The 28 components of N. poeticus essential oil and 37 of R. damascena Mill. absolutes of Moldovan origin were identified by GC-MS analysis. The major component of N. poeticus essential oil was γ-terpineol (52.62%). In addition to previously described terpene constituents: (Z)-β-ocimene (6.81%), eucalyptol (5.48%), (E)-β-ocimene (2.78%), β-caryophyllene (0.88%), β-myrcene (0.41%) - several compounds not previously described in Narcissus oil were identified, including lilac alcohols B and D (0.53 and 0.42%, respectively), lilac aldehydes A and C (0.43% and 0.78%, respectively), etc. The chemical constituents of R. damascena absolutes belong to several classes. The main constituent, as expected, is phenylethyl alcohol, the content of which varies from 59.85% to 78.17%. The terpene fraction is represented by several compounds like β-cytronellol (0.79-6.53%), nerol (5.89%), elemol (0.37%) and α-eudesmol (0.32%). The in vitro assessment of the essential oil from N. poeticus and R. damascena absolutes against four bacterial strains and two fungal species showed high antibacterial and antifungal activity, with effective concentrations ranging from 150 to 300 mg/mL for N. poeticus oil and from 300 to 600 mg/mL or R. damascena absolutes.
The paper presents data on fluoride concentrations in the Dniester River and Dubasari reservoir, the waters of which are used for multiple purposes, including use as a source of drinking water. Water samples were taken seasonally from 2011 to 2024. The concentration of fluoride ions was determined photometrically using an acidic solution of zirconyl chloride and alizarin red S. Fluorides ranged from 0.05 to 1.07 mg/L in the Dniester sector from Naslavcea (entry point of the river into the territory of the Republic of Moldova) to Dubasari reservoir, and from 0.05 to 0.93 mg/L downstream of the Dubasari dam. They varied from 0.02 to 0.95 mg/L in the reservoir waters. Mean annual concentrations of fluorides in the entire Dniester River, including the Dubasari reservoir, oscillated from 0.15±0.07 to 0.81±0.10 mg/L during the study period. Concentrations below 0.5 mg/L were recorded in 76.6% of analysed water samples. Higher concentrations were observed during periods of low waters, when the river was predominantly supplied by groundwater. In most cases, due to the modified regime of the Dniester resulting from the river regulation, no clear seasonal dynamics were recorded.
Sunflower (Helianthus annuus L.) pollen is a chemically rich but underexplored matrix containing bioactive lipids with nutraceutical and pharmaceutical relevance. Lipid fractions were isolated from hand-collected pollen samples across three distinct agroclimatic zones in Moldova via mini-Soxhlet extraction. Subsequent alkaline saponification and acid methylation enabled GC-MS characterization of fatty acid methyl esters (FAMEs) and unsaponifiable constituents. The mean lipid yield (9.23% w/w) exhibited regional variability, with the highest value in the sample from Visoca (9.90%), likely due to climatic modulation of lipid biosynthesis. Chromatographic profiling resolved >40 constituents, including: Polyunsaturated fatty acid esters (e.g., methyl linolenate, a ω-3 precursor); diterpenoid derivatives (methyl labdatrien-19-oate); oxygenated sterols (lanostan-3-one); lipophilic vitamins (α-tocopherol, retinol derivatives). Chemometric analysis revealed stress-induced shifts in metabolite distribution, with heat/water deficits favouring terpenoid accumulation. The lipidome's structural diversity-spanning hydrocarbons, esters, and ketones-suggests multifunctional bioactivity (antioxidant, anti-inflammatory). These findings position sunflower pollen as a sustainable source of phytochemical precursors for functional ingredients. Further studies should address structure-activity relationships, stabilization strategies, and green extraction optimization.
