Search Results (1,062)

Biosurfactants are environmentally friendly surface-active compounds with promising applications in environmental remediation. In this study, a biosurfactant-producing bacterium, Bacillus (B.) velezensis SHB.28, was isolated from heavy metal-contaminated soil and evaluated for its ability to produce biosurfactants using date syrup as a low-cost agro-industrial substrate. Screening assays including drop-collapse (DC), oil spreading (OS), and emulsification index after 24 h E₂₄ (%) confirmed strong biosurfactant production. Culture conditions were optimized, revealing that 30 °C, pH 6, and a C/N ratio between 10% and 20% provided optimal production. Under optimized conditions, the crude biosurfactant extract yield reached 2.16 g/L within 24 h, accompanied by a reduction in surface tension from 69 to 29.1 dyn/cm and high emulsification activity. Kinetic modeling showed that emulsification activity followed an exponential growth model (R² = 0.985), whereas surface tension dynamics were well described by a spike decay–plateau model (R² = 0.998). Structural characterization using Fourier-transform infrared spectroscopy (FTIR), electrospray ionization–mass spectrometry (ESI–MS), and nuclear magnetic resonance (NMR) spectroscopy revealed that the biosurfactants are surfactin- and iturin-like cyclic lipopeptides composed of a β-hydroxy fatty acid chain (C₁₃–C₁₅) linked to a cyclic peptide moiety. The biosurfactant exhibited a critical micelle concentration of 100 mg/L and an anionic character with a pH_pzc of 5.7. Furthermore, it demonstrated high efficiency in removing heavy metals, achieving removal efficiencies of 99.88% for Fe²⁺, 99.69% for Pb²⁺, and 94.72% for Cu²⁺, outperforming conventional surfactants such as SDS and Tween 80. These findings highlight the potential of date syrup-derived surfactin and iturin from B. velezensis SHB.28 as sustainable and efficient biosurfactants for environmental remediation and heavy metal removal applications. Full article

A series of novel substituted derivatives of the closo-decaborate anion [B₁₀H₁₀]²⁻ bearing alkoxy spacer chains of varying length derived from ring-opened crown ethers (12-crown-4, 15-crown-5, and 18-crown-6) with pendant L-amino acid methyl ester residues (L-tryptophan and L-histidine) have been synthesized. The synthetic approach involved the nucleophilic ring-opening of oxonium crown ether derivatives of the closo-decaborate anion followed by coupling with amino acid methyl esters via mixed anhydride activation. The obtained compounds were characterized by multinuclear NMR spectroscopy (¹H, ¹¹B, ¹³C), IR spectroscopy, elemental analysis, and electrospray ionization mass spectrometry (ESI-MS). The compounds were obtained as sodium salts and evaluated for their in vitro cytotoxic and antiviral properties against the influenza A virus strain A/Moscow/78/2020 (H1N1)pdm09, which contains the S31N mutation conferring resistance to adamantane-class drugs. Cytotoxicity was assessed on MDCK cells, and antiviral activity was determined by cell ELISA. The results revealed a clear structure–activity relationship: the length of the alkoxy spacer chain significantly influenced both antiviral activity and selectivity. The shortest spacer (derived from 12-crown-4) proved to be optimal, while elongation of the chain led to a decrease in antiviral potency. The compound containing a 12-crown-4-derived spacer and a tryptophan methyl ester residue exhibited the highest selectivity index (SI = 155) with low cytotoxicity (CC₅₀ = 155 µg/mL) and high antiviral activity (IC₅₀ = 1.0 µg/mL). Tryptophan-containing derivatives consistently outperformed their histidine analogues, confirming the key role of the indole side chain in antiviral activity. Overall, the closo-decaborate platform with crown ether-derived spacers and amino acid ester pendant groups represents a promising scaffold for the development of low-toxicity, highly selective inhibitors of influenza A virus replication. The compound with the 12-crown-4-derived spacer and a tryptophan methyl ester residue merits further investigation as the most promising among the synthesized samples. Full article

