Nitrate Anions Research Articles

Ion-chromatographic determination of common anions in drinking water in some regions of the Republic of Armenia

The present study investigated the anion composition of drinking water from various cities and villages in Armenia, including spring water and tap water samples. The simultaneous separation was achieved for fluoride, chloride, bromide, nitrite, nitrate, sulfate, and phosphate anions with the correlation coefficients >0.998. Validation of the method was carried out in accordance with the requirements of guidelines in terms of selectivity, specificity, system suitability, linearity, accuracy, precision, lower limits of detection and quantitation, robustness, and stability. The method was suitable for routine drinking water quality assessment in line with the national or World Health Organization (WHO) regulations. The validated method was further used to analyze drinking water samples from different regions of Armenia. The observed concentrations for the anions in drinking water complied with the WHO limits for drinking water with some exceptions. The test method can be submitted to quality control laboratories as a convenient and practical tool for routine analysis and monitoring studies.

A novel copper(II) complex with a salicylidene carbohydrazide ligand that promotes oxidative stress and apoptosis in triple negative breast cancer cells.

We report the synthesis, characterization, anti-cancer activity and mechanism of action of a novel water-soluble Cu(II) complex with salicylidene carbohydrazide as the ligand and o-phenanthroline as the co-ligand. The synthesized complex (1) was characterized by FT-IR, EPR, and electronic spectroscopy, as well as single crystal X-ray diffraction. This compound was found to be paramagnetic from EPR spectra and X-ray crystallography revealed that the molecule crystallized in an orthorhombic crystal system. The crystal lattice was asymmetric containing two distinct binuclear copper complexes containing the Schiff base as the major ligand, o-phenanthroline as a co-ligand, two nitrate anions, and two water molecules. The Cu(II) in the first site coordinated with the enolised ligand comprising enolate O-, phenolate O-, and the imine N and N,N from o-phen. The major part of this complex exists as Cu(II) coordinated with two H2O molecules at the second site with nitrate acting as the counter anion. However, a smaller portion of the complex exists where Cu(II) is coordinated with NO3- and H2O, and the remaining water molecule acts as lattice water. It was tested for DNA binding and cleavage properties which revealed that it binds in an intercalative mode to CT-DNA with Kb value of 1.25 × 104 M-1. Furthermore, cleavage studies reveal that the complex has potential for efficient DNA cleavage under both oxidative and hydrolytic conditions. It was able to enhance the rate of cleavage by 2.8 × 108 times. The complex shows good cytotoxicity to breast cancer monolayer (2D) as well as spheroid (3D) systems. The IC50 values for MDA-MB-231 and MCF-7 monolayer culture was calculated as 1.86 ± 0.17 μM and 2.22 ± 0.08 μM, respectively, and in (3D) spheroids of MDA-MB-231 cells, the IC50 value was calculated to be 1.51 ± 0.29 μM. It was observed that the complex outperformed cisplatin in both breast cancer cell lines. The cells treated with complex 1 underwent severe DNA damage, increased oxidative stress and cell cycle arrest which finally led to programmed cell death or apoptosis in triple negative breast cancer cells through an intrinsic pathway.

Removal of selenate from wastewater using a bioelectrochemical reactor: The importance of measuring selenide and the role of competing anions

Removal of selenate (SeO42-) from selenate-contaminated wastewater is challenging due to the commonly co-existing and competing anions of sulfate (SO42-) and nitrate (NO3-). This study investigates SeO42− reduction to elemental selenium (Se0) in a cathode-based bioelectrochemical (BEC) reactor and a conventional biofilm reactor (i.e., an upflow anaerobic reactor). The simulated wastewater contained SeO42− at a typical concentration of 5 mg Se/L, SO42− at a typical concentration of 1000 mg S/L, and NO3− at concentrations that varied from 0 to 10 mg N/L. The impact of sulfate on the BEC reactor was much lower than that on the conventional reactor: The selenium removal, defined as (selenate in influent – dissolved selenium in effluent)/selenate in influent, was 99 % in the BEC reactor versus 69 % in the conventional biofilm reactor. The lower selenium removal in the conventional reactor was mainly due to the >10 times higher reduction of sulfate, which directly caused competition between sulfate and selenate for the common resources such as electrons. The more reduction of sulfate in the conventional reactor further led to 45 times higher production of selenide. Selenide is usually assumed to be minimal and therefore not measured in the literature. This simplification may significantly overestimate selenium removal when the influent sulfate concentration is very high. NO3- in the influent of the BEC reactor promoted selenium removal when it was less than 5.0 mg N/L but inhibited selenate removal when it was more than 7.5 mg N/L. This was supported by the microbial community analysis and intermediate (nitrite) analysis.

