Search Results (644)

Hydrolates are aromatic aqueous solutions saturated with volatile water-soluble compounds of essential oil. Despite their potential, hydrolates remain less explored than essential oils. In this work, the hydrolate of Pelargonium odoratissimum (L.) L’Hér. has been analyzed by multiple analytical techniques in order to describe its chemical composition. Headspace (HS-) and Direct Immersion-Solid Phase Microextraction-Gas Chromatography/Mass spectrometry (DI-SPME-GC/MS) and Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) were employed to reveal the VOC emission from the hydrolate. Further, a direct injection of the pure hydrolate and of the hydrolate after extraction with hexane was performed by Large-Volume Injection Gas Chromatography/Mass Spectrometry (LVI-GC/MS) and GC/MS. The results obtained by HS- and DI-SPME-GC/MS highlighted a nearly overlapping chemical profile with linalool, isomenthone, and α-terpineol as the main volatiles. On the other hand, analysis of the hydrolate by GC/MS after solvent extraction revealed a lower overall number of compounds but allowed the detection of thujone and cis-linalool oxide. In comparison, LVI-GC/MS was the technique that allowed the identification of a higher number of volatiles with citronellol, linalool, and α-terpineol as the principal compounds. Finally, PTR-ToF-MS was a fundamental approach to quantify and evaluate total terpene emissions from this complex matrix starting from low-molecular-weight compounds such as acetylene, methanol, acetaldehyde, acetone, and ethanol, which were the most abundant. Among the detected compounds, dimethyl sulfide and small amounts of dimethyl-furan and 2-butylfuran were also identified. Overall, the findings showed that the hydrolate was rich in monoterpene compounds while sesquiterpene compounds were missing. A very low intensity relating to sesquiterpenes was recorded only by PTR-ToF-MS technique. Full article

Compounds known as liquid organic hydrogen carriers (LOHCs) offer a promising pathway for storing hydrogen. Beyond the use of pure hydrocarbons, the incorporation of oxygen atoms offers a way to modify thermodynamic properties and potentially improve suitability for hydrogen storage. This study explores the effect of oxygen functionalization in aromatic ethers and lactones on the reaction equilibrium of reversible hydrogenation. To address this question, reaction enthalpies and entropies are calculated using both experimental and theoretically determined pure substance data. The equilibrium position shift in the hydrogenation of furan derivatives has been shown to follow a similar trend to that of their hydrocarbon counterparts upon the addition of aromatic rings. This shift is, however, more pronounced in the case of the furan-based systems. The effect is reflected in increasing Gibbs reaction energies during the dehydrogenation process. Both the formation of lactones and the addition of a second ring to the furan core leads to a further increase in the Gibbs reaction energy. The highest value is observed for dibenzofuran, with a Gibbs reaction energy of 36.6 kJ∙mol⁻¹ at 500 K. These findings indicate that, from a thermodynamic perspective, hydrogen release is feasible at temperatures below 500 K, which is an important feature for the potential application as a hydrogen storage system. Full article

Polygonum multiflorum (PM) residues represent an underutilized biomass resource, with pyrolysis offering a promising route for valorizing its biomass into valuable chemicals and biochar. This study elucidated how the intrinsic physicochemical properties of PM residue governed its pyrolysis kinetics, thermodynamics, mechanisms, and product distribution across varying thermal regimes (slow pyrolysis at 20 °C/min vs. fast pyrolysis). The primary devolatilization stage (174–680 °C) dominated the pyrolysis process. Applying three model-free kinetic approaches (FWO, KAS, Starink) over 0.1 < α < 0.7, this study observed a dramatic shift in apparent activation energy (219.7–354.7 kJ/mol). Major gaseous pyrolysis products identified included alcohols, aldehydes, ketones, acids, aromatic hydrocarbons, phenolics, CO, and CO₂. Ketones constituted the predominant fraction (23.80%), followed by acids (18.18%), phenolic derivatives (18.18%), N-containing compounds (14.28%), and furans (4.54%). The findings of this study contribute significant theoretical understanding and practical solutions for the effective pyrolysis and resource recovery from Polygonum multiflorum processing byproducts. Full article

