Search Results (351)

Rutin is a naturally occurring flavonoid with well-documented antioxidant and pharmacological properties. In this study, a manganese(II) complex with rutin (Mn(II)-Rut) was synthesized in a solid state and characterized using FT-IR, Raman spectroscopy, thermogravimetric and elemental analysis, confirming its composition as C₂₇H₂₇O₁₆Mn₂·5H₂O. The IR spectra indicated that rutin coordinates manganese ions through the carbonyl group at the C4 position and the hydroxyl group at the C5 atom, as well as the catecholic system. The antioxidant potential of both Mn(II)-Rut and rutin was evaluated using several spectrophotometric assays. The Mn(II)-Rut complex showed stronger activity in most spectrophotometric assays than rutin, i.e., in ABTS assay, 50.37 ± 2.64% vs. 41.49 ± 1.38%; in CUPRAC assay, 0.468 ± 0.006 mM Trolox vs. 0.379 ± 0.007 mM Trolox; and FRAP assay, 0.201 ± 0.002 µM vs. 0.189 ± 0.003 µM. However, the DPPH assay complex showed a diminished effect compared with ligand (IC₅₀ 2.78 ± 0.13 µM vs. 0.98 ± 0.04 µM for rutin). Quantum-chemical calculations were also performed using the Gaussian09 program to determine the optimized geometric structures, electron charge distribution, and the energies of the HOMOs and LUMOs in the analyzed molecules in order to discuss the antioxidant mechanism of the molecules. Enzymatic assays demonstrated that the Mn(II) complex with rutin exhibited a stronger α-amylase inhibitory effect compared to free rutin, which showed the potential antidiabetic activity of the compound. The results suggest that the Mn(II) complex of rutin possesses better antioxidant and α-amylase inhibitory activity than the ligand alone. Full article

Phenolic compounds are plant-derived antioxidants crucial for human health and food preservation. Their bioactive potential including anti-inflammatory, antimicrobial, and anti-carcinogenic properties makes them a vital focus in nutritional, pharmaceutical, and agricultural research. This review critically evaluates the methodologies for their extraction, detection, and quantification to accurately assess antioxidant activity. Oxidative stress in biological systems and food matrices necessitates accurate analytical methodologies for assessing antioxidant behavior, which include both in vitro, in vivo and ex vivo approaches. Sample pretreatment and extraction techniques are critical for reliable analysis and vary depending on the matrix, compound polarity, and target phenolic subclass. We compare conventional extraction techniques (Soxhlet, maceration) with advanced methods like ultrasound-assisted, microwave-assisted, and supercritical fluid extraction. Detection methods reviewed include spectrophotometric assays (e.g., DPPH, FRAP, ORAC), electrochemical sensors, and chromatographic techniques (e.g., HPLC, HPLC−MS). While each method has distinct advantages, a lack of standardization remains the primary challenge, driven by variations in protocols and the vast chemical diversity of phenolics. This review underscores the critical need for integrated, standardized approaches to ensure the accurate and comparable evaluation of antioxidant activity in research and industry. Full article

This study presents a quantitative investigation of substituent effects on the stability of 1:2 complexes formed between para-substituted 2-phenylbenzimidazole ligands and Cu(II) or Co(II) ions. The ligands, featuring hydroxyl (–OH), chloro (–Cl), and nitro (–NO₂) substituents, were synthesized via copper acetate-mediated oxidative cyclization. Stability constants (log K) were determined spectrophotometrically using both the Benesi–Hildebrand and Job methods, which yielded perfectly consistent results and confirmed ML₂ stoichiometry. For both metal series, the stability decreases in the order –OH > –Cl > –NO₂. Excellent linear correlations were obtained between log K and Hammett σ constants, yielding reaction constants of ρ = −0.79 for Cu(II) and ρ = −1.00 for Co(II). These negative ρ values confirm that electron-donating substituents enhance complex stability by increasing electron density on the donor nitrogen. Furthermore, the stability constants for Cu(II) complexes are approximately two orders of magnitude higher than those for Co(II), in agreement with the Irving–Williams series. This work establishes a clear, predictive structure–stability relationship and validates the combined methodological approach for quantifying metal–ligand interactions in tunable benzimidazole systems. Full article

