Search Results (132)

Methylglyoxal (MGO) is a highly reactive a-dicarbonyl compound produced in foods and endogenously in humans and constitutes a predominant precursor of advanced glycation end products that contribute to the pathology of several diseases, including diabetes and neurodegenerative diseases. In this study, the efficiency of pyrogallol, gallic acid, ethyl, and propyl gallate in trapping MGO was investigated at pH 6.5 to 8.0. Pyrogallol was the most efficient MGO-trapping agent, followed by gallic acid, whereas the alkyl gallates were notably less efficient, particularly at slightly acidic and neutral pH. The increase of pH from slightly acidic to alkaline enhanced the MGO-trapping efficiency of all compounds, albeit to a different extent that correlated inversely to the pK_a of the most acidic -OH phenolic group, demonstrating the contribution of the deprotonated forms of the phenolic compounds in the enhanced reactivity towards MGO. The reaction products of pyrogallol, identified as the most efficient compound in MGO-trapping, were analyzed and characterized by liquid chromatography-mass spectrometry (LC-MS). Both mono-MGO and di-MGO conjugated adducts of pyrogallol were detected, with the mono-MGO adduct being dominant solely at acidic pH and the di-MGO pyrogallol adducts becoming prevalent at neutral and alkaline pH. Therefore, the pH was determined as a main factor that controls the reaction pathways of the phenolic compounds with MGO. Full article

Estradiol (E2) plays an important role in cell proliferation and certain brain functions. To reveal its mechanism of action, its detectability is essential. Only a few fluorescent-labeled hormonally active E2s exist in the literature, and their mechanism of action usually remains unclear. It would be of particular interest to develop novel labeled estradiol derivatives with retained biological activity and improved optical properties. Due to their superior optical characteristics, aza-BODIPY dyes are frequently used labeling agents in biomedical applications. E2 was labeled with the aza-BODIPY dye at its phenolic hydroxy function via an alkyl linker and a triazole coupling moiety. The estrogenic activity of the newly synthesized fluorescent conjugate was evaluated via transcriptional luciferase assay. Docking calculations were performed for the classical and alternative binding sites (CBS and ABS) of human estrogen receptor α. The terminal alkyne function was introduced into the tetraphenyl aza-BODIPY core via selective formylation, oxidation, and subsequent amidation with propargyl amine. The conjugation was achieved via Cu(I)-catalyzed azide–alkyne click reaction of the aza-BODIPY-alkyne with the 3-O-(4-azidobut-1-yl) derivative of E2. The labeled estrogen induced a dose-dependent transcriptional activity of human estrogen receptor α with a submicromolar EC₅₀ value. Docking calculations revealed that the steroid part has a perfect overlap with E2 in ABS. In CBS, however, a head-tail binding deviation was observed. A facile, fluorescent labeling methodology has been elaborated for the development of a novel red-emitting E2 conjugate with substantial estrogenic activity. Docking experiments uncovered the binding mode of the conjugate in both ABS and CBS. Full article

The functionalisation of lignin-derived phenolics (guaiacol, 4-propylguaiacol, eugenol, isoeugenol, phenol, m-cresol, catechol, syringol, syringaldehyde, and vanillin) for the synthesis of thermoplastic polyurethanes (PUs) and polyester (PE) resins is herein described. Diols were synthesised from phenolics in a one-step reaction using either glycerol carbonate or ethylene carbonate as a greener, solvent-free synthetic route. Nine of the diols were selected for the synthesis of Pus, and two of the diols were used for the synthesis of PE resins, with their physical and thermal properties characterised. Analysis of the PUs by differential scanning calorimetry (DSC) confirmed their amorphous nature, while thermogravimetric analysis (TGA) suggested improved thermal stability for all PUs with the addition of an alkyl or aldehyde substituent on the benzene ring regardless of the diisocyanate used. However, lower PU thermal stabilities were observed with the use of an aliphatic diisocyanate over an aromatic diisocyanate in the absence of an additional substituent. Analysis of the PEs by DSC also confirmed that the clear resins were all amorphous, and gel permeation chromatography (GPC) revealed significantly higher molecular weights and dispersities when an aliphatic diacid was utilised over an aromatic diacid. Full article