Eu(III) complexes derived from 2-quinolinecarbohydrazide Schiff base ligand, relations between structure and luminescence properties

A series of Eu(III) complexes were obtained following the template condensation of 2-quinolinecarbohydrazide and 2,6-diacetylpyridine, namely: [Eu(H2pbqh)(NO3)3]·MeOH (1), [Eu(Hpqh)(NO3)3]·2MeCN (2), [Eu(H2pbqh)(SCN2)(MeOH)2](SCN) (3) and [Eu2(pbqh)2(NO3)2(H2O)2]·2.5MeOH (4). The structures of complexes and a new H2pbqh ligand (N',N'''-((1E,1′E)-pyridine-2,6-diylbis(ethan-1-yl-1-ylidene))bis(quinoline-2- carbohydrazides)) were elucidated by single-crystal X-ray diffraction. H2pbqh coordinate pentadentate ONNNO and forms mononuclear complexes 1 and 3. The bis-deprotonated ligand pbqh2- act as hexadentate/bridging mode generates the binuclear complex in 4. The partially condensed ligand Hpqh, tetradentate ONNO, was recorded in complex 2. The crystallographic results reveals that the coordinated H2pbqh/Hpqh ligands and Eu3+ cation form a planar structure in these complexes and nitrate anions coordinate chelate, completing the coordination sphere of Eu3+. The solid state photoluminescent emission was investigated highlighting the nitrate complexes 1 and 2 that exhibit red intense luminescence (λmax = 618 nm). Moreover, the computational calculations reveal different pathways of energy transfer from ligand to Eu3+ electronic states explaining the luminescent behavior.

Crystal structure and Hirshfeld surface analysis of (nitrato-κ2 O,O′)(1,4,7,10-tetraazacyclododecane-κ4 N)nickel(II) nitrate

The crystal structure of the title compound, [Ni(C8H20N4)(NO3)]NO3, at room temperature, has monoclinic (P21/n) symmetry. The structure displays intermolecular hydrogen bonding. The nickel displays a distorted bipyramidal geometry with the symmetric bidentate bonded nitrate occupying an equatorial site. The 1,4,7,10-tetraazacyclododecane (cyclen) backbone has the [4,8] configuration, with three nitrogen-bound H atoms directed above the plane of the nitrogen atoms towards the offset nickel atom with the fourth nitrogen-bound hydrogen directed below from the plane of the nitrogen atoms. The nitrate anion O atoms are seen to hydrogen bond to the H atoms bound to the N atoms of the ligand.

Solution and Surface Solvation of Nitrate Anions with Iron(III) and Aluminum(III) in Aqueous Environments: A Raman and Vibrational Sum Frequency Generation Study.