Tomato fruit rot severely impacts yield and quality, causing economic losses. This study aimed to identify the pathogenic fungi associated with post-harvest tomato fruit rot and characterize the transcriptomic responses of tomatoes. Pathogens were isolated from diseased tomato fruit tissues and identified using morphology, phylogenetic analysis, and in vitro pathogenicity tests. The genome of Cladosporium oxysporum Co-1 was assembled and annotated. RNA-seq analysis was used to profile transcriptional changes in tomatoes infected with C. oxysporum Co-1, with RT-qPCR validating the RNA-seq data and spectrophotometric assays analyzing the host physiological responses. Three pathogenic fungi were isolated. Colonies of C. oxysporum exhibited a near-circular shape, with colonies transitioning from an olive-green center to gray-green at the edges, and based on ITS, β-tubulin, and EF-1α gene sequences, this isolate exhibited 99% identity with C. oxysporum. The other two fungal isolates were identified as Alternaria alternata and Fusarium incarnatum, respectively, based on morphological and multi-locus sequence analysis. All three strains induced fruit rot and browning in tomatoes, confirming their pathogenicity. The genome size of C. oxysporum Co-1 was 34,515,558 bp, comprising 52 scaffolds with a GC content of 52.82%, and encoding 10,081 protein-coding genes. RNA-seq analysis showed dynamic gene expression changes in tomatoes infected with strain A, with differentially expressed genes enriched in pathogenicity-related pathways. Spectrophotometric assays revealed that peroxidase and superoxide dismutase activities decreased initially followed by an increase post-inoculation with C. oxysporum, indicating that tomatoes defend against pathogen infection through the antioxidant enzyme system. These findings revealed the pathogenic fungi were associated with post-harvest tomato rot disease, provided genomic resources for C. oxysporum, and provided insight into the host’s response to this strain. Full article

A simple, rapid, and cost-effective UV–Vis spectrophotometric method was developed and validated for the determination of levofloxacin in rat plasma to support the evaluation of a novel antimicrobial mesh implant containing levofloxacin, chitosan, gelatin, tinctura propolis, citric, acid and glycerin. Plasma samples were treated with 0.1 M HCl, and absorbance was measured at 290 nm. The method was validated according to FDA and ICH guidelines, including assessments of linearity, sensitivity, accuracy, precision, and specificity. The calibration curve was linear over the concentration range of 2.5–12.5 μg/mL (R² = 0.999, p < 0.001). The limit of detection and limit of quantification were 0.21 μg/mL and 0.62 μg/mL, respectively. Intra- and inter-day precision showed low relative standard deviation values (0.2% and 0.25%), while recovery ranged from 94.8% to 96.4%, confirming acceptable accuracy. No significant interference from plasma matrix components was observed. Compared with chromatographic techniques, the proposed method provides an accessible alternative for routine bioanalysis and therapeutic monitoring. The validated assay is suitable for assessing prolonged levofloxacin release from implantable drug delivery systems in preclinical studies. Full article

Gluten-free foods may help address oxidative stress and inflammation linked to gluten-related disorders. This study characterized the phytochemical profile of a 70% ethanolic extract from commercial white quinoa (Chenopodium quinoa Willd.) flour (Peru) and evaluated its antioxidant and anti-inflammatory activity in vitro and in vivo in a rat model of acute inflammation. Total polyphenols and flavonoids were quantified spectrophotometrically, while individual phenolics were profiled by HPLC-DAD-ESI-MS. Antioxidant capacity was assessed in vitro using DPPH, FRAP, H₂O₂, and nitric oxide (NO) scavenging assays. For in vivo testing, male Wistar rats received for 10 days quinoa extract (100%—1 g/mL, 50–0.5 g/mL, or 25–0.25 g/mL) either therapeutically (after turpentine-induced inflammation) or prophylactically (before induction), with diclofenac and Trolox as reference controls; systemic oxidative stress (TOS, TAC, OSI, AOPP, MDA, NO, 3-NT, total thiols) and inflammatory mediators (NF-κB p65, IL-1β, IL-18, caspase-1, IL-10) were measured by spectrophotometry/ELISA and explored multivariately by PCA. Quinoa extract contained measurable phenolic and flavonoid levels (TPC 1.25 mg GAE/g d.w.; TFC 68.5 mg QE/100 g d.w.) and was dominated by flavonoid glycosides and hydroxybenzoic acids. It showed strong radical-scavenging/reducing activity in vitro. In vivo, the extract dose-dependently attenuated turpentine-induced nitro-oxidative stress and reduced key pro-inflammatory markers (notably NF-κB, IL-1β, IL-18, and caspase-1), in several endpoints matching or exceeding diclofenac/Trolox effects, while IL-10 was largely unchanged. These findings support white quinoa flour extract as a phytochemical-rich, gluten-free ingredient with promising antioxidant and anti-inflammatory potential, warranting further translational investigation. Full article

