Distal-less homeobox 1 (DLX1) has emerged as a promising urinary biomarker for prostate cancer. This study developed a label-free piezoelectric acoustic biosensor for selective DLX1 detection using a quartz crystal microbalance (QCM). The QCM gold electrode was sequentially functionalized with L-cysteine, graphene oxide (GO), and an amine-terminated DLX1 capture probe covalently immobilized through EDC–NHS-mediated amide bond formation. Stepwise surface functionalization was characterized by X-ray photoelectron spectroscopy (XPS), supported by contact angle measurements, X-ray diffraction, and field-emission scanning electron microscopy. XPS provided multi-element evidence for Au–S thiolate formation, GO deposition, amide coupling, probe immobilization, and Watson–Crick hybridization with the synthetic DLX1 target. Under optimized conditions, the biosensor exhibited a linear response to DLX1 concentrations and achieved a limit of detection of 81.19 nM. Non-complementary sequences, including PCA3 and SARS-CoV-2, produced frequency shifts below 9 Hz, confirming high selectivity. Comparative experiments showed that GO-mediated covalent immobilization was essential for reliable detection, whereas direct DNA attachment to bare Au generated anomalous positive frequency shifts, which were attributed to weak physisorption. The proposed platform offers a sensitive and selective strategy for quantitative DLX1 detection and may support future point-of-care nucleic acid diagnostics.
Synthetic azo dyes are relevant paprika adulterants and a food-safety concern when used in undeclared or non-authorized forms. This study investigated the quantification of three representative dyes—Allura Red (E129), Orange II, and Ponceau 4R (E124)—spiked into paprika powder from 0 to 6% w/w using a benchtop Fourier-transform NIR (FT-NIR) Büchi NIRFlex N-500 spectrometer and a handheld ASD QualitySpec Trek Vis-NIR spectrometer. The experimental design included 17 concentration levels per dye, 3 independently prepared spiked batches per level, randomized measurements over approximately 3 months, and 3 replicate spectral acquisitions per filled cuvette. Measurements were performed in the 10,000–4000 cm−1 region with the benchtop FT-NIR instrument and in the 20,408–4000 cm−1 region with the handheld Vis-NIR instrument. Spectra were evaluated by principal component analysis (PCA) and partial least squares (PLS) regression, with robustness assessed by grouped cross-validation and independent test-set validation using held-out concentration levels. To support model interpretation, anharmonic NIR spectra of the dyes were simulated using DVPT2 calculations and compared with the experimentally relevant loading regions. For FT-NIR, independent test-set validation gave RMSEP values of 0.315, 0.205, and 0.338% w/w and R2TSV values of 0.970, 0.987, and 0.965 for Allura Red, Orange II, and Ponceau 4R, respectively. For Vis-NIR, the corresponding RMSEP values were 0.328, 0.262, and 0.334% w/w, with R2TSV values of 0.968, 0.979, and 0.964. The models required only two to three latent variables. Orange II gave the strongest FT-NIR model, reflecting its more distinct NIR spectral response, while all Vis-NIR models remained compact two- to three-factor models due to the additional visible-region absorption of the azo chromophores. The simulated spectra supported assignment of the main FT-NIR model-relevant regions to aromatic C–H overtones and dense combination-band manifolds, while the Vis-NIR models were driven mainly by visible chromophore absorption.
