Tetrodotoxin and saxitoxins in sharpnose pufferfish Canthigaster rivulata from Nagasaki, Japan

Marine pufferfish of the genus Canthigaster living in the vicinity of coral reefs are thought to be toxic in the skin because they are unpalatable to predators, however, very little is known about the toxin profile of most species of this genus. In the present study, to fully clarify the toxin profile of the Canthigaster marine pufferfish, the composition, concentration, and intra-body distribution of toxins contained in marine pufferfish Canthigaster rivulata, collected from three sampling locations in Nagasaki Prefecture, Japan, were investigated using high-performance liquid chromatography with post-column fluorescence derivatization (HPLC-FLD) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Instrumental analyses revealed that marine pufferfish C. rivulata is capable of carrying both tetrodotoxin (TTX) and saxitoxins (STXs) simultaneously, and the skin and ovaries are the most toxic tissues, with other tissues such as the liver being weakly toxic. Overall, TTX was more abundant than STXs in C. rivulata, but there were differences between individuals, with some possessing more STXs than TTX. Higher STXs content was detected in the skin of individuals from Tameshi than in those from Kakidomari. Despite individual and regional differences, C. rivulata has been identified as a Canthigaster marine pufferfish that possesses a large amount of TTX and STXs.