Search Results (302)

Ulomoides dermestoides (Yangchong) is a tenebrionid beetle used in traditional medicine across Asia and Latin America. While crude extracts show effects on inflammation, oxidative stress, and other conditions, systematic integration of its bioactive substances, mechanisms, and translational potential is lacking. This review consolidates its chemical basis, comprising volatile benzoquinones, terpenes, and alkenes, alongside non-volatile fatty acids, proteins (antioxidant enzymes, glycoproteins), and phenolics. Pharmacological evidence indicates multi-target modulation of reactive oxygen species (ROS), cytokines, leukocyte recruitment, endothelial activation, and thromboinflammation. Recent advances include proteomic identification of antioxidant protein complexes, neuroprotection in a Parkinson’s disease model, chromosome-level genome assembly, and isolation of the UDP-glucose pyrophosphorylase 2a (UGP2A) glycoprotein, which alleviates thrombosis partly via toll-like receptor 4/myeloid differentiation primary response 88 (TLR4/MyD88)-mediated endothelial anti-inflammatory effects. However, most evidence remains preclinical, relying on non-standardized crude extracts, and benzoquinone-containing fractions display potential cytotoxicity and genotoxicity. Future research should integrate bioassay-guided isolation, structural characterization, multi-omics, pharmacokinetic/pharmacodynamic (PK/PD) analysis, standardized quality markers, and rigorous safety evaluation to transform U. dermestoides from an empirical insect-derived medicinal resource into a scientifically validated source of preclinical antioxidant and anti-inflammatory candidate substances. Full article

Chlorinated benzoquinones such as 2,6-dichlorobenzoquinone (DCBQ) are toxic disinfection by-products that may persist in treated waters, requiring post-treatment strategies. In this study, the photo-Fenton process was evaluated for DCBQ degradation, with a focus on the influence of pH on kinetics, oxidation behavior, and water quality evolution. Experiments were conducted using 50.0 mg/L DCBQ, 1.0 mg/L Fe²⁺, and 2.0 mM H₂O₂ under UV irradiation (150 W) within a pH range of 3.0–12.0. Degradation followed apparent second-order kinetics, with maximum rates at acidic pH. At initial pH 3.0–5.0, rapid pollutant removal was accompanied by efficient aromaticity (UV₂₅₄) and color elimination, intense dissolved oxygen consumption, transient turbidity peaks due to intermediate formation, and increases in total dissolved solids, indicating extensive oxidation and a high degree of organic matter transformation, as inferred from indirect physicochemical indicators. At near-neutral pH, oxidation was slower, with delayed aromatic and chromophoric decay and moderate accumulation of intermediates. Mildly alkaline conditions exhibited limited radical activity, stable turbidity, and reduced mineralization. Under strongly alkaline conditions, oxidation was largely inhibited, with persistent aromaticity and negligible oxygen consumption. These findings highlight the importance of integrating advanced oxidation processes with adsorption-based systems for efficient and sustainable water treatment of emerging contaminants. Full article

Chlorophenols (CPs), such as 4-chlorophenol (4-CP) and 2,4-dichlorophenol (2,4-DCP), are persistent and toxic organic pollutants commonly found in industrial effluents. This study investigates their photocatalytic degradation using a TiO₂-based heterogeneous catalyst under UV irradiation, in the presence of hydrogen peroxide. The degradation kinetics were analyzed using both pseudo-first order and nonlinear Langmuir–Hinshelwood (L–H) models, accounting for competitive adsorption and successive oxidation of intermediates. Gas chromatography–mass spectrometry (GC–MS) identified key intermediates, including hydroquinone, catechol, chlorocatechols, and benzoquinone. Nonlinear kinetic modeling of coupled differential equations accurately reproduced the temporal profiles of both the parent compounds and their intermediates, providing mechanistic insights into multi-step hydroxylation, dechlorination, and oxidation processes. The results demonstrate that photocatalytic oxidation effectively mineralizes chlorophenols within 500–600 min, and the developed kinetic model offers a predictive tool for optimizing photocatalytic remediation strategies for chlorinated aromatic pollutants. The novelty of this study lies in the development of a nonlinear Langmuir–Hinshelwood kinetic model integrating experimentally identified degradation intermediates, competitive adsorption phenomena, and parallel photocatalytic reaction pathways for both 4-chlorophenol and 2,4-dichlorophenol oxidation systems. Full article