This study highlights the role of computational approaches in advancing the design of corrosion inhibitors by virtually screening novel candidate molecules. In silico treatment based on quantitative structure-activity relationship (QSAR) analysis was performed on already published experimental results of corrosion inhibition efficiency (IE%) of mild steel in acidic media for eighteen furan derivatives. The theoretical treatments are based on density functional theory (DFT) at B3LYP level. It was found that the global minimum of the furan derivatives can be reached at a medium basis set of 6-21G. A sophisticated model consisting of four descriptors excluding the sulphur correction term with physical meaning and good statistical criteria of squared correlation coefficient (r2) and standard error (SE) equal to 0.914 and 5.029, respectively, is presented. The suggested model can be considered as a powerful tool for understanding the role of chemical composition in preventing corrosion which helps researchers in the development process. The in silico treatment was utilized for suggesting twelve furan derivatives with an extremely high IE% which might be used as excellent materials for corrosion inhibition when synthesized and applied experimentally.
Magnesium oxide (MgO) nanoparticles were synthesized using two distinct stabilizing agents-sodium dodecyl sulphate (SDS) and Aloe Vera extract (AVE)-in order to evaluate how electrostatic versus biopolymeric stabilization affects nucleation, crystallite formation, and final structural properties. The nanoparticles were obtained through a precipitation route followed by calcination at 500-1100°C. XRD analysis confirmed the formation of nanocrystalline MgO, with the crystallite size being slightly influenced by the choice of stabilizing agent. SDS promoted electrostatic micellar templating, resulting in faster nucleation and smaller but defect-richer crystallites, whereas Aloe Vera acted as a steric capping agent that delayed supersaturation and enabled more ordered crystal growth. FTIR and XPS analyses revealed temperature-dependent dehydroxylation and surface carbonation effects, consistent with nanoscale MgO chemical reactivity. The optical bandgap ranged from 5.4 to 6.0 eV, exhibiting a blue shift relative to bulk MgO due to nanoscale confinement and surface defect states. Overall, the results demonstrate that the precipitation environment plays a decisive role in controlling MgO crystallization kinetics, defect chemistry, and nanoparticle stability, with Aloe Vera providing superior steric stabilization against agglomeration compared to SDS.
A new polymeric complex of cadmium(II) was synthesized under solvothermal conditions by the reaction of 5-(4-carboxy-5-methyl-1H-1,2,3-triazol-1-yl) isophthalic acid (H3L) with cadmium nitrate tetrahydrate in a mixture of N,N-dimethylacetamide and water. The obtained compound was investigated using single crystal X-ray diffraction, thermogravimetry, infrared and photoluminescence spectroscopies. The polymeric complex obtained is an infinite 2D coordination polymer with the general formula {[Cd3L2(H2O)6]·2H2O}n (1). The intense photoluminescence emission of cadmium (II) complex was observed in the blue-violet region of the spectrum.
Melissa officinalis L. and Urtica dioica L. were investigated for their phytochemical profiles as well as their antioxidant and anti-lithiatic properties. LC-MS/MS analysis revealed that M. officinalis possessed a more complex and diverse composition, particularly rich in flavonoids (myricetin, and quercetin derivatives) and phenolic acids (caffeic, oleanolic, and salicylic), especially in its ethyl acetate fraction, indicating their lipophilic nature. In contrast, U. dioica exhibited a simpler chemical profile, with significant amounts of myricetin, riboflavin, sinapic acid, catechin, and β-carotene in its aqueous fraction. These compositional differences correspond to distinct biological activities. Antioxidant assays (DPPH, ABTS, FRAP) indicated that the ethyl acetate fraction of M. officinalis exhibited the highest radical-scavenging activity. Furthermore, its aqueous extract showed significant anti-lithiatic efficacy, inhibiting calcium oxalate crystal formation by 87.12% at a concentration of 2 mg/mL.
This study provides an integrated chemical and biological evaluation of hydro-methanolic extracts from the leaves, flowering heads, and tubers of Bunium ferulaceum Sm. Phytochemical profiling revealed organ-dependent variations, with leaves rich in phenolics (53.13 mg GAE/g), flavonoids (21.45 mg QE/g), and tannins (10.17 mg TAE/g), while tubers showed the highest triterpene content (8.15 μg UAE/mg). These compositional differences in functional phytochemical classes were statistically correlated with biological responses: triterpenes showed a strong association with anti-inflammatory effects (r= -0.97), while polyphenols, particularly phenolics and flavonoids, were correlated with antibacterial activity (r= -0.91 and -0.90, respectively). The chemical data highlight the coexistence and complementary mechanisms of polyphenols and triterpenoids, supporting a structure-activity relationship that underlies the pharmacological potential of B. ferulaceum. Overall, the study emphasizes the chemical rationale behind its bioactivity, providing a solid basis for future isolation and mechanistic studies.