Brown algae, such as Dictyota dichotoma, contain fucoidan, whose bioactivity is linked to its molecular characteristics, which are in turn defined by environmental conditions. D. dichotoma fucoidan from the Sea of Cortez in Mexico (DDFSC) has not been previously investigated. This study aimed to extract DDFSC and investigate its chain conformation, microstructure, and antioxidant activity. The extraction yield was 3.6% (w DDFSC/w lyophilized seaweed). Fourier-transform infrared spectroscopy recorded bands characteristic of fucoidan. Fucose represented the main monosaccharide in DDFSC (49.52% w/w). The sulfate content was 3.40% (w/w). Size-exclusion chromatography with multi-angle light scattering determined the molecular weight, intrinsic viscosity, radius of gyration, and hydrodynamic radius as 880 kDa, 260 mL/g, 34 nm, and 32 nm, respectively. The characteristic ratio (C∞) and the persistence length (q) were 4.5 and 1.5 nm, respectively, suggesting a branched random coil conformation. Dynamic light scattering determined polysaccharide diameters of 27.6 and 173.1 nm. Scanning electron microscopy and atomic force microscopy revealed an irregular morphology and aggregates with rough topography, respectively. The IC50 values for ABTS+ and DPPH radical scavenging assays were 4.21 and 5.64, respectively. The present study constitutes the first insight into DDFSC characterization and establishes a starting point for the development of sustainable future applications using this polysaccharide.
During forest exploitation, large amounts of wood biomass are left as residues after harvesting, even though this material could be valuable in reducing greenhouse gas emissions by replacing fossil fuels and serving as a source of bioactive compounds. Within the context of the European Union’s circular bioeconomy strategy, enhancing the efficacy and rational application of forest logging residues constitutes a critical future objective. To evaluate the possible use of the stumps as forest residue-derived woody biomass for the first time, the chemical composition and presence of bioactive compounds in the xylem and bark of F. angustifolia Vahl. ssp. pannonica Soó & Simon stumps were analyzed, including the content of cellulose, acid-insoluble lignin, acid-soluble lignin, ash, and extractives soluble in toluene–ethanol and hot water. In hot water extracts, total phenolic content, the antioxidant activity determined by scavenging capacity toward DPPH and HPTLC, the content of elements by ICP-OES, and the identification of bioactive compounds by UHPLC-DAD-ESI MS/MS were assessed. Considering the chemical composition, the quality of the xylem of the F. angustifolia (cellulose: 42.46 ± 0.45%; lignin: 25.05 ± 0.02%; hemicelluloses: 19.74 ± 0.46%) was similar to that of the stem. Hot water extracts of the bark of F. angustifolia stumps showed high total phenolic content (33.94 ± 1.43 mg GAE/g DW) and strong antioxidant potential (198.48 ± 3.33 μmol TE/g DW), while toxic metals were not detected. UHPLC-DAD-ESI-MS/MS analysis indicated phenylethanoid glycosides as the dominant compounds in the extracts. The analyzed stumps of Fraxinus angustifolia Vahl. in the “Morović” Forest Administration represent a valuable biomass with potential for further valorization.
Mercury contamination in aquatic environments poses significant risks to ecosystems and human health, underscoring the need for effective remediation technologies. This research examines the physicochemical properties of the synthesised polymer materials, and DFT calculations were used as an initial step for material development to validate our experimental outcomes for the prepared polymers: polyaniline (PANI), polyethersulfone (PES), and polyamidoamine (PAMAM). Furthermore, DFT studies were used to elucidate structure–property relationships in polymers, serving as performance predictors for mercury adsorption and selectivity, as well as for their applicability in electronic sensors. The characterisation techniques indicated the high functional group densities of PAMAM dendrimers for effective chelation, while the semi-crystalline structure of PANI improves metal binding. DFT calculations reveal that PAMAM exhibits the smallest HOMO–LUMO energy gap, indicating a high reactivity towards mercury ions. Binding energies indicate that PAMAM forms the most stable single-ion complex; PAM1Hg (0.242 eV, 23.37 kJ mol−1), whereas PES exhibits enhanced interaction at elevated mercury concentrations, resulting in stable multi-Hg complexes, PES3Hg (0.136 eV, 13.13 kJ/mol). The findings indicate that nitrogen-rich functional groups and aromatic systems play a crucial role in mercury binding, highlighting the promise of conductive polymers for creating effective adsorbents aimed at mercury remediation in industrial wastewater.
