Closed Anaerobic Biotransformation Products of Organoarsenic Compounds inFucus distichus

Abstract

The closed anaerobic decomposition extracts ofFucus distichusincubated with seawater and sediment, and without sediment as control, were subjected to extractions and isolation on Sephadex LH 20 and Cellulose Thin Layer Chromatography. The decomposition extracts and isolates were analyzed by using both the Hydride Generation Gas Chromatography Atomic Absorption Spectrometry (HG-GC-AAS) and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICPMS) to identify the arsenic species in the equilibrium mixtures of the seaweed and filtrates separately. In the methanol seaweed extract, equilibrium mixture of arsenosugars (AS) AS1 and AS2 and their biotransformation products of dimethylarsinoylethanol (DMAE) and dimethylarsinic acid (DMAA) were identified. In the methanol filtrate extract of the mixture, only DMAE and DMAA were identified. However, in the control methanol filtrate extract five organoarsenic species, AS1 and AS2, one unidentified hidden organoarsenic species, DMAE and DMAA were identified in the equilibrium mixture. This result confirmed that the hidden organoarsenic species inFucus distichus, AS1 and AS2, and an unidentified organoarsenic compounds are biotransformed to only DMAE and DMAA under an anaerobic condition. This also suggests that DMAE and DMAA are strong intermediate candidates for the generation of arsenobetaine, from arsenoribosides in the marine food webs.