Vanadium antidiabetic mimetics

The discovery of the insulinomimetic elfect of vanadium ions and their complexes as potential agents for treatment of diabetes has been considered as the most remarkable progress in the diabetic therapy over the last two decades [2,4c]. Since a series of landmark studies in 1979 and 1980 demonstrated the ability of vanadate and vanadyl to have insulin-like biological effects of glucose uptake and metabolism in skeletal muscle and adipose tissue in vivo, much work has been focused on exploring the insulin-mimetic properties of vanadate and vanadyl both in vitro and in vivo and on developing new vanadium compounds as potential insulin alternatives in diabetes treatment [156-162], which 

Oxidation of cysteine to cystine was carried on under a pseudo-first order condition in the presence of excess of cysteine on the oxidant  

It was suggested that ligands exert a large modulatory role in determining the oxidative ability of these vanadium 0x0 diperoxo complexes affecting both the coordination of cysteine and the reduction potentials of the oxidants. 

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Vanadium has effects similar to and different from that of insulin [100,101,124], The antidiabetic influence of the metal can be considered insulin-enhancing, rather than insulin-mimetic, because vanadium compounds cannot totally substitute for insulin in any model of diabetes that strictly requires insulin, such as the BB rat [125], a model of type 1 diabetes. In addition, vanadium can exert its antidiabetic effects via a mechanism or combination of mechanisms distinct from that of insulin. The metabolic actions of vanadium on metabolism do not include all of the actions of insulin, yet normal animals produce less serum insulin when given vanadium. The terms insulin-mimetic or insulin-like frequently appear in the literature for actions of vanadium that cannot be classified as similar to or different from that of insulin in the experimental system utilized. 

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