Search Results (962)

We hypothesized that compounds containing ether linkages within their backbone structures, when exposed to hydroxyl radicals (•OH), can generate ultra-weak photon emission (UPE) as a result of the formation of triplet excited carbonyl species (³R=O*). To evaluate this hypothesis, we investigated the UPE of four compounds, each at a final concentration of 185.2 µmol/L: EGTA (ethylene glycol-bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid), a potent chelator of divalent cations, and three crown ethers—12-crown-4, 15-crown-5, and 18-crown-6—containing two, four, five, and six ether bonds, respectively. •OH was generated using a modified Fenton reagent—92.6 µmol/L Fe²⁺ and 2.6 mmol/L H₂O₂. The highest UPE was recorded for the Fe²⁺–EGTA–H₂O₂ (2863 ± 158 RLU; relative light units), followed by 18-crown-6, 15-crown-5, and 12-crown-4 (1161 ± 78, 615± 86, and 579 ± 109 RLU, respectively; p < 0.05), corresponding to the number of ether groups present. Controls lacking either H₂O₂ or Fe²⁺ exhibited no significant light emission compared to the buffer medium. These findings support the hypothesis that ether bonds, when oxidatively attacked by •OH, undergo chemical transformations resulting in the formation of ³R=O* species, the decay of which is associated with UPE. In crown ethers exposed to Fe²⁺-H₂O₂, the intensity of UPE was correlated with the number of ether bonds in their structure. Full article

This study presents the synthesis and physicochemical characterization of coordination compounds formed between chrysin, a natural flavonoid, and transition metal ions: Mn(II), Co(II), and Zn(II). The complexes were obtained under mildly basic conditions and analyzed using elemental analysis, thermogravimetric analysis (TGA), silver-assisted laser desorption/ionization mass spectrometry (SALDI-MS), FT-IR spectroscopy, and ¹H NMR. The spectroscopic data confirm that chrysin coordinates as a bidentate ligand through the 5-hydroxyl and 4-carbonyl groups, with structural differences depending on the metal ion involved. The mass spectrometry results revealed distinct stoichiometries: 1:2 metal-to-ligand ratios for Mn(II) and Co(II), and 1:1 for Zn(II), with additional hydroxide coordination. Biological assays demonstrated that Co(II) and Mn(II) complexes exhibit enhanced antibacterial and anti-biofilm activity compared to free chrysin, particularly against drug-resistant Staphylococcus epidermidis, whereas the Zn(II) complex showed negligible biological activity. Full article

The Maillard reaction refers to the reaction between carbonyl compounds with reducing properties and amino-containing compounds that undergo condensation and polymerization to produce melanoidins. In flour product processing, the Maillard reaction is a critical chemical reaction influencing color, flavor, nutrition, and safety. A moderate Maillard reaction contributes to desirable color and flavor profiles in flour products, whereas an excessive reaction leads to amino acid loss and the formation of harmful substances, posing potential health risks. This review summarizes the substrate sources, reaction stages, influencing factors, impact on quality, and mitigation strategies of harmful products, aiming to provide a reference for regulating the Maillard reaction in flour product processing. Currently, most existing mitigation strategies focus on inhibiting harmful products, while research on the synergistic optimization of color and flavor remains insufficient. Future research should focus on elucidating the molecular mechanisms of reaction pathways, understanding multi-factor synergistic effects, and developing composite regulation technologies to balance the sensory quality and safety of flour products. Full article

