Tetrodotoxins in the flatworm Planocera multitentaculata

The marine polyclad flatworm Planocera multitentaculata is known to possess high levels of tetrodotoxin (TTX), but the presence of TTX analogues in the species has been unexplored. In this study, TTX and several analogues such as 5,6,11-trideoxyTTX, monodeoxyTTXs, dideoxyTTXs, and 11-norTTX-6(S)-ol were identified in three adults and egg plates of P. multitentaculata using high resolution liquid chromatography-mass spectrometry (HR-LC/MS) for the first time. [Display omitted] •Toxic flatworm and its egg plate contain multiple TTX analogues such as 5,6,11-trideoxyTTX, monodeoxyTTXs.•The TTX profile of the flatworm corresponds closely to that of T. alboplumbeus inhabiting the same coastal habitat.•T. alboplumbeus likely accumulates TTXs from feeding on the toxic flatworm and its egg plate.