A new concept: the use of vanadium complexes in the treatment of diabetes mellitus

Emulsion liquid membrane (ELM) enhanced by nanoparticles and ionic liquid for extracting vanadium ions from wastewater

Emulsion liquid membrane (ELM) stands out as an extraction process that has drawn much attention due to its promising prospects in industrial wastewater treatment technology. Nevertheless, the pivotal challenge is to reach high membrane stability to overcome the obstacle of applying ELM at the industrial scale. In this study, ELM was boosted by using nanoparticles (superparamagnetic iron oxide (Fe2O3)) in the stripping phase (W1) and ionic liquid (1-methyl-3-octyl-imidazolium-hexafluorophosphate [OMIM][PF6) in the oil phase (O) for recovering/extracting vanadium from synthetic wastewater to near completion and at the same time enhancing emulsion stability to be appropriate for industrial application. The vanadium recovery/extraction percentage has been raised significantly in 3 min to 99.6% when adding 0.01% (w/w) Fe2O3 NPs (20 to 50 nm in size) in the internal phase (W1) and 5% (v/v) [OMIM]PF6 ionic liquid in the oil phase (O). Also, the emulsion stability was considerably improved, and the leakage percentage was reduced to 16% after 3 days. The results of this study could be used in the future to remove additional heavy metal ions from industrial effluents.

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.

The different effects of intramuscularly-injected lactate on white and brown adipose tissue in vivo

BACKGROUND

Lactate is an important product of glycolysis metabolism during exercise and has long been recognized as an important metabolic signaling molecule involved in inhibiting lipolysis and promoting lipogenesis, which consequently leads to regulated adipose tissue metabolism. However, recent studies have shown that lactate promotes the browning of white adipose tissue (WAT), which induces heat production and energy expenditure and ultimately causes weight loss. These studies assessing the effects of lactate on lipid metabolism in adipose tissue have revealed conflicting data, making it an important area worthy of further research.

METHODS

In this study, using intramuscular injection of lactate to the gastrocnemius, we identified the role of lactate treatment on lipid metabolism and mitochondrial biogenesis of white adipose tissue and brown adipose tissue (BAT).

RESULTS

Our results showed that lactate treatment activated the cAMP/PKA signaling pathway and promoted the expression of lipolysis-related proteins (AMPK, HSL, ATGL) and mitochondrial biomarkers (PGC-1α, COXIV) of WAT, while BAT showed an opposite trend after lactate treatment. Further studies showed that lactate treatment significantly increased serum epinephrine and promoted β3-AR protein expression in WAT and significantly decreased in BAT.

CONCLUSION

Our study shows that lactate seems to regulate β3-adrenergic receptors differently in WAT and BAT, thereby eliciting disparate responses in adipose tissue.

Biological Properties of Transition Metal Complexes with Metformin and Its Analogues

Metformin is a widely prescribed medication for the treatment and management of type 2 diabetes. It belongs to a class of biguanides, which are characterized by a wide range of diverse biological properties, including anticancer, antimicrobial, antimalarial, cardioprotective and other activities. It is known that biguanides serve as excellent N-donor bidentate ligands and readily form complexes with virtually all transition metals. Recent evidence suggests that the mechanism of action of metformin and its analogues is linked to their metal-binding properties. These findings prompted us to summarize the existing data on the synthetic strategies and biological properties of various metal complexes with metformin and its analogues. We demonstrated that coordination of biologically active biguanides to various metal centers often resulted in an improved pharmacological profile, including reduced drug resistance as well as a wider spectrum of activity. In addition, coordination to the redox-active metal centers, such as Au(III), allowed for various activatable strategies, leading to the selective activation of the prodrugs and reduced off-target toxicity.

Vanadyl sulphate ameliorates biomarkers of endothelial injury and coagulation and thrombosis in a rat model of hyperglycaemia

BACKGROUND

We sought to determine whether the insulin mimicking agent, vanadyl sulphate (Van) can inhibit biomarkers of endothelial injury and coagulation and thrombosis induced by a moderate level of hyperglycaemia.

