Occurrence of 11-oxotetrodotoxin in the red-spotted newt, Notophthalmus viridescens, and further studies on the levels of tetrodotoxin and its analogues in the newt's efts

An analogue of tetrodotoxin (TTX), 11-oxoTTX, was semi-purified from the red-spotted newt, Notophthalmus viridescens, and identified by ESI-MS and 1H NMR spectra. The levels of TTX, 11-oxoTTX and 6-epiTTX in early stage of development (efts) of this newt were investigated by a post-column fluorescent-HPLC system, and compared with those of adult newts. The level of 11-oxoTTX in both of adults and efts were remarkably high, almost close to those of TTX, while 6-epiTTX was a minor component in both stages. The level of 6-epiTTX in efts (1.8±1.3 μg/g, SD, <f>n=10</f>) was significantly larger than that in adults (0.51±0.26 μg/g, SD, <f>n=12</f>) <f>(p<0.05),</f> while no significant difference was observed in the levels of TTX and 11-oxoTTX between efts (13±7.4 and 9.1±5.6 μg/g) and adult newts (16±6.3 and 13±6.2 μg/g, respectively) <f>(p>0.05).</f> [Copyright &y& Elsevier]