For the first time, singlet oxygen was shown to be generated by quercetin and gallic acid under mild conditions (37 °C, pH 7) and exclusion of light. In contrast to kaempferol, quercetin induced its own oxidative fragmentation, yielding protocatechuic acid (3,4-dihydroxybenzoic acid) and 2,4,6-trihydroxybenzoic acid as the corresponding counterparts. If a 4-molar excess of gallic acid was coincubated, quercetin fragmentation reached 25 mol %, but now also kaempferol gave 7 mol % p-hydroxybenzoic acid. The hydroxybenzoic acids formed always showed the B-ring substitution pattern of the precursor flavonol. This reactive oxygen chemical quenching mechanism initiated by pericyclic cycloadditions was underlined by the use of singlet oxygen released from endoperoxides. Isolation and characterization of a quercetin-methanol solvent adduct pointed toward the parallel occurrence of physical quenching. The importance of singlet oxygen-mediated flavonol degradation in food matrices was verified by the detection of the fragmentation products in minced onion and leek samples.

The study investigated the biochemical and bioactive profiles of three wild inedible mushrooms— Cortinarius trivialis , Mycena pura , and Mycena rosea —focusing on polyamine (PA) content, polyphenols, proteins, antioxidants, and acetylcholinesterase (AChE) inhibition. Among the three PAs measured (putrescine (PUT), spermidine (SPD), and spermine (SPM)), C. trivialis showed the highest levels of PUT and SPD, distinguishing it metabolically. In contrast, M. pura and M. rosea had lower PA levels but were richer in proteins and phenolics. Notably, M. rosea had the highest protein content (42.46%), while M. pura exhibited the greatest total phenolic and flavonoid content, correlating with its strong antioxidant activity across multiple assays. M. rosea demonstrated selective ABTS radical scavenging and the most potent AChE inhibition (93.24 ± 7.90%), suggesting potential neuroprotective benefits. Phenolic profiling revealed species‐specific compounds: C. trivialis was rich in p ‐hydroxybenzoic and quinic acids, while Mycena species contained protocatechuic acid and trace flavonoids. Principal component analysis underscored distinct biochemical clustering: M. pura with antioxidant‐rich phenolics, M. rosea with neuroprotective SPD content, and C. trivialis with elevated PUT. This is the first report detailing PA composition and AChE inhibition in these mushrooms, highlighting their unique and complementary antioxidant and neuroprotective potential.

Chemical composition, antiproliferative, and cell death potential of crude and digested jabuticaba (Myrciaria cauliflora) leaf extracts in HepG2 human hepatocellular carcinoma cells in 2D and 3D culture: a bioprospecting approach.

This study compared Sphagnum papillosum, Rhytidiadelphus triquetrus, and Ditrichum gracile in terms of total phenolic content (TPC), total flavonoid content (TFC), antioxidant activities (DPPH, ABTS, ferric reducing antioxidant power [FRAP]), phenolic profiles, fatty acid compositions, and mineral contents. S. papillosum had the highest TPC (986.11mg GAE/kg) and ABTS activity (9732.14mg Trolox/kg). R. triquetrus showed the highest TFC (874.01mg QE/kg) and was rich in protocatechuic (18803mg/g) and 4-hydroxybenzoic acids (23.219mg/g). Although D. gracile had lower antioxidant activity, it contained high lipid (6.71%) and ash (27.66%) levels, along with substantial potassium (73573.86mg/kg) and calcium (26135.94mg/kg) accumulation. Palmitic acid (C16:0) was the dominant fatty acid in all species. These results demonstrate significant biochemical variation among the studied mosses, underlining their potential as sources of natural antioxidants, bioindicators of environmental stress, and candidates for bioremediation.