A comprehensive overview is provided on factors and processes influencing the final quality of a cup of coffee, with an emphasis on the brewing method’s central role. Coffee quality assessment, both at the bean and cup level, combines objective parameters (color, moisture, bean defects, density) with a notable degree of subjectivity, as consumer sensory perception is ultimately decisive. The brewing technique is described as a critical determinant of the final chemical, physical, and sensory attributes. Key parameters such as aroma profile, pH, titratable acidity, total and filtered solids, lipid and fatty acid content, viscosity, foam (crema), and colorimetric indices are detailed as essential metrics in coffee quality evaluation. Roasting creates most of coffee’s key aroma compounds. The brewing method further shapes the extraction of both volatile and other bioactive compounds like caffeine, chlorogenic acids, and lipids. Brewing methods significantly affect acidity, “body,” and crema stability, while water quality, temperature, and pressure are shown to impact extraction results and sensory properties. Attention is paid to how methods such as Espresso, filter, French press, and cold brew yield distinct physicochemical and sensory profiles in the cup. Overall, the review highlights the multifaceted nature of coffee cup quality and the interplay between raw material, processing, and preparation, ultimately shaping the coffee sensory experience and market value. Full article

Current diagnostic methods for bacterial infections in critically ill patients, including ventilator-associated pneumonia (VAP), are time-consuming, while empirical antibiotic therapy contributes to rising resistance. Bacteria-derived volatile organic compounds (VOCs) are being explored as specific biomarkers for pathogen identification and treatment monitoring. This study expands knowledge of Escherichia coli metabolism by identifying VOCs produced by both multidrug-resistant and susceptible strains, characterizing their temporal profiles during growth, and assessing VOC profile changes after imipenem exposure. Reference strains and 21 clinical isolates (derived from BAL samples of VAP patients) were cultured under controlled conditions. Headspace VOCs were preconcentrated using multibed sorption tubes and analyzed by gas chromatography–mass spectrometry (GC-MS), with compound identities confirmed using external standards. Sampling at seven time points over 24 h cultures revealed three VOC emission patterns: continuous release, temporary maximum, and compound uptake. In total, 57 VOCs were identified from the susceptible strain and 41 from the resistant one, with dimethyl disulfide, 2-butenal, ethyl acetate, and furan elevated in the resistant strain. Imipenem addition altered VOC production in the susceptible strain, with levels of six compounds elevated and seven reduced, while resistant profiles remained stable. Clinical isolates produced 71 VOCs, showing greater metabolic diversity and highlighting the relevance of isolate-derived VOCs in future studies. Full article

Isoegomaketone [(E)-1-(furan-3-yl)-4-methylpent-2-en-1-one; 1] is abundant in the essential oil of Perilla species and exhibits various biological activities, such as anticancer and anti-inflammatory effects. In order to discover compounds with reduced toxicity or enhanced biological activity through structural modification of natural product-derived components, isoegomaketone was irradiated with an electron beam at five different doses, and (±)-8-methoxy-perilla ketone (2) was obtained with the highest yield of 3.8% (w/w) at 80 kGy. Its structure was identified by one-dimensional and two-dimensional nuclear magnetic resonance spectroscopy and high-resolution chemical ionization mass spectrometry. Compound 2 inhibited nitric oxide production and inducible nitric oxide synthase mRNA expression in a dose-dependent manner in lipopolysaccharide-stimulated RAW 264.7 cells. It also dose-dependently suppressed the mRNA expression of pro-inflammatory mediators such as IL-1β, IFN-β, and MCP-1, while having no significant effect on IL-6 mRNA levels. Furthermore, ELISA analysis demonstrated that 2 reduced MCP-1 protein expression but did not affect the protein level of TNF-α or IL-6. This study provides a reference for the structural analysis of compounds related to 2 by presenting NMR data acquired with chloroform-d, and is the first to report the anti-inflammatory properties of 2. Full article

