Search Results (868)

Vascular aging is a key determinant of cardiovascular risk and is characterized by endothelial dysfunction, oxidative stress, inflammation, arterial stiffness, and alterations of the endothelial glycocalyx. In recent years, increasing scientific interest has focused on whether selected nutritional supplements can modulate these mechanisms. The objective of this narrative review is to summarize and critically evaluate the current evidence regarding the effects of selected nutritional supplements on endothelial function and vascular health, with emphasis on their proposed mechanisms of action, available preclinical and clinical evidence, and current limitations. This review examines nutritional supplements targeting nitric oxide biology (L-arginine/L-citrulline and citrulline derived from watermelon), polyphenol-rich foods and extracts (cocoa flavan-3-ols and grape polyphenols), mitochondrial redox balance (coenzyme Q10 and the mitochondria-targeted antioxidant MitoQ), endothelial glycocalyx-supporting formulations, olive-derived bioactive compounds, curcumin, and S-allyl cysteine. Across studies, improvements have been reported primarily in surrogate vascular endpoints, including flow-mediated dilation, pulse wave velocity, and blood pressure, although effect sizes vary and substantial heterogeneity exists among studies. Overall, current evidence suggests that several nutritional supplements may improve surrogate markers of vascular function; however, evidence demonstrating reductions in major cardiovascular events or cardiovascular mortality remains limited. Future research should prioritize adequately powered randomized controlled trials with longer follow-up, standardized supplement formulations, and clinically meaningful cardiovascular outcomes to more clearly define the role of nutritional supplements in cardiovascular prevention. Full article

The reactivity of a range of cyclic monoterpenes in the presence of a crude peroxygenase-containing preparation from oat flour as a biocatalyst and tert-butyl hydroperoxide as an oxidant was evaluated, with the aim of highlighting the chemo- and stereoselectivity features of the enzyme. Most of the tested terpenes were converted to the corresponding epoxides or related diols via hydrolytic or rearrangement processes. The study on both the enantiomers of cis-carveol revealed that the enzyme catalyzed the formation of an epoxide ring with the same stereopreference, independently from the chirality of the pre-existent stereogenic centers, affording the two diastereoisomeric 1,2-epoxides with (1S,2R) configuration. The use of a commercial mixture of cis/trans (–)-carveol as the substrate, instead, resulted in the exclusive conversion of the cis-isomer and recovery of the unreacted trans-isomer, thus suggesting some influence of the configuration of allylic alcohol group on the recognition ability of the enzyme. A different reactivity of substrate enantiomers was also evidenced in the epoxidation of terpinene-4-ol, while perillaldehyde underwent exclusive oxidation to perillic acid. The biocatalyzed oxidation proceeds with high stereocontrol and offers a sustainable method for valorization of terpenes to fine chemicals, avoiding costs related to enzyme purification and disposal of toxic metal catalysts. Full article

Maintaining effective fluid-loss control in water-based drilling fluids under coupled high-salinity, high-temperature, and high-density conditions remains a critical challenge in deep and ultra-deep drilling operations. In this study, a low-molecular-weight polymer fluid-loss additive (LM-ASQF) was synthesized via redox-initiated copolymerization of acrylamide, dimethyldiallylammonium chloride, and sodium allyl sulfonate. The synthesis route and proposed polymer structure were further illustrated to clarify the incorporation of amide, quaternary ammonium, and sulfonate functional units within the LM-ASQF molecular architecture. The polymer exhibited a controllable number-average molecular weight of 18.2–29.4 kDa with a unimodal distribution. Thermal analysis confirmed that no main-chain-dominated degradation occurred below 220 °C, indicating structural stability under high-temperature conditions. In drilling-fluid systems containing NaCl, CaCl₂, and mixed salts (0–20%), LM-ASQF maintained stable rheological properties, with apparent viscosity ranging from 26.1 to 41.6 mPa·s, while the API fluid loss was controlled within 5.8–11.2 mL. After thermal aging at 220 °C for 16 h, the API fluid loss remained below 13 mL in both freshwater and mixed-salt systems. In high-density systems (1.80–2.40 g/cm³), the drilling fluids preserved continuous rheological structures and showed no abrupt increase in filtration. Mechanistically, fluid-loss control was primarily attributed to synergistic interfacial adsorption of amide groups, hydration stabilization induced by sulfonate functionalities, and particle rearrangement-driven filter-cake densification, rather than viscosity enhancement through long-chain entanglement. This mechanism enables effective filtration control without excessive viscosity increase, thereby maintaining rheological compatibility under complex conditions. These results demonstrate that the low-molecular-weight design strategy provides a reliable approach for achieving stable fluid-loss control in water-based drilling fluids under high salinity, elevated temperature, and high-density conditions. Full article

