Vanadium Research Articles

Exploring the Biological Effects of Anti-Diabetic Vanadium Compounds in the Liver, Heart and Brain.

The prevalence of diabetes mellitus and diabetes-related complications is rapidly increasing worldwide, placing a substantial financial burden on healthcare systems. Approximately 537 million adults are currently diagnosed with type 1 or type 2 diabetes globally. However, interestingly, the increasing morbidity rate is primarily influenced by the effects of long-term hyperglycemia on vital organs such as the brain, the liver and the heart rather than the ability of the body to use glucose effectively. This can be attributed to the summation of the detrimental effects of excessive glucose on major vascular systems and the harmful side effects attributed to the current treatment associated with managing the disease. These drugs have been implicated in the onset and progression of cardiovascular disease, hepatocyte injury and cognitive dysfunction, thereby warranting extensive research into alternative treatment strategies. Literature has shown significant progress in utilizing metal-based compounds, specifically those containing transition metals such as zinc, magnesium and vanadium, in managing hyperglycaemia. Amongst these metals, research carried out on vanadium reflected the most promising anti-diabetic efficacy in cell culture and animal studies. This was attributed to the ability to improve glucose management in the bloodstream by enhancing its uptake and metabolism in the kidney, brain, skeletal muscle, heart and liver. Despite this, organic vanadium was considered toxic due to its accumulative characteristics. To alleviate vanadium's toxic nature while subsequently manipulating its therapeutic properties, vanadium complexes were synthesized using either vanadate or vanadyl as a base compound. This review attempts to evaluate organic vanadium salts' therapeutic and toxic effects, highlight vanadium complexes' research and provide insight into the novel dioxidovanadium complex synthesized in our laboratory to alleviate hyperglycaemia-associated macrovascular complications in the brain, heart and liver.

Synthetic V(V)-peroxido-zwitterionic species catalyze benzene oxidation under mild reaction conditions

A series of dinuclear complexes were synthesized, involving vanadium with N-methylglycine (sarcosine)/N,N’-dimethylglycine in aqueous media and H2O2, capable of exerting catalytic activity. Specifically, the ternary V(V) tetraperoxido dinuclear species (NH4)2[V2O2(O2)4(CH3NH2CH2COO)] (symmetric conformer) (1), (NH4)2[V2O2(O2)4(CH3NH2CH2COO)] (asymmetric conformer) (2), K2(Η2Ο)[V2O2(O2)4(CH3NH2CH2COO)] . H2O (3) (asymmetric conformer), and K2(Η2Ο)2[V2O2(O2)4{(CH3)2NHCH2COO)}] (4) (asymmetric conformer) were synthetically isolated in crystalline form. Compounds 1 and 2 are the same, whilst with profound conformational differences exemplified through pH-specific chemistries. The new materials 1–4 were characterized by elemental analysis, FT-IR, Raman, NMR, and UV–Visible spectroscopy, cyclic voltammetry, thermogravimetric analysis (TGA-DTG), and X-ray crystallography. Further support of the spectroscopic and structural profile was achieved through Bond Valence Sum (BVS) and Hirshfeld molecular mapping calculations. In all of the studied compounds, pH appears to be a crucial factor in the synthesis and isolation. The physicochemical characterization of the hybrid materials justified further use of compound 3 as a potential hydroxylation catalyst of benzene under a variable set of mild reaction conditions. The products of the catalytic reaction systems investigated were identified and quantified by gas chromatography–mass spectrometry (GC-MS) and gas chromatography–flame ionization detection (GC-FID), respectively. The results a) exemplify the involvement of the hybrid dinuclear vanadium compounds in the pursued benzene transformations, and b) distinctly demonstrate the structural and chemical characteristics justifying the emergence of catalytic action of vanadium under mild conditions (40 °C) in reactions toward organic substrates (e.g. benzene) as the basis for the pursuit of selective industrial applications, affording readily available useful compounds.