The damage caused by the Nilaparvata lugens to rice plants will become aggravated under elevated CO2 (eCO2), emphasizing the urgent necessity to enhance rice defences against N. lugens under eCO2 conditions. The phenylpropanoid pathway is composed of several branches and is known to enhance plant resistance. Inhibiting key enzymes in certain branches can compensatorily activate other branches, thereby strengthening plant defence. In this study, rice plants were treated with the cinnamic acid-4-hydroxylase (C4H) inhibitor piperonylic acid (PA) and the 4-coumarate:CoA ligase (4CL) inhibitor 3,4-(methylenedioxy) cinnamic acid (MDCA), and their effects on N. lugens and rice plants were investigated under ambient CO₂ (aCO2) and eCO2. The results demonstrated that PA and MDCA treatments reduced N. lugens feeding and survival, especially under eCO2. Additionally, PA and MDCA treatments activated the ROS system and phenylpropanoid pathway in rice plants, and increased hydroxybenzoic acid derivatives contents under eCO2, with only minor changes observed under aCO₂. Further analysis illustrated that these compounds suppressed N. lugens feeding and survival, and could bind to and induce the activities of detoxification enzymes in N. lugens. These findings demonstrate that PA and MDCA enhance rice resistance under eCO₂, providing a potential strategy to mitigate pest damage exacerbated by climate change.

Comparative evaluation of DNS, PAHBAH, and BCA colourimetric assays for quantifying reducing sugars.

UVB-activated permanganate enables rapid emerging organic contaminants decontamination through synergistic HO• and reactive manganese species.

In this study, the hydrolytic degradation behavior of high-performance bio-based aromatic-aliphatic liquid crystal copolyesters (BTLCP)—synthesized from 4-hydroxybenzoic acid (HBA), phloretic acid (HPPA), vanillic acid (VA), and lactic acid (LA)—in proteinase K, phosphate buffer, and dilute alkaline solutions has been systematically and comparatively investigated. The degradation behavior was found to be correlated with the copolyester’s rigid and flexible molecular chain structure and composition. The weight loss after degradation was positively correlated with the LA content, as the aliphatic ester groups and amorphous regions of the molecular chain were most susceptible to chemical attack. The molecular chain further ruptured as degradation proceeded, causing the molecular weight to decrease sharply before leveling off after the seventh degradation period. Concurrently, the morphology of the copolyester flakes became coarser and more porous with increasing degradation time, suggesting a combined surface and bulk corrosion mechanism. Although the degraded copolyesters retained their liquid crystal behavior, the isotropic transition was observed below 350 °C, indicating a decrease in molecular chain rigidity. Moreover, the hydrophilicity of the copolyesters increased dramatically after degradation, especially for those containing more LA units, due to the generation of -OH and -COOH end groups from molecular chain scission. In summary, the results reveal that the hydrolytic degradation rate can be regulated by adjusting the composition and degradation medium. The synthesized BTLCPs containing more LA units exhibit excellent degradation performance and hydrophilicity, highlighting their potential for applications in biomedical and packaging fields.

Sideritis lanata (“mountain tea”) is widely consumed; however, its water-extractable chemotype and associated biological activities remain underdefined. In this study, an ultrasound-assisted aqueous extract was characterized to link chemical composition with biological function. The extract exhibited a moderate phenolic load, with a total phenolic content (TPC) of 22.27 mg gallic acid equivalents per gram (GAEs/g) and a total flavonoid content (TFC) of 7.50 mg rutin equivalents per gram (REs/g). Phenolic profiling by liquid chromatography–electrospray ionization–tandem mass spectrometry (LC–ESI–MS/MS) revealed a phenolic-acid–dominated signature, mainly hydroxycinnamic acids led by chlorogenic acid (691 µg/g), followed by caffeic acid (231 µg/g), p-coumaric acid (211 µg/g), and ferulic acid (50.4 µg/g), together with abundant hydroxybenzoic acids such as 3- and 4-hydroxybenzoic acids (188 and 183 µg/g, respectively). Antioxidant activity, evaluated using six complementary assays, was moderate and assay-dependent, with stronger metal-chelating activity (IC50 = 1.31 mg/mL) and ferric reducing antioxidant power (FRAP; EC50 = 1.38 mg/mL), followed by phosphomolybdenum (EC50 = 2.03 mg/mL), and weaker cupric reducing antioxidant capacity (CUPRAC; EC50 = 3.10 mg/mL), ABTS (IC50 = 3.64 mg/mL), and DPPH (IC50 = 5.13 mg/mL). The extract inhibited acetyl- and butyrylcholinesterase and tyrosinase with comparable potency (2.69, 2.53, and 2.64 mg/mL, respectively), while weaker inhibition was observed for α-glucosidase (10.63 mg/mL) and α-amylase (19.93 mg/mL). In A549 lung carcinoma cells, viability decreased concentration-dependently; at the half-maximal inhibitory concentration (IC50), tumor necrosis factor-alpha (TNF-α) increased to 26.73 ng/mL, whereas transforming growth factor-beta (TGF-β) and interleukin-1 beta (IL-1β) decreased to 9.4 and 10.83 pg/mL, respectively, while at ½ × IC50 TNF-α was 1.3 ng/mL and TGF-β reached 46.6 pg/mL. Overall, this hydroxycinnamate- and hydroxybenzoate-rich aqueous extract exhibits moderate, target-selective antioxidant and enzyme-inhibitory activities together with dose-dependent immunomodulatory effects.

