Structural elucidation of palytoxin analogs produced by the dinoflagellate Ostreopsis ovata IK2 strain by complementary use of positive and negative ion liquid chromatography/quadrupole time-of-flight mass spectrometry.
BACKGROUND
The ovatoxins are palytoxin analogs of a dinoflagellate origin implicated in human intoxication. The structures of ovatoxin-a, ovatoxin-d, and ovatoxin-e produced by the IK2 strain of Ostreopsis ovata collected in Japan were elucidated using liquid chromatography/quadrupole time-of-flight mass spectrometry (LC/QTOFMS). The novel structures and a new insight into the spectral data are presented.


METHODS
The structural elucidations were carried out by complementary use of positive and negative ion LC/QTOFMS. Ostreocin-D (C127H219N3O53), another palytoxin congener previously elucidated by negative fast-atom bombardment collision-induced tandem mass spectrometry (FAB CID MS/MS), was used as a reference.


RESULTS
Positive ion spectra allowed deduction of hydroxyl positions based on the conjugated polyene structures produced, while the negative ion spectra allowed assignments of cleavage sites of C-C bonds. The analysis could be performed using a small sample without extensive purification.


CONCLUSIONS
Ovatoxin-a IK2 (C129H223N3O52), ovatoxin-d IK2 (C129H223N3O53), and ovatoxin-e IK2 (C129H223N3O53) were tentatively assigned to 42-hydroxy-17,44,70-trideoxypalytoxin, 42-hydroxy-17,70-dideoxypalytoxin and 42,82-dihydroxy-17,44,70-trideoxypalytoxin, respectively. The wide applicability of the method was suggested.
Agilent Technologies, 9-1 Takakura-chou, Hachiouji-shi, Tokyo 192-8510, Japan.
Hideaki
H
Uchida
Yohsuke
Y
Taira
Takeshi
T
Yasumoto
D000178:Acrylamides / Q000737:chemistry* / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods*; D003064:Cnidarian Venoms; D004141:Dinoflagellida / Q000737:chemistry / Q000378:metabolism*; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D000095702:Polyether Toxins
D000178:Acrylamides; D003064:Cnidarian Venoms; C010272:palytoxin; D000095702:Polyether Toxins