Hydrated trivalent metal nitrate salts, Fe(NO3)3·9H2O and Al(NO3)3·9H2O, in both solid and aqueous phases are investigated. Raman and surface-selective vibrational sum frequency generation (SFG) spectroscopy, are used to shed light on ion-ion interactions and hydration in several spectral regions spanning low frequency (440-550 cm-1) to higher frequency modes of nitrate and water (720, 1050, 1250-1450, and 2800-3750 cm-1). These frequencies span the metal-water mode, nitrate in-plane deformation, nitrate symmetric and asymmetric modes, and the OH stretch of condensed phase water molecules. Comparison to NaNO3, and in some cases KNO3, is also shown, providing insight. Splitting and frequency shifts are observed and discussed for both the solid state and solution phase. The Lewis acidity of Fe3+ and Al3+ ions plays a significant role in the observed spectra, in particular for the nitrate asymmetric band splitting and frequency shift. The spectral response from water solvation for iron and aluminum nitrates is nonlinear as compared to linear for sodium nitrate, suggesting significantly different solvation environments that are limited by water hydration capacity at higher concentrations. Moreover, a non-hydrogen bonded OH, dangling OH, from hydrating water molecules is observed spectroscopically for Al and Fe nitrate solutions. Furthermore, aluminum nitrate perturbs the surface water structure more than iron nitrate despite aluminum being a weaker Lewis acid. The surface water structure is thus found to be unique for the Al(NO3)3 solutions as compared to both Fe(NO3)3 and NaNO3, such that surface solvation is more pronounced. This observation exemplifies the nature of the Fe(III) and Al(III) ions and their substantial influence on the surface water structure.

Unexpected bell-shaped double layer capacitance promoted by nitrate anions at a-CNx / aqueous electrolyte interface and simulated with the lattice-gas model

Amorphous carbon nitride thin fims, a-CNx, are potentially low cost candidates for electrochemical nitrate treatment by comparison to boron doped diamond electrodes. In aqueous media, a-CNx electrodes are characterized by a large potential window and, in acidic pH solutions, no surface charge capacitive contribution. In perchloric acid at pH 1, nitrate reduction occurs at the negative limit of a potential domain without any significant redox reaction over almost 1 Volt. In this domain, in the presence of a nitrate salt, a bell-shaped behaviour was observed for the interfacial capacitance. Differences were evidenced according to the solvation state of the cations (Na+, K+, Li+, Cs+, (CH3)4N+, (C2H5)4N+), depending on the cation size. Experimental capacitance data were simulated by using the phenomenological theory developed by Kornyshev in the case of ionic liquids. A good agreement was obtained assuming a compact layer in series with the highly structured diffuse layer and taking into account the short-range ion-ion interactions. Thus, at the a-CNx/aqueous electrolyte interface, nitrate anions are engaged into strong anion-cation interactions (ion pairing) especially with small sized cations, leading to nitrate anion trapping in the multilayered interfacial region with a possible negative effect on the nitrate ions electroreduction.

A new explanation for the synergistic promoted mechanism of nitrate and nitrite anion species for the high performance MgO adsorbent

The mechanism of CO2 capture on the nitrate and nitrite anion species synergistic promoted MgO has been rarely studied and still not fully understood. Herein we report a systematic investigation on the CO2 adsorption performance of molten salts-promoted MgO adsorbent to deeply reveal the synergistic promoted mechanism of nitrate and nitrite. A series of MgO-based solid adsorbents were synthesized and applied for CO2 capture using NaNO2/KNO3 as promoters. The addition of mixed nitrate and nitrite promoters greatly enhances the adsorption capacity of MgO, exhibiting CO2 capture up to 10.25 mmol·g−1 under optimal conditions. The MgO-based adsorbent in the form of nanosheets has faster adsorption kinetics and better stability, and the possible reaction mechanism of MgO modified by nitrate and nitrite was proposed. Firstly, NO3– interacts with the lattice oxygen (O12-) of MgO to form NO2– and O22–. Secondly, Mg2+ interacts with the free NO2– to form [Mg···NO2]+ and further overcomes the energy barrier to generate [Mg2+···O2–] ion pairs. O22– is not stable and prone to side reaction. However, NO2– can be converted into O2–, and O2– is further generated to O22–, facilitating regeneration of NO3–. The introduction of molten salt can significantly reduce the reaction energy barrier, and the energy barrier required to generate [Mg2+···O2–] ion pairs is reduced from 6.86 eV to 3.50 eV. Adsorption kinetics studies reveal that the nano-flake MgO facilitates the full contact with the promoter and has faster reaction kinetics in the surface reaction control stage. These insights into the synergistic promoted mechanism of nitrate and nitrite anion species is expected to provide guidance for the further design of the high performance MgO-based CO2 adsorbent.

Synthesis, characterization, and crystal structure of hexa-kis-(1-methyl-1H-imidazole-κN 3)zinc(II) dinitrate.