Reliable determination of macro- and micronutrients in cereal plant tissues is essential for agronomic management, environmental monitoring, and interlaboratory data comparability. However, most existing plant certified reference materials (CRMs) are derived from temperate-region matrices and do not adequately represent cereals cultivated under semi-arid conditions, where differences in mineral composition may lead to matrix-related analytical bias. In this study, a new multi-element plant reference material, Cereal Plant Powder 2023 (CPP-23), was developed from composite wheat (Triticum aestivum and T. durum) samples collected across major Moroccan agro-ecological zones. The material was processed, homogenized, and evaluated for homogeneity and stability in accordance with ISO 33405:2024, with no significant short- or long-term variability observed. Elemental characterization was performed using microwave-assisted acid digestion followed by ICP-OES for major and trace elements, while total nitrogen was determined using the Kjeldahl method. Method validation demonstrated satisfactory linearity (R2 > 0.995), precision, and trueness against established reference materials. Certified values were assigned through an interlaboratory comparison involving eight ISO/IEC 17025-accredited laboratories using robust statistical estimators (ISO 13528:2022). Expanded uncertainties (k = 2) were below 15% for all analytes. While these results indicate acceptable internal consistency, the relatively limited number of participating laboratories and the absence of independent analytical validation techniques represent important constraints. CPP-23 provides a matrix-representative material suitable for quality control and method validation in semi-arid agricultural systems. Nevertheless, its ability to reduce analytical bias relative to existing CRMs and its applicability to specific use cases require further experimental validation.
The utilisation of cosmetic plant waxes as sustainable functional ingredients in personal care formulations is on the rise. This is due to their emollient, structuring and film-forming properties. Nevertheless, the intricate lipid composition of these substances engenders considerable analytical difficulties, impeding the reliable characterisation and quality assessment thereof. In this study, an optimised gas chromatography–mass spectrometry (GC–MS) workflow was developed and evaluated for the compositional profiling of waxes derived from R. succedanea and R. verniciflua, two East Asian botanical species that have historically been utilised in cosmetic and lacquer-related applications. Wax samples originating from China, Vietnam, Korea, and Japan were extracted using solvents of different polarity, including petroleum ether, dichloromethane (DCM), ethyl acetate, and acetone. Following the process of BSTFA derivatisation, the extracts were subjected to analysis by GC–MS to evaluate the efficiency of the extraction process and the chemical composition of the extracts. DCM was found to provide the highest extraction yields and the most representative compositional profiles. Across all samples, palmitic acid was identified as the predominant constituent (80–90%), followed by lower amounts of oleic acid, stearic acid, and minor monoacylglycerols. The proposed analytical workflow exhibited satisfactory reproducibility and effective discrimination of lipid constituents, thereby substantiating its application in comparative compositional evaluation, potential support for future quality assessment studies, and formulation development of cosmetic plant waxes.
The global reliance on commodity oils has intensified the search for alternative plant-based sources capable of meeting increasing worldwide demand. The utilization of fruits from the Brazilian Savanna and their associated byproducts offers numerous possibilities, as these native species are rich in nutrients and bioactive compounds with nutraceutical potential. However, gaps remain in the characterization of their lipid profiles, particularly with respect to processing residues. Therefore, the objective of this study was to investigate the fatty acid profiles of various parts of araticum (Annona crassiflora), baru (Dipteryx alata), buriti (Mauritia flexuosa), and pequi (Caryocar brasiliense) fruits using gas chromatography coupled with mass spectrometry (GC–MS). The total content of monounsaturated fatty acids exceeded that of saturated fatty acids in residues, including baru pulp and peel, buriti peel, and pequi seed. Notably, essential fatty acids were abundant in the fruit side streams, with omega-9 fatty acids particularly abundant in buriti peel. Baru seeds were notable for their high omega-6 fatty acid content, which was also observed in the pulp and peel of baru. Lipid quality indices (AI, TI, h/H, and HPI) varied substantially among fruit fractions. The lowest TI values were observed in buriti peel (0.2) and pequi pulp (0.2), while high h/H and HPI values were found in buriti peel (155.8 and 46.5, respectively), pequi pulp (133.4 and 48.6, respectively), and araticum seed (48.8 and 13.3, respectively). These results indicate favorable lipid quality characteristics in some fruit fractions and highlight the potential of these byproducts as alternative sources of nutritionally relevant lipids. Their utilization may also support sustainable and responsible consumption, provide additional income opportunities for producers, and contribute to biome preservation. Further biological and clinical studies are needed to determine whether these lipid characteristics translate into measurable health effects.
