UK-based researchers now have found indications that arsenobetaine is not that inert in human metabolism as previously thought.
Biological, chemical and physical characteristics are primarily dependent on the compound but not on the elements making up the compound. Therefore, the toxicity of metal and metalloid species cannot be assessed by total
element concentration. As an example, inorganic arsenic is highly toxic but
arsenobetaine is thought to be harmless and is ingested in seafood on a
daily basis by a large percentage of the world's population.
Arsenobetaine has always been referred to as a non-toxic but readily bioavailable compound and the available data would suggest that it is neither metabolised by nor accumulated in humans.Fig.: Structure of ArsenobetaineThe new study
Using arsenic speciation analysis, researchers from the University of Aberdeen have investigated the urine of five volunteers on an arsenobetaine exclusive diet for twelve days and their study shows that arsenobetaine was consistently excreted by three of the five volunteers. From the expected elimination pattern of arsenobetaine in rodents, no significant amount of arsenobetaine should have been detectable after 5 days of the trial period. Contrary to the established belief that arsenobetaine is neither accumulated nor generated by humans, the presented results would suggest that either accumulated arsenobetaine in the tissues is slowly released over time or that arsenobetaine is a human metabolite of dimethylarsinic acid or inorganic arsenic from the trial food, or both. Either possibility is intriguing and raises fundamental questions about human arsenic metabolism and the toxicological and environmental inertness of arsenobetaine. The new study
Chris Newcombe, Andrea Raab, Paul N. Williams, Claire Deacon, Parvez I. Haris, Andrew A. Meharg, Jörg Feldmann
, Accumulation or production of arsenobetaine in humans?
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September 7, 2006: New Agilent HPLC column for routine determination of arsenic species in
human urine by HPLC-ICP-MS
last time modified: February 24, 2010