Background: Paracetamol is widely used for acute pain management in orthopedic trauma; however, interindividual variability in analgesic response remains insufficiently understood. Cytochrome P450 2E1 (CYP2E1), a key enzyme involved in paracetamol metabolism and the formation of the toxic metabolite N-acetyl-p-benzoquinone imine (NAPQI), may contribute to this variability. This study aimed to investigate the relationship between CYP2E1 gene polymorphisms and the analgesic efficacy of paracetamol in patients with lower extremity fractures. Methods: A total of 127 patients with lower extremity fractures and 100 healthy controls were included. All patients received 1000 mg of intravenous paracetamol. Pain intensity was assessed using the Visual Analog Scale (VAS) at baseline and at 30, 60, and 120 min after administration. Genotyping of CYP2E1 polymorphisms (*1A, *5B, *6, and *7B) was performed using PCR-RFLP. Differences in the VAS scores and analgesic response were analyzed according to genotype. Results: Paracetamol administration resulted in a significant reduction in pain scores at all time points (p < 0.001). Patients carrying the CYP2E15B variant exhibited significantly higher VAS scores and a weaker early analgesic response compared to non-carriers (p ≤ 0.001). Similarly, CYP2E11A carriers demonstrated higher pain scores across all time points (p < 0.05), although the magnitude of effect was less pronounced. No significant differences were observed for the CYP2E16 variant. Due to low frequency, CYP2E17B could not be reliably analyzed. Conclusions: Paracetamol is an effective analgesic in patients with lower extremity fractures; however, CYP2E1 polymorphisms may modulate individual pain perception and early analgesic response. In particular, the *5B and, to a lesser extent, *1A variants are associated with higher pain scores. These findings support the potential role of pharmacogenetic approaches in personalized pain management. Full article

The development of durable and practical polymer-supported photocatalytic materials that are suitable for use in continuous-flow systems has become an increasingly pressing issue in the field of water treatment. In this study, FeTiO₃/BiOCl heterojunction structures were synthesized at different ratios and integrated into a poly(vinylidene fluoride) (PVDF) matrix to develop photocatalytic thin-film systems. The resulting materials were characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and UV–visible diffuse reflectance spectroscopy (UV-DRS) analyses. In photocatalytic experiments conducted under visible light, a 66.3% removal of doxycycline was achieved for pristine FeTiO₃ within 180 min, whilst the FTO@BiOCl(III) composite reached 74.4%. In the PVDF-based thin-film system, the film catalyst demonstrated a removal efficiency of 68.9%. When the pH effect was investigated, the highest total removal of 90.3% was achieved under pH 6.0 conditions. Radical scavenging experiments revealed that superoxide radicals were the predominant active species (a decrease to 30.5% in the presence of benzoquinone (BQ). In experiments conducted in the air-lift reactor system, the P-FTO@BiOCl(III) film achieved approximately 65% removal after 9 h and maintained its structural stability. The PVDF-supported FeTiO₃/BiOCl heterojunction thin-film system offers a noteworthy alternative for environmental applications due to its suitability for continuous systems, structural stability and effective photocatalytic performance. Full article

Polydopamine (PDA) is a promising biomimetic material, but its structural complexity hinders rational control over its light absorption properties. The purpose of this study was to develop a simple post-synthetic method to tune the absorption spectrum of PDA using Bobbit’s salt (4-acetylamino-2,2,6,6-tetramethylpiperidine-1-oxoammonium salt) as a mild oxidant. Conventional PDA nanoparticles were treated with Bobbit’s salt either in pure water or in a 1:1 methanol–water mixture to obtain two modified samples. Structural analysis conducted using Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and mass spectrometry demonstrated that Bobbit’s salt selectively oxidized catechol units to ortho-benzoquinone moieties, with the C–O/C=O ratio decreasing from 71:29 in the untreated PDA to 51:49 in the water-treated sample, while nitrogen functionalities remained unchanged. Consequently, the sample prepared in pure water showed generally lower absorbance across the visible–near-infrared range, whereas the sample prepared in the methanol–water mixture exhibited enhanced ultraviolet absorption but reduced near-infrared absorption. When coated onto polyvinylidene fluoride membranes, the water-treated PDA produced a brighter and more reddish-yellow appearance. On transparent poly(methyl methacrylate) substrates, the same coating also enhanced ultraviolet blocking and reduced visible transmittance. These findings conclude that Bobbit’s salt is an effective and selective reagent for tailoring the optical properties of PDA, with potential applications in protective coatings and light-modulating materials. Full article