ОБОСНОВАНИЕ ИСПОЛЬЗОВАНИЯ БИОМОДИФИЦИРОВАННОЙ СОИ В ПРОИЗВОДСТВЕ ПРОДУКЦИИ НИЗКОГЛИКЕМИЧЕСКОГО ДЕЙСТВИЯ

The objective of the study is to substantiate and develop the technology of soybean-mineral concentrate (SMC) and soybean-mineral paste (SMP) based on biomodified soybeans for the use of SMC and SMP in the formulations of low-glycemic products. Objectives: to study the dynamics of accumulation of chelated ions of mineral substances in the process of biomodification of soybeans in a vanadium minera¬lized aqueous medium, to determine the chemical composition of the obtained SMC. The objects of the study are soybean seeds of zoned varieties Oktyabr-70, Lydia, SMC. To determine the chemical composition of the developed SMC, standard methods for studying food products were used, corresponding to the normative and technical documentation valid in the Russian Federation. Determination of mineral substances was carried out by mass spectrometry in inductively coupled argon plasma on an ICP-MS ELAN DRC II device by Perkin Elmer (USA). Construction of mathematical models in the form of second-order regression equations and their analysis were carried out using the Appol program and the Pareto-optimal solution method (KPS program). The paper indicates the features of diabetes mellitus development based on modern research, substantiates the possibility of using chelated vanadium as an ingredient in the production of hypoglycemic food products. A number of literary sources indicating the oxidative and hypoglycemic ability of vanadium compounds are analyzed. The paper presents the results of a study of soybean seed biomodification in a vanadium mineralized aqueous medium and the accumulation of minerals by endoproteinases of germinating soybean seeds. As a result, a two-fold increase in chelated mineral elements is noted: Na1+, Ca2+, K1+, Mg2+, V4+. A technology has been developed for the production of soybean-mineral concentrate (SMC) and soybean-mineral paste (SMP) for the subsequent use of these ingredients in the formulation of low-glycemic products. The chemical composition of the SMC is represent¬ted by proteins 40 %, fats – 20, carbohydrates – 10, water – 6 %.

Lattice dynamic and anomalous thermal transport of calcium sodium vanadates

Calcium sodium vanadate compounds, including NaCaVO4 and Na2CaV4O12, have garnered significant interest for their extensive potential in various practical applications. Nonetheless, a comprehensive understanding of their intrinsic thermophysical properties remains elusive. Here, we present a comprehensive theoretical study on the lattice dynamic, thermodynamic properties, and thermal transport of NaCaVO4 and Na2CaV4O12. The thermodynamic properties including the heat capacity, thermal expansion coefficient, and Gibbs free energy over a wide range of temperatures are obtained. Moreover, utilizing the unified theory, we reveal the hierarchical thermal transport properties of NaCaVO4 and Na2CaV4O12, with diffusive channels making a significant contribution to the lattice thermal conductivity (κL). This contributes to the weak temperature dependence of κL, deviating from the typical κL ∼T-1 trend. With the consideration of normal and diffusive phonons, we predict the ultralow thermal conductivities of NaCaVO4 and Na2CaV4O12, which is derived from the bonding heterogeneity with the coexistence of weak Na-O (Ca-O) bonds and strong V-O bonds. This work offers crucial insights into the lattice dynamics and thermophysical characteristics of metal layered vanadates, potentially enhancing the utility of calcium sodium vanadate in various technological implementations.

Dexamethasone-Induced Insulin Resistance Attenuation by Oral Sulfur-Oxidovanadium(IV) Complex Treatment in Mice.

Vanadium compounds are known to exert insulin-enhancing activity, normalize elevated blood glucose levels in diabetic subjects, and show significant activity in models of insulin resistance (IR). Faced with insulin resistance, the present work investigates the antidiabetic performance of a known oxidovanadium(IV)-based coordination compound-[VIVO(octd)]-and effects associated with glucocorticoid-induced insulin resistance in mice. The effects of [VIVO(octd)] were evaluated in a female Swiss mice model of insulin resistance induced by seven days of dexamethasone treatment in comparison with groups receiving metformin treatment. Biological assays such as hematological, TyG index, hepatic lipids, glycogen, oxidative stress in the liver, and oral glucose tolerance tests were evaluated. [VIVO(octd)] was characterized with 51V NMR, infrared spectroscopy (FTIR), electron paramagnetic resonance (EPR), electronic absorption spectroscopy, and mass spectrometry (ESI-FT-MS). The [VIVO(octd)] oral treatment (50 mg/kg) had an antioxidant effect, reducing 50% of fast blood glucose (p < 0.05) and 25% of the TyG index, which is used to estimate insulin resistance (p < 0.05), compared with the non-treated group. The oxidovanadium-sulfur compound is a promising antihyperglycemic therapeutic, including in cases aggravated by insulin resistance induced by glucocorticoid treatment.

