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Glucose-lowering properties of vanadium compounds: Comparison of coordination complexes with maltol or kojic acid as ligands

1997; Elsevier BV; Volume: 68; Issue: 2 Linguagem: Inglês

10.1016/s0162-0134(97)00082-2

1873-3344

Violet G. Yuen, Peter Caravan, Lucio Gelmini, Nicholas R. Glover, John H. McNeill, Ika A. Setyawati, Ying Zhou, Chris Orvig,

Metal-Catalyzed Oxygenation Mechanisms

Bis(kojato)oxovanadium(IV) [abbreviated VO(ka)2], a close chemical analog of the insulin-mimetic lead compound bis(maltolato)oxovanadium(IV)—abbreviated BMOV or VO(ma)2—is reported and its reaction chemistry and insulin-mimetic properties are presented. VO(ka)2 [log K1 = 7.61 (10), log K2 = 6.89(6), log β2 = 14.50 (16)] has a reaction chemistry which directly parallels that of VO(ma)2. In aqueous solution it is more slowly oxidized by molecular oxygen to [VO2 (ka)2]− than is VO(ma)2 to [VO2(ma)2]−. Variable pH electrochemistry and variable pH51 V NMR of solutions of VO(ka)2 are presented and contrasted with the corresponding results for VO(ma)2. Time course studies (24 hr) in STZ-diabetic rats following the oral or ip administration of VO(ka)2, VO(ma)2, VO2+ (vanadyl) as vanadyl sulfate (VOSO4), and [VO2(ma)2]− as its [NH4]+ salt have been performed, as have chronic oral studies comparing VO(ka)2 and VO(ma)2 over a six week period. In all studies, the most potent form of vanadium was the neutrally charged, water soluble, complex VO(ma)2.