Hafnia (hafnium oxide) nanostructures, both unmodified and silica-modified with minor and major silica content, were synthesized using an adapted sol–gel method with D-L tartaric acid as an internal template. After thermal treatment, structural non-stoichiometry and light absorptive properties were identified in the resulting hafnium-based nanostructures, indicating their potential for various applications, including photocatalysis. The ability of these materials to photogenerate reactive oxygen species (ROS), namely superoxide anion radicals (•O₂₋) under simulated solar light (AM 1.5) and singlet oxygen (¹O₂) under visible light (λ > 390 nm), was evaluated and monitored by UV–Vis and photoluminescence spectroscopy. Functionalization of hafnium-based oxides with protoporphyrin IX was employed to enhance singlet oxygen photogeneration. The reactivity of the generated (¹O₂) was assessed by quenching of DL α-tocopherol photoluminescence under visible light irradiation. Photocatalytic experiments conducted under anaerobic conditions demonstrated the ability of the hafnia-based nanostructures to reduce 1,4-benzoquinone (BQ) to 1,4-hydroquinone (H₂Q). Furthermore, embedding the hafnia-based powders into polyvinyl alcohol hydrogels enabled the obtainment of photoactive coatings on glass substrates, for which their mechanical properties were evaluated using force–distance spectroscopy measurements. Morphological and structural characterization of the materials was performed using scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM), atomic force microscopy (AFM), X-ray diffraction and fluorescence (XRD, XRF), X-ray photoelectron spectroscopy (XPS), N₂ adsorption–desorption measurements, UV–Vis spectroscopy, photoluminescence (PL) spectroscopy, and zeta potential measurements. These investigations revealed that adding silica induces significant modifications in the morphology, texture, and structure of the hafnia, thereby enhancing the functional properties of the resulting materials. Full article

This study evaluates the pH-dependent ozonation of 2,6-dichloro-1,4-benzoquinone to optimize sustainable oxidation strategies for water treatment. Experiments were conducted over a wide pH range under controlled temperature and ozone dosage. DCBQ was fully degraded within minutes following first-order kinetics, regardless of pH. Acidic to neutral systems experienced a progressive pH decrease due to the formation of oxygenated transformation products, whereas strongly alkaline conditions remained stable due to buffering effects. Aromaticity removal followed a second-order kinetic and increased with pH, reflecting enhanced aromatic ring cleavage under alkaline conditions. Color was rapidly eliminated for all tested pH values, while turbidity remained low at pH ≤ 10 but increased under extreme alkalinity due to colloidal aggregation. While previous studies have examined the influence of pH on ozone reaction pathways, its combined effect on ozonation performance and gas–liquid mass transfer remains largely unexplored. Dissolved ozone measurements enabled estimation of the gas–liquid mass transfer coefficient, which decreased linearly with increasing pH, revealing a direct coupling between pH-controlled ozone reactivity and transfer efficiency. Overall, pH 9–10 was identified as the optimal operational range, balancing effective aromaticity removal, ozone stability, and minimal turbidity, thus providing practical strategies for the treatment of chlorinated quinones in water. Full article

Piezo-enhanced photocatalysis is progressively considered an eco-friendly technology for contaminant removal, harvesting not only solar energy but also mechanical vibrations found in nature. Multiferroic materials present a coupled effect of various properties and can potentially increase the applicability of this process. In this study, Cr- doped bismuth ferrite thin film was deposited on SrTiO₃ substrate by HiPIMS, and its photo-, piezo-, and piezo-photocatalytic efficiencies in Rhodamine B (RhB) degradation were analyzed. The highest removal percentage was found under the simultaneous exposure of visible light and mechanical vibrations, reaching 86.2% after 180 min. The calculated efficiencies for photo- and piezocatalysis were 12.2% and 83.7%, respectively. The rate constant (k) for piezo-photocatalysis was 16.1 times higher than that found during photocatalytic experiments. To assess the contribution of each reactive species to the decomposition process, different reagents were added to the Rhodamine B contaminated solution. The results revealed that when p-benzoquinone was used, the degradation efficiency declined significantly from 86.2% to 37.6%, suggesting that superoxide radicals (O₂^•−) play a key role in decomposing RhB molecules. The structural, chemical, optical, and ferroelectric changes caused by the catalytic processes were analyzed and linked to the proposed degradation mechanisms. The poor photocatalytic efficiency was linked to an improper band structure and an improper polarization orientation of the ferroelectric domains in the as-deposited film. The degradation mechanisms in piezo-photocatalysis were driven partly by the band bending caused by mechanical vibrations and partly by the reorientation of the induced polarization of the domains in the unstrained film. Full article