New Nanosized V(III), Fe(III), and Ni(II) Complexes Comprising Schiff Base and 2-Amino-4-Methyl Pyrimidine: Synthesis, Properties, and Biological Activity.

A new synthesis of mixed ligand complexes vanadium(III), iron(III), and nickel(II), [M : L1 : L2], where L1 = Schiff base 2-((E)-((4-(((E)-benzylidene)amino)phenyl)imino)methyl)-naphthalene-1-ol (C24H18N2O) as for L2 = AMPY 2-amino-4-methyl pyrimidine (C5H7N3) were prepared in powder and investigated. Element analysis, molar conductivity, FT-IR, UV-vis, and magnetic susceptibility values have been acquired to describe the generated complexes. The values of vanadium(III), iron(III), and nickel(II) compounds are, respectively, 2.88 BM, 5.96 BM, and 2.92 BM, demonstrating that all compounds conform to the recommended octahedral geometry. Thermal gravimetric analysis (TGA) is used to further assess the complexes and establish the temperature stability and degradation of the metal complexes. The calculations abstracted from XRD patterns propose nanosized complexes (average size 29-50 nm). The microstructures of the samples have also been investigated by scanning electron microscopy (SEM). The disc diffusion method was used to assess and analyze the inhibition of the growth of compounds against harmful bacterial and fungal strains. The prepared complexes were tested against three strains of bacteria, one gram-positive strain (Bacillus subtilis), two gram-negative strains (Escherichia coli and Pseudomonas aeruginosa), and one fungus (Aspergillus fumigatus). The complexes inferred antimicrobial activity against the studied organisms. Specifically, vanadium(III) and nickel(II) are more effective than iron(III), making them promising drugs.

A Non-Toxic Binuclear Vanadium(IV) Complex as Insulin Adjuvant Improves the Glycemic Control in Streptozotocin-Induced Diabetic Rats.

Diabetes mellitus (DM) complications are a burden to health care systems due to the associated consequences of poor glycemic control and the side effects of insulin therapy. Recently. adjuvant therapies, such as vanadium compounds, have gained attention due to their potential to improve glucose homeostasis in patients with diabetes. In order to determine the anti-diabetic and antioxidant effects of the oxidovanadium(IV) complex (Et3NH)2[{VO(OH}2)(ox)2(µ-ox)] or Vox2), rats with streptozotocin (STZ)-induced diabetes were treated with 30 and 100 mg/kg of Vox2, orally administered for 12 days. Vox2 at 100 mg/kg in association with insulin caused a 3.4 times decrease in blood glucose in STZ rats (424 mg/dL), reaching concentrations similar to those in the normoglycemic animals (126 mg/dL). Compared to insulin alone, the association with Vox2 caused an additional decrease in blood glucose of 39% and 65% at 30 and 100 mg/kg, respectively, and an increased pancreatic GSH levels 2.5 times. Vox2 alone did not cause gastrointestinal discomfort, diarrhea, and hepatic or renal toxicity and was not associated with changes in blood glucose level, lipid profile, or kidney or liver function. Our results highlight the potential of Vox2 in association with insulin in treating diabetes.

A Comparative Study about Production of Va nadium Carbide via Self Propagating High Temperature Synthesis and Reduction

Vanadium carbide is important for industrial applications because of its high hardness, high temperature resistance, high chemical, and thermal stability. It is generally obtained from the reaction between V and C powders at a high temperature ranging from 1100 to 1500°C. Investigations on these high strength, high abrasion resistant, hard materials have been intensified in recent years and consequently, significant improvements have been achieved. In this study, VC alloys are produced with low cost processes, by reducing the oxides of their components by SHS methods and ball mill-assisted carbothermal reduction. In the experimental stage, V2O5 was used as oxidized Vanadium source, Cblack as carbon source, magnesium and Cblack as reductant. In the study, VC powders were synthesized by two different methods and optimum production conditions were determined. Furthermore, the effect of different stoichiometric charge components and the effect of experiment durations were realized by X-ray diffraction, HSC Chemistry, and SEM analyses for different reductants.