The growing interest in sustainable food systems has spurred research into the valorisation of agro-industrial by-products as sources of bioactive compounds. This review provides a comprehensive overview of the phytochemical composition, bioactivity, biotransformation, and potential nutraceutical applications of by-products from chestnut (Castanea sativa Mill.) and grape (Vitis vinifera L.). Recent studies identify matrices such as chestnut leaves, shells, and burs, as well as grape pomace, skins, seeds, stems, and vine shoots, as rich in phenolic compounds, dietary fibres, vitamins, and minor bioactives, with antioxidant, anti-inflammatory, and antimicrobial properties. Emerging evidence highlights the importance of gastrointestinal digestion and microbial biotransformation in modulating the bioavailability and biological efficacy of phenolic compounds, particularly fibre-bound phenolics. The review further discusses state-of-the-art analytical approaches for chemical characterisation, including chromatographic and spectrophotometric methods, as well as emerging strategies for extraction, encapsulation, and delivery to enhance stability and bioavailability. Finally, the integration of chestnut and grapevine by-products into nutraceuticals, functional foods, and natural preservatives is critically examined from technological, safety, regulatory, and sustainability perspectives. Overall, this synthesis underscores the potential of these underutilised biomass streams as multifunctional raw materials that support waste valorisation, resource efficiency, and the development of next-generation health-promoting ingredients aligned with circular bioeconomy principles. Full article

The aim of this study was to obtain and characterize grape seed extract and to demonstrate its potential immunomodulatory properties in the autoimmune disease systemic lupus erythematosus (SLE). A Syrah grape seed extract was obtained using 70% aqueous ethanol, magnetic stirrer, 3 h. The obtained extracts were concentrated by vacuum evaporation and dryer at 40 °C. The total phenolic content (TPC), the total amount of flavonoids (TF) and procyanidins (PC), and the antioxidant (AO) capacity of the extract were determined by spectrophotometric methods. The individual composition of the extract was demonstrated by the high-performance liquid chromatography (HPLC) method. The effect of grape seed extract (GSE) on peripheral blood mononuclear cells (PBMC) from healthy donors and patients with SLE was studied to compare Th1 and Th2 subsets and their expression of key activation markers—CD25 and HLA-DR. PBMC were cultured in the presence or absence of GSE, and the effects on Th1 and Th2 cells were analyzed by flow cytometry. GSE treatment increased the proportion of Th1 cells in both healthy individuals and SLE patients. In addition, a significant upregulation of the late activation marker HLA-DR was observed on Th1 cells obtained from patients with systemic lupus erythematosus (SLE). No significant effects were found on Th2 cell populations. These findings indicate that GSE can stimulate Th1-mediated immune responses in SLE, proving its potential immunomodulatory properties beyond its known antioxidant effects. Full article

Wire explosion (WE) inherently generates particle ensembles spanning the nano- to microscale, posing challenges for conventional characterization methods in terms of capturing the full particle population. To address this issue, spectrophotometric analysis combined with algorithmic spectrum reconstruction based on Mie theory and constrained distribution models were employed to characterize copper WE products formed in aqueous surroundings within the 4–12 kV discharge voltage range. Three independent fitting strategies, specifically a semimanual fitting, an evolutionary algorithm, and a grid search, were applied to retrieve the size distributions and relative shares of copper and copper oxide particles as a function of discharge voltage. Based on experimental and theoretical findings, lognormal and normal distributions across the 10–300 nm diameter range were assumed as constraints for oxide and metallic fractions, respectively. The reconstructed metallic copper population exhibited mean diameters ranging from 123 to 181 nm, while oxidized fractions followed lognormal distributions centred near 10 nm mode diameters. Voltage-dependent trends revealed an optimal discharge regime between 6 kV and 8 kV, where the exploded fraction reached approximately 63% and the metallic mass share exceeded 80%. These results confirmed that spectrophotometry represents an essential tool for the quantitative characterization of such complex, wide-range systems. Full article