The synthesis of heterocyclic compounds has gained significant attention in organic chemistry due to their diverse pharmacological properties. However, traditional synthetic approaches often involve hazardous chemicals, high energy consumption, and tedious workup procedures, leading to environmental concerns and low yields. In response, green chemistry strategies have emerged, emphasizing safer and more sustainable alternatives. Among these, magnetic nanoparticle (MNP)-based catalysts have shown remarkable promise in facilitating one-pot multicomponent reactions (MCRs), offering enhanced catalytic efficiency, ease of recovery, and reusability. This article provides a comprehensive overview of multicomponent reactions (MCRs) for the construction of a wide range of heterocyclic scaffolds—including chromenes, pyrazoles, phenazines, triazoles, tetrazoles, xanthenes, furans, indoles, imidazoles, pyridines, pyrimidines, oxazoles, and acridine derivatives—catalyzed by magnetic nanoparticles under sustainable and environmentally benign conditions. This review highlights recent advances (2018–2024) in the development and application of modified magnetic nanoparticles for green multicomponent synthesis. Emphasis is placed on their structural features, catalytic roles, and benefits in eco-friendly organic transformations. Full article

Thermal impregnation (TI) is a traditional method of sugar infusion, but it has disadvantages such as long processing time and uneven sugar distribution. Therefore, developing sugar impregnation methods to enhance product flavor, nutritional value, and processing efficiency is critical for addressing potential quality loss and efficiency bottlenecks in traditional preserve processing technologies. This study took the TI process widely adopted in Xinjiang over the long term as a reference and systematically compared the effects of vacuum impregnation (VI) and ultrasonic-assisted impregnation (UI) on the flavor characteristics and physicochemical properties of plum preserves. Volatile organic compounds (VOCs) were identified using gas chromatography–ion mobility spectrometry (GC-IMS) coupled with multivariate analysis, while taste attributes were quantified via electronic tongue (E-tongue). Physicochemical parameters, including titratable acidity (TA), browning index (BI), color parameters (L*, a*, b*), total polyphenol content (TPC), total flavonoid content (TFC), and texture profile analysis (TPA), were also evaluated. GC-IMS identified 60 VOCs, predominantly comprising aldehydes (20), alcohols (10), ketones (6), acids (4), esters (3), furans (3), ketols (2), and unidentified compounds (12). The VI-treated samples exhibited distinct aromatic profiles, retaining a higher proportion of key volatile compounds. E-tongue results showed that VI significantly enhanced sourness, umami, and aftertaste complexity compared with UI and TI (p < 0.05). Physicochemical analyses showed that VI maximally preserved bioactive compounds, with a TPC of 1.23 ± 0.07 mg GAE/g and TFC of 17.55 ± 0.81 mg RE/g. Additionally, VI minimized enzymatic browning (BI: 0.37 ± 0.03), maintained color brightness (L*: 31.85 ± 1.56), maintained favorable textural properties (hardness: 187.63 ± 4.04 N), and retained the highest TA content (0.77 ± 0.05%). In contrast, UI and TI led to significant quality degradation, characterized by pronounced browning and texture deterioration: the BI values were 0.61 ± 0.02 (UI) and 0.83 ± 0.03 (TI), and hardness values were 176.53 ± 5.81 N (UI) and 156.25 ± 4.55 N (TI). These findings provide critical references for sugar impregnation techniques and a scientific basis for flavor regulation in prune preserve production. Full article

Carob is the legume of the carob tree (Ceratonia siliqua L.), which is cultivated in many parts of the Mediterranean area. It is mainly used as animal feed and in the formulations of human foods. Due to the high concentration of sugars in carob pods, this fruit could be used as a raw material to produce distillates. In this study, the effect of the distillation system (Charantais alembic versus Charantais alembic with column) on the chemical and sensory characteristics, as well as on the ethanol yield of carob spirits, was analyzed. The ethanol recovery using Charantais alembic was 74.9%, and for Charantais alembic with column, it was 85.8%. Regarding the chemical composition, esters, furanic compounds, and alcohols were the most abundant compounds in the distillates. Principal component analysis was used to identify the different distillate fractions, first distillations, and residues. Nevertheless, the corresponding distillate fractions for both distillation systems were plotted near to each other due to the similar concentration of the volatile compounds. The spirits obtained from both distillation systems were not differentiated by organoleptic triangular and two-alternative forced-choice (2-AFC) tests according to the results of the semi-trained and professional panels. Both spirits were sensorial characterized as floral, fruity, and alcoholic. Full article