The advancement of non-thermal disinfection technologies represents a critical pathway for ensuring food safety, meeting environmental sustainability requirements, and meeting consumer preferences for clean-label products. This study systematically evaluated the combined preservation effect of ultrasonic-assisted slightly acidic electrolyzed water (US+SAEW) on mirror carp fillets during refrigeration. Results demonstrated that US+SAEW exhibited superior antimicrobial efficacy compared to individual US or SAEW, achieving reductions of 0.73, 0.74, and 0.79 log CFU/g in total viable counts (TVC), Aeromonas bacteria, and lactic acid bacteria counts compared to the control, respectively. Furthermore, the combined intervention significantly suppressed microbial proliferation throughout the refrigeration period while simultaneously delaying protein and lipid degradation/oxidation induced by spoilage bacteria, thereby inhibiting the formation of alkaline nitrogenous compounds. Consequently, lower levels of pH, total volatile basic nitrogen (TVB-N), protein carbonyl, and thiobarbituric acid reactive substances (TBARS) were observed in US+SAEW compared to the other treatments. Multimodal characterization through low-field nuclear magnetic resonance (LF-NMR), texture, and color analysis confirmed that US+SAEW effectively preserved quality characteristics, extending the shelf life of mirror carp fillets by four days. This study provides a novel non-thermal preservation strategy that combines microbial safety maintenance with quality retention, offering particular advantages for thermolabile food. Full article

Magenta Cherry or Eugenia (Syzygium paniculatum Gaertn) is an underutilized berry species with an interesting source of functional components. This study aimed to evaluate these berries’ morphometric, nutritional, and phytochemical characteristics at two ripening stages, CM: consumer maturity (CM) and OM: over-maturity. Morphometric analysis revealed size and weight parameters comparable to commercial berries such as blueberries. Fresh fruits were processed into pulverized material, and in this, a proximate analysis was evaluated, showing high moisture content (88.9%), dietary fiber (3.56%), and protein (0.63%), with negligible fat, indicating suitability for low-calorie diets. Phytochemical screening by HPLC identified gallic acid, chlorogenic acid, hydroxycinnamic acid, ferulic acid, quercetin, rutin, and condensed tannins. Ethanol extracts showed stronger bioactive profiles than aqueous extracts, with significant antioxidant capacity (up to 803.40 µmol _Trolox/g via Ferric Reducing Antioxidant Power (FRAP assay). Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopic analyses established structural transformations of hydroxyl, carbonyl, and aromatic groups associated with ripening. These changes were supported by observed variations in anthocyanin and flavonoid contents, both higher at the CM stage. A notable pigment loss in OM fruits could be attributed to pH changes, oxidative degradation, enzymatic activity loss, and biotic stressors. Antioxidant assays (DPPH, ABTS, and FRAP) confirmed higher radical scavenging activity in CM-stage berries. Elemental analysis identified minerals such as potassium, calcium, magnesium, iron, and zinc, although in moderate concentrations. In summary, Syzygium paniculatum Gaertn fruit demonstrates considerable potential as a source of natural antioxidants and bioactive compounds. These findings advocate for greater exploration and sustainable use of this native berry species in functional food systems. Full article

Coffee is one of the most widely consumed beverages worldwide, primarily due to the stimulating effects attributed to its caffeine content. However, excessive intake of caffeine results in negative effects, including palpitations, anxiety, and insomnia. Therefore, low-caffeine coffee has captivated growing consumer interest, highlighting its significant market potential. Traditional decaffeination methods often lead to non-selective extraction, resulting in a loss of desirable flavor compounds, thereby compromising coffee quality. In recent years, microbial fermentation has emerged as a promising, targeted, and safe approach for reducing caffeine content during processing. Additionally, mixed-culture fermentation further enhances coffee flavor and overcomes the drawbacks of monoculture fermentation, such as low efficiency and limited flavor profiles. Nonetheless, several challenges are yet to be resolved, including microbial tolerance to caffeine and related alkaloids, the safety of fermentation products, and elucidation of the underlying mechanisms behind microbial synergy in co-cultures. This review outlines the variety of microorganisms with the potential to degrade caffeine and the biochemical processes involved in this process. It explores how microbes tolerate caffeine, the safety of metabolites produced during fermentation, and the synergistic effects of mixed microbial cultures on the modulation of coffee flavor compounds, including esters and carbonyls. Future directions are discussed, including the screening of alkaloid-tolerant strains, constructing microbial consortia for simultaneous caffeine degradation for flavor enhancement, and developing high-quality low-caffeine coffee. Full article

