pH-metric chemical speciation modeling and studies of in vitro antidiabetic effects of bis[(imidazolyl)carboxylato]oxidovanadium(IV) complexes

Binding Zinc and Oxo-Vanadium Insulin-Mimetic Complexes to Phosphatase Enzymes: Structure, Electronics and Implications

We explore the structural and electronic properties of representative insulin-mimetic oxovanadium and zinc complexes as computed in vacuum, in water clusters and upon binding to PTEN and PTP1B phosphatases. Albeit diverse, the enzymes' active sites represent evolutionary variant choices of the same type of biochemistry. Though different in respect to covalency and the orbital nature of bonding, theory predicts comparable ionic radii, bond lengths and square pyramidal coordination for the considered vanadyl and zinc systems when in an aqueous environment. Employing docking, DFT and quantum mechanics/molecular mechanics methods, we address possible polar interactions in the protein environments and compute infrared/Raman modes and optical electronic properties, which may be suitable for the structural analysis of the specific chemical moieties in binding studies. Accounting for how protein embedding may alter the electronic states of metal centres, we discuss artificial intelligence-assisted protein field engineering to assist biomedical and quantum information applications.

Vanadium Complexes with Thioanilide Derivatives of Amino Acids: Inhibition of Human Phosphatases and Specificity in Various Cell Models of Metabolic Disturbances

In the text, the synthesis and characteristics of the novel ONS-type vanadium (V) complexes with thioanilide derivatives of amino acids are described. They showed the inhibition of human protein tyrosine phosphatases (PTP1B, LAR, SHP1, and SHP2) in the submicromolar range, as well as the inhibition of non-tyrosine phosphatases (CDC25A and PPA2) similar to bis(maltolato)oxidovanadium(IV) (BMOV). The ONS complexes increased [14C]-deoxy-D-glucose transport into C2C12 myocytes, and one of them, VC070, also enhanced this transport in 3T3-L1 adipocytes. These complexes inhibited gluconeogenesis in hepatocytes HepG2, but none of them decreased lipid accumulation in the non-alcoholic fatty liver disease model using the same cells. Compared to the tested ONO-type vanadium complexes with 5-bromosalicylaldehyde and substituted benzhydrazides as Schiff base ligand components, the ONS complexes revealed stronger inhibition of protein tyrosine phosphatases, but the ONO complexes showed greater activity in the cell models in general. Moreover, the majority of the active complexes from both groups showed better effects than VOSO4 and BMOV. Complexes from both groups activated AKT and ERK signaling pathways in hepatocytes to a comparable extent. One of the ONO complexes, VC068, showed activity in all of the above models, including also glucose utilizatiand ONO Complexes are Inhibitors ofon in the myocytes and glucose transport in insulin-resistant hepatocytes. The discussion section explicates the results within the wider scope of the knowledge about vanadium complexes.

Biospeciation of Oxidovanadium(IV) Imidazolyl-Carboxylate Complexes and Their Action on Glucose-Stimulated Insulin Secretion in Pancreatic Cells

The reaction of the vanadyl ion (VO2+) with imidazole-4-carboxylic acid (Im4COOH), imidazole-2-carboxylic acid (Im2COOH) and methylimidazole-2-carboxylic acid (MeIm2COOH), respectively, in the presence of small bioligands (bL) [oxalate (Ox), lactate (Lact), citrate (Cit) and phosphate (Phos)] and high-molecular-weight (HMW) human serum proteins [albumin (HSA) and transferrin (hTf)] were studied in aqueous solution using potentiometric acid-base titrations. The species distribution diagrams for the high-molecular-mass (HMM) proteins with oxidovanadium(IV) under physiological pH were dominated by VO(HMM)2, VOL(HMM) for unsubstituted ligands (L- = Im4COO- and Im2COO-). However, for the N-substituted MeIm2COOH, the species distribution diagrams under physiological pH were dominated by VOL2, VO(HMM)2 and VO2L2(HMM). These species were further confirmed by LC-MS, MALDI-TOF-MS and EPR studies. The glucose-stimulated insulin secretion (GSIS) action of the complexes was investigated using INS-1E cells at a 1 µM concentration, which was established through cytotoxicity studies via the MTT assay. The neutral complexes, especially VO(MeIm2COO)2, showed promising results in the stimulation of insulin secretion than the cationic [VO(MeIm2CH2OH)2]2+ complex and the vanadium salt. Oxidovanadium(IV) complexes reduced insulin stimulation significantly under normoglycaemic levels but showed positive effects on insulin secretion under hyperglycaemic conditions (33.3 mM glucose media). The islets exposed to oxidovanadium(IV) complexes under hyperglycaemic conditions displayed a significant increase in the stimulatory index with 1.19, 1.75, 1.53, 1.85, 2.20 and 1.29 observed for the positive control (sulfonylurea:gliclazide), VOSO4, VO(Im4COO)2, VO(Im2COO)2, VO(MeIm2COO)2 and VO(MeIm2CH2OH)22+, respectively. This observation showed a potential further effect of vanadium complexes towards type 2 diabetes and has been demonstrated for the first time in this study.