Successful treatment of neonatal COQ2 deficiency with 4-hydroxybenzoic acid.

The increasing demand for rapid identification of bacteria capable of degrading environmentally relevant organic compounds highlights the need for scalable and selective analytical tools. Cupriavidus necator catabolizes several hydroxybenzoic acids, including 2-hydroxybenzoate (salicylate, 2-HBA), 4-hydroxybenzoate (4-HBA), and 3-hydroxybenzoate (3-HBA), funneling them into central aromatic catabolism via monooxygenation to 2,5-dihydroxybenzoate (gentisate, 2,5-dHBA) and 3,4-dihydroxybenzoate (protocatechuate, 3,4-dHBA) followed by the oxidative cleavage reaction, enabling complete conversion to tricarboxylic acid (TCA) cycle intermediates. To quantify how readily C. necator is able to activate catabolic genes in response to hydroxybenzoic acid, an extracellular ligand, we applied an approach centered on a transcription-factor (TF)-based biosensor that combines ligand-bound regulator activity with a fluorescent reporter. This approach allowed to evaluate the ligand sensitivity by determining gene activation threshold ACmin and half-maximal effective concentration EC50. Amongst studied hydroxybenzoic acids, 2-HBA and 4-HBA sensors from C. necator showed very low thresholds 4.8 and 2.4 μM and EC50 values of 19.91 and 13.06 μM, indicating high sensitivity to these compounds and implicating a scavenging characteristic of associated catabolism. This study shows that the TF-based-biosensor approach applied for mapping functional sensing ranges of hydroxybenzoates combined with the research and informatics of catabolism can advance our understanding of how gene expression regulation systems have evolved to respond differentially to the availability and concentration of carbon sources. Furthermore, it can inform metabolic engineering strategies in the prevention of premature pathway activation or in predicting competitive substrate hierarchies in complex mixed environments.

Distal peptide elongation by a protease-like ligase and two distinct carrier proteins

The trend toward sustainable protein substitutes is driven by growing concerns about food security, sustainability, and human health. Spent brewer's yeast and wine lees are two by-products of the beer and wine industry with high potential, owing to their complex composition, which remains insufficiently exploited. The purpose of this study was to perform a comparative analysis of the two by-products under two different drying techniques to observe if there are significant changes in composition: oven-drying and freeze-drying. Two samples of wine lees from producers in the Republic of Moldova were used-Asconi Winery and Cricova Winery (Republic of Moldova)-as well as a sample of spent brewer's yeast offered by Efes Vitanta Moldova Brewery. The samples were characterized in terms of physicochemical properties, antioxidant activity (total polyphenol content (TPC), individual polyphenol content, and DPPH assay scavenging activity), color, mineral content, structural composition (FT-IR analysis), and microstructure, as well as organic acid and B vitamin content. The highest protein content was recorded in the samples from Cricova (45.35-46.81%). Regarding the polyphenols, the oven-dried Efes sample exhibited a TPC value of 3.98 mg GAE/g, while the highest DPPH value of 88.92% was observed in the Asconi sample. All analyzed samples showed a diverse composition of individual phenolic compounds, including 4-hydroxybenzoic acid, vanillic acid, caffeic acid, and rosmarinic acid. Wine lees samples have the highest content of B vitamins, with vitamin B3 being the most abundant across all samples, followed by vitamin B6. The microstructural examination revealed autolyzed yeast cells, with more permeable cell walls, favorable to subsequent valorization treatments, and in some cases, cells form clusters in a mother-daughter junction due to serial re-pitching.

