Isolation and identification of (44-R,S)-44,55-dihydroxyyessotoxin from Protoceratium reticulatum, and its occurrence in extracts of shellfish from New Zealand, Norway and Canada

Abstract 44,55-Dihydroxyyessotoxin ( 1 ) was isolated from extracts of Protoceratium reticulatum and identified by analysis of its one- and two-dimensional NMR and mass spectra. In addition, LC–MS methods revealed the presence of compounds tentatively identified as (44- R,S )-44,55-dihydroxy-41a-homoyessotoxin ( 2 ) and (44- R,S )-44,55-dihydroxy-9-methyl-41a-homoyessotoxin ( 3 ). LC–MS analyses indicate that 1 is a constituent of P. reticulatum in New Zealand and Norway, and it was present in three species of mussels from New Zealand, Norway, and Canada.