MATERIAL AND METHODS

Hyperglycaemia was induced in rats by a single injection of streptozotocin (STZ, 50 mg/kg) two weeks after being fed on a high-fat diet (model group). The treatment group started Van (20 mg/kg/day) treatment one-week post STZ injection and continued on Van until being sacrificed at week 10.

RESULTS

Administration of Van to the model group significantly (p < .05) ameliorated dyslipidemia and biomarkers of inflammation (TNF-α, IL-6, and hsCRP) and endothelial injury (E-selectin, P-selectin, sICAM-1, sVCAM-1, and ET-1). Van also significantly inhibited hyperglycaemia-induced blood levels of coagulation (vWF) and thrombosis (PAI-1 and fibrinogen) biomarkers.

CONCLUSIONS

Vanadyl sulphate effectively suppresses hyperglycaemia-induced endothelial injury, coagulation and thrombosis, which is associated with the inhibition of inflammation and dyslipidemia.

Synthesis and Characterization of Novel Chickpea Protein Hydrolysate-Vanadium Complexes Having Cell Inhibitory Effects on Lung Cancer A549 Cells Lines

Designing new types of drugs with preferred properties against cancer is a great issue for scientists dealing with synthesis and study of biological activity. Several organometallic compounds used in chemotherapy reveal side effects. Peptides from edible sources having no side effects may play a transport role in the delivery of anticancer metal ions into targeted tumor cells. For the last two decades, peptide-metal complexes have been considered as potential anticancer agents. In this work, oxovanadium complexes of peptides from Chickpea (Cicer arietinum L.) seeds' protein hydrolysate were investigated. The albumin fraction of Chickpea seeds protein was hydrolyzed with a combination of enzymes papain, trypsin, and alcalase. The hydrolysate was combined with vanadyl ions and obtained oxovanadium complexes were studied by FTIR, SEM-EDX, and TG-DSC analyses, and cell inhibition activity against A549 cells was detected by MTT Assay. In a result, activity of the complexes (IC₅₀ = 14.39 µg/mL) increased 1.7-fold compared to the activity of inorganic salt of vanadium (IC₅₀ = 24.75 µg/mL) against A549 cells. The complexes (CPH-V) were fractionated through Sephadex G-15, and the second active fraction, named CPH-V G15-II was studied by nano-Q-TOF LC/MS. Nine peptides with a molecular mass range of 437-1864 Da were identified. Seven of them were theoretically considered as cell-penetrating peptides. These results could serve first steps for deeper fundamental research on food-derived peptide-vanadium complexes.

Virtual Screening Based Discovery of PTP1B Inhibitors and Their Biological Evaluations

Background :

The discovery of novel antidiabetics for the treatment of type 2 diabetes mellitus (T2DM) is an important task nowadays because the current treatment approaches have certain limitations. The reported studies showed that the protein tyrosine phosphatase 1B (PTP1B) is a valuable target, can be used to develop significant antidiabetic molecules.

Objective:

In the present investigation, computational methods and biological evaluation studies have been applied to develop novel PTP1B inhibitors with good enzyme binding affinity and activity.

Methods:

Virtual screening (docking) analysis of SPECS database compounds on PTP1B enzyme was performed using Schrodinger software. In vitro and in vivo biological evaluations had been conducted with the identified hits.

Results:

The results revealed that the molecules identified through these studies have shown significant interactions with the active site residues of the PTP1B enzyme. The compounds S1 and S2 provided significant binding interactions with the residues (Arg221 and Gln262) and have shown considerable in vitro PTP1B inhibitory activity and in vivo antidiabetic activity. The compounds S1 and S2 possessed 35.44±0.12% and 33.68±0.08% inhibitory activities, respectively.

Conclusion:

These identified hits will be used as a template for design and development of novel PTP1B inhibitors with a compatible pharmacokinetic profile.