Natural compounds are increasingly explored as complementary strategies to enhance the effectiveness of chemotherapy and reduce toxicity. Among these are isothiocyanates (ITCs), bioactive metabolites derived from glucosinolates in cruciferous vegetables, which have gained substantial attention for their chemopreventive and antileukemic potential. ITCs exert diverse biological effects driven by the high reactivity of the –NCS group, enabling covalent modification of key cellular proteins and modulation of signaling pathways. Well-studied representatives, including sulforaphane (SFN), allyl isothiocyanate (AITC), 6-(methylsulfinyl)hexyl isothiocyanate (6-MITC), benzyl isothiocyanate (BITC), and phenethyl isothiocyanate (PEITC), exhibit diverse antileukemic activities, including cytotoxic, pro-apoptotic, differentiation-inducing, and cell-cycle-modulating effects. Although individual compounds differ in their relative potency and predominant biological responses, their activities are generally mediated through multiple interconnected mechanisms including oxidative stress modulation, mitochondrial dysfunction, regulation of apoptosis-related proteins, and interference with key signaling pathways. In addition to apoptosis, several ITCs have also been reported to induce autophagy, ferroptosis, or cellular differentiation in leukemic cells. Taken together, the existing evidence highlights ITCs as promising candidates for leukemia chemoprevention or therapy, acting through multi-targeted mechanisms that may complement conventional treatment strategies. Further studies are needed to clarify their selectivity, mechanistic diversity, and translational potential. Full article

Trimethylsilyl ethers of monoprotected isosorbide derivatives have been subjected to multicomponent Hosomi–Sakurai reactions with allyl trimethylsilane and various aldehydes (aromatic or aliphatic) under the catalysis of trimethylsilyl triflate. This study has allowed for establishing that: (a) the best results are obtained in reactions involving TMS ethers of the endo-OH group; (b) the most suited protecting group is the tert-butyldiphenylsilyl ether. With this ideal substrate, a scope was studied using both aromatic and aliphatic aldehydes. Good yields and excellent diastereoselectivities were typically achieved with aromatic aldehydes, unless they were very encumbered at the ortho position or strongly electron-poor. With simple aliphatic enolizable aldehydes, it may be useful to use an excess of aldehydes because of self-condensation processes. These results open the way to conjugates of bio-based isosorbide with aldehyde-derived fragments, joined through a very stable ether group. Full article

The synthetic strategy relies on the highly diastereoselective alkylation at the C4 position of L-pyroglutamic acid derivatives, followed by a decarboxylation-allylation process that enables the incorporation of diverse substituents, including aromatic substituents, affording trans-3,5-disubstituted γ-lactams with excellent diastereiosmeric ratio (dr > 98:2). The resulting γ-lactams were efficiently transformed into a series of α,γ-disubstituted γ-amino acids through hydrogenation and acidic hydrolysis. Furthermore, cross-metathesis reactions with styrene and 1-decene enabled the introduction of structurally diverse lipophilic side chains, furnishing the corresponding γ-amino acids in good overall yields (71–77%) and high diastereoisomeric ratio from >98:2 to 92:8. In addition, N-allylation followed by ring-closing metathesis and hydrogenation provided access to a previously unexplored conformationally constrained γ-amino acid. Overall, seven α,γ-disubstituted γ-amino acids, including fluorinated and conformationally restricted derivatives, were synthesized from common intermediates with high stereocontrol. The developed methodology offers a versatile platform for the preparation of structurally diverse and underexplored γ-amino acid building blocks of potential interest in peptide synthesis, medicinal chemistry, and antimicrobial agent development. Full article