Urushiol, the principal bioactive component of natural lacquer, has emerged as a promising candidate for developing eco-friendly antimicrobial coatings due to its unique catechol structure and long alkyl chains. This review systematically elucidates the molecular mechanisms underpinning urushiol’s broad-spectrum antimicrobial activity, including membrane disruption via hydrophobic interactions, oxidative stress induction through redox-active phenolic groups, and enzyme inhibition via hydrogen bonding. Recent advances in urushiol-based composite systems—such as metal coordination networks, organic–inorganic hybrids, and stimuli-responsive platforms—are critically analyzed, highlighting their enhanced antibacterial performance, environmental durability, and self-healing capabilities. Case studies demonstrate that urushiol derivatives achieve >99% inhibition against both Gram-positive and Gram-negative pathogens, outperforming conventional agents like silver ions and quaternary ammonium salts. Despite progress, challenges persist in balancing antimicrobial efficacy, mechanical stability, and biosafety for real-world applications. Future research directions emphasize precision molecular engineering, synergistic multi-target strategies, and lifecycle toxicity assessments to advance urushiol coatings in medical devices, marine antifouling, and antiviral surfaces. This work provides a comprehensive framework for harnessing natural phenolic compounds in next-generation sustainable antimicrobial materials. Full article

Passenger car tires (PCTs) usually consist of a silica/silane-filled Butadiene Rubber (BR) or Solution Styrene Butadiene (SSBR) tread compound. This system is widely used due to improvements observed in rolling resistance (RR) as well as wet grip compared to carbon black-filled compounds. However, the covalent bond that couples silica via silane with the rubber increases the challenge of recycling these products. Furthermore, this strong covalent bond is unable to reform once it is broken, leading to a deterioration in tire properties. This work aims to improve these negative aspects of silica-filled compounds by developing a novel coupling system based on non-covalent interactions, which exhibit a reversible feature. The formation of this new coupling was accomplished by reacting silica with silane and a phenolic resin in order to obtain simultaneous π–π interactions and hydrogen bonding. The reaction was performed using two different silanes (amino and epoxy silane) and an alkyl phenol–formaldehyde resin. The implementation of the new coupling resulted in improved crosslink density, better mechanical performance, superior fatigue behavior, and a similar rolling resistance indicator. Full article

The application of biochar to traditional soil and soilless growth media in agriculture has been reported to increase plant production. However, it remains unclear which biochar component drives this process or which biogeochemical process is attributed to better plant productivity. Therefore, this study aims to determine how biochar organic carbon (C) composition and thermal stability influence nitrogen availability and tomato production. Soilless growth media composed of a mixture of 60% and 40% coconut coir (CC) (Cocos nucifera L.) and fine pine bark (PB) (Pinus genus), respectively, was amended with 0, 1, 2, 3, 4, 6, 8, 10, and 12% biochar per dry weight. The amended media were used to grow Red Bounty tomatoes (Lycopersicum esculentum) for three months. After harvesting tomatoes and determining yield, organic C composition and C thermal stability of the biochar amended soilless growth media mixtures were determined using solid-state ¹³C nuclear magnetic resonance (¹³C NMR) and multi-elemental scanning thermal analysis (MESTA), respectively. Thermal stability data were used to determine the “R400 index”, and nitrate (NO₃⁻) concentration was determined using the water extractable method. Results showed that biochar-amended media significantly increased pH (p < 0.0001) and NO₃⁻ (p = 0.0386) compared to the no-char control. Biochar amended soilless media organic C composition was dominated by O-alkyl-C as a result of a higher fraction of soilless media; however, total C, carboxyl-C, phenolic-C, and aromatic-C increased with increasing biochar content and related negatively to R400, which decreased with increasing biochar content. Nitrate retention and tomato yield increased with increasing total C, carboxyl-C, phenolic-C, and aromatic-C and decreasing R400. This indicates that the stable form of C, carboxyl-C, phenolic-C, aromatic-C, and low R400 enhanced NO₃⁻ sorption, reducing leaching and enhancing its availability for tomato growth. Full article

