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In vitro антиоксидативна активност хидразида никотинских киселина: експериментална и теоретска студија
No full textThe formation of reactive oxygen species (ROS) in the human body can lead to cell damage. Despite the body’s natural defences, including the enzyme superoxide dismutase, novel antioxidant small molecules are needed. In this work, in vitro antioxidant activity of seven nicotinic acid amides (NcAs) derived from nicotinic acid and mono-thiocarbohydrazones was investigated using DPPH, ABTS, CUPRAC and TAC assays. The compounds exhibited IC50 values between 0.202 to 1.297 mM in the DPPH assay, which improved to 0.114–0.638 mM upon the addition of water in the system. In the ABTS assay, IC50 values ranged from 0.107 to 0.365 mM. CUPRAC and FRAP assays indicated reducing antioxidant power of 1.973–4.650 and 1.564–3.472 mM L-1, respectively. Moderate antioxidant activity was also observed in the phosphomolybdenum assay for total antioxidant capacity. The density functional theory calculations revealed that the S–H bond of thioenol 1 tautomer, with a low bond dissociation enthalpy (BDE) of around 270 kJ mol-1, is the favourable site for hydrogen atom transfer (HAT) to reactive free radicals. Additionally, all compounds exhibited high stability constants with Fe2+ and Fe3+ (Ks ≈ 108), forming complexes with ML stoichiometry.Формирање реактивних кисеоничних врста у организму може да оштети ћелије.Поред природних одбрамбених механизама као што је ензим супероксид-дизмутаза,потребни су и нови мали молекули као антиоксиданси. У овом раду испитивана је антиоксидативна активност више амида никотинске киселине, синтетисаних у реакцији саmono-тиокарбо-хидразонима, помоћу DPPH, ABTS, CUPRAC и TAC метода. IC50 вредностису биле између 0,202 и 1,297 mM за DPPH (0,114–0,638 mM уз додатак воде) и 0,107––0,365 mМ за ABTS. Дистрибуција електронског спина је показала да је S–H веза тиоенолног облика испитиваних никотинамида погодно место за транфер атома водоника нареактивне слободне радикале. Сва једињења су показала високе константе стабилностикомплекса типа ML са Fе2+ и Fе3+
Exploiting the Versatile Reactivity of Aryldiazonium Tetrafluoroborate Salts in the Synthesis of New Isochromene-Fused CF3-Substituted Pyrazoles with Anticancer Potential
No full textPyrazoles, and in particular their fluorinated derivatives, are valuable heterocyclic moieties in medicinal chemistry. Our research group recently developed a one-pot, two-step synthesis of pyrazolo[3,4-c]isochromenes, combining two privileged structures into a single hybrid molecule. Based on the preliminary anticancer screening results of these derivatives, herein, we designed a next-generation compound library focused on the derivatization of a specific portion of the 1-(trifluoromethyl)-3,5-dihydroisochromeno[3,4-c]pyrazole scaffold via late-stage functionalization. The diverse reactivity of aryldiazonium tetrafluoroborate salts was leveraged to achieve this and generate a small but varied compound library. The new series was tested for their anticancer properties and selected derivatives demonstrated pro-apoptotic activity in the human cervical carcinoma cell lines HeLa. The obtained results highlight these structures as valid candidates for further biological studies, while the streamlined synthetic route offers a facile approach to further structural analogs
Strong CH/O hydrogen bonds of phenanthroline transition metal complexes and water
No full textCH/O hydrogen bonds are considered weak, but we have recently shown that these interactions between a coordinated 2,2’-bipyridine and water can even be stronger than hydrogen bonds between waters. [1] Continuing this work, we investigated CH/O hydrogen bonds of coordinated phenanthroline and a water molecule using Cambridge Structural Database (CSD) search and quantum mechanical (QM) calculations. CSD results showed that water molecules tend to form bifurcated CH/O interactions. For QM calculations, the following interaction types were investigated: C2, C3, C4, and bifurcated C1-C2, C2-C3, C3-C4, and C4-C4 (Fig. 1). The strongest interaction energy at DLPNO-CCSDT/CBS level of -4.935 kcal/mol was obtained for a square planar palladium(II) complex with C3-C4 interaction type, which is almost as strong as the water-water hydrogen bond (-5.0 kcal/mol). [2
Recent Progress in Nanomaterials for Electrochemical Sensing of Natural Bioactive Compounds
No full textThe market for bioactive compounds of natural origin has expanded greatly over the past
few years. These compounds can be found as individual supplements or food additives.