Objectives: This study aims to identify the reactive metabolite of acetaminophen (AAP) and the cyanopyrrolidine metabolite of saxagliptin in human induced pluripotent stem cell-derived hepatic organoids (HHOs) and to compare them with human liver microsomes (HLMs) and plateable cryopreserved human hepatocytes (CHHs) to evaluate the feasibility of HHOs for reactive metabolite screening and metabolite profiling. Methods: AAP (50 μM) or sax-agliptin (50 μM) was incubated for 1 h at 37 °C in HLMs with or without NADPH-generating solution and 0.5 mM reduced glutathione (GSH). AAP (50 μM) was incubated for 24 h in HHOs and CHHs at 37 °C in a CO₂ incubator. AAP and saxagliptin metabolites in the reaction mixtures were analyzed using ultra-performance liquid chromatography coupled with tandem mass spectrometry. Results: N-acetyl-p-benzoquinone imine (NAPQI) was identified in the incubation mixture of HLMs with AAP, and its levels were reduced in the presence of GSH, accompanied by increased formation of AAP–GSH adduct. Incubation of AAP with HHOs for 24 h resulted in the formation of NAPQI, AAP–GSH, AAP–glucuronide, and AAP–sulfate. Moreover, CYP1A2 induction using omeprazole treatment increased the formation of AAP and AAP–GSH conjugate from phenacetin, reflecting enhanced CYP1A2 activity in both CHHs and HHOs. The findings indicate that HHOs are a suitable platform for reactive metabolites, such as NAPQI and AAP–GSH adducts, under chronic exposure and metabolic modulator intervention. Additionally, CHHs and HHOs exhibited similar saxagliptin metabolite profiles after incubation with saxagliptin and generated cysteine conjugates of saxagliptin and its hydroxylated metabolite. Conclusions: HHOs system can be used as an in vitro model for screening reactive metabolites, comparable to those obtained with CHHs. Full article

Freshwater fungi have attracted considerable attention as a potential source of lead compounds with diverse and novel chemical structures and biological activities in drug discovery. This review summarizes 307 natural products of freshwater fungi from 1988 to the end of October 2025. These compounds are categorized into fourteen structural types, including fatty acids and their lactones (compounds 1–18), furans and furanones (compounds 19–31), pyrans and pyranones (compounds 32–109), benzoquinones, phenols and phenolic acids (compounds 110–141), naphthalenes and naphthalenones (compounds 142–192), authraquinones and xanthones (compounds 193–211, depsidones (compounds 212–217), macrolides (compounds 218–234), polyesters (compounds 235–237), alkaloids (compounds 238–251), peptides (compounds 252–280), terpenoids (compounds 281–300), steroids (compounds 301 and 302), and other compounds (compounds 303–307). Some of them displayed promising biological activity, mainly comprising antibacterial, cytotoxic, and nematicidal activities. The preliminary analysis of the Structure––Activity Relationship (SAR) of important compounds is also discussed. In the last section, current challenges and prospective research perspectives are briefly proposed based on opinions from previous reviews. This review would contribute to the understanding of the utilization and development of natural products derived from freshwater fungi as potent medical resources in the future. Full article

Water pollution is one of the most critical societal and environmental challenges and remains a persisting problem worldwide. The origin of this pollution is diverse, while organic matter occupies a significant portion, originating from different sources. This creates major environmental and health risks, requiring reliable and sensitive analytical tools for effective monitoring. The permanganate index stands as a conventional assessment method for organic pollution, but it demonstrates compound non-specificity toward compounds and limited sensitivity to various contaminant structures. This research introduces cyclic voltammetry as a standalone electrochemical method that provides sensitive detection and characterization of organic oxidizing compounds. Six organic compounds, including gallic acid, phenol, oxalic acid, ascorbic acid, salicylic acid and p-benzoquinone, were used as model compounds and studied in aqueous media. These compounds were analyzed individually, in single-compound mode, to characterize their redox behavior and to identify the voltammetric peaks. Subsequently, a multi-compound analysis was studied to check for the validity of the concept in a more complex matrix. Notably, a strong linear correlation was observed between the measured charge and the theoretical permanganate index, highlighting the quantitative reliability of the electrochemical method. Comparing the obtained results with the permanganate index method confirmed the superiority of cyclic voltammetry in terms of response time and detection capability. The outcomes demonstrate that cyclic voltammetry functions as a robust alternative to the classical chemical oxidation method for environmental water assessment. Full article

