Vanadium detoxification: Chemical and biochemical aspects

Abstract

The biological effects, biodistribution, pharmacological activity, and toxicology of vanadium are areas of increasing research interest. Although numerous biochemical and physiological functions have been suggested for this element, and despite the amount of the knowledge so far accumulated, vanadium still does not have a clearly defined role in the higher forms of life [1 – 5]. So far, the best evidence for a biological role of vanadium comes from bacteria (the so-called alternative nitrogenases in which vanadium replaces molybdenum in the FeMo-cofactor of some Azotobacter species) [3] [4] [6 – 9] and from plants (vanadiumdependent haloperoxidases found in some algae, lichens and fungi) [3] [4] [8 – 10]. On the other hand, experiments with laboratory animals have shown that vanadium deprivation enhances abortion rates, reduces milk levels during lactation, and produces thyroidal disorders. It has also been suggested that vanadium participates in the regulation of ATP-ases, phosphoryl transferases, adenylate cyclase, and protein kinases and potentiate different growth factors [5] [9] [11] [12]. Environmental contamination by vanadium has dramatically increased during the last decades, especially in the most developed countries, due to the widespread use of fossil fuels, many of which liberate finely particulate V2O5 to the atmosphere during combustion [13 – 15]. Therefore, and also owing to the emerging interest in the pharmacological effects of some of its compounds [16 – 20], the toxicology and detoxification of vanadium constitute areas of increasing research interest. The older literature about vanadium toxicology has been reviewed in the classical work of Faulkner-Hudson [21], and we have analyzed the most relevant aspects of its detoxification some years ago [22]. The pertinent information is extended and updated in the present review.