The synthesis of three structurally distinct copper(II) coordination compounds was conducted under different pH conditions, employing iminodiacetic acid (IDAH2) as the ligand. In a neutral medium, compound 1 was obtained as a two-dimensional ionic coordination polymer with the formula {(NH2(CH3)2)2[Cu3(IDA)4]·1.75H2O}n, featuring layered [Cu3(IDA)4]n 2n- anions stabilized by hydrogen bonding networks (pH= 6-6.5). In a basic medium (pH= 8-8.5), compound 2 was isolated as a neutral 2D molecular coordination polymer, {[Cu3(IDA)2(IDAH)2]·5H2O}n, based on trinuclear copper units bridged by bi- and monodeprotonated ligands. Acidic conditions (pH= 3) led to the formation of compound 3,((CH3)2OH)2[Cu(IDA)2]·[Cu(IDAH)2]. The compound exhibits an ionic structure composed of a neutral and anionic mononuclear complexes, charge-balanced by protonated dimethylether cations. The observed structural diversity is attributable to the various deprotonation states of the ligand, in association with the nature of the outer-sphere components. A detailed investigation into the infrared (IR) spectra of the compounds provided substantial evidence supporting the proposed coordination modes and hydrogen-bonding interactions. These interactions have been demonstrated to play a pivotal role in the formation of extended supramolecular architectures in all three compounds.
In this work, the synthesis of Schiff bases derived from trans-(R,R)-diaminocyclohexane by microwave irradiation (MW) is presented. The reaction yields varied between 31% and 69%, being influenced by the electronic nature of the substituents (H, Cl, Br, NO2, MeO, t-BuO, BnO, and 4-(4-Me)PhO) and the reaction temperature. The spectrophotometric properties of the products were investigated by UV-Vis spectrophotometry, revealing bathochromic and hypsochromic effects attributable to the different substituent groups. These effects were interpreted by DFT calculations with the B3LYP functional using the 6-311G(d,p) basis set. The results suggest that the electronic properties of the substituents in the para position have a significant impact on the spectroscopic characteristics of the Schiff bases. The synthesized Schiff bases exhibit great potential for applications in areas such as optical sensors and functional materials, as the substituents can precisely modulate their spectrophotometric properties. This opens up new opportunities for designing compounds with tunable properties for various technological and scientific applications.
The modification of zeolite with activated charcoal for hydrogen adsorption was investigated. The aims of this research were to activate natural zeolite (Z), modify Z with commercial activated charcoal (AC/Z), and study the properties of these materials for hydrogen storage. The Z was prepared by the desilication method. The obtained Z was modified by activated charcoal using the wet impregnation method. The obtained materials were characterised by surface area analyser, X-ray diffraction, fourier transform infrared spectroscopy, and scanning electron microscopy with energy dispersive spectrometry. The hydrogen storage performance (at 298 K and 1 atm) was observed by Hydrogen-temperature programmed desorption (H2-TPD). The results showed that the presence of activated charcoal on the zeolite surface increased the specific surface area, reached 188.54 m2/g. However, Z exhibited the highest hydrogen storage capacity of 0.57 mmol/g.
In this study, it was investigated by molecular docking, the interaction of fourteen natural compounds (artemisinin, bilobalide, bilobetin, chelerythrine, chelidonin, epicatechin, gelsemic acid, ginkgolide A, isosilybin, silicristin, silybin, taraxacin, taraxacoside, and taraxinic acid) from Silbum marianum, Chelidonium majus, Ginkgo biloba, Gelsemium sempervirens, Artemisia annua, and Taraxacum officinale with three cancer-related GPCRs: the apelin receptor, the β2-adrenoceptor, and the A2B adenosine receptor. QuickVina2 was used to determine the binding affinities and identify the nature of the strongest interactions. Several compounds (bilobetin, isosilybin, chelidonin, silicristin, and artemisinin) showed high binding affinities and interactions with key residues responsible for the receptor activity. These results highlight the potential of phytochemicals in modulating the activity of GPCRs and may form the basis for further experimental validation.
