Identification of D-Cysteamide in European Flat Oyster

Abstract

An unknown substance co-eluted with taurine on an amino acid autoanalyzer was found in the aqueous ethanol extract of the oyster Ostrea edulis. The compound was extracted from 100 g of soft parts from 13 specimens, isolated using Dowex 50 (H+ form) and Amberlite CG 400 (OH form) columns, and crystallized from hot 50% aqueous ethanol. The yield was 16 mg as colorless needles. Its chemical and stereochemical structure was determined to be D-cysteamide [(S)-2-amino-3-sulfopropan amide] by FAB mass, 1H and 13C NMR, IR, and CD spectra and elemental analysis. In order to confirm the assigned structure, L-Cysteamide was synthesized from L-cysteine methyl es ter hydrochloride in a crystalline form. The synthetic compound was identical with a natural one in mobilities on the amino acid autoanalyzer and TLC and in FAB mass, 'H and 13C NMR spectra but showed a reverse Cotton effect in the CD spectrum.

Chemistry and biology of the aminosulfonate cysteinolic acid: discovery, distribution, synthesis and metabolism

“…d - 6 is a marine natural product that has been isolated from the axoplasm of the squids Loligo pealii and Dosidicus gigas , 44 and the flat oyster Ostrea edulis . 45…”