Restricting the use of chemical pesticides in forestry requires the search for alternative solutions. These could be volatile organic compounds produced by three investigated species of bacteria (Bacillus amyloliquefaciens (ex Fukumoto) Priest, B. subtilis (Ehrenberg) Cohn and B. thuringiensis Berliner), which inhibit the growth of the pathogen F. oxysporum Schltdl. emend. Snyder & Hansen in forest nurseries. The highest inhibition of fungal growth (70%) was observed with B. amyloliquefaciens after 24 h of antagonism test, which had a higher content of carbonyl compounds (46.83 ± 8.41%) than B. subtilis (41.50 ± 6.45%) or B. thuringiensis (34.62 ± 4.77%). Only in the volatile emissions of B. amyloliquefaciens were 3-hydroxybutan-2-one, undecan-2-one, dodecan-5-one and tetradecan-5-one found. In contrast, the main components of the volatile emissions of F. oxysporum were chlorinated derivatives of benzaldehyde (e.g., 3,5-dichloro-4-methoxybenzaldehyde) and chlorinated derivatives of benzene (e.g., 1,4-dichloro-2,5-dimethoxybenzene), as well as carbonyl compounds (e.g., benzaldehyde) and alcohols (e.g., benzyl alcohol). Further compounds were found in the interactions between B. amyloliquefaciens and F. oxysporum (e.g., $\alpha$-cubebene, linalool, undecan-2-ol, decan-2-one and 2,6-dichloroanisole). Specific substances were found for B. amyloliquefaciens (limonene, nonan-2-ol, phenethyl alcohol, heptan-2-one and tridecan-2-one) and for F. oxysporum (propan-1-ol, propan-2-ol, heptan-2-one and tridecan-2-one). The amounts of volatile chemical compounds found in B. amyloliquefaciens or in the bacterium–fungus interaction can be used for further research to limit the pathogenic fungus. In the future, one should focus on the compounds that were found exclusively in interactions and whose content was higher than in isolated bacteria. In order to conquer an ecological niche, bacteria increase the production of secondary metabolites, including specific chemical compounds. The results presented are a prerequisite for creating an alternative solution or supplementing the currently used methods of plant protection against F. oxysporum. Understanding and applying the volatile organic compounds produced by bacteria can complement chemical plant protection against the pathogen, especially in greenhouses or tunnels where plants grow in conditions that favour fungal growth. Full article

Olive tree branches (OB) and leaves (OL) from the Viseu region (Portugal) were studied for their chemical composition and liquefaction behavior using polyalcohols. Chemical analysis revealed that OL contained higher ash content (4.08%) and extractives, indicating more bioactive compounds, while OB had greater α-cellulose (30.47%) and hemicellulose (27.88%). Lignin content was higher in OL (21.64%) than OB (16.40%). Liquefaction experiments showed that increasing the temperature from 140 °C to 180 °C improved conversion, with OB showing a larger increase (52.5% to 80.9%) compared to OL (66% to 72%). OB reached peak conversion faster, and the optimal particle size for OB was 40–60 mesh, while OL performed better at finer sizes. OL benefited more from higher solvent ratios, whereas OB achieved high conversion with less solvent. FTIR analysis confirmed that acid-catalyzed liquefaction breaks down lignocellulosic structures, depolymerizes cellulose and hemicellulose, and modifies lignin, forming hydroxyl, aliphatic, and carbonyl groups. These changes reflect progressive biomass degradation and the incorporation of polyalcohol components, converting solid biomass into a reactive, polyol-rich liquid. The study highlights the distinct chemical and processing characteristics of olive branches and leaves, informing their potential industrial applications. Full article