Mine ramps, serving as a critical transportation hub in underground mining activities, are beset by severe issues of dust pollution and secondary dust generation. While dust suppressants are more efficient than the commonly used sprinkling methods in mines, traditional single-function dust suppressants are inadequate for the complex application environment of mine ramps. Building on the development of conventional single-function dust suppressants, this research optimized the components of bonding, wetting, and moisturizing agents. Through single-factor optimization experiments, a comparison was made of the surface tension water retention property and viscosity of diverse materials, thus enabling the identification of the primary components of the dust suppressant. By means of synergistic antagonism experiments, the optimal combination of the wetting agent and bonding agent with excellent synergy was ascertained. Ultimately, the wind erosion resistance and rolling resistance were measured through three-factor orthogonal experiments, and the optimal ratio of the dust suppressant was established. Specifically, fenugreek gum (FG) was selected as the bonding agent, cane sugar (CS) as the moisturizing agent, and alkyl phenol polyoxyethylene ether (Op-10) as the wetting agent. The research findings demonstrate that the optimal ratio of dust suppressant is 0.3 wt% fenugreek gum (FG) + 0.06 wt% alkyl phenol polyoxyethylene ether (Op-10) + 3 wt% cane sugar (CS). Under these conditions, the dust fixation rate can reach up to 97~98% at a wind speed of 8 m/s. The maximum rolling resistance can reach 65~73% after grinding the samples for 1 min. The surface tension of the solution is 13.74 mN/m, and the wetting performance improved by 81% compared to pure water. This dust suppressant is of great significance for improving the working environment of workers and ensuring the sustainable development of the mining industry. Full article

Chemicals in personal care and consumer products are suspected to disrupt endocrine function and affect reproductive health. However, the link between mixed exposure and long-term amenorrhea is not well understood. This study analyzed data from 684 women (2013–2018 National Health and Nutrition Examination Survey) to assess exposure to eight polyfluorinated alkyl substances (PFASs), 15 phthalates (PAEs), six phenols, and four parabens. Various statistical models for robustness tests and mediation analysis were used to explore associations with long-term amenorrhea and the role of serum globulin. Biological mechanisms were identified through an integrated strategy involving target analysis of key chemicals and long-term amenorrhea intersections, pathway analysis, and target validation. Results showed that women with long-term amenorrhea had higher exposure levels of Perfluorodecanoic acid, Perfluorohexane sulfonic acid (PFHxS), Perfluorononanoic acid, n-perfluorooctanoic acid (n_PFOA), n-perfluorooctane sulfonic acid, and Perfluoromethylheptane sulfonic acid isomers. Logistic regression with different adjustments consistently found significant associations between elevated PFAS concentrations and increased long-term amenorrhea risk, confirmed by Partial Least Squares Discriminant Analysis. Mediation analysis revealed that serum globulin partially mediated the relationship between PFAS exposure and long-term amenorrhea. Network and target analysis suggested that PFHxS and n_PFOA may interact with Signal Transducer and Activator of Transcription 3 (STAT3). This study highlights significant associations between PFAS exposure, particularly PFHxS and n_PFOA, and long-term amenorrhea, with serum globulin and STAT3 serving as mediators in the underlying mechanisms. Full article

Biobased organic diols derived from the phenolic aldehyde by-products in the depolymerization of lignin (4-hydroxybenzaldehyde, vanillin, and syringaldehyde) for the synthesis of polyesters and polyurethanes is described. Methods to prepare lignin-based diols involved a two-step synthetic route using either a hydroxy alkylation and aldehyde reduction or an aldehyde reduction and Williamson–Ether substitution. The preparation of five polyesters (PEs) and ten polyurethanes (PUs) from lignin-based diols was also performed and their physical and thermal properties were analyzed. DSC analysis confirmed the amorphous nature of all synthesized polymers, and GPC analysis revealed broad dispersities and high molecular weights. Two PE polyols were also derived from a vanillin-based diol at concentrations of 10 and 25 wt% for their usage in sustainable PU foams. PU foams were prepared from these polyols, where it was found that only the foam containing the 10 wt% formulation was suitable for mechanical testing. The PU foam samples were found to have good hardness and tensile strengths compared to both control foams, showing potential for the incorporation of biobased polyols for PU foam formation. Full article

