Synthesis, structure, luminescence properties, quantum chemistry and cytotoxic effects of two vanadium(IV) complexes with polypyrazolylborates, HB(pz)3VO(acac) and HB(3,5-Me2pz)3VO(acac)·CH3CN (pz = pyrazole)

The First Anticancer Tris(pyrazolyl)borate Molybdenum(IV) Complexes: Tested in Vitro and in Vivo-A Comparison of O,O-, S,O-, and N,N-Chelate Effects

The synthesis, characterization and biological activity of molybdenum(IV) complexes containing Trofimenko's scorpionato ligand, hydrotris(3-isopropylpyrazolyl)borate (TpiPr ), in addition to varying biologically active as well as other conventional ligands is described. Ligands employed include (O,O-) (S,O-) (N,N-) donors that have been successfully coordinated to the molybdenum center by means of oxygen-atom transfer (OAT) reactions from the known MoVI starting material, TpiPr MoO2 Cl. The synthesized complexes were characterized by standard analytical methods and where possible by X-ray diffraction analysis. The aqueous stability of the compounds was studied by means of UV/Vis spectroscopy and the impact of the attached ligand scaffolds on the oxidation potentials (MoIV to MoV ) was studied by cyclic voltammetry. Utilizing polyvinylpyrrolidone (PVP) as a solubilizing agent, adequate aqueous solubility for biological tests was obtained. Anticancer activity tests and preliminary mode of action studies have been performed in vitro and in vivo.

Stabilities and Biological Activities of Vanadium Drugs: What is the Nature of the Active Species?

Diverse biological activities of vanadium(V) drugs mainly arise from their abilities to inhibit phosphatase enzymes and to alter cell signaling. Initial interest focused on anti-diabetic activities but has shifted to anti-cancer and anti-parasitic drugs. V-based anti-diabetics are pro-drugs that release active components (e.g., H₂ VO₄^- ) in biological media. By contrast, V anti-cancer drugs are generally assumed to enter cells intact; however, speciation studies indicate that nearly all drugs are likely to react in cell culture media during in vitro assays and the same would apply in vivo. The biological activities are due to V^V and/or V^IV reaction products with cell culture media, or the release of ligands (e.g., aromatic diimines, 8-hydroxyquinolines or thiosemicarbazones) that bind to essential metal ions in the media. Careful consideration of the stability and speciation of V complexes in cell culture media and in biological fluids is essential to design targeted V-based anti-cancer therapies.

A new oxovanadium complex enhances renal function by improving insulin signaling pathway in diabetic mice

AIM

Since vanadium complexes have insulin-mimetic effects and can be used to treat complications of diabetes, we aimed to screen a new oxovanadium complex with a low toxicity, and investigate its insulin-mimetic effects, as well as the mechanism of improvement to diabetic mouse renal function.

METHODS

Cells were treated with oxovanadium complexes, and viability was assessed by MTT assay. Diabetic mouse model was established using alloxan. Blood urea nitrogen (BUN) and serum creatinine (SCr) in the mice were measured using an automatic biochemical analyzer, and blood glucose was measured using a Glucoval Compact meter. Expression of proteins related to the insulin signaling pathway in the renal cortex of mice was measured by Western blot analysis.

RESULTS

Diabetic mice developed high blood glucose, BUN and SCr levels compared with control mice. The new oxovanadium complex with 3,5-dimethyl-pyrazolyl ligand, VO(HB(3,5-Me2pz)3)(3,5-Me2pz)(SCN)(SCNH)2, showed low toxicity and significantly reduced blood glucose, BUN and SCr levels in the diabetic mice. Additionally, p42/p44MAPK and Akt phosphorylation was markedly increased in diabetic mice and was decreased by treatment with the new oxovanadium complex. Caveolin-1 (Cav-1) expression was greatly decreased in diabetic mice and significantly increased after treatment with the new oxovanadium complex.

CONCLUSIONS

The new oxovanadium complex, with 3,5-dimethyl-pyrazolyl ligand, improves kidney function in diabetic mice, and its mechanism may involve regulation of the insulin signaling pathway.

Synthesis, structures and properties of the catalytic bromination reaction of a series of novel scorperate oxidovanadium complexes with the potential detection of hydrogen peroxide in water

A series of scorpionate oxovanadium (IV) complexes: [VO(Tp(4I))(pz)(SCN)]·1/2CH2Cl2 (1), [VO(Tp)(pzTp)]·2H2O (2), [VO(Bp)(Tp(4I))] (3) and [VO(C5H7O2)(Tp(4I))]·CH3OH (4) (Bp: [H2B(pz)(2-)], Tp: [HB(pz)(3-)], Tp(4I): [HB(4I-pz)(3-)], pzTp: [B(pz)(4-)]) have been synthesized and characterized by elemental analysis, IR spectra, UV-Vis spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction and thermal gravimetric analysis (TG). Structural analysis shows that the coordination environment of vanadium atom is N5O, to form a distorted octahedron geometry. In addition, the catalytic activities of the bromination reactions for complexes 1 and 2 in phosphate buffer with phenol red as a trap were evaluated primary by UV/Vis spectroscopy, and a practical application of H2O2 detection was firstly observed in the catalytic reaction system.