The chemical composition and bioactivities of dry methanol extracts from roots, leaves and fruits of Prangos trifida (Apiaceae), collected in Serbia, were investigated. LC-DAD-QTOF-MS/MS analysis revealed 30 compounds, primarily polyphenols and coumarins. The root and leaf extracts were rich in chlorogenic and/or 3,5-di-O-caffeoylquinic acid (18.20-26.14 mg/g extract), and the fruit extract in oxypeucedanin hydrate and prantschimgin (46.50 and 71.64 mg/g). The leaf extract exhibited the highest total phenolic content (62.86 mg quercetin equivalents/g), total antioxidant activity (FRAP = 0.71 mmol Fe2+/g) and DPPH radical scavenging ability (44.08 mg quercetin equivalents/g). Antimicrobial activity testing (11 bacteria and three yeasts, microdilution method) showed that the most active were the root and leaf extracts against Micrococcus luteus, Staphylococcus aureus, S. epidermidis and Candida albicans (MIC = 0.625-5 mg/mL). The fruit extract showed the strongest cytotoxicity against tested stomach, colon and hypopharynx cancer cell lines (MTT test), with the highest selectivity toward hypopharynx cancer FaDu cells (selectivity index 4.71; determined in relation to non-cancerous VERO cells). No antiviral activity against herpesvirus type 1 was found. The results indicate that P. trifida represents a promising source of polyphenols and coumarins, notably expanding current knowledge on its chemical composition and supporting its potential relevance for pharmaceutical and food industry applications.
Comparative interpretation of antioxidant activity across complex natural-product extracts and multi-component formulations is often limited by heterogeneous endpoints, assay-specific reporting, and incompatible units. In this study, we establish a dimensionless Effect Factor (EF) framework as a standardized comparative indexing system for matched-condition comparison of antioxidant-related readouts. EF maps four widely used antioxidant-related readouts—ABTS, DPPH, total phenolic content (TPC), and total flavonoid content (TFC)—into a common dimensionless index space while preserving endpoint meaning through two complementary tracks: potency-type EF and content-type EF. Using a standardized extraction and assay pipeline, we generated EF indices for 586 extracts prepared under water and 30% ethanol conditions and organized them into EF-indexed databases. EF is not intended as a predictive or biologically validated efficacy metric, but as a standardized comparative indexing framework that enables reproducible benchmarking, database-level referencing, and structured interpretation of heterogeneous antioxidant-related data under harmonized experimental conditions. These results establish the EF-indexed resource as a scalable and expandable comparative infrastructure for natural-product research.
Despite its widespread use in pharmaceuticals, cosmetics, and animal nutrition, the environmental implications of nicotinamide remain largely underexplored. Given its high solubility and prevalent presence in wastewaters, nicotinamide has been proposed as a potential environmental marker and emerging contaminant. This study focuses on the evaluation and modeling of medium and ionic strength effects on the acid-base behavior of nicotinamide in aqueous solution. To this aim, the protonation constants of nicotinamide were determined in aqueous media containing various supporting electrolytes (sodium chloride, tetramethylammonium chloride, tetraethylammonium iodide) at T = 298.15 K and different ionic strengths. The medium and ionic strength dependencies were described through well-established thermodynamic models, including the Extended Debye-H & uuml;ckel equation, the Specific ion Interaction Theory, and the Pitzer approach. Additionally, the Setschenow constant of nicotinamide was determined through distribution measurements between 1-octanol and NaCl(aq) solutions. Furthermore, a critical data analysis was performed to assess the reliability of the proposed models and provided interaction parameters. Overall, this work thoroughly describes the acid-base behavior of nicotinamide in different aqueous media and its distribution between aqueous and organic phases, offering fundamental insights for the assessment of its chemical speciation in real systems, which is crucial for future applications in environmental monitoring and remediation strategies.