Antihypoxic effect of almid-containing metal-complex compounds in the experiment

BACKGROUND: To increase resistance to hypoxia, various methods of hypoxic training, mental effects, and use of pharmacological antihypoxants are employed.&#x0D; AIM: To test new metal-complex compounds containing the antihypoxant almid in mice under conditions of acute hypoxia to determine their protective properties.&#x0D; MATERIALS AND METHODS: In the first stage of the study, four new metal-complex compounds of magnesium, calcium, titanium, and vanadium containing the antihypoxant almid were screened in experiments on mice (n = 550) under acute hypoxic conditions with hypercapnia. The antihypoxants almid and amtizole were used as comparison substances. Acute hypoxia was induced by placing the animals in pharmacy glasses with a volume of 0.25 L with closed lapped stoppers. The substances were administered intraperitoneally at doses of 25, 50, and 100 mg/kg previously dissolved in 0.3 mL of NaCl solution. The incubation period was 60 min. The antihypoxic effect was considered confirmed if the lifespan increased by ≥20%. “Lifespan” refers to the time interval from the moment the mice were placed in a pharmacy glass to the development of the first agonal inhalation, after which the animals were quickly removed to preserve life. The rectal temperature of the animals was measured before the introduction of substances, immediately before being exposed to acute hypoxic conditions with hypercapnia, and after removal. Twenty-four hours after the first stage of the experiment, mice of the control group and mice that proved their ability to resist acute hypoxia with hypercapnia were repeatedly exposed to acute hypoxic conditions with hypercapnia after the use of substances.&#x0D; RESULTS: A distinct antihypoxic effect exceeding the effectiveness of the comparison substances was obtained only in one substance—πQ2460 with titanium as a metal-complexing agent—and a ligand in the form of fumaric acid. After the administration of πQ2460, a dose-dependent decrease in rectal temperature was observed in mice. The lifespan of animals increased with an increase in the dosage of πQ2460, i.e., by 43.9%, 103.1%, and 152.8% for doses of 25, 50, and 100 mg/kg, respectively. The results of the second stage of the experiment confirmed the stable protective effect of πQ2460 but with an equalization of the effect of the studied doses, which increased the lifespan under acute hypoxic conditions with hypercapnia to an average of 60–70 min (control group, 40.5 min).&#x0D; CONCLUSION: Among the compounds containing the antihypoxant almid in the complex molecule, πQ2460 (metal, titanium; ligand, fumaric acid) was found to have a stable protective dose-dependent effect on the development of acute hypoxia with hypercapnia in mice exceeding that for almid and the reference antihypoxant amtizole. The antihypoxic effect of πQ2460 persisted 24 h after its administration but leveled off for the studied doses—25, 50, and 100 mg/kg. Considering the data obtained during the comparison of the indicators of resistance to acute hypoxia in the control group, a hypothesis was proposed regarding the possibility of forming a preconditioning effect in animals from the primary effects of acute hypoxia.

Facing diseases caused by trypanosomatid parasites: rational design of multifunctional oxidovanadium(IV) complexes with bioactive ligands

Searching for new prospective drugs against Chagas disease (American trypanosomiasis) and Leishmaniasis, a series of five heteroleptic vanadium compounds, [VIVO(L-H)(mpo)], where L are 8-hydroxyquinoline derivatives and mpo is 2-mercaptopyridine N-oxide, are synthesized and characterized. Comprehensive characterizations are conducted in solid state and in solution. The compounds are evaluated on epimastigotes and trypomastigotes of Trypanosoma cruzi and in promastigotes of Leishmania infantum, alongside on VERO cells, as a mammalian cell model. The compounds exhibit activity against both forms of T. cruzi and promastigotes of L. infantum, with the trypomastigote infective stage of T. cruzi displaying the highest sensitivity. The most selective vanadium compound [VIVO(L2-H)(mpo)], with L2 = 5-chloro-7-iodo-8-hydroxyquinoline, globally shows adequate selectivity towards the parasite and was selected to carry out further in-depth biological studies. [VIVO(L2-H)(mpo)] significantly impacted the infection potential of cell-derived trypomastigotes and hindered the replication of the T. cruzi amastigote form. Low total vanadium uptake by T. cruzi parasites and preferential accumulation in the soluble proteins fraction, with negligible localization in the DNA fraction, are determined. A trypanocide effect is observed across various concentrations of the compound. The generation of oxidative stress and the induction of mitochondria-dependent apoptosis are proposed as the main mechanisms of the parasite’s death by the VIVO compounds. Both theoretical predictions and experimental data support the hypothesis that inhibiting the parasite-specific enzyme NADH-fumarate reductase activity plays a crucial role in the trypanocidal action of these complexes. Globally, [VIVO(L-H)(mpo)] complexes could be considered interesting anti-T. cruzi agents that deserve further research.