It has been evaluated the dynamics of the self-purification processes of the Dniester River waters in the section from Dubasari to Vadul lui Voda based on the analysis of the parameters: biochemical oxygen demand (BOD5), chemical oxygen demand (CODCr), thiol content, and the inhibition capacity of the waters in carrying out chemical self-purification processes through free radicals (ΣkiSi). According to the BOD5 values, the Dniester waters belong to quality classes II and I, and according to the CODCr parameter, they fall into quality classes II and III. The thiol content is typical of fresh waters (10⁻6 M), and they are of natural origin. The inhibition capacity classifies the river's waters as slightly and moderately polluted. Along the river, were observed a decrease in biological self-purification processes and an increase in the intensity of free radical processes in the Criuleni area, indicating an additional inflow of reducing compounds into the Dniester waters from its tributary, the Raut River. Additionally, a tendency was noted for the aquatic environment quality restoration in the Vadul lui Voda area.
Arsenic contamination in drinking water poses significant health risks worldwide, making the development of efficient removal technologies a critical area of research. This study explores the enhancement of graphene's arsenic (As) adsorption capabilities through metal doping at various positions on its surface. Using density functional theory, the interactions between arsenic and graphene doped with selected metals were simulated, evaluating the influence of different doping positions on adsorption efficiency. The results demonstrated that metal doping significantly improves the arsenic removal capacity of graphene, with variations observed depending on the doping configuration. These findings contribute to a deeper understanding of the adsorption mechanisms in graphene-based materials and offer a computational approach for designing advanced adsorbents for environmental remediation.
Novel spectrophotometric methods and bioassays have been developed and validated for clarithromycin quantitation in tablets. Spectrophotometric techniques were based on charge transfer complexation through naphthoquinone derivatives. Reactions were carried out in alkaline medium using 1,2-naphthoquinone-4-sulphonate and phylloquinone, which showed an absorption maximum at 452 and 455 nm, respectively. While bioassay was conducted dependent on the inhibitory effect upon the strain of Bacillus subtilis ATCC 9372, by applying cylinder-plate. Linear calibration curves with correlation coefficients of 0.9980-0.9998 were obtained. Molar absorptivity and Sandell's sensitivity were less than 10.73 L/mole/cm and 0.0099 μg/cm, respectively, with a detection limit down to 0.27 μg/mL and quantification limits of 0.68-0.78 μg/mL. The validation of the developed methods was performed for selectivity, precision, accuracy and robustness. Recoveries were found between 97.5-101.9% with % RSD being bellow to 3.5%. A comparative analysis was established and the methods were successfully applied for clarithromycin quantification in dosage forms.
Scale formation in pipelines and on equipment surfaces is a serious problem in many branches of industry. Different scales are formed in cooling water systems and caused heat transfer problems. A common method for controlling scale deposition is the use of chemicals which act as antiscalants. This study focuses on the selection of antiscalant and the parameters of the process for the creation of resource-saving technologies for the use of water in industry. To inhibit the scale formation in cooling water systems, antiscalant RT-2024-4 was used, characterised and the ability of the reagent to mitigate the scale formation was tested. Artesian, tap water and water from the Desna River and model solutions with a hardness of 7.33-14.65 mg-eq/L were used as test objects. The conducted studies show that the temperature increase in the range of 80-90°С and the time of thermostating in the range of 2-5 hours have practically no effect on the stabilisation and anti-scale effects. The statistical data processing method was used to analyse the experimental data. High stability of water with respect to scale formation was established. The expediency of using the scale stabilizer RT-2024-4 for mineralised and highly mineralized waters was shown.