Spectrophotometry offers the advantage of low cost and less time consumption, making it still attractive as a method of analysis, especially when coupled with multivariate calibration models. This enhancement solves the majority of the drawbacks of UV-VIS spectrophotometry, which have to do with the entangled spectra of complex mixtures. In this study, a multivariate model was developed and validated for the determination of perindopril erbumine, amlodipine besylate and indapamide, addressing previously unresolved challenges by systematically covering three fixed-dose combinations with differing component ratios and by achieving accuracy suitable for the assay determination. The experimental plan involved a Taguchi orthogonal array design with three factors at five levels. In order to create multivariate calibration models, principal component regression, partial least squares and concentration residual augmented least squares regression algorithms were tested. Principal component regression combined with a genetic algorithm for feature selection was chosen as the optimal model based on prediction performance estimated by nested cross-validation with cluster-based sample splitting. The developed method was also evaluated for its environmentally friendly potential while the analytical method validation procedure confirmed its applicability for the assay testing of the fixed-dose drug combination.
We studied experimentally and computationally the structures and optical properties of sulfur (S), selenium (Se) and tellurium (Te) ring clusters. We encapsulated S, Se and Te into AFI, MOR, CHA and LTA zeolites via vapor adsorption or high-pressure injection from melt and studied Raman and optical absorption spectra (RS and OAS, respectively) of zeolite single crystals with incorporated S, Se and Te ring clusters. Importantly, strict orientation of the rings in zeolite crystals allowed us to study the polarization/orientation dependency of ring RS and OAS. The obtained experimental spectra are found to be in agreement with density functional theory results (DFT using the PBE0 functional and def2-TZVP basis sets) for S8, Se6, Se8, Se12, Te6 and Te8 ring molecules. The agreement is especially good for Te rings, while for S and Se rings harmonic frequency scaling factors are required. The S and Se rings display light-induced effects, which we attribute to the presence of conical intersections between their ground and excited electronic states, resulting in isomerization and subsequent fragmentation. We consider this effect using the Se6 ring example. This phenomenon is important for understanding photostructural changes not only in chalcogen clusters but also in bulk materials such as amorphous selenium.
Secondary electrospray ionization mass spectrometry (SESI-MS) has emerged as a powerful technique for the real-time, non-invasive analysis of volatile organic compounds (VOCs) in complex matrices, such as exhaled breath and microbial volatilomes. However, its transition to routine application is hindered by significant challenges in absolute quantification, unambiguous identification, and standardization. This review provides a comprehensive overview of these limitations and the emerging solutions proposed to overcome them. Matrix effects, including gas-phase ion suppression and C-trap competition, are examined alongside mitigation strategies such as spectral stitching and standard addition. To enhance quantification stability, advanced standard delivery systems and dynamic quality control protocols are evaluated. The identification bottleneck—stemming from the absence of chromatographic separation—is addressed through the use of curated databases and advanced fragmentation techniques, such as incremental quadrupole acquisition to resolve overlapping spectra (IQAROS), to resolve isobaric interferences. Furthermore, the role of chemometrics in extracting biological fingerprints is discussed. Finally, the need for harmonized reporting standards and multicenter validation is emphasized to ensure cross-study reproducibility. Resolving these methodological gaps is essential for the clinical and industrial translation of SESI-MS.
