Anti-platelet and Antioxidant Properties of White Wine By-product Extracts

Aim: This study aimed to evaluate the antioxidant and anti-platelet properties of water-ethanol grape pomace (GP) extracts from the five white wine varieties Asyrtiko (As), Athiri (Ath), Chardonnay (Ch), Malagouzia (Mal), and Semillon and to explore their potential as sources of bioactive compounds for functional foods or supplements. Materials and Methods: GP from each variety was extracted using 80% ethanol. Extracts were assessed for total phenolic content, antioxidant activity (via DPPH assay and Cu 2 ⁺-induced serum oxidation), and anti-platelet activity by inhibiting platelet-activating factor (PAF)-, adenosine diphosphate (ADP)- and thrombin receptor activating peptide (TRAP) - induced aggregation in human platelet-rich plasma. A combined extract (AACMS) from all varieties was further analyzed for macronutrient content, fatty acid composition, and phenolic profile. Results: Extracts from As and Ath had the highest phenolic content and demonstrated the strongest DPPH radical scavenging activity along with Ch. All extracts delayed serum oxidation and inhibited PAF-induced platelet aggregation. The extract from Mal was the least effective against ADP and TRAP-induced platelet aggregation. The AACMS extract contained high levels of polyunsaturated fatty acids and catechin and epicatechin as major phenolics. Conclusions: Despite being less potent than red GP, white GP extracts possess notable antioxidant and anti-platelet properties. Their bioactivity and nutritional composition support further exploration for dietary applications, particularly through refined extraction techniques to enhance their health-promoting potential.