In Vitro Antithrombotic Properties of Salmon (Salmo salar) Phospholipids in a Novel Food-Grade Extract

Marine and salmon polar lipids (PLs) extracted by conventional extractions with non- food-gradesolvents (CE-salmon-PLs) possess antithromboticbioactivities against platelet-activating factor(PAF) and thrombin. Similar effects of food-grade-extracted (FGE) marine PLs have not yet been reported. In this study, food-gradesolvents were used to extract PLs from Irish organic farmedsalmon (Salmo salar) fillets (FGE-salmon-PLs), while their antithromboticbioactivities were assessed in human platelets induced by platelet aggregation agonists (PAF/ thrombin). FGE-salmon-PLs were further separated by thin layer chromatography (TLC) into lipid subclasses, and the antithromboticbioactivities of each subclasswere also assessed. LC-MS was utilized to elucidate the structure-activity relationships. FGE-salmon-PLs strongly inhibited PAF-induced platelet aggregation, while their relevant anti- thrombineffects were at least three times more potent than the previously reported activities of CE-salmon-PLs. TLC-derived lipid fractions corresponding to phosphatidylcholines (PC) and phosphatidylethanolamines (PE) were the most bioactive lipid subclassesobtained, especially against thrombin. Their LC-MS analysis elucidated that they are diacyl- or alkyl-acyl- PC and PE moieties baring ω3 polyunsaturated fatty acids (PUFA) at their sn-2 position, such as eicosapentaenoic acid (EPA) or docosahexaenoic acid(DHA). Our results concerning the potent antithromboticeffects of FGE-salmon-PLs against both PAF and thrombinpathways strongly suggest that such food-gradeextracts are putative candidates for the development of novel cardioprotective supplements and nutraceuticals.