Due to the importance of this market, incorrect data on their composition can often be
found. Therefore, monitoring their concentration is of great importance. Although there
are various methods for their selective and sensitive determination, electrochemical sensors
represent an important tool in this field. With the development of nanotechnology, additional
importance has been given to these sensors. Strictly controlled synthesis procedures
can yield nanomaterials with unique morphological properties and significantly improved
electrocatalytic capabilities. The integration of two or more nanomaterials in the form
of a nanocomposite and/or nanohybrids allows for the synergistic effect of each of the
components. Thus, excellent final characteristics are obtained in the field of electrochemical
sensors, such as improved sensor stability, selectivity, and lower detection limits. In
recent years, various forms of carbon nanomaterials, polymer films, metal and metal oxide
nanoparticles (or simply metal/metal oxide nanoparticles), MOFs, porous nanomaterials,
MXenes, and others with clearly defined characteristics represent an important step forward
in this field. Carefully prepared, these materials achieve strong interactions with
selected analytes, which results in significant progress in analytical methods for monitoring
biologically active compounds. Therefore, this review summarizes the latest trends in this
field, focusing on the method of material preparation, final morphology and electrocatalytic
properties, selectivity, and sensitivity. Conclusions and expected future directions in this
field are also given in order to improve current analytical performance
Aroma Profiling and Sensory Association of Six Raspberry Cultivars Using HS-SPME/GC-MS and OPLS-HDA
No full textIn this study, six club raspberry varieties were examined for their aromatic profiles and
sensory qualities, and statistical approaches were used to determine how aroma components
affect consumer impressions. Analysis of the aroma’s chemical composition was
performed utilizing headspace SPME and GC-MS. MS-DIAL -v5.5.250627 software was
used to identify components from commercial libraries, after 10 repetitions for each variety,
followed by manual verification. A sensory evaluation of fresh fruits, with 55 volunteers,
was statistically analyzed and linked to chemical composition using multivariate analysis
and the OPLS-HDA classification method, which was employed for the first time. Tula
Magic was scored the highest in the sensory evaluation compared to Adelita, Himbo Top,
Glen Dee, San Rafael, and Cascade Harvest. 2-Heptanol (fresh, lemongrass-like, herbal,
floral, fruity, green), heptanal (fresh, aldehydic, fatty, green, herbal), and 2-methyl-6-hepten-
1-ol (oily-green, herbaceous-citrusy) separated Tula Magic from the other varieties assessed.
The same components were recognized in OPLS as positive contributors to the flavor score,
while terpenoids like trans-β-ionone, α-ionone, and α,β-dihydro-β-ionone, as well as
2-heptanone, scored slightly lower. This suggests that a fine balance between the individual
components is key to the overall aroma sensation
Optimization of the microwave-assisted extraction of bioactive compounds from Satureja hortensis L.: an artificial neural network approach, chemical profile, extraction kinetics, and thermal properties
No full textIntroductionSummer savory is still not investigated thoroughly despite its potential and beneficial effects. Therefore, we aimed to investigate its chemical profile, thermal properties, extraction kinetics, and to optimize extraction process.MethodsHerein, an artificial neural network (ANN) was used as a nonlinear regression-based optimization model to optimize the microwave-assisted extraction of summer savory leaves. To achieve the goal, 17 experiments were conducted, combining different extraction times (20–40 min), ethanol concentrations (68–80%), and irradiation powers (400–800 W). Investigated responses included total phenolic content (TPC), total flavonoid content (TFC), DPPH, and ABTS assays. Kinetics was investigated by using four models, while thermal behavior was studied using DSC and TGA.ResultsThe highest outputs were: 256.36 mg GAE/g (GAE-gallic acid equivalents) (40 min, 40% ethanol, and 600 W) for TPC, 35.78 mg RU/g (rutin equivalents) (40 min, 60% ethanol, and 400 W) for TFC, 15.89 μg/mL (20 min, 60% ethanol, and 400 W) for DPPH, and 23.06 μg/mL (30 min, 60% ethanol, and 600 W) for ABTS. As a result of optimization, we obtained optimal extraction conditions (40 min, 52.8% ethanol, and 656.1 W) and predicted responses (246.50 mg GAE/g for TPC, 35.66 mg RU/g for TFC, and IC50 and EC50 values of 17.79 