To investigate the effect of body size on muscle quality of common carp (Cyprinus carpio L.), we systematically tracked the dynamic changes in nutrient content, texture, and volatile organic compounds (VOCs) among small-sized (~100 g), medium-sized (~250 g), and large-sized (~600 g) fish (SYRC, MYRC, and HYRC, respectively) over a 30-week feeding trial. The results indicated that the HYRC showed significantly reduced moisture and lipid content, along with increased protein content, hydroxyproline, hardness, and chewiness compared to the SYRC (p < 0.05). The long-chain polyunsaturated fatty acids (LC-PUFAs) and fish lipid quality in the MYRC were significantly lower than those in both the SYRC and HYRC (p < 0.05). The HYRC demonstrated an elevated health-promoting index and a reduced atherogenicity value compared to the SYRC (p < 0.05). The contents of alcohol, ketones, and furans in the HYRC increased by 32.53%, 44.62%, and 144.29%, respectively, compared with those in the SYRC (p < 0.05), including key VOCs in aquatic products such as oct-1-en-3-ol and pent-1-en-3-ol. In conclusion, the SYRC have higher levels of LC-PUFAs and lower hardness; the MYRC have poor levels of LC-PUFAs; and the HYRC have an optimal synergy of nutrition, texture, and VOCs, but the overaccumulation of undesirable VOCs requires mitigation. This provides theoretical references and data support for fish quality optimization, processing, and consumption guidelines. Full article

Cooked-rice aroma strongly affects consumer choice, yet the chemical traits distinguishing glutinous rice from normal-amylose japonica rice remain underexplored because earlier studies targeted only a few dozen volatiles using one-dimensional gas chromatography–mass spectrometry (GC-MS). In this study, four glutinous and seven normal Japanese cultivars were cooked under identical conditions, their headspace volatiles trapped with MonoTrap and qualitatively profiled by comprehensive GC × GC-TOFMS. The two-dimensional platform resolved 1924 peaks—about ten-fold previous coverage—and, together with hierarchical clustering, PCA, heatmap visualization and volcano plots, cleanly separated the starch classes (78.3% cumulative PCA variance; Euclidean distance > 140). Volcano plots highlighted 277 compounds enriched in the glutinous cultivars and 295 in Koshihikari, including 270 compounds that were not previously documented in rice. Normal cultivars were dominated by ethers, aldehydes, amines and other nitrogenous volatiles associated with grainy, grassy and toasty notes. Glutinous cultivars showed abundant ketones, furans, carboxylic acids, thiols, steroids, nitro compounds, pyrroles and diverse hydrocarbons and aromatics, yielding sweeter, fruitier and floral accents. These results expand the volatile library for japonica rice, provide molecular markers for flavor-oriented breeding and demonstrate the power of GC × GC-TOFMS coupled with chemometrics for grain aroma research. Full article

Candidiasis arises from the proliferation of Candida species in the human body, especially in individuals with compromised immune systems. Efficient therapeutic management of candidiasis is often hampered by the limited availability of potent antifungal drugs and the emergence of drug-resistant strains. We have previously identified the N-[(4-sulfamoylphenyl)methyl][1,1′-biphenyl]-4-carboxamide to have fungistatic and fungicidal properties, likely due to the hydrophobic biphenyl–chemical features affecting the structural organization of Candida spp. cell membrane. Here, we designed and synthesized a novel series of twelve 5-arylfuran-2-carboxamide derivatives bearing a new hydrophobic tail as bioisosteric replacement of the diphenyl fragment. Its antifungal effectiveness against C. albicans, C. glabrata, and C. parapsilosis, including ATCC and clinically isolated strains, was assessed for all compounds. The most active compound was N-benzyl-5-(3,4-dichlorophenyl)furan-2-carboxamide (6), with fungistatic and fungicidal effects against C. glabrata and C. parapsilosis strains (MIC = 0.062–0.125 and 0.125–0.250 mg/mL, respectively). No synergistic effects were observed when combined with fluconazole. Interestingly, fluorescent microscopy analysis after staining with SYTO 9 and propidium iodide revealed that compound 6 affected the cell membrane integrity in C. albicans strain 16. Finally, carboxamide 6 exhibited a dose-dependent cytotoxicity on erythrocytes, based on assessing the LDH release. Full article