This study involved the synthesis of magnetic materials derived from pomelo peel (PP@Fe3O4), durian peel (DP@Fe3O4), and banana peel (BP@Fe3O4). The characteristics of these materials were examined using SEM, FTIR, XRD, and BET techniques. The adsorption parameters for methylene blue using these magnetic materials, including pH, material concentration, and adsorption duration, were investigated to optimise adsorption efficiency. Results indicated that the most effective material amounts were 0.09 g, 0.18 g, and 0.06 g for PP@Fe3O4, DP@Fe3O4, and BP@Fe3O4, respectively, in 25 mL of methylene blue solution, corresponding to concentrations of 3.6 g/L, 7.2 g/L, and 2.4 g/L. Similarly, the optimal pH values for adsorption were found to be 5.9, 7.7, and 7.4, while the most efficient adsorption times were determined to be 95.3, 42.2, and 128.4 minutes, respectively. Under these conditions, the highest methylene blue adsorption efficiencies achieved were 97.7%, 97%, and 98.9%, respectively. These materials were also employed to assess the chemical oxygen demand index in select water samples.
This paper details the synthesis of palygorskite/biochar/iron oxide composites and their utilization for the remediation of water solutions contaminated with uranium(VI). The synthesis procedure involved the combination of iron chloride, starch, and palygorskite with subsequent pH adjustment, drying of the formed precipitate, and pyrolysis at 600°C. The synthesis of mesoporous materials, primarily composed of iron oxides, including magnetite and hematite, was confirmed using various characterization techniques, including FTIR, SEM, and XRD. It was shown that the adsorption of uranium(VI) reached a maximum of 100.2 μmol/g, exhibiting the highest affinity, which is associated with significant magnetite involvement, which facilitates the reduction processes of uranium(VI) to uranium(IV). The findings demonstrated that the uranium removal process was enhanced by a rise in pH, with significant adsorption and possible precipitation occurring under neutral conditions, so using these composite materials is suitable for in situ remediation of water solutions contaminated by uranium(VI).
This paper reports the synthesis of a substituted aminomethyl zinc phthalocyanine (AmPcZn) and its covalent grafting onto chitosan via an ethyl chloroformate-mediated reaction. Chitosan-based copolymers containing 10%, 20%, 30%, and 60% (w/w) AmPcZn were successfully obtained. The chemical structure of the synthesized AmPcZn was confirmed by 1H-NMR spectroscopy and elemental analysis, which were consistent with the expected molecular composition. The grafting reaction and structural integrity of the resulting copolymers were investigated using Fourier-transform infrared (FTIR) and UV-Vis spectroscopies. FTIR spectra revealed characteristic amide and carbonyl stretching bands, confirming covalent bond formation between chitosan and AmPcZn. UV-Vis measurements showed a concentration-dependent increase in absorbance and a typical splitting of the Q-band with band at 605 nm and 715 nm, indicating the successful incorporation of the phthalocyanine moiety into the polymeric matrix.
Zinc oxide nanoparticles were synthesized via a green route using Nicotiana plumbaginifolia plant extract, serving as a novel bio-reducing and stabilizing agent. Structural analysis through X-ray diffraction confirmed the hexagonal wurtzite crystalline structure, while Fourier-transform infrared spectroscopy and energy-dispersive X-ray spectroscopy affirmed the presence of Zn-O bonds and high purity. Morphological characterization by scanning electron microscopy and transmission electron microscopy revealed spherical nanoparticles with sizes ranging from 16 to 24 nm. The calculated optical band gap was 3.33 eV. A prominent FTIR peak at 480 cm⁻¹ indicated Zn-O stretching vibrations. The Zinc oxide nanoparticles exhibited significant antibacterial activity against Pseudomonas aeruginosa (18 mm), Escherichia coli (19 mm), Klebsiella pneumoniae (19 mm), and Staphylococcus aureus (18 mm) at 100 μL, as evaluated by the well diffusion method. Additionally, the nanoparticles showed strong antioxidant activity, achieving 75.59% DPPH radical scavenging at 250 μg/mL, indicating potential biomedical applications.
