Possibility of Diarrheal Effect by Eicosapentaenoic Acid(EPA) and Autoxidized EPA.

Formation of Free Polyunsaturated Fatty Acids and Their Metabolites in Oyster, Crassostrea gigas, by Treatment with Acetate

“…We prevously reported that peritoneal injection of EPA and its oxidized products induces death in mice (Sajiki and Takahashi, 1992) and diarrhea, as indicated by the loop test using rabbit intestine (Sajiki et al, 1993). The remarkable increase of PUFA observed in oysters treated with acetate at 37 °C for 3 h suggests a close association with poisoning by vinegar-pickled oysters.…”

“…We have reported that the viscera of Japanese anchovy contained more PUFA, mainly EPA and DHA, than the flesh Takashashi, 1991, 1992). High concentrations of EPA, besides autoxidized EPA, can cause diarrhea in rabbits (Sajiki et al, 1993). There are many outbreaks of gastroenteritis from consumption of vinegarpickled oyster in Japan.…”

Impact of Vinegar Acetic Acid on Hydrolysis and Oxidation of Lipids in Tissues of the Oyster, Crassostrea gigas, at 37 .degree.C

“…It is considered that PUFA are easily oxidized because of the possession of many double bonds, and their oxidative metabolites were toxic to various organisms (Oarada et al, 1989;Kanazawa and Ashida, 1991). In our previous works, autoxidative products of EPA reacted more strongly to hemoglobin and resulted in a higher possibility of diarrhea in rabbits than free EPA (Sajiki et al, 1993). Recently, it has been reported (Grataroli et al, 1992) that fish oil induced the decrease in ex vivo production of prostaglandin E2 (PGE2), an enzymically oxidized metabolite of arachidonic acid (AA) in gastric mucosa, because of the decrease in the membrane AA level, and a high dose of fish oil enhanced catabolism of PGE2.…”

“…Furthermore, mice toxicity was stronger in the fraction containing free fatty acids, their oxidative metabolites, and monoglyceride than in other lipid fraction such as triglyceride (TG). It has been reported that free eicosapentaenoic acid (EPA), one of the PUFAs, abundantly found in marine products, and its autoxidized substances caused mouse lethal toxicity and diarrhea in rabbits (Sajiki et al, 1993). Since free PUFAs had stronger toxicity to mice than saturated fatty acid (SFA), monounsaturated fatty acids (MFA), and esterified PUFA (Takagi et al, 1984), it is considered that the formation of PUFA in acetic acid treated oyster at 37 °C, equivalent to the body temperature, might be related to gastroenteritis induced by the ingestion of oysters.…”