4′-Hydroxymethoxychalcones represent structurally diverse chalcone derivatives that are attractive substrates for microbial functionalization; however, the impact of methoxy substitution position on their cascade biotransformation by fungi remains poorly understood. In this study, three regioisomeric 4′-hydroxymethoxychalcones, featuring ortho-, meta-, or para-methoxy groups on ring B, were transformed using eight entomopathogenic fungal strains belonging to the genera Beauveria, Isaria, and Metarhizium. Metabolic profiles were monitored over a 10-day period using ultra-high-performance liquid chromatography coupled with diode-array detection (UHPLC-DAD), and the structures of the major products were elucidated primarily by one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and further supported by high-resolution electrospray ionization quadrupole time-of-flight mass spectrometry (HR-ESI-QTOF-MS). The investigated microorganisms catalyzed multistep transformations encompassing the reduction of the α,β-unsaturated carbonyl system, methylglucosylation, O-demethylation, and the formation of secondary polar metabolites. Although ene-reduction constituted the predominant initial reaction for all substrates, the relative distribution of subsequent metabolites varied depending on both the fungal strain and, to a lesser extent, the position of the methoxy group. The ortho-methoxy derivative exhibited the highest propensity for O-demethylation; the meta-substituted substrate generated the most heterogeneous secondary metabolite profiles, whereas the para-methoxy analogue showed the most consistent accumulation of methylglucosylated dihydrochalcones. These findings indicate that methoxy substitution position does not alter the common core biotransformation pathway, but can modulate the relative efficiency of individual steps and the extent of secondary metabolism. Full article

Many genotoxic impurities (GTIs) remain “invisible” to conventional LC-MS due to poor ionization or chemical instability under electrospray ionization, yet their sub-ppm acceptable intake limits under ICH M7(R2) demand exceptional analytical sensitivity. Derivatization—the chemical introduction of ionizable moieties, stable tags, or MS/MS information carriers—offers a powerful strategy to overcome this limitation. This review provides a critical systematic overview of derivatization techniques for LC-MS analysis of GTIs over the past decade (2015–2025, based on a literature search across PubMed, Web of Science, and Scopus). We construct a functional-group-based strategic framework covering alkyl halides, nitroaromatics, sulfonyl chlorides, hydroxylamine, alcohols, aldehydes, carboxylic acids, and amines, while placing specific emphasis on typical impurities within these classes such as methyl iodide, methyl chloride, nitrobenzene, and benzenesulfonyl chloride, and discuss the evolution of reagents from simple “reaction tags” to “MS/MS information carriers” that provide characteristic neutral losses or product ions for enhanced selectivity. Quantitative analysis reveals that derivatization typically enhances ESI response by 2–3 orders of magnitude, consistently achieving LODs below 1 ppm—the ICH M7(R2) threshold. Key analytical trade-offs are critically evaluated, including the balance between derivatization efficiency and reaction time, by-product management, and the fundamental kinetic and chromatographic constraints that render post-column derivatization impractical for most GTIs. We conclude with perspectives on high-throughput automation, smart multifunctional reagents, online integration, and green chemistry, aiming to provide a practical roadmap for developing robust, sensitive, and regulatory-compliant LC-MS methods for GTI control. Full article

Bamboo leaves contain structurally diverse flavonoid glycosides; whereas, compound-level information for Bambusa textilis remains limited. In this study, a flavonoid-enriched 40% ethanol fraction prepared from B. textilis leaves by petroleum-ether partitioning and AB-8 resin adsorption was analyzed by ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC-ESI-Q-TOF-MS/MS) in negative-ion mode. Retention times and MS/MS spectra were compared with seven in-house reference standards, while the remaining constituents were annotated from accurate-mass measurements, diagnostic product ions, fragmentation behavior, and data from the literature. According to Metabolomics Standards Initiative criteria, seven compounds were assigned at Level 1 and twenty-four were reported as Level 3 annotations because their exact positional structures were not confirmed by additional standards or NMR. Thirty-one flavonoid-related constituents were annotated in the analyzed fraction, encompassing six glycoside classes; most annotations, by count, were apigenin- or luteolin-derived. These annotations add compound-level information for the analyzed B. textilis fraction and allow qualitative comparison with other bamboo flavonoid profiles. Because the sample was selectively enriched, the results do not describe the complete leaf metabolome or compound concentrations. Additional standards or NMR analysis are needed to confirm the glycosylation positions of tentatively annotated compounds. Full article