This study introduces a framework for estimating the optical scattering properties of thin-film phantoms using a custom-built Spectral-Domain Dental Optical Coherence Tomography (DEN-OCT) system operating within the 780–900 nm spectral range. The purpose of this work was to assess the performance of this system. The system exhibited high depth-resolved imaging performance with an axial resolution of approximately 16.30 µm, a signal-to-noise ratio of about 32.4 dB, and a 6 dB sensitivity roll-off depth near 2 mm, yielding an effective imaging range of 2.5 mm. Thin-film phantoms with controlled optical characteristics were fabricated and analyzed using Beer–Lambert and diffusion approximation models to evaluate attenuation behavior. Samples representing different tissue analogs demonstrated distinct scattering responses: one sample showed strong scattering similar to hard tissues, while the others exhibited lower scattering and higher transmission, resembling soft-tissue properties. Spectrophotometric measurements at 840 nm supported these trends through characteristic transmittance and reflectance profiles. While homogeneous samples conformed to analytical models, the highly scattering sample deviated due to structural non-uniformity, requiring Monte Carlo simulation to accurately describe photon transport. OCT A-scan analyses fitted with exponential decay models produced attenuation coefficients consistent with spectrophotometric data, confirming the dominance of scattering over absorption. The integration of OCT imaging, optical modeling, and Monte Carlo simulation establishes a reliable methodology for quantitative scattering estimation and demonstrates the potential of the developed DEN-OCT system for advanced dental and biomedical imaging applications. The innovation of this work lies in the integration of phantom-based optical calibration, multi-model scattering analysis, and depth-resolved OCT signal modeling, providing a validated pathway for quantitative parameter extraction in dental OCT applications. Full article

The aim of this study was to investigate the biochemical properties of free and immobilized mushroom tyrosinase (EC 1.14.18.1) entrapped in calcium alginate beads for phenol oxidation in a batch system. Tyrosinase activity was determined spectrophotometrically at 400 nm under optimal conditions. The effects of key operational parameters on phenol oxidation kinetics were evaluated for both enzyme systems. The Michaelis–Menten constant (K_M) of the immobilized enzyme (0.94 ± 0.2 mM) was approximately twice that of the free enzyme (0.56 ± 0.04 mM), while its maximum reaction velocity (V_Max = 101.4 ± 2.2 µmol L⁻¹ min⁻¹) decreased by nearly 30-fold (V_Max(App) = 3.63 ± 0.3 µmol L⁻¹ min⁻¹). Immobilization also shifted the optimal pH of the enzyme to pH 6.0. The optimum temperature and activation energy for phenol oxidation were determined as 55 °C and 52.48 kJ/mol for immobilized tyrosinase, whereas they were 45 °C and 39.58 kJ/mol for the free enzyme. The highest level of activity was obtained with alginate beads of 2.6 mm diameter, and the immobilized preparation exhibited enhanced operational stability, completely retaining its initial activity after five reuse cycles. Overall, these findings suggest that mushroom tyrosinase immobilized in alginate beads is a promising system for phenol removal from wastewater. Full article

Plant oils are increasingly explored as sustainable functional ingredients in topical emulsions due to their emollient properties and reported photoprotective potential. This study aimed to formulate physically stable W/O emulsions containing selected plant oils (olive, avocado, sesame, flaxseed, and grape seed oils) at two concentrations (15% and 30%) and to evaluate their physicochemical, rheological, occlusive, and UV-protective properties. All formulations were confirmed as W/O systems with skin-compatible pH values and demonstrated shear-thinning, non-Newtonian flow with varying degrees of thixotropy. Increasing oil content from 15% to 30% reduced shear stress, consistency index, and viscoelastic moduli, indicating a softer internal structure. Moreover, the viscosities of the emulsions were not solely determined by the viscosities of the individual oils, suggesting significant interactions with the emulsifier system. High occlusion factors were demonstrated for all emulsions, with the highest values observed for 30% olive- and grape seed oil–based formulations. Spectrophotometric SPF assessment revealed measurable UV-protective activity only for emulsions containing 30% olive, avocado, or flaxseed oil (SPF > 1). All formulations exhibited satisfactory physical stability under mechanical and thermal stress. These findings demonstrate that plant oils can modulate the structure and performance of W/O emulsions and may serve as valuable supportive ingredients in the development of photoprotective cosmetic products. Full article