The synthesis of the title compound, [Zn(C4H6N2)6](NO3)2, is described. This complex consists of a central zinc metal ion surrounded by six 1-methyl-imidazole ligands, charge balanced by two nitrate anions. The complex crystallizes in the space group P. In the crystal, the nitrate ions are situated within the cavities created by the [Zn(N-Melm)6]2+ cations, serving as counter-ions. The three oxygen atoms of the nitrate ion engage in weak C-H⋯O inter-actions. In addition to single-crystal X-ray diffraction analysis, the complex was characterized using elemental analysis, 1H NMR, 13C NMR, and FTIR spectroscopy.

Effect of Inorganic Anions on the Structure of Alkali-Activated Blast Furnace Slag

Analyzing the effect of anions on the structure of geopolymers is crucial because anions can significantly influence the material’s chemical stability, mechanical properties, and long-term durability. Understanding these effects helps optimize geopolymer compositions for various applications, such as construction materials and waste encapsulation. This research report describes the effects of nitrate, sulfate, and phosphate anions on alkali-activated blast furnace slag’s structural integrity and properties. Advanced techniques like XRD, FT-IR, Raman spectroscopy, and XPS have been employed to analyze structural modifications caused by anions, providing insights into their interactions and effects. These anions generally decrease compressive strength by disrupting geopolymerization and altering microstructure. For example, sulfate ions lead to the formation of ettringite, while phosphate ions bind calcium into separate phases. We can also observe microstructural changes, such as increased porosity with phosphate, which significantly reduces strength. Nitrate’s effect is less detrimental but still influences the overall structural dynamics.

Fibrous anion exchanger with ternary amino groups as a component of the substrate for plants growing

A set of studies necessary to determine the suitability of a fibrous anion exchanger with ternary amino groups based on industrial polyacrylonitrile fiber Nitron C as a component of ion substrates was carried out. A laboratory-prepared ion exchanger sample had a working exchange capacity equal to 0.9 meq/g for the nitrate anion, which limits the biological productivity of the substrate for growing plants, in the physiological pH range = 5.5–7.5 and the concentration of the equilibrium nutrient solution is 0.02 eq/l. This capacity is at the level of the best granular ion exchangers and significantly exceeds the capacity of the previously used fibrous ion exchangers for growing plants in zero gravity conditions on space stations in 1970–1994 (Mir, Soyuz TM-10 – TM-17). The synthesized ion exchanger is a polyampholyte and contains three types of ion exchange groups, has high hydrophilicity and mechanical properties that allow it to be processed into textiles and used for any purpose, in which fibrous ion exchangers can be used (air and water purification, human protection means, etc.).

Multiple Roles of Anions on the Degradation Efficiency and Mineralization Pathway of Recalcitrant Acetaldehyde by Vacuum Ultraviolet (185 nm) Oxidation.

Vacuum-UV (185 nm, VUV) is widely applied to polish reverse osmosis permeate (ROP), such as the production of electronics-grade ultrapure water. In this study, the VUV oxidation of acetaldehyde, a common carbonyl in ROP, was found to be influenced by anions even at low concentrations. Interestingly, the influencing extent and mechanism varied depending on the anions. Bicarbonate minimally affected the VUV-photon absorption and •OH consumption, but at 5000 μg-C·L-1, it decreased the degradation of acetaldehyde by 58.7% possibly by scavenging organic radicals or other radical chain reactions. Nitrate strongly competed for VUV-photon absorption and •OH scavenging through the formation of nitrite, and at 500 μg-N·L-1, it decreased the removal rate of acetaldehyde degradation by 71.2% and the mineralization rate of dissolved organic carbon by 53.4%. Chloride competed for VUV-photon absorption and also generated reactive chlorine species, which did not affect acetaldehyde degradation but influenced the formation of organic byproducts. The radical chain reactions or activation of anions under VUV irradiation could compensate for the decrease in oxidation performance and need further investigation. In real ROPs, the VUV oxidation of acetaldehyde remained efficient, but mineralization was hindered due to nitrate and chloride anions. This study deepens the understanding of the photochemistry and feasibility of VUV in water with low concentrations of anions.

