Antithrombotic properties of Spirulina extracts against platelet-activating factor and thrombin

Abstract Spirulina (Arthrospira maxima) components have shown several health-benefits, including immunomodulatory and anti-inflammatory properties. Even though a few studies have examined the effects of some Spirulina-derived ingredients on platelets, none studied the effects on platelet aggregation induced by inflammatory and thrombotic mediators, namely platelet-activating actor (PAF) and thrombin. In the present study, the antithrombotic properties of compounds extracted from Spirulina, namely phycocyanobilin (PCB), phycocyanin-protein, polysaccharides (PS) and lipid extracts, but also of bioactive HPLC-separated lipid-fractions, were assessed in washed rabbit platelets (WRP) activated by PAF and thrombin. All extracts showed strong anti-PAF and anti-thrombin activities in WRP. PCB showed the strongest inhibitory effects on PAF/thrombin-induced platelet aggregation, with a stronger anti-thrombin effect, followed by the relative strong anti-PAF inhibitory effects of the total lipid extracts. HPLC-separation of Spirulina lipid extracts into lipid subclasses’ fractions showed that specific polar lipid fractions of glyco-lipids and PAF-like phosphatidylcholine moieties exhibited the strongest anti-PAF effects. Some of these lipid-fractions and PCB, when assessed at higher concentrations on WRP showed also an anti-PAF agonistic effect, with the PS extract exhibiting the strongest platelet-aggregatory effect. In conclusion, the results suggested that Spirulina seems to be a sustainable source of bioactive compounds with strong anti-PAF and anti-thrombin properties, and thus a potential candidate for developing food supplements and nutraceuticals against inflammation, thrombosis and related disorders. However, more studies are needed to explore the potential and safety of further use of Spirulina.