻¹. The best fit of the experimental data was obtained for models accounting for the heterogeneous nature of the adsorbent surface, particularly the Tóth model. The obtained results clearly demonstrate that modification of OMS with a cationic surfactant possessing a long alkyl chain significantly enhances the adsorption capacity of silica toward quercetin, which is of considerable importance for the design of mineral carriers for bioactive compounds. Full article

In order to prepare alkyl-functionalized reduced graphene oxide more simply, economically and environmentally, we adopt a two-step method of first reduction and then surface grafting. Graphite oxide (GtO) is first exfoliated to thermally-reduced graphene oxide (TRGO) and then, in a heat-induced solid-state reaction, converted to lauryl-functionalized TRGO (LTRGO). During the second step, lauryl radicals generated from the decomposition of lauroyl peroxide (LPO) open the epoxide rings on TRGO, covalently grafting the alkyl chains. The average water contact angle of LTRGO is 135.5°, and it disperses stably in base oil without surfactants or other additives. Four-ball test results show when the dosage of LTRGO is 75 mg/L, the average friction coefficient and wear scar diameter of the Formosa Plastics base oil (100 N) are decreased by 20.8% and 15.4%, respectively. The morphology and element analysis after ball-on-disk friction tests showed that the stable LTRGO physical friction adsorption film and metal oxide friction chemical reaction film could be formed between the friction pairs, thus reducing the friction wear. Full article

Oxidative stress results from the excessive production of reactive oxygen species (ROS), which cause cellular and molecular damage and contribute to chronic diseases. Given the recognized antioxidant potential of benzimidazole derivatives—particularly 2-mercaptobenzimidazole—this study aimed to synthesize novel organosilicon S-silylalkylthioethers (I–IV) and N-alkylsilylthioethers (1a–3f) derived from this scaffold and to evaluate their antioxidant and antibrowning properties. The S-silylalkylthioethers were obtained by reacting 2-mercaptobenzimidazole with different chloroalkylsilanes under reflux in ethanol, followed by a reaction with alkyl halides in aprotic media at room temperature to prepare the N-alkylsilylthioethers. Structural elucidation was achieved through 1D and 2D NMR and FT-IR. Antioxidant activity was assessed using DPPH, the total antioxidant capacity, and ferric-reducing assays. The results showed several derivatives with notable antioxidant responses, revealing a clear relationship between carbon chain length, logP values, organosilicon substitution patterns, and radical-scavenging efficiency. Spearman correlation analysis further confirmed that DPPH activity is inversely related to total carbon number, molecular size, molecular weight, and LogP (ρ = −0.68 to −0.73, p < 0.001) and moderately negatively correlated with N-alkyl chain length (ρ = −0.47, p = 0.027), while S-alkyl chains showed no significant effect. These findings highlight the potential of these benzimidazole–organosilicon hybrids as antioxidant candidates and demonstrate how physicochemical properties govern their reactivity and antiradical capacity. Full article

The extent of consumer approval for lamb is intimately connected to meat quality standards. Within this context, the distinctive ‘mutton taint’ serves as a critical benchmark for assessment, a characteristic that is largely governed by the concentrations of three fundamental branched-chain fatty acids (KBCFA), specifically 4-methyloctanoic acid (MOA), 4-ethyloctanoic acid (EOA), and 4-methylnonanoic acid (MNA). While Allium mongolicum Regel (AMR)—an Allium species prevalent in arid Asian regions known for its abundant bioactive constituents—is known to improve meat quality and mitigate these off-flavors, the potential mediating role of the rumen fluid in this process remains unclear. This study investigated whether rumen fluid transplantation (RFT) from AMR-fed donors could mimic the impacts of directly adding AMR to the diet on KBCFA accumulation and meat attributes. Thirty male lambs (23 ± 2 kg BW) were allocated at random into three distinct treatments (n = 10): a control set (CON), a dietary supplementation group administered 15 g/d of AMR (AMG), along with a rumen fluid transplantation treatment (RTG) inoculated with rumen fluid from AMR-fed donors. The carcass traits, physicochemical properties, and makeup of amino acids, as well as the fatty acid constitution of the longissimus thoracis muscle, were subjected to analysis. Data revealed that the levels of KBCFAs associated with off-flavors were markedly lowered in both the AMG and RTG. Specifically, decreases ranging from 49% to 64% were observed in MOA, EOA, and MNA concentrations (p < 0.05). Relative to the control group, drip loss and cooking loss were reduced in the treatment groups (p < 0.05), whereas ash (p = 0.047) and crude protein (p = 0.001) were increased. Moreover, the interventions improved the composition of essential amino acids (EAA), flavor-enhancing amino acids, and polyunsaturated fatty acids (PUFAs). In conclusion, rumen fluid transplantation effectively replicates the beneficial effects of dietary AMR on meat quality, particularly in reducing taint-related KBCFA. Such outcomes imply that rumen microbial communities likely act as a crucial mediator in controlling meat flavor. Full article

The search for new antibacterial agents is an important task due to the emergence of resistance to widely used drugs. Bromine-, chlorine-, and nitro-substituted phenyl ring azomethines with long alkyl chains (C₁₂, C₁₄, C₁₆, and C₁₈) were synthesized and characterized using several experimental methods (NMR and IR spectroscopy, elemental analysis, mass spectrometry). Antibacterial and antifungal activity was tested on several cultures; the synthesized compounds show activity at the level of some commercial antiseptics. Lipophilicity (an important descriptor for predicting biological properties) of the experimentally synthesized and isomeric molecules was determined by three different approaches: quantum chemistry, machine learning (GraphormerLogP model), and an atom contribution model (RDKit library). The quantum-chemical method can account for any spatial arrangements and can be considered the most accurate of the approaches used, but it requires significant computational time. The atom contribution model is the fastest of the methods used, but it gives underestimated results, and different isomers have exactly the same values, in contrast to the quantum chemistry results. Machine learning-based methods (GraphormerLogP) demonstrate acceptable accuracy, sensitivity to isomerism, and orders-of-magnitude higher throughput, making them an optimal tool for high-throughput screening. Full article

In this study, the corrosion behavior of pure aluminum in methyl esters with different degrees of unsaturation and chain lengths, as found in biodiesel, was investigated using electrochemical techniques. The methyl esters evaluated included methyl acrylate (C₄H₆O₂) and methyl linoleate (C₁₉H₃₄O₂), which were added to methyl propionate (C₄H₈O₂) and methyl oleate (C₁₉H₃₆O₂), respectively. The electrochemical techniques employed were electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN), complemented by detailed scanning electron microscopy (SEM) analyses. The results indicated that both the corrosion rate and the susceptibility to localized corrosion, such as pitting, increased with higher degrees of unsaturation and longer alkyl chain lengths. The corrosion process remained under charge transfer control and was not directly influenced by these factors. However, the charge transfer resistance decreased with increasing unsaturation and chain length, consistent with the observed increase in corrosion rate. Full article