Raw lacquer, a natural polymer derived from the bast of lacquer trees (Toxicodendron vernicifluum), is renowned as the “King of Coatings” due to its exceptional film-forming properties, abrasion resistance, corrosion resistance, and biocompatibility. However, its inherent limitations—including stringent drying conditions, slow curing rates, deep coloration, and difficult application—have severely restricted its modernization and widespread adoption. This review systematically summarizes recent research advances in the modification and application of raw lacquer, focusing on four major modification strategies: (1) Nanocomposite modification—incorporating functional nanofillers such as Al₂O₃, cellulose nanofibrils (CNF), polydopamine (PDA) melanin-like nanoparticles, and SiO₂ to significantly enhance film hardness, compactness, UV-aging resistance, and drying kinetics. (2) Chemical structure modification—employing molecular design strategies including aminoanthraquinone grafting, tung oil blending, water-based emulsification, and terpene/allyl group functionalization to improve hydrophobicity, flexibility, fast-drying properties, and achieve dual photo/oxygen curing. (3) Biomass synergistic composites—utilizing natural polymers such as chitosan and lignin, along with bio-inspired adhesion mechanisms (e.g., PDA), to confer advanced functionalities including antibacterial and antifouling properties. (4) Curing behavior regulation—precisely controlling drying kinetics through inorganic salt ion microenvironment engineering, nonionic surfactants, and salicylaldehyde Schiff base-based driers. Building upon these foundations, this review further expands on the emerging high-value applications of modified lacquer in preventive conservation of cultural heritage, advanced functional coatings (anti-corrosion, super-hydrophobicity, flame retardancy), biomedical materials (hemostasis, antibacterial activity, drug-controlled release, water treatment adsorption), and intelligent responsive flexible electronics. Finally, addressing challenges including weak fundamental research, bottlenecks in green industrialization, and lack of standardization, future development directions are proposed encompassing interdisciplinary innovation, sustainable modification strategies, integration of multifunctional intelligent systems, and big data-driven research paradigms, aiming to provide theoretical guidance and technical references for the high-value utilization and modernization of lacquer resources. Full article

The controlled synthesis of long hydrophobic blocks in amphiphilic block copolymers remains challenging in living anionic ring-opening polymerization (LAROP), particularly when competing effects such as back-biting and solubility limitations are involved. In this study, we investigated the temperature-dependent growth of poly(allyl glycidyl ether) (PAGE) blocks in PEO-b-PAGE block copolymers synthesized via LAROP using potassium naphthalenide as a co-initiator. Systematic variation in reaction parameters revealed that reaction temperature plays a significant role in governing effective PAGE block extension and dispersity control. Lower temperatures facilitated the formation of longer PAGE blocks with dispersities below 1.1 and DP values approaching targeted compositions, whereas elevated temperatures limited block growth. A group method of data handling (GMDH) polynomial neural network was employed as an auxiliary tool to prioritize influential variables within the experimental design matrix. The GMDH-guided analysis consistently identified temperature as the most influential variable, in agreement with experimental observations. These results provide quantitative insight into the temperature-controlled propagation behavior of PAGE in LAROP systems and offer a practical framework for improving block copolymer synthesis under kinetically and thermodynamically constrained conditions. Full article

