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 nip hobles (Jordan and Snyder), Takifugu alboplumbeus (Richardson), Chelon odon patoca (Hamilton-Buchanan), Lagocephalus spadiceus (Richardson), Takifugu ocellatus (Osbeck) and Diodon holocanthus (Linnaeus). The fir st three species were confirmed to be toxic (6-120 mouse units (MU)ig) by mouse bioassay. To isolate tetrodotoxin (TTX) from a common local puffer, Takifugu niphobles, two hundred grams of viscera (ovary, intes tine and liver) was minced and extracted with acidic methanol. The cru de toxin obtained was further purified by Sephadex G-50-50 gel filtrat ion and Whatman CM-52 cation exchange column chromatography. Purificat ion afforded two unidentified toxins, unknown 1 and unknown 2, which g ave single fluorescent spots under UV irradiation (366 nm) with Rf val ues 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, respectiv ely. Unknown 1 was concluded to be TTX, whereas unknown 2 was probably a derivative of TTX, whose exact identification would require further chemical analyses.