Background/Objectives: Sphagneticola trilobata is a phytochemically rich medicinal plant, yet its antioxidant-active fractions and redox-related mechanisms remain incompletely characterized. This study combined metabolite profiling, antioxidant screening, network pharmacology, pharmacokineticprediction, and molecular docking to characterize active flower and leaf fractions and prioritize antioxidant-related targets. Methods: Petroleum ether, methylene chloride, and ethyl acetate fractions of S. trilobata flowers and leaves were analyzed by ultra-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC–ESI–MS/MS). The predominant metabolite was isolated and spectroscopically characterized. Antioxidant activity was assessed using 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric reducing antioxidant power (FRAP). Metabolites from the most active fractions were investigated by target prediction, protein–protein interaction (PPI) analysis, enrichment analysis, SwissADME, and docking. Results: UPLC–ESI–MS/MS tentatively identified 59, 18, and 16 metabolites in the petroleum ether, methylene chloride, and ethyl acetate fractions, respectively, including diterpenes, phenolic acids, flavonoids, fatty acids, triterpenes, and coumarin-related metabolites. Butein was isolated as the predominant metabolite from the ethyl acetate flower fraction, which showed the strongest antioxidant activity, with IC₅₀ values of 5.85 ± 0.14 µg/mL in ABTS and 9.11 ± 0.75 µg/mL in FRAP, followed by the ethyl acetate leaf fraction. Network analysis identified 61 and 82 antioxidant-relevant targets for the flower and leaf ethyl acetate fractions, respectively, with enrichment in inflammation-, apoptosis-, transcription-, hypoxia-, lipid stress-, and kinase-related pathways. Docking suggested fraction-specific compatibility with EGFR/PTGS2/STAT3 for flower metabolites and AKT1/PTGS2 for leaf metabolites. Conclusions: S. trilobata ethyl acetate fractions, particularly the flower fraction, represent promising antioxidant sources with experimentally supported activity and computationally prioritized redox-related hypotheses requiring further validation. Full article

For the evaluation of the chemical composition of Inula hookeri f. major Ling, ultra-high-performance liquid chromatography quadrupole-Exactive Orbitrap mass spectrometry (UHPLC-Q-Exactive-Orbitrap MS) was integrated with feature-based molecular networking (FBMN) and SIRIUS. The chromatographic separation of the chemical components from Inula hookeri f. major Ling was conducted on a Hypersil GOLD™ aQ C₁₈ (100 mm × 2.1 mm, 1.9 μm) using gradient elution, with a 0.1% formic acid aqueous solution and acetonitrile as the mobile phase. Mass spectrometric analysis was performed in both positive and negative ion modes using an electrospray ionization (ESI) source. Based on the obtained high-resolution fragment ions, FBMN was conducted to enable the clustering and visualization of structurally similar compounds. Molecular formulas were predicted and MS/MS fragment ions were interpreted with the assistance of SIRIUS. A total of 162 compounds were tentatively annotated from Inula hookeri f. major Ling, including terpenoids, phenylpropanoids, fatty acids, organic acids, and other types of compounds. The application of the strategy incorporating UHPLC-Q-Exactive-Orbitrap MS, FBMN, and SIRIUS enables the systematic characterization of the chemical composition of Inula hookeri f. major Ling. Full article