μg/mL and 25.79 μg mL for DPPH and ABTS assays, respectively). The experimentally obtained values for the investigated responses were 242.25 mg GAE/g, 36.30 mg RU/g, 17.10 μg/mL, and 24.48 μg/mL for TPC, TFC, IC50, and EC50, respectively. Total content of the quantified phenolic compounds was 91.47 μg/mL. The principal compound was rosmarinic acid (80.99 μg/mL), followed by chlorogenic acid (2.64 μg/mL), rutin (1.45 μg/mL), and apigenin (1.31 μg/mL).DiscussionThe validity of the developed ANN model has been confirmed experimentally after preparing the extract under optimal conditions. Kinetic modeling showed that Model II provided the best fit for TFC, while Model IV provided the best fit for TPC. Optimally prepared extract showed high antioxidant activity and thermal behavior and could be used in food and pharmaceutical industry as an additive
Laccase-mediated synthesis of phloridzin oligomers: An insight into the influence of reaction conditions and evaluation of oligomers’ biological activity
No full textThe effect of key experimental factors on phloridzin oligomerization catalyzed by Trametes versicolor laccase was investigated, and biological activity of synthesized oligomers was evaluated. Mass spectrometry analysis of the obtained reaction mixture showed the presence of oligomers with the degrees of polymerization two and three with dimer as the major product. The detected masses of the formed oligomers indicated the repetition of phloridzin units in their structure and the loss of two hydrogen atoms during the linkage formation, while NMR analysis of the major dimer confirmed the presence of two phloridzin molecules linked via a C5-C5 bond. The effect of temperature, substrate, and enzyme concentration on phloridzin conversion and products’ yield was examined, and for achieving the highest products yield (4.1 mg/ml), optimal factors were 40 °C temperature, 5 mg/ml phloridzin concentration and 0.5 mg/ml laccase concentration. Synthesized oligomers showed good antioxidant activity compared to phloridzin and very good potential to be used as skin prebiotics since they exhibited inhibitory effect on opportunistic pathogen Staphylococcus aureus and stimulating effect on commensal bacteria Staphylococcus epidermidis in a broad range of tested concentrations. The highest prebiotic capacity was demonstrated at a concentration of 0.0195 mg/ml in S. epidermidis and S. aureus co-culture
Research data related to allergenicity prediction of blood clams proteins identified from 2D gel spots
No full textAllergenicity prediction algorithms, including AlgPred 2.0 (webs.iiitd.edu.in/raghava/algpred2/batch.html)13, AllerCatPro 2.0 (allercatpro.bii.a-star.edu.sg)14, and SEP-AlgPro (balalab-skku.org/SEP-AlgPro)15 were utilized through their respective web servers. Each tool predicted whether a given protein was allergenic (1) or non-allergenic (0), except for AllerCatPro 2.0, where an average score of ≥0.5 classified the protein as an allergen. AlgPred 2.0 outputs were treated as two separate predictions—the ML score and the Hybrid score—each using a classification cutoff of 0.3. SEP-AlgPro was excluded from allergen prediction when the input sequence exceeded 1000 residues. A protein was considered an allergenic hit if it received at least two positive predictions from the three algorithms, with a minimum combined score of 1.5.These research data belong to publication which will be submitted to Food Chemistry journal (Elsevier)
Identifying the True Catalyst: A Mn(II) Salt versus Mn(II) Complexes in Epoxidation with m‐Chloroperbenzoic Acid
No full textThe oxidant meta-chloroperbenzoic acid (m-CPBA) is used widely for the epoxidation of alkenes, yet its efficiency is often limited under ambient conditions. In this study we investigate the catalytic activity of a Mn(II) salt and mononuclear Mn(II) complexes, two of which are reported here for the first time, in the epoxidation of alkenes with m-CPBA under ambient conditions. Time-resolved Raman spectroscopy was used to monitor substrate conversion, oxidant consumption, and product formation. The data reveal that simple Mn(II) salts exhibit significantly higher catalytic activity than Mn(II) complexes, indicating that ligand coordination inhibits the reactivity of the manganese centre. The catalytic efficiency of Mn(II) perchlorate was particularly notable, achieving near-complete oxidation of styrene within minutes under mild conditions. Furthermore, epoxidation of a range of alkenes demonstrated that Mn(II) salts provide broad substrate scope and high selectivity. These findings suggest that simple Mn(II) salts can serve as highly efficient and cost-effective catalysts in alkene epoxidations with m-CPBA