Purification and identification of arsenobetaine from the muscle of an octopus Paroctopus dofleini.

Abstract

The major arsenic compound in the muscle of an octopus Paroctopus dofleini was purified by column chromatographies on ion-exchangers and Bio-Gel P-2. The arsenic content of the purified compound was estimated to be 44%; this is close to that (41%) of arsenobetaine. In thin layer chromatography and electrophoresis, the purified arsenic compound gave a single spot positive to the Dragendorff reagent at the same Rf and mobility as arsenobetaine. No characteristic UV absorption was observed with the purified compound. The 1H-NMR spectrum of the purified compound showed two significant signals at δ 1.88 (s, 9H) and 3.31 (s, 2H), which corresponded to those at δ 1.87 (s, (CH3)3 AS) and 3.28 (s, CH2) reported for arsenobetanine. No difference was found between the IR spectra of the purified compound and arsenobetaine. Judging from these results, the major arsenic compound in the muscle of P. dofleini was concluded to be arsenobetaine (CH3)3AS+CH2COO-. Moreover, arsenobetaine accounted for more than 90% of the total arsenic in P. dofleini.