Aged garlic extract suppresses platelet aggregation by changing the functional property of platelets

Aged garlic extract (AGE), a garlic preparation rich in water-soluble cysteinyl moieties, has been reported to have multiple beneficial effects on cardiovascular disease including inhibition of platelet aggregation. However, the mode of AGE action on platelets has not been clear. In this study, we examined the effect of AGE on the functional property of platelet by administering AGE to rats and evaluating the platelet aggregation in response to collagen in vitro. We found that AGE treatment significantly reduced the ability of platelet to aggregate and this effect of AGE was manifested on the 14 day, but not 7 day of treatment. In addition, AGE treatment produced platelets that responded to collagen by significantly increasing the amount of both the extracellular ATP and the extra- and intracellular TXB₂. AGE treatment also dose-dependently suppressed the phosphorylation of collagen-induced ERK, p38 and JNK. However, AGE administration did not affect the bleeding time. These findings suggest that AGE treatment results in suppression of platelet aggregation by changing the functional property of platelets to respond to collagen.