title: Bis- and tris(pyridyl)amine-oxidovanadium complexes: characteristics and insulin-mimetic potential.
abstract: Two novel vanadium complexes, [V(IV)O(bp-O)(HSO4)] (1) and [V(IV)O(bp-OH)Cl2] x CH3OH (2 x CH3OH), where bp-OH is 2-{[bis(pyrid-2-yl)methyl]amine}methylphenol, were prepared and structurally characterised. EPR spectra of methanol solutions of 2 suggest exchange of Cl- for CH3OH and partial conversion to [VO(bp-OH)(CH3OH)3]2+. Speciation studies on the VO2+-bpOH system in a water/dmso mixture (4:1 v/v) revealed [VO(bp-O)(H2O)n]+ as the dominating species in the pH range 2-7. The insulin-mimetic properties of 1 and 2, [V(IV)O(SO4)tpa] (3), [V(IV)O(pic-trpMe)2] (5) and the new mixed-ligand complexes [V(V)O(pic-trpH)tpa]Cl2 (4Cl2) and [V(V)O(pic-OEt)tpa]Cl2 (6Cl2), tpa = tris(pyrid-2-yl)methylamine, picH-trpH = 2-carboxypyridine-5-(L-tryptophan)carboxamide (picH-trpMe is the respective tryptophanmethyl ester), pic-OEt = 5-carboethoxypyridine-2-carboxylic acid, were evaluated with rat adipocytes, employing two lipolysis assays (release of glycerol and free fatty acids (FFA)), respectively and a lipogenesis assay (incorporation of glucose into lipids). The IC50 values for the inhibition of lipolysis in the FFA assay vary between 0.41 (+/-0.03) (5) and 21.2 (+/-0.6) mM (2), as compared to 0.81 (+/-0.2) mM for VOSO4.
authors.affiliation: Inorganic Chemistry Research Group, Chemical Physics, Center for Chemistry and Chemical Engineering, Lund University, SE-22100, Lund, Sweden.
authors.forename: Jessica
authors.initials: J
authors.lastname: Nilsson
authors.forename: Eva
authors.initials: E
authors.lastname: Degerman
authors.forename: Matti
authors.initials: M
authors.lastname: Haukka
authors.forename: George C
authors.initials: GC
authors.lastname: Lisensky
authors.forename: Eugenio
authors.initials: E
authors.lastname: Garribba
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Yoshikawa
authors.forename: Hiromu
authors.initials: H
authors.lastname: Sakurai
authors.forename: Eva A
authors.initials: EA
authors.lastname: Enyedy
authors.forename: Tamás
authors.initials: T
authors.lastname: Kiss
authors.forename: Hossein
authors.initials: H
authors.lastname: Esbak
authors.forename: Dieter
authors.initials: D
authors.lastname: Rehder
authors.forename: Ebbe
authors.initials: E
authors.lastname: Nordlander
mesh_terms: D017667:Adipocytes / Q000378:metabolism; D000818:Animals; D018360:Crystallography, X-Ray; D004578:Electron Spin Resonance Spectroscopy; D006863:Hydrogen-Ion Concentration; D007328:Insulin / Q000737:chemistry / Q000378:metabolism; D050155:Lipogenesis; D008968:Molecular Conformation; D051381:Rats; D017968:Vanadium Compounds / Q000737:chemistry*
chemical_list: D007328:Insulin; D017968:Vanadium Compounds; C034028:vanadyl sulfate