C13-Norisoprenoids are important contributors to the aroma of Riesling wine. Their quantification is analytically challenging due to their low concentrations, the lack of commercial standards and their pronounced sensitivity to analytical conditions, reflecting their chemical lability, as well as the dynamic nature of the wine matrix, leading to high reactivity and, consequently, remarkable structural diversity. Here, we developed an assay for the analysis of C13-norisoprenoids in wine using headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS/MS). After evaluating different fiber materials, a statistical design of experiments (DoE) approach was employed to systematically optimize key HS-SPME parameters, including incubation, extraction and desorption conditions. Selected reaction monitoring (SRM) transitions were established for all targeted C13-norisoprenoids, allowing the assay to provide relative quantification of more than 40 compounds using representative labeled and unlabeled standards to generate linear calibration curves. Following method validation, this approach was applied to a young German Riesling wine to investigate the effect of various acidic hydrolysis conditions on the norisoprenoid profile as well as on specific compounds. A central composite design (CCD) was used to systematically study the impact of pH, temperature, and hydrolysis time. Quantitative data were obtained for 22 C13-norisoprenoids demonstrating that hydrolysis conditions strongly affected the norisoprenoid composition. pH and temperature showed a greater influence than reaction time. Response surface models (RSM) indicated that TDN, Vitispirane and TPB in particular are predominantly formed under strongly acidic and high-temperature conditions, whereas others such as Riesling acetal and actinidols are formed under milder conditions. The results indicate that hydrolysis conditions should be tailored to the specific norisoprenoid under investigation and the research question, particularly when simulating conditions of accelerated wine ageing for analytical purposes.
Oxalic acid is extensively used in industrial chemical processes, purification systems, hydrometallurgical operations, and advanced oxidation environments where rapid and environmentally sustainable analytical methodologies are increasingly required for process monitoring and quality control. In this study, a micro-Raman spectroscopy methodology was developed for the direct quantification of oxalic acid in aqueous systems at moderate-to-high concentrations (0.079-0.793 M). The analytical strategy was based on the integrated Raman response of the carbonyl stretching region (1700-1750 cm(-1)), selected due to its strong concentration-dependent behavior, spectral definition, and reduced interference from the aqueous matrix. The proposed methodology demonstrated excellent analytical performance, including high linearity (R-2 > 0.998), satisfactory precision, and reliable concentration-dependent reproducibility throughout the evaluated concentration range. To evaluate operational robustness, matrix-matched standards incorporating temperature variation (25-40 degrees C), turbidity (0-57 mg/L), dissolved Ca2+ (0-58 mg/L), and dissolved Fe3+ (0-7 mg/L) were prepared to simulate chemically perturbed industrial environments. Principal Component Analysis (PCA) demonstrated that the carbonyl vibrational region retained organized concentration-dependent spectral behavior despite operational perturbations. Partial Least Squares (PLS) regression models developed under these matrix-informed conditions preserved strong predictive capability (R-2 approximate to 0.997), while preliminary prediction of process-related samples yielded excellent agreement between predicted and reference concentrations (R-2 = 0.990). Although operational perturbations produced substantial attenuation of Raman intensity, particularly at lower concentration levels, the carbonyl Raman band remained spectrally detectable and analytically interpretable throughout all evaluated conditions. Electronic-structure analysis using Natural Bond Orbital (NBO) and Atoms-in-Molecules (AIM) methodologies demonstrated that the strong analytical behavior of the nu(C=O) vibrational mode is associated with enhanced electron-density localization, covalent stabilization, and favorable polarizability characteristics of the carbonyl bond. The combined experimental, chemometric, and computational results demonstrate the feasibility of matrix-informed micro-Raman spectroscopy as a rapid, reagent-free, and operationally robust methodology for oxalic acid monitoring in chemically perturbed aqueous industrial systems.
The herbal tea industry has experienced substantial growth, particularly regarding green tea (Camellia sinensis). In the manufacturing of filter tea, fine herbal dust is generated as a residual by-product during grinding and sieving and is typically discarded as waste. This study aims to explore the application of ultrasound-assisted extraction (UAE) for secondary valorisation of green tea herbal dust by investigating the effects of various parameters on extraction efficiency. Antiradical activity of UAE extracts was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the total phenolic content (TPC) was measured using Folin-Ciocalteu's assay. Furthermore, selected phenolics were quantified by HPLC and qualitatively characterised by liquid chromatography coupled with electrospray ionisation and quadrupole time-of-flight tandem mass spectrometry (LC-ESI-QToF-MS/MS). The results demonstrate that UAE parameters have a pronounced influence on the antioxidant activity, TPC, and individual polyphenolic profile of green tea herbal dust extracts. Ethanol-water mixtures at a ratio of around 40-60%, as well as moderate impulse regimes (around 60%) and extraction times (around 10 min), were the most suitable for extracting green tea polyphenols. Epigallocatechin gallate was the predominant phenolic component in most extracts, alongside epicatechin, epigallocatechin, catechin, and gallic acid. The findings highlight the UAE technique as a robust, green, and scalable method for valorising green tea by-products, thereby facilitating the development of high-value natural extracts for applications in the food, pharmaceutical, and cosmetic industries.