Solution chemistry of oxidovanadium(IV) complexes with two bis-kojic acid derivatives

Despite the recognized importance of vanadium compounds in biological systems, including insulin-mimetic properties of oxidovanadium(IV) complexes, namely those with two units of natural occurring mono-hydroxypyrone ligands, as kojic acid, few is known about the vanadium complexation properties with bis-hydroxypyrones ones. We describe herein detailed solution equilibrium studies of the VIVO2+ complexes with two bis-kojic acid derivatives, L1 and L8, containing, respectively, a methylenic (–CH2-) and 1-ethylenic (–CH(CH3)-) linkage between the kojic units. The set of the results obtained from potentiometry, UV–Vis spectrophotometry and EPR spectroscopy studies allowed to conclude that they both can form stable binuclear species due to their capacity to bind simultaneous two oxidovanadium(IV) ions. The structures and coordination modes of the binuclear complexes species were mainly based on the EPR results, and also supported by DFT calculations. Molecular docking of the complexes with hen egg white lysozyme showed an efficient hydrogen binding interaction, a relevant feature for potential beneficial effects on the complex transport or even on the inhibition of its enzymatic activity.

Vanadate-Based Fibrous Electrode Materials for High Performance Aqueous Zinc Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) are considered as attractive energy storage systems with great promise owing to their low cost, environmental friendliness and high safety. Nevertheless, cathode materials with stable structure and rapid diffusion of zinc ions are in great demand for AZIBs. In this work, a new kind of potassium vanadate compound (KV3 O8 ) is synthesized with fibrous morphology as an excellent cathode material for AZIBs, which shows outstanding electrochemical performance. KV3 O8 exhibits a high discharge capacity of 556.4 mAh g-1 at 0.8 A g-1 , and the capacity retention is 81.3% at 6 A g-1 even after a long cycle life of 5000 cycles. The excellent performance of the KV3 O8 cathode is benefited from the structural stability, sufficient active sites, and high conductivity, which is revealed by in situ X-ray diffraction and various other characterizations. This work offers a new design strategy into fabricating high efficiency cathode materials for AZIBs and beyond.

Jedinjenja vanadijuma - novi mogući lekovi u terapiji šećerne bolesti

The general goals of diabetes treatment are to maintain optimal individualized glycemic targets and to prevent complications. Today, there are significant barriers to successful diabetes therapy, such as parenteral drug administration, decreased therapeutic efficacy after an initial improvement in glycemia, inaccessibility of new medicines in lower-income countries, and high drug prices. Accordingly, significant research attention has been devoted to the development of a cheap and comfortable antidiabetic agent, which demonstrates success in lowering blood glucose levels as well as fewer toxicity properties. In recent years, the effects of inorganic and organic vanadium compounds have been investigated in diabetes treatment. These studies have found the low bioavailability of orally administered inorganic vanadium salts; thus, effective doses to reduce blood glucose levels to normal may cause serious adverse events. In addition, the only study with an organo-vanadium compound (bis(maltolato)oxovanadium(IV)), which has reached Phase IIa clinical trial, was terminated after three months due to renal complications. Moreover, despite a growing interest in polyoxovanadates for treating diabetes in the last few years, the toxic potentials of these compounds are still unknown. However, the precise mechanism of their antidiabetic actions remains unclear. A broad spectrum of possible mechanisms and hypotheses, such as enhancement of insulin secretion and enhanced sensitivity to insulin, as well as suppression of hepatic glucose production and decrease of intestinal glucose absorption, have been presented. In conclusion, besides the promising results obtained in animal and human studies, no vanadium compound has successfully reduced blood glucose with acceptable safety and tolerability. More studies of vanadium benefit-risk could lead to a new era in vanadium biomedicine.