Sulfide-enhanced carboxymethyl cellulose stabilised nano zero-valent iron for chromium(VI) mitigation in water: Evidence from batch and column studies

The primary source of chromium pollution in water is industrial operations such as electroplating, leather tanning, and textile manufacture, which use chromium for its ability to resist corrosion. Hexavalent chromium (Cr(VI)), the most detrimental variant, presents significant health hazards, such as cancer. It is crucial to effectively manage and decrease chromium levels to protect human and environmental health, especially in industrial regions where its presence in water is a persistent issue. This work examined the removal of Cr(VI) by sulfidated carboxymethyl cellulose stabilised nano zerovalent iron (S-CMC-nZVI). S-CMC-nZVI exhibited outstanding uniformity and corrosion resistance. Batch experiments revealed that several factors influenced the degree to which S-CMC-nZVI particles eradicated Cr(VI). The parameters to be considered included pH, initial Cr(VI) concentration, coexisting ions, and S/Fe molar ratio. When the sulfur to iron molar ratio was increased from 0 to 0.4, Cr(VI) removal efficiency increased from 73.89 % to 99 %. A pseudo-second-order kinetic model described Cr(VI) removal, and the Langmuir isotherm model determined the highest adsorptive capacity (311.02 mg/g). The presence of bicarbonate and nitrate anions have minimal inhibitory effects on removal of Cr(VI). Experiments on polluted groundwater showed that synthesised nanoparticles may remove Cr(VI) over a long time. Column investigations showed that increasing S-CMC-NZVI concentration increased Cr(VI) removal. The Adsorption, reduction and coprecipitation were major processes responsible for Cr(VI) removal. The research demonstrates that S-CMC-nZVI is a promising material for the in-situ remediation of Cr(VI)-contaminated groundwater.

Mer-[Ni(dien)2]Cl2.H2O and mer-[Ni(dien)2](NO3)2 complexes (dien= diethylenetriamine): Synthesis, physical, computational studies, antioxidant activity, and their use as precursors for Ni/NiO nanoparticles’ preparation

Two new Ni(II) complexes, mer-[Ni(dien)2]Cl2.H2O (I) and mer-[Ni(dien)2](NO3)2 (II), where dien= diethylenetriamine and mer refers to meridional coordination, have been prepared under ambient conditions. Complex (I) crystallizes in the P21/c space group of the monoclinic system, with a = 13.5000(4) Å, b = 8.7170(3) Å, c = 13.9430(4) Å, β = 102.091(2)° and V = 1604.41 Å3, whereas complex (II) crystallizes in the Pbca space group of the orthorhombic system, with a = 8.8117(6) Å, b = 14.0023(8) Å, c = 26.7603(17)Å and V = 3301.79 Å3. Both structures contain the [Ni(C4H13N3)2]2+ cation, together with two chloride anions and a water molecule for (I) and two nitrate anions for (II). The metal centre is coordinated to six nitrogens of the neutral dien ligands in a slightly distorted octahedral geometry. The two compounds have been characterised by FTIR and UV-Vis spectroscopy. Their morphology and size were studied by scanning electron microscopy (SEM). The thermal behaviour of the title compounds was also investigated. Calcination of the two complexes in air yielded Ni/NiO nanoparticles. The structures of both complexes were optimised and their simulated geometric parameters and vibrational modes were discussed and correlated with the experimental data. The antioxidant potential of both complexes was evaluated using DPPH, ferric reducing power tests and phosphomolybdenum assay.