The separation of chiral compounds is a challenging issue in various fields, e.g., biochemistry, the pharmaceutical industry, food chemistry, forensics, agriculture, etc. Very often, one of the two enantiomers can exhibit different activity. Therefore, the separation and analysis of enantiomers requires analytical methods for, e.g., quality control, pharmacokinetic studies, etc. Their separation is usually performed by high-performance liquid chromatography (HPLC), gas chromatography, supercritical fluid chromatography and microfluidic techniques such as capillary electrophoresis (CE), nano-liquid chromatography, and capillary electrochromatography (CEC). CEC is a modern analytical technique that combines the features of HPLC and CE (high selectivity and high chromatographic efficiency, respectively). The enantiomers are moved to the detector by an electroosmotic flow generated by the application of high voltage. In this review, the main features of CEC, and the basic principles of enantiomer separation are briefly summarized. Selected applications (appearing 2023–2026 February) employing packed capillaries, and monolithic and open tubular columns, are presented and discussed.
The species Psychotria densicostata M & uuml;ll.Arg. is a shrub belonging to the Rubiaceae family, endemic to Brazil. So far, there are reports neither of phytochemical work on nor of biological evaluation of it. This study investigated its alkaloid profile and evaluated the inhibitory effects of extracts, alkaloid-enriched fractions and one of its major constituents on human neutrophil elastase (HNE). The monoterpene indole alkaloids (MIAs) strictosidine (1), (3 alpha,5 alpha)-5-carboxystrictosidine (2), strictosidine lactam (3), lyaloside (4), lyalosidic acid (5), 5-carboxystrictosamide (6), 3,4-dehydrostrictosidinic acid (7), and N-glucopyranosyl vincosamide (8) were characterized in mixture, in its leaves, and/or stems by using an integrated approach combining nuclear magnetic resonance (NMR) techniques, high performance liquid chromatography coupled to a tandem mass spectrometer with an electrospray ionization source (HPLC-ESI-MS/MS), and molecular networks. The crude leaf extract and an alkaloid-enriched fraction derived from it showed inhibitory activity against HNE. These results contribute to the chemical knowledge of the species and suggest its potential biological property.
Hot-melt extrusion (HME) is widely used in pharmaceutical manufacturing; however, reliable analytical tools are required to simultaneously monitor drug content and excipient stability under thermal processing. In this study, a selective and robust HPLC-UV method was developed and validated for the concurrent determination of triamcinolone acetonide (TA) and triethyl citrate (TEC) in HME polymeric films and porcine buccal mucosa. Chromatographic separation was achieved on a C18 column using an acetonitrile-water mobile phase (30:70, v/v) at a flow rate of 0.6 mL min-1, with detection at 240 nm for TA and 210 nm for TEC. The method was validated for selectivity, linearity, precision, and accuracy, including selectivity assessment in the presence of mucosal extract and polymeric matrix components, and recovery of TA in porcine buccal mucosa. Excellent linearity was obtained over 0.20-12.5 & micro;g mL-1 for TA and 4.5-30.0 & micro;g mL-1 for TEC (r >= 0.998), with precision below 6.3% and TA recovery exceeding 94%. Application to extruded films confirmed uniform analyte distribution and enabled simultaneous monitoring of TA degradation and TEC loss under thermal stress. These results demonstrate that the proposed method is suitable for formulation development, process monitoring, and stability assessment of HME-based pharmaceutical systems.