Vanadium as potential therapeutic agent for COVID-19: A focus on its antiviral, antiinflamatory, and antihyperglycemic effects

An increasing evidence suggests that vanadium compounds are novel potential drugs in the treatment of diabetes, atherosclerosis, and cancer. Vanadium has also demonstrated activities against RNA viruses and is a promising candidate for treating acute respiratory diseases. The antidiabetic, antihypertensive, lipid-lowering, cardioprotective, antineoplastic, antiviral, and other potential effects of vanadium are summarized here. Given the beneficial antihyperglycemic and antiinflammatory effects as well as the potential mechanistic link between the COVID-19 and diabetes, vanadium compounds could be considered as a complement to the prescribed treatment of COVID-19. Thus, further clinical trials are warranted to confirm these favorable effects of vanadium treatment in COVID-19 patients, which appear not to be studied yet.

In vitro antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline-based ligands – the substituent effect

This is the first comprehensive study demonstrating the antiproliferative effect of vanadium complexes bearing 8-hydroxyquinoline (quinH) ligands, including the parent and –CH₃ (Me), –NO₂, –Cl and –I substituted ligands, on HCT116 and A2780 cancer cell lines.

Design and Biological Evaluation of Novel Imidazolyl Flavonoids as Potent and Selective Protein Tyrosine Phosphatase Inhibitors

BACKGROUND

Protein tyrosine phosphatases 1B are considered to be a desirable validated target for therapeutic development of type II diabetes and obesity.

METHODS

A new series of imidazolyl flavonoids as potential protein tyrosine phosphatase inhibitors were synthesized and evaluated.

RESULTS

Bioactive results indicated that some synthesized compounds exhibited potent protein phosphatase 1B (PTP1B) inhibitory activities at the micromolar range. Especially, compound 8b showed the best inhibitory activity (IC50=1.0 µM) with 15-fold selectivity for PTP1B over the closely related T-cell protein tyrosine phosphatase (TCPTP). Cell viability assays indicated that 8b is cell permeable with lower cytotoxicity. Molecular modeling and dynamics studies revealed the reason for selectivity of PTP1B over TCPTP. Quantum chemical studies were carried out on these compounds to understand the structural features essential for activity.

CONCLUSION

Compound 8b should be a potential selective PTP1B inhibitor.

Identification of novel imidazole flavonoids as potent and selective inhibitors of protein tyrosine phosphatase

A series of imidazole flavonoids as new type of protein tyrosine phosphatase inhibitors were synthesized and characterized. Most of them gave potent protein phosphatase 1B (PTP1B) inhibitory activities. Especially, compound 11a could effectively inhibit PTP1B with an IC₅₀ value of 0.63 μM accompanied with high selectivity ratio (9.5-fold) over T-cell protein tyrosine phosphatase (TCPTP). This compound is cell permeable with relatively low cytotoxicity. The high binding affinity and selectivity was disclosed by molecular modeling and dynamics studies. The structural features essential for activity were confirmed by quantum chemical studies.

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.

Roots of Acetate-Vanadium Linkage Isomerism: A QTAIM Study

The possibility of linkage isomerism in a number of vanadium(IV) and vanadium(V) complexes with acetate was surveyed using Density Functional Theory (DFT) and Bader's Quantum Theory of Atoms in Molecules (QTAIM). The results show that vanadium-acetate linkages may be classified as bidentate symmetrical, bidentate asymmetrical, or monodentate, the latter being observed in about 40% of the cases. These latter ones correspond to situations where the two oxygen atoms of the acetate moiety are not equivalent. They are associated with an energy penalty of about 263 kJ·mol(-1), as determined by the distribution of the scaled kinetic energy of the atomic basins forming the acetate ligand. In the presence of bidentate symmetrical vanadium-acetate linkages, the inner valence-shell charge concentrations on the vanadium atom deviate from the traditional VSEPR-derived arrangement, with an energy penalty of about 780 kJ·mol(-1). A compromise situation is partially accomplished in the case of bidentate asymmetrical linkages, which allow a Gillespiean-like arrangement of the inner valence-shell charge concentrations. In this case, one of these local charge concentrations lies close to a V-OAcO bond, which slightly disrupts the equivalence between the two oxygen atoms in the acetate ligand.

Synthesis, characterization and anti-diabetic assay of diorganotin(iv) azo-carboxylates: crystal structure and topological studies of azo-dicarboxylic acid ligand and its cyclic tetranuclear dimethyltin(iv) complex

Two novel cyclic tetranuclear and a cyclic dimeric diorganotin(iv) azo-dicarboxylates have been reported. The complexes exhibited effective anti-diabetic activity.