The presence of 12β-deoxydecarbamoylsaxitoxin in the Japanese toxic dinoflagellate Alexandrium determined by simultaneous analysis for paralytic shellfish toxins using HILIC-LC–MS/MS

Autor: Renpei Yoshioka, Shigeki Tsuchiya, Mari Yotsu-Yamashita, Yasukatsu Oshima, Takuo Omura, Yuko Cho, Keiichi Konoki
Rok vydání: 2015
Předmět:
Zdroj: Harmful Algae. 49:58-67
ISSN: 1568-9883
DOI: 10.1016/j.hal.2015.09.003
Popis: A differential screening study using high-resolution (HR)-hydrophilic interaction chromatography (HILIC)-electrospray ionization (ESI)–quadrupole time-of-flight mass spectrometry (Q-TOF MS) was conducted to identify saxitoxin (STX) analogues in the marine dinoflagellate toxic sub-clone Alexandrium tamarense Axat-2 and the non-toxic sub-clone UAT-014-009 derived from the same Japanese isolate. One unknown compound was identified only in the toxic sub-clone and was found to have the molecular formula C 9 H 16 N 6 O 2 . This structure differed from that of decarbamoyl STX (dcSTX; C 9 H 16 N 6 O 3 ) by the loss of a single oxygen. A 12-deoxy-dcSTX standard (a mixture of 12α- and β-deoxy-dcSTX) was chemically prepared from dcSTX by reduction with sodium borohydride. The unknown compound in the toxic strain of A. tamarense was identified as 12β-deoxy-dcSTX by comparison of its HR-HILIC-LC–MS retention time and HR–MS/MS spectrum with those of the chemically prepared standard, and the identification was confirmed by high-sensitivity HPLC analysis with post-column fluorescent derivatization. Moreover, two Japanese isolates of A. catenella showing toxin profiles different from that of A. tamarense were also found to contain 12β-deoxy-dcSTX. Previously, 12β-deoxy-dcSTX was isolated from the freshwater cyanobacterium Lyngbya wollei , which produces a unique set of STX analogues. This study is the first evidence of the presence of 12β-deoxy-dcSTX in marine dinoflagellates.
Databáze: OpenAIRE
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