Relationships among Bioactive Compounds Content and the Antiplatelet and Antioxidant Activities of Six Allium Vegetable Species

Abstract

Allium vegetables are widely consumed for their characteristic flavor. Additionally, their consumption may provide protection against cardiovascular disease due to their antiplatelet (AA) and antioxidant activities (AOXA). Although AA and AOXA in Allium are generally-recognized, comparative studies of antiplatelet and antioxidant potency among the main Allium vegetables are lacking. Also, the relationship between organosulfur and phenolic compounds and these biological activities has not been well stablished. In this study, we characterized and compared the in vitro antiplatelet (IVAA) and antioxidant activities of the most widely consumed Allium species. The species total organosulfur and phenolics concentration, and their HPLC profiles of 11 phenolic compounds were characterized and used to investigate associations between these compounds and IVAA and AOXA. Furthermore, antiplatelet activities in chive and shallot were characterized for the first time. Our results revealed that the strongest antiplatelet agents were garlic and shallot, whereas chive had the highest AOXA. Leek and bunching onion were the weakest species for both biological activities. Significant positive correlations were found between IVAA and total organosulfur (R=0.74) and phenolics (TPs) content (R=0.73); as well as between AOXA and TPs (R=0.91) and total organosulfur content (R=0.67). Six individual phenolic compounds were associated with AOXA, with catechin, epigallocatechin, and epicatechingallate having the strongest correlation values (R>0.80). Overall, our results suggest that both organosulfur and phenolic compounds contribute similarly to Allium AA, whereas phenolics, as a whole, are largely responsible for AOXA, with broad variation observed among the contribution of individual phenolic compounds.