Evaluation of anti-platelet activity of grape pomace extracts.

Platelets aggregation plays a crucial role in atherothrombosis. Therefore, the aim of the present study was to examine the anti-platelet activity of winery by-products extracts, to find the most potent one and to be further analyzed in order to be used for food fortification. For this purpose, grape pomace from four red varieties was extracted with four solvents of different polarity. The extracts' phenolic content, antioxidant capacity and their ability to inhibit human platelet aggregation against PAF, ADP, TRAP were determined by Light Transmission Aggregometry. The ethanolic extract was further analyzed concerning its anti-platelet effect and its chemical composition by LC-MS/MS and GC-MS. The ethanolic and Bligh-Dyer water phase extracts showed the highest phenolic compounds/anthocyanin content and the best antioxidant activity. However, the most potent inhibition of platelet aggregation was revealed by ethanol extracts, followed by the Bligh-Dyer lipoid phase extracts. Ethanolic extract, found to contain micro-constituents such as phospho-compounds, phenolic compounds and fatty acids. The most abundant phenolic compounds were catechin, epicatechin and quercetin and the most abundant fatty acids were linoleic acid (C18:2n6), linolenic acid (C18:3n3) and palmitic acid (C16:0). Ethanolic extract was capable of inhibiting platelets aggregation in a wide range of agonist concentrations and it also seems that its action is sustained when platelets from coronary heart disease patient were used. Ethanol extract of winery by-products exerts a potent anti-platelet effect and its valorization could lead to the production of functional foods with cardioprotective properties.