Metabolomic aging clocks—quantitative models that estimate biological age based on small-molecule profiles in biological fluids—have become dynamic tools for assessing individual aging trajectories and predicting the risk of age-related diseases. Although NMR-based approaches have been previously reviewed, the analytical landscape of mass spectrometry (MS)-based metabolomic clocks has not been systematically assessed. This review examines the key components of the MS-based analytical workflow underlying the development of metabolomic aging clocks, including biological matrix selection, chromatographic separation strategies, MS instrumentation, data preprocessing, metabolite annotation, and machine learning-based modeling approaches. Twelve published studies on MS-based metabolomic clocks were identified and systematically compared. These clocks provide predictions of chronological age with mean absolute errors of 3.5–10 years and demonstrate robust associations between metabolomic age acceleration and cardiometabolic risk, frailty, and mortality. Recurrent age-related metabolite classes include tryptophan–kynurenine pathway metabolites, acylcarnitines, sphingolipids, modified nucleosides, and tricarboxylic acid (TCA) cycle intermediates. Currently, liquid chromatography with electrospray ionization (LC-ESI) coupled to high-resolution QTOF or Orbitrap instruments dominates current workflows, with elastic net regression being the most commonly applied modeling strategy. Significant heterogeneity in analytical conditions, incomplete methodological descriptions, and limited cross-study validation remain key obstacles to clinical application. Standardization of pre-analytical protocols, the use of certified reference materials, and harmonized validation frameworks are identified as critical priorities for advancing mass spectrometry-based metabolomic clocks toward clinical translation. Full article

Antioxidant profiling of black locust (Robinia pseudoacacia L.) stem bark was performed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay off-line coupled to high-performance liquid chromatography–diode array detection–electrospray ionization mass spectrometry (DPPH–HPLC–DAD–ESI–QMS). The ethyl acetate, methanol, and n-hexane extracts exhibited similar chemical profiles for the antioxidant amphipathic phenolic compounds; however, the ethyl acetate extract was the richest in them, and n-hexane yielded several compounds in higher ratios. A total of 21 compounds displayed antioxidant activity and were further characterized by HPLC–high-resolution tandem MS (HRMS/MS). Nine compounds were identified as previously described antioxidants from the black locust stem bark, including 3-O-caffeoyl oleanolic acid (1), and the oleyl (4), octadecyl (6), gadoleyl (7), eicosanyl (9), (Z)-9-docosenyl (10), docosyl (12), tetracosyl (15), and hexacosyl (17) caffeates. Further ten caffeate and two ferulate esters were tentatively identified as 3-O-caffeoyl oleanolic, ursolic, or betulinic aldehyde (2), and hexadecyl (3), heptadecyl (5), hydroxy-hexacosyl (8), henicosyl (11), tetracosenyl (13), tricosyl (14), hexacosenyl (16), octacosenyl (18), and octacosyl (20) caffeates, and hexacosyl (19) and octacosyl (21) ferulates that were reported for the first time in R. pseudoacacia. Furthermore, this is the first report about the antioxidant activity of the previously undescribed compounds 8, 13, 16, and 18, as well as known compounds 11 and 14. Full article

Helichrysum arenarium (L.) Moench is a European native species typically associated with dry, sunny, sandy, and nutrient-poor habitats. In European herbal practice, preparations from H. arenarium inflorescences are traditionally used for the symptomatic relief of digestive complaints. Polyphenolic constituents, particularly flavonoid and chalcone derivatives, are among the most characteristic compounds detected in the inflorescences. Intensive harvesting and degradation of natural habitats have increased pressure on wild populations. Since H. arenarium is legally protected in many countries, biotechnological approaches for plant biomass production represent a promising alternative. In the present study, shoot and callus cultures were established, and detailed extract profiling was performed using ultra-high-performance liquid chromatography coupled with diode-array detection and electrospray ionization multistage mass spectrometry (UHPLC-DAD-ESI-MS³). Cytotoxic, antioxidant, anti-inflammatory, wound-healing, anti-collagenase, and anti-hyaluronidase activities were also evaluated. In vitro-derived materials were compared with inflorescences and shoots of the maternal plant. The analyzed materials showed pronounced tissue-dependent metabolic differentiation. The highest callus growth rate was observed for the Ha-C-1 line, which also accumulated the highest levels of chlorogenic acid (25.80 ± 3.09 mg/g dry extract) and isochlorogenic acid A (55.83 ± 13.78 mg/g dry extract). Apigenin was detected in the inflorescence extract, reaching 3.55 ± 1.42 mg/g dry extract. The extracts did not markedly affect HaCaT viability at 15.63–500 µg/mL, while the strongest bioactivities were observed for inflorescence and maternal plant extracts. Full article