Background/Objectives: Transition metal complexes of imidazoles exhibit a variety of biological activities. This makes them promising metal-based drugs for use in medicine. The aim of this research is to investigate the complexes of zinc(II) with N-vinyl, N-allyl, and N-propargylimidazoles, represented by the formula [ZnL₂Cl₂], as potential drug candidates. Methods: Structural studies of the obtained complexes were performed using single-crystal X-ray diffraction analysis, IR and NMR spectroscopy. DFT calculations were used to determine structural, electronic and thermochemical parameters of the complexes. QSAR analysis was performed using PASS. The wound-healing and antihypoxic activities were studied in vivo using models of wounds and acute hypoxia of various origins. The antimicrobial activity of the complexes was evaluated against Staphylococcus aureus Wood 46, Escherichia coli M-17, and the yeast fungus Candida albicans 927. The cytotoxic activity was tested using several cell lines, including monkey kidney (Vero) cells, human cervical cancer cells (Hep2C and HeLa), human lung carcinoma (A549), and human embryonal rhabdomyosarcoma (RD). Results: New complexes of N-allylimidazole and N-allyl-2-methylimidazole with ZnCl₂ were synthesized and characterized. All the studied complexes possess diverse biological activities. While the antimicrobial activity was modest, a distinct antifungal activity was observed. The cytotoxicity of the complexes was found to be mainly in relation to Hep2c and RD cell lines. Conclusions: Based on the results of QSAR analysis and experimental findings, the diverse biological activities of the compounds indicate that they are promising lead structures for further optimization in drug development. Full article

1,2,4-Trisubstituted chiral homoallylic alcohols are valuable intermediates in natural product synthesis and complex molecular architectures; however, their catalytic asymmetric synthesis remains challenging due to the need for precise control of regioselectivity, diastereoselectivity, E/Z geometry, and enantioselectivity. Herein, we report a palladium-catalyzed enantiospecific three-component reaction of aldehydes, borylated allyl acetates, and dimethylzinc for the efficient synthesis of 1,2,4-trisubstituted anti-(Z)-homoallylic alcohols. The present method employs readily accessible chiral borylated allyl acetates and proceeds with high levels of stereochemical control, providing a practical approach to structurally complex homoallylic alcohols. Full article

In the present work, we synthesize 2-(4-allyl-2-methoxyphenoxy)-1-(4-phenylpiperazin-1-yl)ethan-1-one, a semisynthetic derivative of the natural product eugenol. The compound was synthesized via a three-step synthetic pathway involving esterification, hydrolysis, and subsequent coupling with 4-phenylpiperazine, as confirmed by FTIR, ¹H NMR, ¹³C NMR, and mass spectrometric data. Full article

The tumor microenvironment, including extracellular pH (pHe), has emerged as a key regulator of tumor cellular function. Although extracellular acidification sensing and function are well established, the effect of extracellular alkalinization on cellular functioning remains unclear. Here, we report that transient receptor potential ankyrin 1 (TRPA1) functions as an alkaline sensor and mediator of cell death in melanoma cells. Exposure to alkaline pHe (8.1) or allyl isothiocyanate (AITC), a TRPA1 agonist, significantly reduced melanoma cell viability. We found that cell death was propidium iodide-positive and annexin V-negative, suggesting that pHe or AITC treatment induced necrosis rather than apoptosis. TRPA1 activation induced sustained Ca²⁺ influx, which was suppressed by either extracellular Ca²⁺ removal or treatment with the TRPA1 inhibitor, HC-030031, both of which attenuated cell death. Pharmacological screening has identified phosphatidylcholine-specific phospholipase D1 (PLD1) as a positive regulator of cell death. We confirmed that transfection with PLD1 siRNA significantly reduced AITC-induced cell death, whereas PLD2, PLD3, and NAPE-PLD siRNAs had no effect. These observations suggest that the vulnerability of melanoma cells to alkaline pHe is mediated by activation of the TRPA1-PLD1 axis. Thus, TRPA1 and PLD1 are potential targets for therapeutic intervention in melanoma. Full article