For the first time, hybrid nanocomposites based on poly(2,5-dichloro-3,6-bis(phenylamino)-p-benzoquinone) (PCPAB) and multi-walled carbon nanotubes (MWCNTs) were obtained and the influence of the preparation method on their structure and functional properties was demonstrated. The nanocomposites were obtained both by ultrasonic mixing of PCPAB and MWCNTs, and via in situ oxidative polymerization of CPAB in the presence of MWCNTs or MWCNTs with the addition of ZnO. The formation of hybrid nanocomposites occurs due to non-covalent interaction (π-stacking) between the graphene structures of the MWCNT surface and the phenyl rings of PCPAB. It was found that during the in situ oxidative polymerization of CPAB in the presence of MWCNTs, the growth of polymer chains occurred in close proximity to the filler surface, which led to the formation of a polymer coating. ZnO particles, localized on MWCNTs, on the one hand, prevent their aggregation, and on the other hand, create additional polymerization reaction centers due to the coordination of the Zn-O bond at the H and O atoms of the monomer. An increase in the concentration of reaction centers as a result led to a 2–2.5-fold reduction in the induction polymerization period. According to SEM data, in this case, a more ordered and denser polymer layer is formed due to intermolecular complexation between the main and side chains of the growing polymer with the participation of Zn²⁺ ions formed as a result of the transformation of ZnO to ZnCl₂ in the acidic reaction medium of polymerization. The results of the study of the frequency dependences of conductivity indicate a hopping mechanism of conductivity of nanocomposites. The electrical conductivity of nanocomposites depends on their production method and the MWCNT content and varies between 0.5 and 1.1 S∙cm⁻¹, which is 6–12 times higher than the conductivity of the original polymer. Thermogravimetric analysis revealed that the nanocomposites exhibit enhanced thermal stability compared to PCPAB. The best results were shown by nanocomposites with a higher content of MWCNTs, for which the residual mass at 450 °C was 51–53%. Full article

1,4-Dimethoxy-2,3-dinitrobenzene (1) reduction using sodium hydrosulfite resulted in 3,6-dimethoxybenzene-1,2-diamine (2) and 3,6-dimethoxy-2-nitroaniline (3) in 24% and 59% yields, respectively. Nitroaniline 3 was acetylated with acetyl chloride to give N-(3,6-dimethoxy-2-nitrophenyl)acetamide (4) in a 65% yield and with acetic anhydride to give N-acetyl-N-(3,6-dimethoxy-2-nitrophenyl)acetamide (5) in 78% yield. Novel compounds 4 and 5 were characterized by FT-IR, ¹H and ¹³C-NMR, and HRMS. The X-ray crystal structure of acetamide 4 is also presented. Full article

Our recent work has focused on red light-mediated photoreduction of p-benzoquinones and both o-, and p-naphthoquinones using methylene blue and the chlorophyll metabolite, pheophorbide A as photosensitizers. Photoreduction of biologically relevant quinones mimics photoreduction of plastoquinone by chlorophyll in photosynthesis. We examined photo-oxidation and photoreduction reactions of catechols because their oxidation to o-quinones by reactive oxygen species is implicated in protein damage in neurodegeneration. Photo-oxidation of catecholamines including dopamine, epinephrine and norepinephrine required red light, methylene blue or pheophorbide A, and molecular oxygen. Their cyclized oxidation products, aminochrome, adrenochrome and noradrenochrome, were detected by UV/visible spectroscopy. Hydrogen peroxide was generated during photo-oxidation by singlet oxygen-dependent oxidation of catecholamines. Inclusion of tertiary amine electron donors decreased cyclized products but did not affect hydrogen peroxide yield consistent with concurrent photo-oxidation followed by photoreduction of the o-quinone intermediate. Unreacted dopamine and norepinephrine were quantified using 3-hydroxyphenyl boronic acid following photochemical reactions. Dopamine and norepinephrine boronate esters absorb at 417 and 550 nm. Photo-oxidation of dihydroxycaffeic acid and dihydroxyphenyl acetic acid was also evaluated by detecting their boronate esters at 475 nm. We hypothesize that photoreduction of transient o-quinones by the combination of red light and dietary chlorophyll metabolites may be a path to limit protein damage and to recycle catechol antioxidants. Full article