Influence of a 6-month physical training program on serum and urinary concentrations of trace metals in middle distance elite runners

Background

The aim of this survey was to determine the effects of an aerobic physical training program of six months duration on the serum and urinary concentrations of essential trace elements among middle distance runners and untrained, non-sportsmen participants.

Methods

24 well-trained, middle-distance (1500 and 5000 m), aerobic male runners (AG) were recruited at the beginning of their training season and 26 untrained males formed the control group (CG). All participants were from the same region of Spain, and all of them had been living in this area for at least two years. Serum and urine of samples of Cobalt (Co), Copper (Cu), Manganese (Mn), Molybdenum (Mo), Selenium (Se), Vanadium (V) and Zinc (Zn) were obtained at the beginning of the training season, and six months later, from all participants. All samples were analyzed with inductively coupled plasma mass spectrometry (ICP-MS).

Results

Two-way ANOVA showed significant differences relative to group effect in serum concentrations of Co, Cu, Mn, Mo, Se and Zn. Attending to time effect, there were differences in Mn (p = 0.003) and Zn (p = 0.001). The group x time interaction revealed differences only in the case of Mn (p = 0.04). In urine, significant differences between group were obtained in Co, Cu, Mn, Se and V. Time effect showed changes in Co, Cy, Mo and Se. Finally, the group and time interaction revealed significant differences in urinary Cu (p = 0.001), Mn (p = 0.01) and Se (p = 0.001).

Conclusions

A six-month aerobic training program for well-trained athletes induced modifications in the body values of several minerals, a fact which may reflect adaptive responses to physical exercise. The obtained data could be interesting for physicians or coaches in order to consider specific modifications in sportsmen’s diets as well as to determine specific nutritional supplementation strategies.

The effect of dioxidovanadium complex (V) on hepatic function in streptozotocin-induced diabetic rats

Diabetics are susceptible to hepatic dysfunction risks due to hyperglycaemia and insulin therapy. Conventional diabetes treatments improve glycaemic control; however, hepatic hazards associated with these agents remains a challenge. Accordingly, this study sought to investigate the effect of a dioxidovanadium complex (V) on the hepatic function in streptozotocin-induced diabetic rats. Sprague-Dawley rats (240-250 g) were divided into 4 groups (n = 6): nondiabetic control, diabetic control, insulin-treated, and vanadium complex groups. The dioxidovanadium (10, 20, and 40 mg/kg) was administered twice every 2nd day for 5 weeks and blood glucose concentration was monitored weekly. At the end of the experimental period, all the experimental groups were sacrificed, and then the lipid profile, liver superoxide dismutase, glutathione peroxidase and malondialdehyde, plasma alanine aminotransferase and aspartate aminotransferase, and C-reactive protein (CRP) concentration were measured. The administration of dioxidovanadium significantly alleviated hyperglycaemia with concomitant attenuation in oxidative stress as evidenced by reduced malondialdehyde concentrations. Furthermore, vanadium complex abolished diabetes-induced dyslipidaemia. Lastly, vanadium complex administration attenuated the increase in alanine aminotransferase, aspartate aminotransferase, and plasma C-reactive protein. These findings suggest that this metallo-compound (dioxidovanadium) may ameliorate liver dysfunction often observed in diabetes.

Inhibitory effects of oxidovanadium complexes on the aggregation of human islet amyloid polypeptide and its fragments