The use of CO₂ as a C1 carbon source for the synthesis of valuable chemicals through biotechnology methods represents an effective strategy to fix carbon dioxide. Phenolic acid decarboxylases possess the capability to introduce a carboxyl group into para-hydroxystyrenes for the regionally selective synthesis of (E)-para-hydroxycinnamic acids, utilizing bicarbonate as a CO₂ source. It is difficult to achieve this reaction with traditional chemical methods, and only a few enzymes have been isolated and characterized. Here, we mined which low amino acid sequence shared its identity with those of related decarboxylases and which heterologously expressed phenolic acid decarboxylase PAD_Cs from Clostridium sp. DSM 8431 in E. coli. The recombinant PAD_Cs displayed maximum activity at 50 °C, and pH 5.0. PAD_Cs showed distinct carboxylation ability. The carboxylated substrates have a wide range of substitution modes on aromatic systems, including alkyl and alkoxy groups as well as halogens. Furthermore, the carboxylation conversion rates were impressive: para-hydroxystyrene exceeded 20% and 2-methoxy-4-vinylphenol surpassed 26%. This study indicated that PAD_Cs might serve as a potential enzyme source in biotechnological CO₂ fixation. Full article

Coal tar naphtha is produced from coal carbonization, moving bed coal gasification, and thermal liquefaction of coal. The naphtha can contain up to 60% aromatics and 15% olefins, as well as nitrogen-, oxygen-, and sulfur-containing compounds. Usually only hydrotreating is considered, but when producing motor gasoline, olefin–aromatic alkylation could reduce the associated octane number loss due to olefin hydrogenation by converting olefins to alkylated phenols and aromatics. The plausibility of using acid-catalyzed alkylation with coal tar naphtha, which contains nitrogen bases, was investigated by studying a model system comprising phenol and 1-hexene in the absence and presence of pyridine. It was found that pyridine only inhibited conversion over a range of amorphous silica–alumina catalysts. The most effective catalyst was Siral 30 (30% silica, 70% alumina) and at 315 °C, 0.05 wt% pyridine caused a 35% inhibition of phenol conversion compared to conversion in the absence of pyridine. Catalyst activity could be restored by rejuvenating the catalyst with clean feed at a higher temperature. The results supported a description of phenol alkylation with olefins that took place by at least two pathways, one involving protonation of the olefin (typical for Friedel–Crafts alkylation) and one where the olefin is the nucleophile. Full article

Lignin is one of the main structural components of lignocellulosic biomass and can be utilized to produce phenolic compounds that can be converted downstream to cycloalkanes and aromatics, which are useful as drop-in road or aviation biofuels. Within this study, the hydrodeoxygenation of model phenolic/aromatic compounds and surrogate mixture simulating the light fraction of lignin fast-pyrolysis bio-oil was performed under mild reaction conditions. Ni/BEA zeolite was selected as a catalyst to investigate the conversion and the product selectivity of alkyl phenols (phenol, catechol, cresols), methoxy-phenols (guaiacol, syringol, creosol), aromatics (anisole, 1,2,3-trimethoxybenzene) and dimer (2-phenoxy-1-phenyl ethanol) compounds towards (alkyl)cycloalkanes. The hydrodeoxygenation of a surrogate mixture of eleven phenolic and aromatic compounds was then studied by investigating the effect of reaction conditions (temperature, time, H₂ pressure, surrogate mixture concentration, and catalyst-to-feed ratio). The conversion of model compounds was in the range of 80–100%, towards a 37–81% (alkyl)cycloalkane yield, being strongly dependent on the complexity/side-chain group of the phenolic/aromatic ring. Regarding the hydrodeoxygenation of the surrogate mixture, 59–100% conversion was achieved, with up to a 72% yield of C₆–C₉ cycloalkanes. Characterization of spent catalysts showed that the hydrodeoxygenation of surrogate mixture led to carbonaceous depositions on the catalyst, which can be limited under lower temperatures and longer reaction conditions, while after regeneration, the physicochemical properties of catalysts can be partially recovered. Full article