In the field of green chemistry, the development of more sustainable and cost-efficient methods for synthesizing primary amines is of paramount importance, with catalyst research being central to this effort. This work presents a facile, aqueous-phase synthesis of highly active cobalt catalysts (Co-Ph@SiO₂(x)) via pyrolysis of silica-supported cobalt–phenanthroline complexes. The optimized Co-Ph@SiO₂(900) catalyst achieved exceptional performance (>99% conversion, >98% selectivity) in the reductive amination of acetophenone to 1-phenylethanamine using NH₃/H₂. Systematic studies revealed that its exceptional performance originates from the in situ pyrolysis of the cobalt–phyllosilicate complex. This process promotes the uniform distribution of metal cobalt nanoparticles, simultaneously enhancing porosity and imparting bifunctional (acidic and basic) properties to the catalyst, resulting in outstanding catalytic activity and selectivity. The catalyst demonstrated broad applicability, efficiently converting diverse ketones (aryl-alkyl, dialkyl, bioactive) and aldehydes (halogenated, heterocyclic, biomass-derived) into primary amines with high yields (up to 99%) and chemoselectivity (>40 examples). This sustainable, non-noble metal-based catalyst system offers significant potential for industrial primary amine synthesis and provides a versatile tool for developing highly selective and active heterogeneous catalysts. Full article

Tomatoes are globally esteemed not only for their nutritional value but also for their complex and appealing aroma, a key determinant of consumer preference. The present study aimed to comprehensively characterise the volatilomic fingerprints of three tomato species—Solanum lycopersicum L., S. lycopersicum var. cerasiforme, and S. betaceum—encompassing six distinct varieties, through the application of headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME/GC-MS). A total of 55 volatile organic compounds (VOCs) spanning multiple chemical classes were identified, of which only 28 were ubiquitously present across all varieties examined. Carbonyl compounds constituted the predominant chemical family, with hexanal and (E)-2-hexenal emerging as putative key contributors to the characteristic green and fresh olfactory notes. Notably, esters were found to dominate the unique volatile fingerprint of cherry tomatoes, particularly methyl 2-hydroxybenzoate, while Kumato and Roma varieties exhibited elevated levels of furanic compounds. Multivariate statistical analyses, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), demonstrated clear varietal discrimination and identified potential aroma-associated biomarkers such as phenylethyl alcohol, 3-methyl-1-butanol, hexanal, (E)-2-octenal, (E)-2-nonenal, and heptanal. Collectively, these findings underscore the utility of volatilomic fingerprint as a robust tool for varietal identification and quality control within the food industry. Full article

Diaryliodonium salts are an important part of hypervalent iodine chemistry, owing to their highly electrophilic character, non-toxicity, and air and moisture stability, have been identified as an important arylating agent. It has been widely applied in the synthesis of natural products, drugs, and bioactive molecules bearing active α-arylation carbonyl units. Within the domain of α-arylation of carbonyl compounds using diaryliodonium salts, there is a notable absence in the literature of a comprehensive compilation dedicated to exclusive arylation processes involving these compounds. In this review, we focus on the overview of the recent advancements in utilizing diaryliodonium salts for α-arylation reactions, encompassing both racemic and asymmetric approaches to various carbonyl compounds including ketones, esters, enolates, and amides. Furthermore, we discuss the unique advantages and inherent limitations of diaryliodonium salts as arylating agents, as well as the underexplored application potentials that warrant further investigation in this rapidly evolving field. Full article

Per- and polyfluoroalkyl substances (PFAS) are of concern because of their potential thyroid hormone system disruption by binding to human transthyretin (hTTR). However, the amount of experimental data is scarce. In this work, new classification and regression QSARs were developed to predict the hTTR disruption based on experimental data measured for 134 PFAS. Bootstrapping, randomization procedures, and external validation were used to check for overfitting, to avoid random correlations, and to evaluate the predictivity of the QSARs, respectively. The best QSARs were characterized by good performances (e.g., training and test accuracies in classification of 0.89 and 0.85, respectively; R², Q²_loo, and Q²_F3 in regression of 0.81, 0.77, and 0.82, respectively) and significantly broader domains compared to the few existing similar models. The application of QSARs application to the OECD List of PFAS allowed for the identification of structural categories of major concern, such as per- and polyfluoroalkyl ether-based, perfluoroalkyl carbonyl, and perfluoroalkane sulfonyl compounds. Forty-nine PFAS showed a stronger binding affinity to hTTR than the natural ligand T4. Uncertainty quantification for each model and prediction further enhanced the reliability assessment of predictions. The implementation of the new QSARs in non-commercial software facilitates their application to support future research efforts and regulatory actions. Full article

