Pharmacologically Active Vanadium Species: Distribution in Biological Media and Interaction with Molecular Targets

Biospeciation of some of the most studied vanadium (symbol V) complexes with biological or medicinal activity is discussed in this review in order to emphasize the importance of the distribution of V species in biological media. The exact knowledge of the chemical species present in blood or cells may provide essential information regarding the biological effect of V potential drugs. In blood serum, vanadium species can interact with low (citrate, lactate, oxalate, amino acids, etc., indicated with bL) and high molecular mass (proteins like transferrin, albumin, immunoglobulins, etc.) components, while the interaction with red blood cells can interfere with the transport of these drugs towards the target cells. The interaction of bLs and proteins is discussed through the analysis of instrumental and computational data. The fate of the active V species, when these are in the real serum samples and when they reach and cross cell membranes, is also discussed. The differences in the V complexes selected in this review (donor atoms, stability, coordination geometry, electric charge, hydrolipophilicity balance, substituents and redox properties) cover all the possible modes of interaction with bLs and proteins, allowing for the biodistribution of the studied compounds to be predicted. This approach could be applied to newly synthesized potential V drugs.