5-caffeoylquinic acid and caffeic acid orally administered suppress P-selectin expression on mouse platelets

Caffeic acid and 5-caffeoylquinic acid are naturally occurring phenolic acid and its quinic acid ester found in plants. In this article, potential effects of 5-caffcoylquinic acid and caffeic acid on P-selectin expression were investigated due to its significant involvement in platelet activation. First, the effects of 5-caffeoylquinic acid and caffeic acid on cyclooxygenase (COX) enzymes were determined due to their profound involvement in regulating P-selectin expression on platelets. At the concentration of 0.05 mu M, 5-caffeoylquinic acid and caffeic acid were both able to inhibit COX-I enzyme activity by 60% (P<013) and 57% (P<017), respectively. At the same concentration, 5-caffeoylquinic acid and caffeic acid were also able to inhibit COX-H enzyme activity by 59% (P<012) and 56% (P<015), respectively. As expected, 5-caffeoylquinic acid and caffeic acid were correspondingly able to inhibit P-selectin expression on the platelets by 33% (P<011) and 35% (P<018), at the concentration of 0.05 mu M. In animal studies, 5-caffeoylquinic acid and caffeic acid orally administered to mice were detected as intact forms in the plasma. Also, P-selectin expression was respectively reduced by 21% (P<016) and 44% (P<019) in the plasma samples from mice orally administered 5-caffeoylquinic acid (400 jug per 30 g body weight) and caffeic acid (50 mu g per 30 g body weight). These data suggest that both 5-caffeoylquinic acid and caffeic acid orally administered can be absorbed and suppress P-selectin expression on mouse platelets. Published by Elsevier Inc.