Isolation and some properties of neosaxitoxin from a xanthid crab Zosimus aeneus

Attempts were made to isolate neosaxitoxin (neoSTX) from a xanthid crab Zosimus aeneus collected at Ishigaki Island, Okinawa Prefecture. Crab specimens were minced and extracted with acidic ethanol, and the extract chromatographed successively on Amberlite IRC-50, Bio-Gel P-2 and Bio-Rex 70 to isolate neoSTX. The neoSTX preparation thus obtained was homogeneous in both thin-layer chromatography and cellulose acetate membrane electrophoresis. The neoSTX preparation showed a1H-NMR spectrum which coincided well with that in literature. The specific toxicity of this toxin was found to be 3, 900MU/mg. The dose-death time curve was clearly distinguishable from the curve of saxitoxin. Acid hydrolysis resulted in formation of a product whose electrophoretic and thin-layer chromatographic behaviors differed from any of known paralytic shellfish poisons.