Accumulation or production of arsenobetaine in humans?

Background:
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 Arsenobetaine

The 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?, J. Environ. Monit., 12 (2010) 832-837. DOI: 10.1039/b921588c


Related studies

C.F. Harrington, E.I. Brima, R.O. Jenkins, Biotransformation of arsenobetaine by microorganisms from the human gastrointestinal tract,  Chem. Speciation Bioavail., 20/3 (2008) 173-180. DOI: 10.3184/095422908X347278

V. W.-M. Lai, S. Yongmei, E. Ting, W. R. Cullen and K. J. Reimer, Arsenic specian in human urine: are we all the same?, Toxicol. Appl. Pharmacol., 2003, 198, 297–306. DOI: 10.1016/J.TAAP.2003.10.033

John S. Edmonds, Letter to the Editor: Can humans metabolize arsenic compounds to arsenobetaine?, Appl. Organomet. Chem., 12/7 (1998) 515-517. DOI: 10.1002/(SICI)1099-0739(199807)12:7<515::AID-AOC737>3.0.CO;2-G

Walter Goessler, C. Schlagenhaufen, Doris Kuehnelt, H. Greschonig, K. J. Irgolic, Can humans metabolize arsenic compounds to arsenobetaine?, Appl. Organomet. Chem., 1997, 11, 327–335. DOI: 10.1002/(SICI)1099-0739(199704)11:4<327::AID-AOC589>3.0.CO;2-Q

H. Yamauchi and B. A. Fowler, Toxicity and Metabolism of Inorganic and Methylated Arsenicals, in:  J. O. Nriagu (ed.), Arsenic in the Environment. Part II: Human Health and Ecosystem Effects, John Wiley & Sons, New York, 1994, pp. 35–53.

T. Kaise and S. Fukui, The chemical form and acute toxicity of arsenic compounds in marine organisms, Appl. Organomet. Chem., 1992, 6, 155–169. DOI: 10.1002/aoc.590060208

R. M. Brown, D. Newton, C. J. Pickford and J. C. Sherlock, Human metabolism of arsenobetaine ingested with fish, Hum. Exp. Toxicol., 9/1 (1990) 41–46. doi: 10.1177/096032719000900109

Hiroshi Yamauchi, Toshikazu Kaise, Yukio Yamamura, Metabolism and Excretion of Orally Administered Arsenobetaine in the Hamster, Bull. Environ. Contain. Toxicol., 36 (1986) 350-355. DOI: 10.1007/BF01623519

Marie Vahter, E. Marafante and L. Dencker, Metabolism of Arsenobetaine in Mice, Rats and Rabbits, Sci. Total Environ., 1983, 30, 197-211. DOI: 10.1016/0048-9697(83)90012-8

G.K.H. Tam, S.M. Charbonneau, F. Bryce, E. Sandi, Excretion of a Single Oral Dose of Fish-Arsenic in Man, Bull. Environ. Contam. Toxicol., 28 (1982) 669-673. DOI: 10.107/BF01605634

H. C. Freeman, J. F. Uthe, R. B. Fleming, P. H. Odense, R. G. Ackman, G. Landry, C. Musial, Clearance of Arsenic Ingested by Man From Arsenic Contaminated Fish, Bull. Environm. Contam. Toxicol. 22 (1979) 224-229. DOI: 10.1007/BF02026934

J. S. Edmonds, Kevin A. Francesconi, J. R. Cannon and C. L. Raston, Isolation, crystal structure and synthesis of arsenobetaine, the arsenical constituent of the western rock lobster Panulirus longipedes cygnus, Tetrahedron Lett., 18 (1977) 1543–154. DOI: 10.1016/S0040-4039(01)93098-9


Related EVISA Resources

Material Database: Arsenobetaine
Link Database: All about Arsenobetaine



Related EVISA News

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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:  May 20, 2024