Vanadium oxide as an electron buffer to stabilize palladium for electrocatalytic hydrodechlorination

The application of Pd catalysts is generally limited by its cost and lower stability. In this study, a series of Pd-based catalysts by loading on vanadium compounds were prepared and...

Prospects for the Search for New Antidiabetic Agents Among Vanadium-containing Complex Compounds (Review)

Introduction. The epidemic increase in the incidence of diabetes mellitus (DM) makes it urgent to search for new antidiabetic agents. In clinical practice, there is an urgent question about improving and/or replacing insulin therapy for the disease. Vanadium compounds are of particular interest in connection with the identification of their multifactorial effects on the body, including insulin-like and hypoglycemic properties, which opens up prospects for the creation of a new generation of therapeutic agents for the treatment of types 1 and 2 diabetes. The focus of this review is on the structure and antidiabetic properties of vanadium complexes.Text. This review is devoted to the analysis of scientific literature on studies of vanadium-containing compounds as potential antidiabetic agents. The mechanisms of antidiabetic activity of vanadium-containing complex compounds are discussed. The prospects for searching for oxovanadium(IV) complexes with O4-coordination have been assessed.Conclusion. As a result of the analysis of the literature data, it was found that vanadium-containing complex compounds have a significant potential for use as antidiabetic agents. The relevance of the search for highly effective oxo-vanadium metal complexes based on ligands close to endogenous substrates, for example, based on derivatives of aroylpyruvic acid, is shown.

Repurposing Therapeutic Drugs Complexed to Vanadium in Cancer.

Repurposing drugs by uncovering new indications for approved drugs accelerates the process of establishing new treatments and reduces the high costs of drug discovery and development. Metal complexes with clinically approved drugs allow further opportunities in cancer therapy-many vanadium compounds have previously shown antitumor effects, which makes vanadium a suitable metal to complex with therapeutic drugs, potentially improving their efficacy in cancer treatment. In this review, covering the last 25 years of research in the field, we identified non-oncology-approved drugs suitable as ligands to obtain different vanadium complexes. Metformin-decavanadate, vanadium-bisphosphonates, vanadyl(IV) complexes with non-steroidal anti-inflammatory drugs, and cetirizine and imidazole-based oxidovanadium(IV) complexes, each has a parent drug known to have different medicinal properties and therapeutic indications, and all showed potential as novel anticancer treatments. Nevertheless, the precise mechanisms of action for these vanadium compounds against cancer are still not fully understood.

Construction of vanadium oxide cathode material with high performance and stability and its application in aqueous zinc-ion battery

The vanadium oxide cathode material is widely regarded as a promising candidate for aqueous zinc-ion batteries (AZIBs). However, its low activity, poor cycling stability, and inadequate rate performance have significantly impeded its commercial viability. In this study, we report a composite electrode material of V2O5 modified with La3+ and phytic acid (LPVO) with enhanced electrochemical performance. The La3+ are capable of intercalating into the interlayer of V2O5, effectively expanding the interlayer spacing for fast Zn2+ transport, and facilitating the exposure of more Zn2+ storage sites with improved capacity. Additionally, the encapsulated phytic acid could serve as a protective layer to prevent the detachment and dissolution of vanadium compounds during cycles, thereby improving the electrochemical stability. Under the current density of 0.1 A g−1, the capacity of LPVO electrode reaches as high as 385 mAh g−1. Even after 2000 charge–discharge cycles, the capacity retention rate remains as high as 75% (at 3 A g−1). Compared to commercial V2O5, the Zn2+ diffusion rate of the LPVO composite is improved by nearly 1000 times, reaching 5∼7 × 10−10 cm2 s−1. This approach is universally applicable to enhance electrochemical performance of diverse layered electrode materials, aiding the rapid advancement of cathode design for AZIBs.