Human islet amyloid polypeptide (hIAPP) is synthesized by pancreatic β-cells and co-secreted with insulin. Misfolding and amyloidosis of hIAPP induce β-cell dysfunction in type II diabetes mellitus. Numerous small organic molecules and metal complexes act as inhibitors against amyloid-related diseases, justifying the need to explore the inhibitory mechanism of these compounds. In this work, three oxidovanadium complexes, namely, (NH₄)[VO(O₂)₂(bipy)]·4H₂O (1) (bipy = 2,2' bipyridine), bis(ethyl-maltolato, O,O)oxido-vanadium(IV) (2), and (bipyH₂)H₂[O{VO(O₂)(bipy)}₂]·5H₂O (3), were synthesized and used to inhibit the aggregation of hIAPP and its fragments, namely, hIAPP19-37 and hIAPP20-29. Results revealed that shortening the peptide sequence decreased the aggregation capability of hIAPP fragments, and the oxidovanadium complexes inhibited the fibrillization of hIAPP better than its fragments. Interestingly, the binding of oxidovanadium complexes to hIAPP and its fragments presented a distinct thermodynamic behavior. Oxidovanadium complexes featured the disaggregation capability against hIAPP, better than against its fragments. These complexes also decreased the cytotoxicity caused by hIAPP and its fragments by reducing the production of oligomers. 3 may be a good hIAPP inhibitor based on its inhibition, disaggregation capability, and regulatory effect on peptide-induced cytotoxicity. Oxidovanadium complexes exhibit potential as metallodrugs against amyloidosis-related diseases.

Decavanadate Inhibits Mycobacterial Growth More Potently Than Other Oxovanadates

51V NMR spectroscopy is used to document, using speciation analysis, that one oxometalate is a more potent growth inhibitor of two Mycobacterial strains than other oxovanadates, thus demonstrating selectivity in its interaction with cells. Historically, oxometalates have had many applications in biological and medical studies, including study of the phase-problem in X-ray crystallography of the ribosome. The effect of different vanadate salts on the growth of Mycobacterium smegmatis (M. smeg) and Mycobacterium tuberculosis (M. tb) was investigated, and speciation was found to be critical for the observed growth inhibition. Specifically, the large orange-colored sodium decavanadate (V10O 28 6 - ) anion was found to be a stronger inhibitor of growth of two mycobacterial species than the colorless oxovanadate prepared from sodium metavanadate. The vanadium(V) speciation in the growth media and conversion among species under growth conditions was monitored using 51V NMR spectroscopy and speciation calculations. The findings presented in this work is particularly important in considering the many applications of polyoxometalates in biological and medical studies, such as the investigation of the phase-problem in X-ray crystallography for the ribosome. The findings presented in this work investigate the interactions of oxometalates with other biological systems.

Therapeutic Application of Zinc and Vanadium Complexes against Diabetes Mellitus a Coronary Disease: A review

During the last two decades, number of peoples suffering from diabetes has increased from 30-230 million globally. Today, seven out of the ten top countries are suffering from diabetes, are emergent countries. Due to alarming situations of diabetes, chemists and pharmacist are continuously searching and synthesizing new potent therapeutics to treat this disease. Now a days, considerable attention is being paid to the chemistry of the metal-drug interactions. Metals and their organic based complexes are being used clinically for various ailments. In this review, a comprehensive discussion about synthesis and diabetic evaluation of zinc and vanadium complex is summarized.

ISSN exercise & sports nutrition review update: research & recommendations

Background

Sports nutrition is a constantly evolving field with hundreds of research papers published annually. In the year 2017 alone, 2082 articles were published under the key words ‘sport nutrition’. Consequently, staying current with the relevant literature is often difficult.

Methods

This paper is an ongoing update of the sports nutrition review article originally published as the lead paper to launch the Journal of the International Society of Sports Nutrition in 2004 and updated in 2010. It presents a well-referenced overview of the current state of the science related to optimization of training and performance enhancement through exercise training and nutrition. Notably, due to the accelerated pace and size at which the literature base in this research area grows, the topics discussed will focus on muscle hypertrophy and performance enhancement. As such, this paper provides an overview of: 1.) How ergogenic aids and dietary supplements are defined in terms of governmental regulation and oversight; 2.) How dietary supplements are legally regulated in the United States; 3.) How to evaluate the scientific merit of nutritional supplements; 4.) General nutritional strategies to optimize performance and enhance recovery; and, 5.) An overview of our current understanding of nutritional approaches to augment skeletal muscle hypertrophy and the potential ergogenic value of various dietary and supplemental approaches.

