A Preliminary Study of Puffer Fishes and Their Toxins Found in Hong Kong Waters

Puffer fishes are commonly found in Hong Kong waters. For this study, we collected and identified six species of local puffers, Takifugu niphobles (Jordan and Snyder), Takifugu alboplumbeus (Richardson), Chelonodon patoca (Hamilton-Buchanan), Lagocephalus spadiceus (Richardson), Takifugu ocellatus (Osbeck) and Diodon holocanthus (Linnaeus). The first three species were confirmed to be toxic (6-120 mouse units (MU)/g) by mouse bioassay. To isolate tetrodotoxin (TTX) from a common local puffer, Takifugu niphobles, two hundred grams of viscera (ovary, intestine and liver) was minced and extracted with acidic methanol. The crude toxin obtained was further purified by Sephadex G-50-50 gel filtration and Whatman CM-52 cation exchange column chromatography. Purification afforded two unidentified toxins, unknown 1 and unknown 2, which gave single fluorescent spots under UV irradiation (366nm) with Rf values of 0.80 and 0.54, respectively, in thin layer chromatography (TLC). The electrospray ionization mass spectra (ESI/MS) of unknowns 1 and 2 had their molecular ion peaks (M+H)+ at m/z 320 and 255, respectively. Unknown 1 was concluded to be TTX, whereas unknown 2 was probably a derivative of TTX, whose exact identification would require further chemical analyses.