3.27 - Biological Activities of V and Cr

Abstract

Vanadium coordination compounds endowed with organic ligands are versatile antidiabetic formulations in vitro and in vivo for the (potential) treatment of diabetes type 1 and type 2. A key compound, bis(ethylmaltolato)oxidovanadium(IV), BEOV, has been introduced into phase IIa clinical tests. Most of the resorbed ‘organic vanadium’ is stripped off its ligand in blood serum and bound to transferrin, which then promotes vanadium's transport, via endocytosis, into the cytosol. The operative likely active form of vanadium probably is vanadate H2VO4−, which targets, inter alia, intracellular protein tyrosine phosphatase and activates the glucose transporter GLUT4. Vanadium is stored in bone tissue with a half-life of about a month, and can thus provide a vanadium pool even in case vanadium supplementations are only applied sporadically and in low doses. Other potential medicinal applications of vanadium include its anticancer potential (possibly because of vanadium's regulatory role with respect to reactive oxygen species), and its inhibitory action against infectious parasites such as those causing amoebiasis, leishmaniasis, and Chagas’ disease. The validity of chromium supplementations on the other hand, tris(picolinato)chromium(III) in particular, which have also been proposed as efficient regulators of, for example, glycemia in type 2 diabetic individuals, awaits assessment and clarification.