Conclusions

This updated review is to provide ISSN members and individuals interested in sports nutrition with information that can be implemented in educational, research or practical settings and serve as a foundational basis for determining the efficacy and safety of many common sport nutrition products and their ingredients.

Pharmacological and Toxicological Threshold of Bisammonium Tetrakis 4-(N,N-Dimethylamino)pyridinium Decavanadate in a Rat Model of Metabolic Syndrome and Insulin Resistance

Vanadium(IV/V) compounds have been studied as possible metallopharmaceutical drugs against diabetes mellitus. However, mechanisms of action and toxicological threshold have been tackled poorly so far. In this paper, our purposes were to evaluate the metabolic activity on dyslipidemia and dysglycemia, insulin signaling in liver and adipose tissue, and toxicology of the title compound. To do so, the previously reported bisammonium tetrakis 4-(N,N-dimethylamino)pyridinium decavanadate, the formula of which is [DMAPH]4(NH4)2[V10O28]·8H2O (where DMAPH is 4-dimethylaminopyridinium ion), was synthesized, and its dose-response curve on hyperglycemic rats was evaluated. A Long-Evans rat model showing dyslipidemia and dysglycemia with parameters that reproduce metabolic syndrome and severe insulin resistance was generated. Two different dosages, 5 µmol and 10 µmol twice a week of the title compound (equivalent to 2.43 mg·V/kg/day and 4.86 mg·V/kg/day, resp.), were administered intraperitoneal (i.p.) for two months. Then, an improvement on each of the following parameters was observed at a 5 µmol dose: weight reduction, abdominal perimeter, fatty index, body mass index, oral glucose tolerance test, lipid profile, and adipokine and insulin resistance indexes. Nevertheless, when the toxicological profile was evaluated at a 10 µmol dose, it did not show complete improvement, tested by the liver and adipose histology, as well as by insulin receptor phosphorylation and GLUT-4 expression. In conclusion, the title compound administration produces regulation on lipids and carbohydrates, regardless of dose, but the pharmacological and toxicological threshold for cell regulation are suggested to be up to 5 µmol (2.43 mg·V/kg/day) dose twice per week.

EPR and 51V NMR studies of prospective anti-diabetic bis(3-hydroxy-4-pyridinonato)oxidovanadium(iv) complexes in aqueous solution and liposome suspensions

EPR/⁵¹V-NMR parallel studies of [VO(3,4-HPO)₂] complexes in MOPS buffer and POPC liposome suspensions provide information regarding solvents for oral administration.

Synthesis of a new insulin-mimetic anti-diabetic drug containing vitamin A and vanadium(IV) salt: Chemico-biological characterizations

Diabetes patients suffer from chronic disorders in the metabolism due to high blood sugar caused by anomalies in insulin excretion. Recently, vanadium compounds have been prepared and functionalized to decrease the level of hyperglycemia. Vitamin A boosts beta cell activity; therefore, the lack of this vitamin plays a role in the development of type 2 diabetes. The aim of this article focused on the synthesis of a new anti-diabetic drug formed from the complexation of a vanadium(IV) salt with vitamin A. Vitamin A acts as a unidentate chelate through the oxygen of its -OH group. The vanadium(IV) compound is surrounded by two vitamin A molecules. The [VO(vitamin A)2(H2O)2] compound was synthesized in a binary solvent system consisting of MeOH/H2O (1:1 ratio) in alkaline media at pH = 8. This compound was characterized using Fourier transform infrared spectra (FT-IR), electronic spectra (UV-vis), effective magnetic moment, electron spin resonance (ESR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal analysis (thermogravimetry (TG)-differential thermal analysis (DTA)). Anti-diabetic efficiency for the vanadium(IV) compound was assessed in streptozotocin (STZ)-induced diabetic mice. The results of the animal studies demonstrate the ability of the vanadium(IV) complex to act as an anti-diabetic agent, as measured by improvements of lipid profile, antioxidant activity (superoxide dismutase), malondialdehyde (MDA), glutathione, methionine synthase, and kidney and liver functions.