Mesoporous carbon with extremely low micropore content synthesized from graphene oxide modified with alkali metal nitrates

High-temperature thermal exfoliation is a simple, rapid, and cost-efficient method for transforming graphene oxide (GO) materials into reduced graphene oxide (rGO) materials. In this study, GO materials were dispersed with alkali metal nitrates (MNO3), leading to the preparation of porous rGO materials characterized by high specific surface area (SSA) and pore volume via high-temperature thermal exfoliation. Experimental data indicate that the metal cations of MNO3 tend to react directly with the oxygen functional groups (OFG) of GO, modulating the OFG content. Simultaneously, nitrate anions have preferential interaction with alkali metal ions and adhere to the surface of the GO. The presence of MNO3 on the surface of GO facilitates the thermal exfoliation process and leads to the formation of structures with an extremely high proportion of mesoporous content. The isothermal gas adsorption results show that the exfoliation efficiency of the samples activated with different nitrate salts decreases in the order rGO-KNO3 > rGO-NaNO3 > rGO-LiNO3. Among these samples, rGO modified with KNO3 exhibited the greatest exfoliation efficiency, with a mesopore-to-micropore volume ratio of 22.4, more than 1.7 times that of rGO. Its SSA and pore volume were 359 m2 g−1 and 1.26 cm3 g−1, respectively. These values significantly surpass those of rGO. Our research findings demonstrate that activation with MNO3 significantly increases the SSA and pore volume of the GO material after high-temperature annealing.

Influence of anions on the structural and catalytic properties of CTA-MCM-41

CTA-MCM-41 — Mobil Composition of Matter 41 with cetyltrimethylammonium cations (CTA+) — is a hybrid silica known for its high basic catalytic activity due to anionic silanolate sites (Si−O-) that are bound to CTA+. The synthesis of this material depends on the properties of CTA+ micelles in aqueous dispersion which, in turn, depend on the surrounding anions. Thus, this study investigated different types and amounts of anions in the synthesis of CTA-MCM-41. Chloride (Cl-), bromide (Br-), iodide (I-), nitrate (NO3-) and hydroxide (OH-) anions in sodium form were added to the synthesis mixture, and the obtained silicas were tested in the transesterification reaction. It is hereby presented a comprehensive study on how micelles-anion interfaces play a key role in the synthesis of this important hybrid silica catalyst, and it was possible to synthesize a more active basic catalyst than the conventional CTA-MCM-41, just by exploring such surface chemistry effects. Three significant features are highlighted: (1) improved catalytic activity of CTA-MCM-41 applied in transesterification; (2) Synthesis of CTA-MCM-41 with higher retention of cations per silica and higher amount of silanolate basic sites; (3) deepening knowledge of the synthesis mechanism of materials from the MCM-41 family. The effects are more pronounced in the order I- > NO3- > Cl-, in accordance with the Hofmeister ion series. Hydroxide anions, however, led to the greatest increase in the number of sites and basic catalytic activity (up to 52.4 %). These results reinforce the validity of the {S+, X-, I-} (S: surfactant; X: anion; I: silica) silica formation mechanism and reveal a synthesis with hydroxide anions that produces a catalyst more active than conventional CTA-MCM-41.

1-(Anthracen-9-ylmeth-yl)-1,4,7,10-tetra-aza-cyclododeca-ne]chlorido-zinc(II) nitrate.

In the title salt, [ZnCl(C23H30N4)]NO3, the central ZnII atom of the complex cation is coordinated in a square-pyramidal arrangement by four nitro-gen atoms from cyclen (1,4,7,10-tetra-aza-cyclo-dodeca-ne) in the basal plane and one chlorido ligand in the apical position. The anthracene group attached to cyclen contributes to the crystal packing through inter-molecular T-shaped π inter-actions. Additionally, the nitrate anion participates in inter-molecular N-H⋯O hydrogen bonds with cyclen.

Synthesis, crystal structure, magnetic studies, DNA binding, molecular docking studies, cytotoxicity and luminescence properties of a new coordination polymer copper(II) complex with 4,4′-trimethylenedipyridine and 1,10-phenanthroline

