Testing antiplatelet and antioxidant activity of the extract of seven varieties of Allium cepa L.

Background: The extracts of Allium cepa are known for their medical use: antioxidant, antiinflammatory, antimicrobial, fibrinolytic and antiplatelet properties. Our study aims to establish, using in vitro tests, the antiplatelet and antioxidant character, the link between them and the extract acidity, from seven varieties of A. cepa. Methodology: The qualitative and quantitative presence of polyphenols and anthocyanins in the extracts was determined using UV-Vis and HPLC. Quantitative determination of the thiosulfinates compounds was calculated using their reaction with 4-mercaptopyridine. Antioxidant character was determined using 3 methods (FC, DPPH and TEAC), and antiplatelet effect was measured by in vitro tests on platelet rich plasma obtained from human blood. Principal Findings/Results: The white variety of A. cepa has the most alkaline pH, the largest amount of thiosulfinate compounds and the most powerful antiplatelet effect, but a very small amount of flavonoids and an antioxidant effect almost nonexistent, in contrast with red variety of A. cepa which is the opposite. Conclusions/Significance: The white variety of A. cepa had very high anitiplatelet activity suggesting the potential use of A. cepa extract in treating cardiovascular diseases.