Vanadium compounds for the treatment of human diabetes mellitus: A scientific curiosity? A review of thirty years of research

In the second part of the 1980s, and in the 1990s, a number of investigators demonstrated -mainly in streptozotocin-induced (STZ) diabetic rats-that the vanadate and vanadyl forms of vanadium possessed a number of insulin-like effects in various cells. It was hypothesized that oral vanadium could be an alternative treatment to parenteral insulin in the therapy of diabetes mellitus. However, the long-term and/or chronic administration of vanadium compounds should also mean tissue vanadium accumulation and risks of toxicity. The purpose of this review was to revise the current-state-of-the-art on the use of vanadium in the treatment of human diabetes. It has been conducted more than three decades after the first report on the beneficial insulin-mimetic effects of oral vanadium administration in STZ-diabetic rats. Although the antidiabetic effects of vanadium in STZ-diabetic rodents are well supported, in the few studies on human patients with positive results, that are available in the literature, vanadium compounds were administered during very short periods. We conclude that vanadium administration for the treatment of human diabetes is misplaced.

Influence of oxodiperoxovanadate complexes on prion neuropeptide fibril formation

Different oxodiperoxovanadate complexes inhibit the fibril formation of prion neuropeptides by different action modes.

Quantitative Assessment of Proliferative Effects of Oral Vanadium on Pancreatic Islet Volumes and Beta Cell Numbers of Diabetic Rats

Background:

Oral vanadyl sulfate (vanadium) induces normoglycemia, proliferates beta cells and prevents pancreatic islet atrophy in streptozotocin-induced diabetic rats. Soteriological method is used to quantitate the proliferative effects of vanadium on beta-cell numbers and islet volumes of normal and diabetic rats.

Methods:

Adult male Sprague-Dawley rats were made diabetic with intravenous streptozotocin injection (40 mg/kg). Normal and diabetic rats were divided into four groups. While control normal and diabetic (CD) groups used water, vanadium-treated normal (VTN) and diabetic (VTD) groups used solutions containing vanadyl sulfate (0.5-1 mg/mL, VOSO₄+5H₂O). Tail blood samples were used to measure blood glucose (BG) and plasma insulin. Two months after treatment, rats were sacrificed, pancreata prepared, and stereology method was used to quantitatively evaluate total beta cell numbers (TBCN) and total islet volumes (TISVOL).

Results:

Normoglycemia persisted in VTN with significantly decreased plasma insulin (0.190.08 vs. 0.970.27 ng/dL, P<0.002). The respective high BG (53249 vs. 14446 mg/dL, P<0.0001) and reduced plasma insulin (0.260.15 vs. 0.540.19 ng/dL, P<0.002) seen in CD were reversed in VTD during vanadium treatment or withdrawal. While the induction of diabetes, compared to their control, significantly decreased TISVOL (1.90.2 vs. 3.030.6 mm³, P<0.003) and TBCN (0.990.1 vs. 3.20.2 x 10⁶, P<0.003), vanadium treatment significantly increased TISVOL (2.90.8 and 4.071.0 mm³, P<0.003) and TBCN (1.50.3 and 3.80.6 x 10⁶, P<0.03).

Conclusion:

Two-month oral vanadium therapy in STZ-diabetic rats ameliorated hyperglycemia by partially restoring plasma insulin. This action was through proliferative actions of vanadium in preventing islet atrophy by increasing beta-cell numbers.