Juniperus communis L. is a conifer widely used in traditional European medicine for the management of inflammatory disorders. However, its effects on oxidative stress and inflammation remain incompletely characterized. The present study investigated the antioxidant and anti-inflammatory potential of an ethanolic needle extract of J. communis using in vitro assays and an in vivo model of acute inflammation induced by turpentine oil in rats. Phytochemical profiling by HPLC–DAD–ESI–MS revealed a polyphenol-rich extract dominated by flavonols, flavanols, and hydroxybenzoic acids, with quercetin derivatives and taxifolin as major constituents. In vitro analyses demonstrated radical-scavenging and reducing capacities, exceeding or comparable to reference antioxidants in DPPH, hydrogen peroxide, ferric-reducing, and nitric oxide scavenging assays. In vivo, both therapeutic and prophylactic administration of the extract significantly attenuated oxidative and nitrosative stress, as evidenced by reductions in total oxidant status, oxidative stress index, malondialdehyde, advanced oxidation protein products, nitric oxide, 3-nitrotyrosine, and 8-hydroxy-2′-deoxyguanosine, alongside restoration of total antioxidant capacity and thiol levels. These effects were concentration-dependent. Concomitantly, inflammatory signaling was suppressed, with decreased NF-κB activity and reduced levels of interleukin-1β and interleukin-18. These results support the use of these extracts, whose benefits have been observed in traditional medicine, providing scientific support for the anti-inflammatory and antioxidant capacity of J. communis extract.

Phytochemical characterization and anti-inflammatory evaluation of compounds extracted from Ficus erecta roots.

Background: Thymol, a natural phenol with antimicrobial and antioxidant activities, and its derivatives offer promising scaffolds for antimalarial drug development, potentially helping overcome resistance. Materials and Methods: In this study, thymol derivatives were synthesized and assessed as antiplasmodial agents against both resistant and sensitive strains of P. falciparum, as well as Plasmodium knowlesi. The ligand molecules were assessed with Plasmodium falciparum chloroquine resistance transporter (PfCRT)’s potential using in silico molecular docking and ADMET analysis. The parent compound, thymol, was chemically modified through esterification and conjugation with hydroxybenzoic acid and cinnamic acid derivatives to generate analogs with varied substitution patterns. Results: The findings showed that among seven successfully synthesized thymol derivatives, compounds 4 and 6 exhibited notable potency against Plasmodium falciparum 3D7 (EC50 = 6.01 ± 1.7 µM and 6.8 ± 1.1 µM, respectively) with high SI values (16.5 and 14.6, respectively), indicating improved selectivity relative to thymol. The cytotoxicity evaluation against HCF mammalian cells revealed that most thymol derivatives were non-toxic, with CC50 values greater than 99 µM, except for compound 3 (CC50 = 71.4 ± 4.5 µM) and compound 1 (CC50 = 58.4 ± 2.3 µM), which exhibited moderate cytotoxic effects. The molecular docking results showed that compounds 3 (−8.4 kcal/mol), 4 (−8.3 kcal/mol), and 6 (−8.3 kcal/mol) exhibited strong binding affinities toward the PfCRT protein. Conclusions: Therefore, thymol derivative compounds 4 and 6 exhibited stronger antiplasmodial activity in vitro against P. falciparum and P. knowlesi with safety profiles against mammalian cells, targeting PfCRT, highlighting their potential as lead antimalarial candidates.

Effect of the grafting degree of phenolic acids on the structural characterization and emulsification properties of soy hull polysaccharides.

Aromatic secondary metabolite interactions with nickel-dependent urease.

This study presents a comparative structural and supramolecular analysis of two newly synthesised co-crystals of phenazine with hydroxybenzoic acid derivatives: 4-hydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid. The crystal structures were characterised...

Bioprospecting and exploration of the chemical profile of Lasiodiplodia sp. extracts: Evaluation of specialized metabolites by similarity calculations, and dereplication with differential 1H NMR.