Identification and Study of Gangliosides from Scomber scombrus Muscle

Scomber scombrus has been implicated in the disease known as scombroid food poisoning (histamine intoxication). However, some investigators claim that scombroid food poisoning is not caused by histamine only. Gangliosides have been found in different type fishes, but in all cases the sources are brain, melanoma, retina, and optic nerve. These complex lipids as well as their derivatives, exhibit important biological activities. In this study, gangliosides (8 × 10 - 4 % w/w in muscle) were isolated from S. scombrus muscle for the first time, and the major one was found to be monosialoganglioside. Gangliosides existed as a proteolipid type complex combined with a protein consisting of high amounts of iron and copper and which seemed to be the red protein. After fractionation of gangliosides onto cation exchange, silica, and C 18 HPLC columns, we detected two compounds which induced aggregation through platelet-activating factor (PAF) way. Both of them were eluted onto HPLC in the region of gangliosides and from the results of the biological experiments as well as from chemical determinations, they seemed to be O -acetyl derivatives of gangliosides. These molecules could partly contribute to scombroid food poisoning since the main symptoms of this disease are well-known actions of PAF.