A chemical investigation of the EtOAc fraction from soft coral Clavularia viridis resulted in the isolation of 12 undescribed dolabellane-type diterpenoids, namely clavirolides W–Z (1–4), clavularols A–H (5–12), and three known analogs (13–15). Their structures were characterized by an extensive analysis of spectroscopic data, including X-ray diffraction and ECD calculations for the assignment of absolute configurations. The structures of 2 and 4–6 are feathered as peroxyl-substituted derivatives, while compounds 7–12 possess additional oxidative cyclization, including epoxide or furan that are rare in the dolabellane family. All these compounds were evaluated for activities on cytotoxic and anti-inflammatory models. Compound 10 exhibited most potential against NO production in the BV2 cell induced by LPS with an IC₅₀ value of 18.3 μM. Full article

(1) Background: This study investigated changes in bioactive components and volatile compounds (VCs) during the production of red millet by comparing two varieties: Miao Xiang glutinous millet (waxy) and Jigu-42 (non-waxy). The samples were solid-state-fermented with “Red Ferment” and evaluated for bioactive components. (2) Methods: Multiple analytical methods—including principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal PLS-DA (OPLS-DA), cluster analysis, and correlation analysis—were employed to systematically compare bioactive components and VCs. (3) Results: Significant varietal differences were observed: (1) Miao Xiang glutinous millet showed higher monacolin K (MK) and fatty acid contents; (2) Jigu-42 contained significantly more polyphenols; (3) linoleic acid dominated the fatty acid profiles of two varieties; and (4) a total of twenty-seven VCs were identified, including six alcohols, four aldehydes, seven ketones (corrected from duplicated count), two aromatic hydrocarbons, three heterocycles, one acid, three furans, and one ether. (4) Conclusions: The two varieties exhibited significant differences in MK, pigment profiles, fatty acid composition, polyphenol content, and volatile-compound profiles. These findings provide scientific guidance for the selection of the appropriate millet varieties in functional food production. Full article

Resistance of various bacterial pathogens to the activity of clinically approved drugs currently leads to serious infections, rapid spread of difficult-to-treat diseases, and even death. Taking the threats for human health in mind, researchers are focused on the isolation and characterization of novel natural products, including plant secondary metabolites. These molecules serve as inspiration and a suitable structural platform in the design and development of novel semi-synthetic and synthetic derivatives. All considered compounds have to be adequately evaluated in silico, in vitro, and in vivo using relevant approaches. The current review paper briefly focuses on the chemical and metabolic properties of resveratrol (1), as well as its oligomeric structures, viniferins, and viniferin-based molecules. The core scaffolds of these compounds contain so-called privileged structures, which are also present in many clinically approved drugs, indicating that those natural, properly substituted semi-synthetic, and synthetic molecules can provide a notably broad spectrum of beneficial pharmacological activities, including very impressive antimicrobial efficiency. Except for spectral verification of their structures, these compounds suffer from the determination or prediction of other structural and physicochemical characteristics. Therefore, the structure–activity relationships for specific dihydrodimeric and dimeric viniferins, their bioisosteres, and derivatives with notable efficacy in vitro, especially against chosen Gram-positive bacterial strains, are summarized. In addition, a set of descriptors related to their structural, physicochemical, pharmacokinetic, and toxicological properties is generated using various computational tools. The obtained values are compared to those of clinically approved drugs. The particular relationships between these in silico parameters are also explored. Full article