Background/Objectives: Atopic dermatitis (AD) is a multifactorial inflammatory skin disorder in which epidermal barrier disruption and dysregulated immune responses drive persistent cutaneous inflammation. Owing to their broad spectrum of biological activities, marine-derived peptides have attracted increasing attention as potential therapeutic agents capable of modulating inflammatory and immune pathways. Methods: In this study, a novel peptide, WPN-15 (NGAIADQQPQRPNIV), was isolated from enzymatic hydrolysates of walleye pollock (Gadus chalcogrammus) tail by-products using an activity-guided purification process consisting of dialysis, fast protein liquid chromatography-gel permeation chromatography (FPLC-GPC), reverse-phase high-performance liquid chromatography (RP-HPLC), and electrospray ionization mass spectrometry (ESI-MS). The anti-inflammatory activity of WPN-15 was first examined in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages, and subsequently validated in a 2,4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis model using six-week-old male BALB/c mice. Results: WPN-15 significantly inhibited nitric oxide production in LPS-stimulated macrophages without causing cytotoxic effects. Topical administration of WPN-15 markedly alleviated DNCB-induced AD-like kin lesions, significantly reduced dermatitis severity scores, and decreased serum interleukin (IL)-6 levels. Histological evaluation further demonstrated that WPN-15 attenuated epidermal hyperplasia, dermal thickening, and mast cell infiltration. Furthermore, WPN-15 significantly downregulated the mRNA expression of IL-1β and IL-6 and inhibited signal transducer and activator of transcription 3 (STAT3) phosphorylation in skin tissues, indicating that its protective effects are mediated, at least in part, through the suppression of the IL-6/STAT3 signaling pathway. Conclusions: WPN-15 effectively attenuated inflammatory responses and pathological features associated with experimental AD. These findings demonstrate that walleye pollock tail by-products represent a valuable and sustainable source of bioactive peptides and support the potential application of WPN-15 as a marine-derived therapeutic candidate for the management of AD. Full article

The stability of anthocyanins is a key factor limiting their use as functional natural colorants. This study evaluated the protective effect of zein on anthocyanins extracted from red corn (Zea mays) chaff, which is an underutilized agro-industrial byproduct. The extraction of anthocyanins was optimized using a Box–Behnken design, employing a 55.5% (v/v) aqueous ethanol solution at 45.21 °C and a solid-to-solvent ratio of 1.86 mg/mL (w/v). The resulting extract was rich in acylated anthocyanins derived from cyanidin, pelargonidin, and malvidin, which were identified using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FIA-ESI-FTICR-MS). The interaction between zein and the anthocyanins was found to be thermodynamically spontaneous (indicated by a negative ΔG), endothermic (ΔH = 19.8 kJ mol⁻¹), and primarily driven by hydrophobic interactions (ΔS = 84.5 J mol⁻¹ K⁻¹). The addition of zein significantly decreased the degradation rate constant of the anthocyanins and increased their half-life, especially at pH 4 and storage temperatures of 4 °C and 20 °C. Moreover, the activation energy (E_a) for the zein–anthocyanin complex formation was lower (ranging from 63.64 to 47.75 kJ mol⁻¹) than that of the extract without zein (ranging from 59.36 to 74.71 kJ mol⁻¹), indicating that the zein complex has lower thermal sensitivity. Additionally, zein enhanced the red hues of the extract (increasing a* to 62.66) and preserved its antioxidant capacity, which even increased by up to 3.5 times under accelerated degradation conditions. Zein serves as an accessible and effective plant-based alternative for stabilizing anthocyanins in acidic environments, with potential applications in the development of functional natural colorants for the food industry. Full article