Bactrocera dorsalis (Hendel) is a major fruit-feeding pest that poses a severe and persistent threat to the horticulture industry in tropical and subtropical regions. Methyl eugenol (ME) is a powerful male-specific attractant phytochemical and pheromone precursor that has been widely exploited in lure-and-kill pest management programs. Upon ingestion, ME is metabolized (E)-coniferyl alcohol (E-CF) and 2-allyl-4,5-dimethoxyphenol (DMP), which are stored in the male rectal glands and released during courtship to attract females. Despite its ecological significance, the fundamental molecular mechanism underlying ME perception remains poorly understood. Here, we performed a comparative transcriptomic analysis of ME-responsive and ME-non-responsive male B. dorsalis across four tissues (head, gut, midleg, and wing). A total of 15,727 genes were annotated, of which 970 were associated with odorant-binding proteins (OBPs), odorant receptors (ORs), gustatory receptors (GRs), ionotropic receptors (IRs), and chemosensory proteins (CSPs), as well as detoxification families comprising cytochrome P450s (CYPs), carboxylesterases (CaEs), glutathione S-transferases (GSTs), and uridine diphosphate (UDP)-glycosyltransferases (UGTs), and the stress-related heat shock proteins (HSPs) genes. Differential expression analysis identified 7222, 7763, and 6105 differentially expressed genes (DEGs) in the head, gut, and wings/midlegs, respectively, between ME-responsive and ME-non-responsive males. Notably, CYPs, UGTs, and HSPs involved in detoxification and stress response were significantly downregulated. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses revealed that CYPs were significantly enriched in metabolic detoxification pathways. These findings reveal a complex molecular interplay between olfaction and detoxification and suggest that ME induces coordinated genetic pathways supporting survival, reproduction, and environmental adaptability. This knowledge provides a foundation for the development of eco-friendly pest management strategies targeting these molecular mechanisms. Full article

Lignin, a complex and heterogeneous polymer, poses significant challenges for effective thermal valorization due to its broad molecular weight distribution and structural diversity. This study systematically compares the effect of lignin’s molecular weight on product distribution under pyrolysis and Ru/C-catalyzed depolymerization conditions. Fractionated lignin samples with distinct molecular weights were subjected to identical thermal and catalytic conversion pathways. Pyrolysis results indicate that, compared with low-molecular-weight (low-MW) lignin, high-molecular-weight (high-MW) lignin more readily generates phenolic compounds, with the relative content of guaiacol increasing by nearly twofold. In contrast, products derived from low-MW lignin contain a higher abundance of unsaturated structures, such as 4-allyl-2,6-dimethoxyphenol, suggesting that side chain cleavage and rearrangement reactions are more pronounced. In contrast, Ru/C-catalyzed depolymerization exhibits a stronger molecular-weight-dependent selectivity, where low-MW lignin is more readily converted into carboxylic acids due to enhanced accessibility of terminal functional groups and reduced structural condensation. This comparative analysis demonstrates that lignin’s molecular weight plays a process-dependent role in governing product distribution, providing guidance for tailored lignin valorization strategies. Full article

The study presents novel photocrosslinked hydrogels based on methacrylated chitosan and methacrylated gelatin/allyl-modified gelatin and compares their properties as drug delivery systems in wound healing applications. The polymers were selected due to their biocompatible, mucoadhesive, cell-interactive properties and flexibility in adjusting their structure, making them suitable candidates for applications that require tissue repair. A range of hydrogel formulations was obtained by modulating the ratio of modified chitosan to two distinct modified gelatins, with photocrosslinking performed using Irgacure 2959 as the photoinitiator. FT-IR analysis, SEM data, and swelling and mechanical properties confirmed the 3D networking and the compatibility between the hydrogel components. Allylic gelatin-based hydrogels present larger pores and a stronger pH-responsive swelling behaviour compared to methacrylated gelatin-based samples, reflecting the higher flexibility of allylic gelatin networks. The hydrogels release bacitracin during the first six hours, with a release profile that follows a non-Fickian diffusion mechanism. Cytocompatibility and wound healing potential were tested in the presence of human and mouse fibroblasts, cells with a pivotal role in the wound healing process. All formulated hydrogels exhibit antioxidant capacity and protein stabilization properties, which are attributed to the presence of chitosan in their composition. The cytocompatibility, in vitro wound healing, and biological properties of the obtained hydrogels, as well as the drug release results, confirm their suitability in wound healing applications. Full article