Vanadium compounds in medicine

Vanadium is a transition metal that, being ubiquitously distributed in soil, crude oil, water and air, also found roles in biological systems and is an essential element in most living beings. There are also several groups of organisms which accumulate vanadium, employing it in their biological processes. Vanadium being a biological relevant element, it is not surprising that many vanadium based therapeutic drugs have been proposed for the treatment of several types of diseases. Namely, vanadium compounds, in particular organic derivatives, have been proposed for the treatment of diabetes, of cancer and of diseases caused by parasites. In this work we review the medicinal applications proposed for vanadium compounds with particular emphasis on the more recent publications. In cells, partly due to the similarity of vanadate and phosphate, vanadium compounds activate numerous signaling pathways and transcription factors; this by itself potentiates application of vanadium-based therapeutics. Nevertheless, this non-specific bio-activity may also introduce several deleterious side effects as in addition, due to Fenton's type reactions or of the reaction with atmospheric O2, VCs may also generate reactive oxygen species, thereby introducing oxidative stress with consequences presently not well evaluated, particularly for long-term administration of vanadium to humans. Notwithstanding, the potential of vanadium compounds to treat type 2 diabetes is still an open question and therapies using vanadium compounds for e.g. antitumor and anti-parasitic related diseases remain promising.

Hypoglycemic, lipid-lowering and metabolic regulation activities of metforminium decavanadate (H2Metf)3 [V10O28]·8H2O using hypercaloric-induced carbohydrate and lipid deregulation in Wistar rats as biological model

Because of the increasing global spread of type 2 diabetes mellitus, there is a need to develop new antidiabetic agents. Recently we have synthesized new decavanadates using metformin as counterion. In particular, the compound containing three metforminium dications has been obtained in high yield and has been completely characterized. Biological studies using Wistar rats that have been fed with a high caloric diet inducing insulin resistance and metabolic syndrome were carried out. Results of the impact on key biochemical parameters mediated by metformin alone and the new compound are here presented. The metforminium decavanadate (H2Metf)3[V10O28]·8H2O, abbreviated as Metf-V10O28, was shown to have pharmacological potential as a hypoglycemic, lipid-lowering and metabolic regulator, since the resulting compound made of the two components with antidiabetic activities, reduces both dosage and time of administration (twice a week). Hence, due to the beneficial effects induced by the metforminium decavanadate we recommend to continue the exploration into the mechanism and toxicology of this new compound.

Natural and semisynthetic protein tyrosine phosphatase 1B (PTP1B) inhibitors as anti-diabetic agents

Natural products offered more opportunities to develop new drugs and leading compounds as potent PTP1B inhibitors for treating T2DM.

Methionine oxidation of amyloid peptides by peroxovanadium complexes: inhibition of fibril formation through a distinct mechanism

Peroxovanadium complexes inhibit the fibril formation of neurodegenerative amyloid peptides by oxidizing methionine residues.

Exploring molecular structures, orbital interactions, intramolecular proton-transfer reaction kinetics, electronic transitions and complexation of 3-hydroxycoumarin species using DFT methods

Optimal structures and electronic properties of various species of 3-hydroxycoumarin (3-HCou) have been explored using density functional theory (DFT) methods under polarizable continuum model (PCM) of solvation. Electron transfer from pyrone to benzene moieties is enhanced upon deprotonation. Anionic and radical species have similar orbital-interaction characteristics but the charges in the former are distributed more uniformly. The rate of intramolecular proton transfer for the neutral species increases many folds upon excitation. The HOMO-LUMO transition with π→π* character mainly accounts for the UV absorption of most 3-HCou species in solution. The wavelengths of maximal absorption predicted using TD-DFT method are in agreement with the previous experiment. For the charged species, calculations with the range-corrected functional yield better agreement with the previous experiment. Anionic 3-HCou species shows high degrees of complexation with chromium(III) and copper(II) compared with oxovanadium(IV) and zinc(II). Either oxovanadium(IV) or zinc(II) prefers forming two isomeric complexes with comparable degrees of formation.