Coronaviruses are responsible for both severe diseases, such as COVID-19, and mild illnesses, such as the common cold. Because coronaviruses are expected to remain continuously prevalent, alternative therapeutic strategies against coronavirus infections should be developed to respond to newly emerging variants. Since many antibiotics, including penicillin, have been isolated from fungi, we screened fungal extracts for antiviral activity against human coronavirus and found that the extract of Valsonectria inflata (VIE) exhibited antiviral effects against human coronavirus. Western blot analysis showed that VIE treatment decreased coronavirus protein expression. Quantitative RT-PCR (qRT-PCR) and plaque formation assays demonstrated that VIE treatment reduced coronavirus production, while scanning electron microscopy (SEM) analysis further confirmed a decrease in the production of infectious viral particles. Finally, VIE treatment ameliorated coronavirus-induced cytotoxicity. We also analyzed the components of VIE, and high-resolution electrospray ionization mass spectrometry (HR-ESI-MS) revealed that VIE contains various secondary metabolites, including terpenoids. These results suggest that VIE may serve as a potential antiviral agent against coronavirus infections. Full article

Background/Objectives: Plant secondary metabolites remain an invaluable source of novel antibacterial phytochemicals in the fight against antibiotic resistance. The medicinal plant Solidago gigantea Ait. (giant goldenrod) is an invasive species in Europe and represents an abundant, yet largely underexplored reservoir of such bioactive compounds. The primary aim of this study was to perform a non-targeted, effect-directed screening, detection, bioassay-guided isolation, structure elucidation, and microbiological assessment of the antibacterial constituents present in the inflorescences of S. gigantea. Methods: Thin-layer chromatography coupled with direct bioautography (TLC–DB) assay using Bacillus subtilis was utilized for the non-targeted, effect-directed analysis of antibacterial components and the evaluation of in vitro antibacterial activity. Successive preparative flash column chromatography, semi-preparative reversed-phase high-performance liquid chromatography (RP-HPLC), and thin-layer chromatography–mass spectrometry (TLC–MS) were employed for the bioassay-guided fractionation and isolation. The structures of the isolated compounds were elucidated using one- and two-dimensional nuclear magnetic resonance (NMR) spectroscopy and high-resolution tandem mass spectrometry (HRMS/MS). The presence of known antibacterial compounds was established via reversed-phase ultra-high-performance liquid chromatography coupled with high-resolution electrospray ionization tandem mass spectrometry (RP-UHPLC–HR-ESI-MS/MS). Results: Two previously undescribed cis-clerodane diterpenoids, the isomeric solidagoic acid L (1) and solidagoic acid M (2), were isolated, identified, and characterized from the ethyl acetate extract of S. gigantea inflorescences. Both compounds exhibited in vitro antibacterial activity against the Gram-positive B. subtilis, confirmed via TLC–DB. In addition, 23 known compounds with antibacterial activity, including 17 clerodane diterpenes, four hydroxylated polyunsaturated fatty acids, and two unsaturated monoacylglycerols, were detected. All of these are reported for the first time in the inflorescences of this plant species. Conclusions: With further optimization, the isolated compounds may represent promising leads for antibacterial drug development. Our findings demonstrate the potential of non-targeted, bioassay-guided approaches for the discovery of novel plant-derived bioactive natural products. Full article

Hair is an easily obtainable, non-invasive biomatrix that allows for the assessment of long-term physiological responses to environmental and anthropogenic stressors in wildlife populations. Herein, an ultra-high-performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UHPLC-ESI-MS/MS) method was validated to verify its suitability for the simultaneous determination of cortisol (CORT) and its metabolite, cortisone (CORN), in hair samples collected from wild-living grey wolves (Canis lupus). Hair samples were extracted with methanol and purified using solid-phase extraction on Strata-X cartridges, which enabled effective mitigation of matrix effects. Data for the glucocorticoids were normalized using internal standards. The method demonstrated good linearity for the target stress hormones, with satisfactory precision (RSD < 15%) and limits of quantification of 4.13 pg/mg for CORT and 2.49 pg/mg for CORN in the hair matrix. Analysis of authentic wolf hair samples revealed CORT and CORN concentrations in the ranges of <4.13–11.86 pg/mg and <2.49–3.67 pg/mg, respectively. The CORT results showed a strong positive correlation with those obtained using enzymatic immunoassays. The method may be applied to assess the impact of stressors on the welfare of wolves, e.g., providing a useful tool for monitoring recovering European populations as they face new challenges associated with expansion into potentially suboptimal habitats. Full article