This paper evaluates the performance of four ethoxylated nonionic surfactants (nonyl phenol vs. C₁₃ alcohols) to act as ancillary collectors with Alkyl Amidoamine (AAA) in the reverse flotation of quartz at pH8 to concentrate iron ores. Compared to 100% AAA, the blend composed of 80% AAA (Flotinor^®5530) plus 20% of isotridecyl alcohol ethoxylated with five groups of ethylene oxide (DP-210 RO) improved quartz recovery (from 54% to 63%, p < 0.05) by increasing contact angle (from 55° to 56°, p < 0.05) and decreasing induction time (26 ms to 23 ms, p < 0.05). Compared to 100% AAA (200 g/t), the blend (160 g/t of AAA + 40 g/t of DP-210 RO) improved the flotation performance of iron ore, yielding richer hematite concentrate (65.3% Fe × 61.4% Fe) and less contaminated with quartz (4% SiO₂ × 10.2% SiO₂), coupled with an increase in Fe recovery from 79.8% × 81.6% in the sunken product as well as SiO₂ recovery from 91.7% to 96.9% in the froth. Results from zeta potential, the hydrodynamic diameter of reagent droplets, and the surface tension of the solution provide insights into the synergism between AAA and DP-210 RO. Full article

Prostate cancer remains a significant global health concern, prompting ongoing exploration of novel therapeutic agents. Licochalcone A, a natural product in the chalcone family isolated from licorice root, is characterized by its enone structure and demonstrates antiproliferative activity in the micromolar range across various cell lines, including prostate cancer. Building on our prior success in enhancing curcumin’s antiproliferative potency by replacing the substituted phenol with a 1-alkyl-1H-imizadol-2-yl moiety, we applied a similar approach to design a new class of licochalcone A-inspired chalcones. The synthesis of these target chalcones involved key [3,3]-sigmatropic rearrangement of aryl prenyl ethers and Claisen–Schmidt condensations, yielding three derivative series. These compounds were evaluated for antiproliferative activity in both androgen receptor (AR)-positive and AR-null prostate cancer cell models using WST-1 cell proliferation assay. Systematic evaluation of licochalcone A across four prostate cancer cell lines indicated a modest advantage over enzalutamide, an FDA-approved AR antagonist, in suppressing 22Rv1 cell proliferation. Interestingly, three ester derivatives by replacing the phenol next to the carbonyl with an alkoxide demonstrated similar antiproliferative potency to licochalcone A in both AR-positive and AR-negative prostate cancer cell lines. This suggests that the phenol moiety on licochalcone A may be a promising site for chemical manipulations to enhance anti-prostate cancer activity. Among the synthesized chalcones, nine derivatives showed improved selectivity for AR-positive LNCaP and 22RV1 cells relative to AR-negative PC-3 and DU145 cells, surpassing licochalcone A in selectivity. Additionally, the antiproliferative potency was highly dependent on the R group attached to the imidazole. Most of the derivatives showed antiproliferative potency against androgen receptor-positive LNCaP and 22Rv1 cells, comparable to that of enzalutamide and licochalcone A. These findings suggest that optimization of licochalcone A-inspired chalcones as potential anti-prostate cancer agents warrants further investigation. Full article

The growing focus on sustainable use of natural resources has brought attention to cashew nut shell liquid (CNSL), a by-product rich in anacardic acids (AAs) with potential applications in diabetes treatment. In this study, three different AAs from CNSL, monoene (15:1, AAn1), diene (15:2, AAn2), and triene (15:3, AAn3), and a mixture of the three (mix) were evaluated as α-glucosidase inhibitors. The samples were characterized by combining 1D and 2D NMR spectroscopy, along with ESI-MS. In vitro assays revealed that AAn1 had the strongest inhibitory effect (IC₅₀ = 1.78 ± 0.08 μg mL⁻¹), followed by AAn2 (1.99 ± 0.76 μg mL⁻¹), AAn3 (3.31 ± 0.03 μg mL⁻¹), and the mixture (3.72 ± 2.11 μg mL⁻¹). All AAs significantly outperformed acarbose (IC₅₀ = 169.3 μg mL⁻¹). In silico docking suggested that polar groups on the aromatic ring are key for enzyme–ligand binding. The double bond at C15, while not essential, enhanced the inhibitory effects. Toxicity predictions classified AAs as category IV, and pharmacokinetic analysis suggested moderately favorable drug-like properties. These findings highlight AAs as a promising option in the search for new hypoglycemic compounds. Full article