Investigation of the cobalt ions diffusion processes in calcium orthovanadate crystals

In this work, the high-temperature diffusion doping method was used for introduction of active cobalt ions into calcium orthovanadate Ca3(VO4)2crystals. Experimental samples were made from a nominally pure CVO single crystal obtained by the Czochralski method. The high-temperature diffusion conditions have been optimized to obtain doped crystals of optical quality during annealing in open and closed zones. Diffusion coefficients of cobalt ions (D) were calculated for various conditions: annealing time 24 - 48 hours; temperature range 1150-1300°C; diffusants - oxide compounds of calcium, cobalt and vanadium: Co3O4, Ca10Co0.5(VO4)7 and Ca3(VO4)2:2wt.%Co3O4; diffusion direction is parallel or perpendicular to the CVO crystal optical axis. The calculated values of the diffusion coefficient varied between 2.09·10-8—1.58·10-7 cm2/s. The activation energy of the diffusion process was determined to be 2.58±0.5 and 2.63±0.5 eV for the [001] and [100] directions, respectively. The maximum cobalt concentration in doped CVO crystals was 2·1020 cm–3. The absorption spectrum of diffusion-doped Ca3(VO4)2:Co samples demonstrates the presence of absorption bands characteristic for Co2+ and Co3+ ions. It was shown that the intensity ratio of the characteristic absorption bands varies depending on the crystal doping method. The optical anisotropy of the crystal increases with dopant concentration increase.

Vanadium Compounds with Antidiabetic Potential.

Over the last four decades, vanadium compounds have been extensively studied as potential antidiabetic drugs. With the present review, we aim at presenting a general overview of the most promising compounds and the main results obtained with in vivo studies, reported from 1899-2023. The chemistry of vanadium is explored, discussing the importance of the structure and biochemistry of vanadate and the impact of its similarity with phosphate on the antidiabetic effect. The spectroscopic characterization of vanadium compounds is discussed, particularly magnetic resonance methodologies, emphasizing its relevance for understanding species activity, speciation, and interaction with biological membranes. Finally, the most relevant studies regarding the use of vanadium compounds to treat diabetes are summarized, considering both animal models and human clinical trials. An overview of the main hypotheses explaining the biological activity of these compounds is presented, particularly the most accepted pathway involving vanadium interaction with phosphatase and kinase enzymes involved in the insulin signaling cascade. From our point of view, the major discoveries regarding the pharmacological action of this family of compounds are not yet fully understood. Thus, we still believe that vanadium presents the potential to help in metabolic control and the clinical management of diabetes, either as an insulin-like drug or as an insulin adjuvant. We look forward to the next forty years of research in this field, aiming to discover a vanadium compound with the desired therapeutic properties.

Ameliorative Effect of a Vanadium-thiosemicarbazone Complex on Oxidative Stress in Stomach Tissue of Experimental Diabetic Rats

Recently, we have shown that oral administrations of an oxidovanadium (IV) complex, VOL, with tetradentate thiosemicarbazone ligand normalizes hyperglycemia of streptozotocin-induced diabetic rats (STZ-rats). For the development of vanadium compounds that exhibit insulin-like behavior, it is essential to know some of the pharmacokinetic properties of these complexes. The goal of the current research is to examine the healing effect of new sythesed VOL complex on the oxidative stress parameters of diabetic stomac tissue. Rats used in the experiments were divided as control, VOL+control, diabetic and diabetic+VOL. The rats were sacrificed after 12 days of the experimental period. The levels of glutathione, lipid peroxidation, non-enzymatic glycosylation, advanced oxidized protein products levels and the activities of some enzymes were measured in stomach tissue of all the experimental animals. Although VOL treatment to diabetic rats increased the stomach glutathione levels; lipid peroxidation, non-enzymatic glycosylation and advanced oxidized protein products levels were decreased. Also, the activities of catalase, superoxide dismutase, glutathione-S-transferase, glutathione peroxidase, glutathione reductase and carbonic anhydrase were increased in VOL treated diabetic group. Whereas, lactate dehydrogenase and xanthine oxidase activities were decreased. According to the obtained outcomes, it can be said that VOL treatment has a healing effect on the stomach tissue of diabetic rats. This effect provided by VOL is most likely due to the insulin-like and antioxidant activity of the complex. In conclusion, we can say that VOL may be a suitable candidate for diabetes treatment.