In the present work, a novel coordination polymer {[Cu(phen)(Tmdipy)(NO3)H2O](NO3) 2.5(H2O)}n (phen = 1,10-phenanthroline, Tmdipy = 4,4′- Trimethylenedipyridine), has been prepared and structurally determined by elemental analysis, IR, EPR, UV–visible and single-crystal X-ray crystallography. The complex crystallized in triclinic space group P -1, and the copper(II) shows a distorted octahedral geometry, with Jahn-Teller distortion occurring in the (4 + 2) CuN4O2 coordination sphere. The crystal structure evidences that the CP1 is formed of dinuclear [Cu(phen)(Tmdipy)(NO3)(H2O)]2 units weakly connected by nitrate anions giving rise to 1D polymeric chain structure. EPR measurement confirms about the distorted octahedral geometry of the complex. By using UV–Vis absorption, fluorescence spectroscopy, and cyclic voltammetric techniques, the binding studies of copper(II) complex with calf thymus DNA (CT-DNA) were investigated. Additionally, the gel electrophoresis method was used to examine the cleavage of pBR322 DNA by copper(II) complex and exhibited potent cytotoxic effects against human cell line (HepG2). Finally, magnetic properties, molecular docking studies and photoluminescence characteristics have been evaluated.

The crystal structure of a mononuclear PrIII complex with cucurbit[6]uril.

A new mononuclear complex, penta-aqua-(cucurbit[6]uril-κ2 O,O')(nitrato-κ2 O,O')praseodymium(III) dinitrate 9.56-hydrate, [Pr(NO3)(CB6)(H2O)5](NO3)2·9.56H2O (1), was obtained as outcome of the hydro-thermal reaction between the macrocyclic ligand cucurbit[6]uril (CB6, C36H36N24O12) with a tenfold excess of Pr(NO3)3·6H2O. Complex 1 crystallizes in the P21/n space group with two crystallographically independent but chemically identical [Pr(CB6)(NO3)(H2O)5]2+ complex cations, four nitrate counter-anions and 19.12 inter-stitial water mol-ecules per asymmetric unit. The nona-coordinated PrIII in 1 are located in the PrO9 coordination environment formed by two carbonyl O atoms from bidentate cucurbit[6]uril units, two oxygen atoms from the bidentate nitrate anion and five water mol-ecules. Considering the differences in Pr-O bond distances and O-Pr-O angles in the coordination spheres, the coordination polyhedrons of the two PrIII atoms can be described as distorted spherical capped square anti-prismatic and muffin polyhedral.

Fruit extracts of various cornelian cherry (Cornus mas L.) cultivars as antioxidant therapy for alleviating nitrative stress in erythrocytes of blood in experimental diabetes mellitus

Natural antioxidants (vitamins, bioflavonoids, anthocyanins, etc.) are used to prevent the development of oxidative-nitrative stress in diabetes mellitus (DM), which helps to restore or avert functional disorders in the cells and tissues of the body. The aim of the study is to investigate the effect of extracts of the fruit of different cultivars of the cornelian cherry, as well as their main iridoid glycoside – loganic acid, on the activity of NO-synthase and the content of stable metabolites of NO in blood erythrocytes of rats with streptozotocin-induced diabetes. Materials and methods. In the work, we used the extract of the fruits of the cornelian cherry “Podolski” cultivar (BDPA 10462), the ripe fruits of which have a red color, and the extract of the “Yantarnyi” (BDPA 14131) and “Flava” (BDPA 8795) cultivars, the ripe fruits of which have a yellow color. Loganic acid was extracted from yellow fruits of the “Yantarnyi” and “Flava” cultivars of Cornus mas L. All studied extracts were administered to rats orally for 14 days from the 10th day after the induction of DM. The dose of administration was 20 mg/kg body weight. Results. The extract of the red fruits is demonstrated the most pronounced effect in normalizing the biomarkers of nitrative stress (activity of NO-synthase and its isoforms, the content of nitrite and nitrate anions) in erythrocytes of rats with diabetes. The extract of the yellow fruits shows a positive effect on the suppression of nitrative stress, which has been indicated by a decrease in the activity of iNO-synthase to the values in the control group of animals. Loganic acid, on the contrary, inhibited the eNO-synthase. In addition, the extract of yellow fruits of cornelian cherry and loganic acid decreased the level of NO3– and increased the content of NO2– in erythrocytes of diabetic rats. Conclusions. Biomarkers of nitrative stress in erythrocytes of rats with streptozotocin-induced diabetes indicated the antioxidant properties of fruit extracts of cornelian cherry, in particular the red fruits, which contain a large amount of anthocyanins.