Structural and redox requirements for the action of anti-diabetic vanadium compounds

This study presents the first systematic investigation of the anti-diabetic properties of non-oxido V(IV) complexes. In particular, the insulin-mimetic activity of [V(IV)(taci)2](4+), [V(IV)(inoH-3)2](2-), [V(IV)(dhab)2], [V(IV)(hyph(Ph))2], [V(IV)(cat)3](2-) and [V(IV)(pdbh)2]--where taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol, ino is cis-inositol, H2dhab is 2,2'-dihydroxyazobenzene, H2hyph(Ph) is 3,5-bis(2-hydroxyphenyl)-1H-1,2,4-triazole, H2cat is catechol and H2pdbh is pentan-2,4-dione benzoylhydrazone--was evaluated in terms of free fatty acid (FFA) release. Among the six compounds examined, only [V(IV)(pdbh)2], [V(IV)(cat)3](2-) and [V(IV)(hyph(Ph))2], which at the physiological pH convert to the corresponding V(IV)O complexes, were found to exhibit a significant insulin-mimetic activity compared to VOSO4. In contrast, [V(taci)2](4+), [V(inoH-3)2](2-) and [V(dhab)2], which at pH 7.4 keep their 'bare' non-oxido structure, did not cause any inhibition of FFA. The results, therefore, suggest that a V(IV)O functionality is necessary for vanadium complexes to exhibit anti-diabetic effects. This agrees with the notion that the biotransformations of V compounds in the organism are more important than the nature of the species.

Inhibition of human amylin fibril formation by insulin-mimetic vanadium complexes

Inhibition of human amylin fibril formation by insulin-mimetic vanadium complexes.

Metal-mediated DNA damage and cell death: mechanisms, detection methods, and cellular consequences

Metal ions cause various types of DNA damage by multiple mechanisms, and this damage is a primary cause of cell death and disease.

The discovery of vanadyl and zinc complexes for treating diabetes and metabolic syndromes

The incidence of diabetes mellitus has increased over the decades because of lifestyle changes. The number of people with diabetes mellitus worldwide is expected to increase from 150 million to 220 million by 2010 and to 300 million by 2025. There are two main types of diabetes mellitus. Type 1 diabetes mellitus is due to the autoimmune-mediated destruction of pancreatic β cells, resulting in absolute insulin deficiency; the patients require exogenous insulin injections. Type 2 is characterized by insulin resistance and abnormal insulin secretion and the patients require exercise, diet control and/or oral hypoglycemics. However, each treatment has some adverse effects, including physical burden, formation of self-antibodies for insulin injections, the severe side effects of hypoglycemics and the discontinuation of insulin synthesis in the pancreas. To overcome these adverse effects and replace the use of these agents, the author attempted to develop new antidiabetic agents with novel structures and mechanisms. This review focuses on the authors' recent development of vanadium and zinc complexes for antidiabetic and antimetabolic syndromes.

Interaction of vanadium(IV) with human serum apo-transferrin

The interaction of V(IV)O-salts as well as of a few V(IV)O(carrier)n complexes with human serum transferrin (hTF) is studied focusing on the determination of the nature and stoichiometry of the binding of V(IV)O(2+) to hTF, as well as whether the conformation of hTF upon binding to V(IV)O(2+) or to its complexes is changed. Circular dichroism (CD) spectra measured for solutions containing V(IV)O(2+) and apo-hTF, and V(IV)O-maltol and apo-hTF, clearly indicate that hTF-V(IV)O-maltol ternary species form with a V(IV)O:maltol stoichiometry of 1:1. For V(IV)O salts and several V(IV)O(carrier)n complexes (carrier ligand=maltolato, dhp, picolinato and dipicolinato) (Hdhp=1,2-dimethyl-3-hydroxy-4-pyridinone) the maximum number of V(IV)O(2+) bound per mole of hTF is determined to be ~2 or lower in all cases. The binding of V(IV)O to apo-hTF most certainly involves several amino acid residues of the Fe-binding site, and as concluded by urea gel electrophoresis experiments, the formation of (V(IV)O)2hTF species may occur with the closing of the hTF conformation as is the case in (Fe(III))2hTF, which is an essential feature for the transferrin receptor recognition.

An evidence-based systematic review of vanadium by the Natural Standard Research Collaboration

An evidence-based systematic review of vanadium by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated, reproducible grading rationale. This article includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.