Experiences of life-threatening stimuli can induce post-traumatic stress disorder (PTSD), which is associated with long-lasting behavioral and neurochemical abnormalities. Despite its increased global incidence, the current treatment options for PTSD remain limited, highlighting the need for novel therapeutic strategies. As oxidative stress and neuroinflammation contribute to PTSD, the use of powerful antioxidants such as thiamine (B1 vitamin) compounds may counteract disease development. Young C57BL/6 mice received thiamine or benfotiamine in drinking water (each at a dose of 200 mg/kg/day) for 21 days, and for the last five days, they were subjected to rat exposure. Mice were studied for anxiety-like behavior, exploration, locomotion, grooming, social interactions, pain sensitivity, brain changes in protein carbonyl (PC), total glutathione (TG), and gene expression of distress and inflammation markers. Rat exposure induced anxiety-like behavior, excessive grooming, and alteration in locomotion, along with other abnormalities. Stressed, untreated mice had elevated levels of PC and TG in the prefrontal cortex, hippocampus, amygdala, and striatum and increased expression of Il-1β, Tnf, c-Fos, Cox-1, and Cox-2. Treatment with thiamine or benfotiamine significantly ameliorated most of these changes in the stressed groups. Thus, thiamine compounds may have therapeutic potential in patients with PTSD, owing to their antioxidant and anti-inflammatory properties. Full article

The pyrrolo[2,3-d]pyrimidine (7-deazapurine) scaffold is a unique heterocyclic system included in the composition of most nucleotides. In this study, series of the pyrrolo[2,3-d]pyrimidine-imines and 3-halo-substituted pyrrolo[2,3-d]pyrimidines were designed and prepared in high yields. Condensed pyrimidines are obtained via carbonyl-amine condensation and carbon-halogen bond formation. Pyrrolo[2,3-d]pyrimidine-imines containing a bromine substituent at position C-4 of the phenyl ring and azepine side-ring exhibited superior antitumor activity on the colon cancer HT-29 cell line; IC₅₀ values were 4.55 and 4.01 µM, respectively. These results revealed an interesting pattern, where condensed pyrimidinones containing an azepine ring demonstrated selective antitumor activity on the colon cancer cell line HT-29. In addition, the molecular docking results suggest that compound 8g provided a thorough understanding of its interactions with the DDR2 active site. This could pave the way for further development and optimization of DDR-targeting drugs, contributing to advancements in cancer therapeutics. This lead compound may serve as design templates for further studies. Full article

Heterocyclic compounds have shown that they hold significant therapeutic activities, highlighting the importance of discovering and developing novel candidates against cancers, infections, and oxidative stress-associated disorders. In this study, we demonstrated the biological activity of our previously synthesized thiazolidinone derivatives (TZDs-1, 6, and 7). Furthermore, we synthesized and structurally characterized a new derivative (TZD-5) using IR, ¹H NMR, and ¹³C NMR spectroscopy, confirming the presence of its key functional groups, namely, carbonyl and imine. Their antioxidant activity was assessed through the DPPH assay, with TZD-5 showing the most potent effect (IC₅₀ = 24.4 µg/mL), comparable to ascorbic acid, an effect attributed to the methoxy group introduced via N-alkylation. Cytotoxicity was evaluated using the MTS assay on normal (HFF-1) and cancerous (HepG2 and A549) cell lines at two time points: 24- and 48 h exposure. Our findings highlight clear differences in cytotoxicity and selectivity among the tested thiazolidinone derivatives. TZD-1 and TZD-6 demonstrated significant, dose-dependent cytotoxic effects on both cancerous (HepG2 and A549) and normal (HFF-1) cell lines, thus limiting their therapeutic potential due to insufficient selectivity. TZD-5 exhibited moderate selectivity with higher susceptibility for HepG2 cells compared to normal cells. Notably, TZD-7 showed the most favorable cytotoxic profile, demonstrating strong selective cytotoxicity toward cancer cell lines with minimal adverse effects on normal fibroblasts. Overall, the results highlight TZD-5 and TZD-7 as promising candidates for antioxidant and selective anticancer therapies. Full article