Background/objective: To evaluate the effectiveness of resin infiltration in managing anterior molar incisor hypomineralization (MIH) defects, focusing on color improvement, lesion size reduction, sensitivity outcomes and patient aesthetic perception. Enamel defects in MIH result from a combination of environmental, systemic, and genetic factors, indicating a multifactorial etiology. These defects, particularly in anterior teeth, pose significant aesthetic and emotional challenges due to their high visibility. This study provides one of the few prospective clinical evaluations of resin infiltration for anterior MIH lesions, assessing not only objective clinical outcomes but also patients’ aesthetic perception. It further introduces a patient-centered approach by comparing aesthetic evaluations made by children and dental professionals over time. Methods: A total of 109 MIH-affected anterior teeth were treated using Icon^® resin infiltration (DMG, Hamburg, Germany) in this registered prospective clinical study (ClinicalTrials.gov: NCT05597956). Participants were classified as children (6–12 years) and adolescents (13–17 years) according to standard pediatric age definitions. Of these, 101 teeth were available for evaluation at the 6-month follow-up due to patient loss to follow-up. The evaluation included photographic follow-up, measurement of lesion size and color, and assessment of sensitivity. During follow-up visits, patients rated the appearance of their lesions using the FDI scale. Results: Before treatment, spectrophotometric analysis showed that lesions exhibited a reddish hue (mean a* = 2.12), were distinctly yellowish (mean b* = 23.20), and clearly differed from surrounding enamel (ΔE = 8.62). The brightness level (L* = 69.81) indicated medium-high luminosity. Lesion size was reduced by an average of 4.5 percentage points. Significant increases in L values and reductions in a* and b* components were observed, with clinically perceptible ΔE changes. Sensitivity improved in 36.6% of patients, who reported a 1–2 point decrease on the SCASS. Moreover, patients’ aesthetic perception significantly improved after Icon^® infiltration resin. Conclusions: Resin infiltration produced noticeable improvements in color, reduced lesion size and sensitivity, and enhanced aesthetic perception, making it a valuable treatment option for managing MIH-affected anterior teeth in children. Full article

Space conditions offer new insights into fundamental biological and molecular mechanisms. The study aimed to evaluate the enzymatic activity of proteinase K (PK) under extreme conditions relevant to space environments: simulated microgravity, hypergravity, and gamma radiation. PK activity was tested using azocasein (AZO) as a chromogenic substrate, with enzymatic reactions monitored spectrophotometrically at 450 nm. A rotating wall vessel (RWV) simulated microgravity, centrifugation at 1000× g (3303 rpm) generated hypergravity, and gamma radiation exposure used cesium-137 as the ionizing source. PK activity showed no remarkable changes under microgravity after 16 or 48 h; however, higher absorbance values after 96 h indicated enhanced AZO proteolysis compared to 1 g (Earth gravity) controls. In hypergravity, low PK concentrations exhibited slightly increased activity, while higher concentrations led to reduced activity. Meanwhile, gamma radiation caused a dose-dependent decline in PK activity; samples exposed to deep-space equivalent doses showed reduced substrate degradation. PK retained enzymatic activity under all tested conditions, though the type and duration of stress modulated its efficiency. The results suggest that enzyme-based systems may remain functional during space missions and, in some cases, exhibit enhanced activity. Nevertheless, their behavior must be evaluated in a context-dependent manner. These findings may be significant to advance biotechnology, diagnostics, and the development of enzyme systems for space applications. Full article

The use of agrochemicals remains indispensable for ensuring fruit production; however, their excessive or inefficient application poses significant environmental and health concerns. Rapid detection of spray deposition is crucial for assessing sprayer performance, improving precision application, and reducing drift and chemical waste. In this context, real-time monitoring technologies represent a promising tool to promote sustainable and efficient crop protection practices. This study refines previous experiences with an array of resistive sensors to quickly measure spray deposition. First, a multi-point calibration curve is introduced to improve the sensors’ accuracy. Furthermore, a multiplexed acquisition system (Sciospec ISX-5) is employed to enable time-resolved measurements of the whole sensor array. The method is validated by spectrophotometry and weight measurements. Wind tunnel trials with fluorescein (FLU) and fluorescein + potassium chloride (FLU + KCl) tracing solutions were conducted. The conductivity of the latter was higher than the former, without biasing the measurement. Both tracers showed good correlation between deposition and conductivity (R² = 0.997 for FLU and 0.995 for FLU + KCl), and the maximum deviation from the spectrophotometric estimates was <10%. Time-resolved measurement showed the build-up of deposition over time, potentially indicating the dimensional composition of the sprayed cloud. The improved workflow provides array-wide, sequential deposition measurements, enabling faster on-site acquisition and efficient analysis. The results demonstrate strong potential for scaling the method to field applications, supporting its further development into real-time deposition mapping tools that could guide precision spraying, optimize agrochemical use, and reduce environmental drift. Full article